The process led to an increase in the overall porosity, thermal stability and its oxidative functionality. The newly synthesised material was named ZrAC. The morphological and textural images revealed the irregular and eroded structures with an increase in porosity of the modified adsorbent. The results of chemical and spectral analysis disclosed that the material had successfully gained the oxidative functionality over the surface that will favour the removal of anionic dye. Equilibrium isotherms and adsorption kinetics studies insinuate that the overall process of adsorption follows the Sips isotherm and pseudo-second order kinetic model, respectively. The monolayer adsorption capacity of ZrAC was found to be superior (506 mg g−1) to AC at 500 mg L−1 concentration of persistent reactive dye. Moreover, the desorption capabilities of ZrAC were found to be more prominent, which finally affirms its potential use in a continuous flow system as a reusable adsorbent. Additionally, the stability of zirconium, corroborated from ICP-MS and XPS data, revealed the stability of zirconium after adsorption cycles thus verified its reusability. Thus, the characterization and experimental results of ZrAC strongly advocated its potential as a future adsorbent for removal of reactive dyes.This study aimed to develop a highly functionalized adsorbent material for the removal of persistent anionic reactive dye. The modification process was commenced  iv) as an impregnated metal. The modification develops the oxidative functionalities and porosity of the sorbent that enhances its efficiency for the removal of RB19.The present work focuses to develop a varied meso-microporous sorbent by using Zr( Coincidentally, the activated carbon faces the same interaction difficulties for complex molecules that constrains its application for different macro-structured pollutants.Activated carbon (AC) is a processed form of carbon-based materials consisting of microscale pores with high surface area, broad surface reactivity, diverse pore size distribution and chemical as well as thermal stability.etc. obstructs the direct application of AC.1 Typical surface characteristics of AC assists in the modification process that makes them more feasible for any targeted pollutants. So nowadays, researchers have been focussing more on the preparation of highly compatible materials that are more specific to the pollutant.6,7 Researchers have already reported that the modification of activated carbon, superimposed crucial and significant impact over the removal of targeted contaminants.5Moreover, some other limitations of AC such as prolonged equilibrium period, tedious regeneration capabilities 8,9 These impregnation and oxidation processes have a higher influence on the modification of AC, as it enhances the number of active sites of the surface. Ion exchange, wet oxidation process, or chemical deposition followed by calcination/reduction step, etc. are the known metal impregnation methods.10,11 Besides this, researchers have also reported that most of the activated carbon comprises mainly of microporous structures that are not uniformly present over the surface. These pores although plays an essential role in the adsorption of smaller molecules but for larger molecules, diffusion and pore blockage, become the major limiting factors.12,13 To overshadow this issue, the modification should be in a way to develop pores of various sizes. Some researchers reported that the mesoporous carbon possesses enlarged porosity, thermal stability and electrical conductivity that plays a pivotal role for adsorption, catalysis and other processes.12,14 Usually, impregnation has been carried out using different transition metals and organometallic compounds of various elements such as Al, Zn, Fe, Ag, and Ti.15–17 The utility of different transition metal is well-known in the field of water treatment as these metals do not leach out into water owing to their high positive character.18 Among different transition elements, zirconium is more superior over other elements in terms of efficiency, cost and toxicity. Literature also suggested the zirconium(iv) application, in the form of metal salts, does not exhibit any toxic effect on the aquatic environment.19–21 Moreover, zirconium impregnation in its hydrated form makes the adsorbents an anion exchanger that promotes more removal of the anionic counterpart.22 Zirconium also exhibits highly electropositive character responsible for a strong affinity towards the electronegative ions, thus also show strong affinity towards the anionic dye.Improvement in the adsorptive capacity of activated carbon has been achieved either by different surface functional groups modification or by impregnation of metals with appropriate chemical or physical treatments or both. Metal impregnation or oxidative functionalization has been carried out, after the activation process by treating with appropriate chemicals in liquid or gaseous phases.19 These dyes are one of the most thrust areas for environmental concerns as they are the top polluters of the environment. These dyes generally released from dyeing and printing units of textiles that possess toxic effluent. Being more soluble with water, its concentration in effluent discharge increases as compared to other groups of dyes. Moreover, their recalcitrant and toxic nature and their high oxygen demand,23 makes them more potent to be removed from the environment using reliable and competent techniques. Adsorption is one of the simplest treatment processes for the removal of dyes wastewater. Some researchers had reported the use of different metal-doped over activated carbon for the removal of different classes of dye, but their adsorption capacity makes them incompatible.24 So, grabbing the advantages of zirconium(iv), the present study mainly devoted on the impregnation of zirconium on AC for the removal of an anionic reactive dye, named Reactive Blue 19 (RB19).Reactive dyes are a well-known anionic dye that is used extensively in dye industries because of their easy dyeing application, availability and vibrant colours.Hence the present study mainly focuses on the pioneer use of zirconium oxychloride salt as an impregnated material on activated carbon to develop a novel adsorbent for the removal of anionic reactive dye RB19. The studies targeted to develop a novel material that is stable, non-toxic, efficient and eco-friendly. The study aimed to synthesise material having high surface oxidative functionality, diverse porosity and thermally stable mesoporous material using simple modified wet oxidation process, that can potentially target reactive dye. The studies also examined and compared all the characteristic features of the novel developed material and raw AC using the different instrumentational tool. FE-SEM, EDX, TGA, BET, XRD and XPS has been used to investigate all the morphological, textural and surface functional features of the novel material. Finally, a series of batch adsorption experiments, isothermal behaviour, rate of adsorption and thermodynamic parameters along with regeneration studies have also been conducted to understand the applicability and feasibility of the developed material.2.2.1.2·8H2O) from Loba Chemicals, while potassium permanganate (KMnO4), and sodium bicarbonate (NaHCO3) were purchased from Remkem Chemical Ltd. The modelled dye, i.e. reactive blue 19 was purchased from Sigma Aldrich. All chemicals were of analytical grade and used without any further treatment.Activated carbon was procured from R & M Chemicals, zirconium oxychloride , equipped with Energy Dispersive Microanalysis (Oxford Liquid Nitrogen free SDD X MAX 50 EDS). For this samples were finely ground and dried entirely before mounting over carbon sticky stub. The platinum coating was performed on both adsorbents to get high-quality images.2) adsorption–desorption isotherms at 77 K using Autosorb-1C, Quanta chrome, USA. The surface areas, porosity and pore size distributions were estimated by BET isotherms and DFT  model with the help of software equipped with the instrument that enables the user to examine the pore size along with pore volume and surface area. The samples were degassed prior to the detailed analysis, to avoid inaccuracy in the results.The textural characteristics of both the samples were calculated by using nitrogen . The samples were analyzed by preparing KBr pellets by mixing both adsorbents with KBr powder in a definite ratio to form a thin disc. The data were recorded from 4000–400 cm−1. XPS measurement was also conducted to study the detailed elemental composition as well as different oxidation states of the surface element. For this, the X-ray photoelectron spectrophotometer  was used having a monochromatic lamp with an average analysis depth of approximately 5 nm.The thermal characteristics of AC and ZrAC were investigated using thermogravimetric analysis (TGA)  from 30 to 900 °C with a ramping rate of 10 °C per minute under nitrogen environment at a flow rate of 200 mL min2.4.−1) were agitated in an Erlenmeyer flask (250 mL capacity) with an adsorbent dose of 70 mg at a speed of 120 rpm for 90 minutes. The initial and final concentration of the dye solution was determined by using UV-Vis spectrophotometer (LabTech Model 9100A) at the maximum wavelength (λmax = 595 nm) of the dye and their concentrations were calculated with the help of the standard curve. The removal percentage was calculated by simple mathematical calculation and maximum adsorbent capacity was calculated using C0 and Ce represent the initial and equilibrium concentration (mg L−1) of the dye solution respectively, V (L) represents the total volume of dye solution used in each experimental run and m (g) represents the dry mass of the adsorbent used for the adsorption process.Preliminary adsorption experiments were carried out to investigate the potential of the ZrAC as compared to AC. The stock solution of the dye was prepared and diluted accordingly as per requirement using Millipore water. Before initiating the batch experiments, a trial set of experiments has been carried out to optimized the pH, dose and agitation time and speed of the respective adsorbents. 100 mL of the dye solution with varying concentrations  and the solid phase (adsorbent) at constant temperature and helps in designing the adsorption systems.Non-linear form of Langmuir isotherm is represented as: is maximum monolayer saturation capacity of the sorbent, Ce (mg L−1) is a concentration of adsorbate at equilibrium condition, qe (mg g−1) is the amount of adsorbate uptake at equilibrium and KL (L mg−1) is Langmuir constant. KF (mg L−1)n represents the Freundlich constant and n is the dimensionless Freundlich intensity parameter, that defines the magnitude of adsorption driving force. In case of best fitting of experimental data with monolayer adsorption mechanism, then the model can also be described by a dimensionless constant named as equilibrium parameter or separation factor,27 represented as RL , KL represents the Langmuir constant and C0 (mg L−1) is the initial adsorbate concentration.Non-linear form of Freundlich isotherm is expressed as:ed as RL . This fa28 The Sips isotherm, in general exhibit the combined form of Langmuir and Freundlich isotherm expression that are deduced for predicting the heterogeneous adsorption system.28 The model is expressed as follows:qmax (mg g−1) represents the predicted maximum adsorption capacity of the adsorbent, n is heterogeneity factor and KS (L mg−1) represents Sips constant.Another isotherm, name Sips isotherm was also used to investigate the adsorption behaviour of the sorption process of both the adsorbent.2.5.i.e. pseudo-first-order, pseudo-second-order and intra particle diffusion model, were used in this work to predict the rate of sorption.Three kinetics models, 2.5.1.29 and expressed as follows:qe (mg g−1) and qt (mg g−1) represents the adsorbent adsorbed the dye molecules at equilibrium and at any time, t respectively. k (min−1) represents the pseudo-first-order kinetics. The values of k and qe have been calculated from slope and intercept of the graph plotted ln(qe − qt) versus t respectively.The linearized form of the model was developed by Lagergren2.5.2.25 The equation based on equilibrium adsorption can be expressed as:K (g mg−1 min−1) is the pseudo-second-order rate constant, qt and qe are same as in pseudo-first-order. The values of qe and K has been calculated from the slope and intercept of plot t/qtversus time, respectively. The pseudo second order rate constant (K) was also used to calculate the initial rate of sorption by following The adsorption equilibrium can also be described as a pseudo-second-order model, assuming that the adsorption rate of encapsulated sites of adsorbent is proportional to the number of vacant sites.2.5.3.30 and was used to identify the adsorption mechanism of any adsorbate onto the adsorbent. The equation is expressed as:ki (mg g−1 min−1/2) represents the intraparticle diffusion model's initial rate constant, C (mg g−1) is the intercept representing a constant related with the thickness of the boundary layer. Also, a higher value of C can directly be correlated to a greater effect on the limiting boundary layer. This model also helps in identifying the reaction pathways and revealing the adsorption mechanism along with predicting the rate-controlling step of the adsorption mechanism.The intraparticle diffusion model was proposed by Weber and Morris2.5.4.G°, kJ mol−1), enthalpy change  and entropy change  by using following equations.25R is a universal gas constant of value 8.314 J mol−1 K−1, T is the absolute temperature in kelvin and Kc represents the unitless distribution coefficient, which can be derived asC0 and Ce represent the initial and equilibrium RB19 dye concentration, respectively.The thermodynamic behaviour of the adsorption can be described by calculating the standard parameters such as Gibbs free energy (ΔG°) can be derived from Van't Hoff equation and the values of ΔH° and ΔS° were calculated from slope and intercept of the linear regression plot between ln Kcversus 1/T, respectively.The values of Gibbs free energy (Δ2.6.2SO4), one alkaline (0.1 M NaOH), one salt (0.1 M NaCl) and distilled water have been used as desorbing agents. Initially, the adsorption process has been carried out with 0.1 g of AC and ZrAC to treat 100 mg L−1 of dye concentration for 90 min (equilibrium time). Then, the loaded adsorbents were separated from the adsorbate solution and again agitated with the eluents at the same reaction time, for desorption study. The desorption percentage was calculated from the following equationCrem and Cret refer to the amount of dye removed and the amount of dye molecules retained on the exhausted adsorbent.The regeneration of the utilized adsorbent has been investigated to evaluate the practical applications and economic feasibility of the adsorption process. The number of eluents of different nature has been investigated for desorption studies. For this one acidic 2(H2O)16]8+ along with HCl and some oxychloride forms. The oxychloride forms further get oxidises to zirconium oxides (ZrO2) while dimmer form reacts with AC and forms complex. Lastly, the formed solid was treated with sodium bicarbonate solution, that being amphoteric, readily reacts with the remaining acidic groups to prevents further complex formation. These modification processes were further validated with different characterization techniques that ensures the formation of metal oxides on the surface of activated carbon.The modification process has been commenced over raw activated carbon to ensure the surface must have a cationic counterpart that will attack the targeted anionic pollutant. For this, a defined methodology has been adapted to develop new material having higher adsorption affinity for the anionic dyes. The probable reaction mechanism of the developed material has been given in 3.2.3.2.1.14,31 The FE-SEM images demonstrated the same; the metals distribution was not uniform throughout and are either present inside the pores or at the boundary of the pores, resulting in the widening of the pores. This changes of the surface morphology of newly developed materials from smooth and regular pores size to rough and irregular surface structure with wider pores occurs, because of the formation of new different active sites on the carbon structure. Also, the surface of modified carbon possessed extended porosity that may be due to the entrenchment of the Zr metals into the pores and their complex formation with the active sites of available oxygen.To study the morphological changes of AC and ZrAC, FE-SEM of both the materials, along with EDX have been carried out and the results are shown in 4 and zirconium oxychloride remarkably increases the oxygen moieties on the ZrAC. The elemental composition results presented in ESI Table S1i.e. oxygen and manganese also confirmed the oxidizing activity inbuilt in case of ZrAC. During the modification processes, the oxygen moieties become more than double as compared with raw activated carbon that shows a good sign for the application part. Thus, the results of FE-SEM and EDX mapping conjointly revealed that the modification changes the structural pattern of the raw AC into the more roughed oxygen-containing surface with diverse pores, that will help into its application.Concomitantly, the EDX results also affirmed that the oxidation process with KMnO3.2.2.2) adsorption–desorption, pore size distribution and pore volume were analyzed using BET, BJH and DFT model respectively. The 2 uptake at very low pressures in case of AC revealed that the existence of more micropores than ZrAC.32 The presence of more developed hysteresis loops in modified carbon exhibits the capillary condensation of pores filling by a secondary process and accredited to the development of mesopores in ZrAC,33 that helps in adsorption of larger molecules. The type of hysteresis loop present in ZrAC might represents either hybrid type of H1 and H2 (a) hysteresis loop that further exhibited the presence of narrower range of uniform mesopores with pore-blocking phenomenon33 or may exhibited bimodal porosity, resulting in step-wise porosity that overview the fact that at lower pressures, the encapsulated mesopores emptied than the open pore of the same sizes.34 Moreover, the pronounced hysteresis loop at higher P/P0 in ZrAC (above 0.45), also affirmed the formation of mesoporosity as suggested by other authors.34,35 A similar transformation of micropores to mesopores and macropores has also been reported by some other scientists,35,36 after impregnation with the metals.To understand the physical properties of the AC and ZrAC, the nitrogen  and the micropore volume of the ZrAC get reduced (approximately 50%) suggesting the filling of pores with the metal.36 Also, the mean pore diameter for ZrAC was found 2.14 nm implying that width of the pores gets enlarged with the impregnation of the Zr particles illustrating deposition of the particles around the pores. The range of pore width clearly represents the mesopores region as per the IUPAC classification.37,38 The results of the specific surface area and the mean pore width are in reverse relationship suggesting a good agreement between them. The contribution of micropore volume to the total pore volume also reduced to affirm the modification has occurred into the micropores area. Microporosity has been changed to meso as well as macro porosity for the extended applications.The graphical instances were further validated with the calculated porosity parameters data from N3.2.3.Tmax) at around 550 °C while the raw AC found to be degraded up to 96.01% of total mass with Tmax 600 °C, representing comparatively less stability of ZrAC. In ZrAC, the initial weight loss around 100–150 °C of about 10–12% that attributed to the loss of volatile compounds and absorbed water present on the surface of the adsorbent. This result was further validated for the above steady-state condition by heat-treated ZrAC . Similar trends were seen in heat-treated ZrAC.For understanding the different properties of the materials with a change in temperature, the thermogravimetric study has been commenced and presented in C Fig. S1. Further40,41 Later one small exothermic was also observed in between 500-585 °C followed by one endothermic peak at around 600 °C that represents a gradual decrease of the base carbon material. Additionally, the results were further assured by the DTG curve that exhibited one small peak in between 100–180 °C followed by one small peak in between 300 °C followed by on sharp peak at 400 °C and a small peak in between 500 to 600 °C, that ascribed the multistep decomposition behaviour of the material. Likewise, in AC a slightly more weight loss of around 15% at 100 °C was observed, because of dehydration of water, indicating high absorbed water in micropores corresponds to high hydrophilicity of the activated carbon surface. This is followed by a gradual decrease in weight up to 41.8% till 600 °C and then final total loss of weight of about 96.01% at around 885 °C indicating gradual degradation of carbon base. Simultaneously, DTA also supported the TGA by showing exothermic peaks at 690 °C only while DTG showed one peak at 634 °C and one small peak at 677 °C representing slow degradation of carbon base material of AC. The temperature degradation of both the samples illustrated that the thermal stability of ZrAC was not enhanced, but enough stable for water treatment42 and their degradation temperature difference also revealed that the ZrAC content 31.44% of the metal counterpart that affirmed the modification was achieved. Thus, a successful transformation of the pristine activated carbon has been achieved by metal impregnation using a wet oxidation process.Later, the DTA graphs manifested the modification process over activated carbon by indicating a broad endothermic peak around 100–150 °C, representing the desorption of water molecules, followed by one sharp exothermic peak at around 400 °C that starts around 300 °C attaining its peak at 400 °C and gradually declines at about 450 °C, suggesting dehydroxylation of the material.3.2.4.−1, in ZrAC curve, represents the O–H stretching vibration in carboxyl and phenol groups,43 while in raw AC peak at 3354 cm−1 corresponds to the adsorbed water due to stretching and bending modes of water. The peaks between 3100–3000 cm−1 are assigned for C–H stretching present mainly in unsaturated compounds and both samples have the same carbon stretching. The weaker peak at 3121 cm−1 in ZrAC and stronger peak at 3130 cm−1 in raw AC revealed that the modification process changes the carbon stretching. The presence of peaks at 2410 cm−1 and 2312 cm−1 in ZrAC represented either the alkynes stretching with elements such as N, O, S or the presence of atmospheric CO2 that the material has adsorbed.36 The IR spectra of ZrAC showed strong peaks in between 1870–1550 cm−1 that are attributed to C PBM data was replaced with SVG by xgml2pxml:<glyph-data id="z.dbd" format="PBM" resolution="300" x-size="8" y-size="10" xml:space="preserve">00000000000000000000000000000000111111110000000011111111000000000000000000000000</glyph-data><svg xmlns="http://www.w3.org/2000/svg" version="1.0" width="13.200000pt" height="16.000000pt" viewBox="0 0 13.200000 16.000000" preserveAspectRatio="xMidYMid meet"><metadata>Created by potrace 1.16, written by Peter Selinger 2001-2019</metadata><g transform="translate scale" fill="currentColor" stroke="none"><path d="M0 440 l0 -40 320 0 320 0 0 40 0 40 -320 0 -320 0 0 -40z M0 280 l0 -40 320 0 320 0 0 40 0 40 -320 0 -320 0 0 -40z"/></g></svg>O group of esters, ketones, amides, carboxylic acids, their salts or may acid anhydrides, disclosing more oxidising functional groups addition after the modification. The presence of one more sharp peak in ZrAC at 1570 cm−1 confirms the presence of CO stretching corresponds to carbonyl group present in aldehydes and ketones39 while another sharp peak centered at 1404 cm−1 showed the presence of C–O–C vibrations of epoxy or alkoxy groups.42,44 Furthermore, the peaks at 1249–1050 cm−1, 1088 cm−1 were assigned for C–O stretching of carbonyl groups and ZrO respectively. Additionally, one small peak at 572 cm−1 represents the presence of organo-halogens, that attributed to Cl− ions get attached to the carbon skeleton,45 whilst one small peak was also found at 487 cm−1 that assigned the presence of Zr(iv), in monoclinal and tetragonal phase of ZrO2 40 in the modified sample. Hence, the excerpt of the FTIR results clearly indicated that the ZrAC comprises of more reactive oxidative functionalities as compared to the native AC that will readily react with the dye molecules. Furthermore, the FTIR spectra of the AC and ZrAC after adsorption of dye molecules were also examined and presented in Fig. S2.−1 were observed representing –OH stretching vibrations while a sharp peak develops at 3137 cm−1 in AC-post. After adsorption, the sharpness of peaks at 2350 cm−1 and 2330 cm−1 in AC and ZrAC respectively, was developed due to alkyl group that interacts with the adsorbents. In ZrAC-post adsorption, a sharp and broad peak at 1569 cm−1 with slight shifting, were observed showing zirconium ions gets interacted with the amine group of dyes molecules.46 Also, at 1168 cm−1 a sharp peak in ZrAC after adsorption is observed resembling the interaction between –OH group with Zr4+ ions.47 The peaks at the region 1500–1600 cm−1 in both the adsorbent indicate the pi–pi interaction of reactive dye molecules with the surface of activated carbon.48 The appearance of vibrational shifted peaks at around 900–700 cm−1 in ZrAC after adsorption, ascribed the metal–oxygen interactions.14The FTIR spectral results were analyzed and represented in 3.2.5.θ range of 10° to 90°, to identify the nature of the materials as well as a polymorphic form of zirconium in ZrAC. Undoubtedly, the graph (θ of around 25° and 44.5° corresponds to the plane (002) and (101) respectively, resembles the graphitic hexagonal structure of the carbon-based material.49,50The powdered X-ray diffractogram has been carried out for AC and ZrAC in the 2he graph  showed tiv) over AC. It has also been observed that the treatment interaction between the metal salt and activated carbon, interfered the graphitic structure leading to its disrupt structure. Similar results of distortion were observed by some other scientists after impregnation of zirconium metals.36,51 Besides this, some few peaks are found to appear in the XRD graph of ZrAC but are not sharp and stronger one. This lack of specific prominent peaks is because of the higher concentration and phase purity of carbon-based material that causes dominance over metal concentration.14 However, the graph shows the XRD patterns of ZrAC, where two small peaks at 2θ angles of 27.54° and 43.23° that may attribute to monoclinic phase while at 36.56° corresponds tetragonal structure of zirconia,36,47 as zirconia exist in three polymorphic phases, i.e. monoclinic, tetragonal and cubic, at ambient temperature. These peaks were further affirmed by conducting heat treatment of the material so that the carbon material has been burn out and their interference would be minimised. The subsequent XRD results of the heat-treated material have been assessed and it was observed that the developed peaks were clear and had been recognized for polymorphic phases of zirconium  in the modified carbon after the impregnation process. 3/2 and 2p1/2 state, respectively of the element showing its catalytic and oxidative properties.52 Similarly, the 3d region of Zr metal [iv) in ZrO2.39 The zirconium metal was observed in two forms, i.e. 3p3/2 and 3d5/2 representing the oxidizing nature of the metal. Again, a small peak of Cl 2p was observed for ZrAC with a binding energy of 198.6 eV, which agreement completely with ZrAC.53The XPS analyses were carried out on representative samples to identify the detailed surface functionality and possible structural form of Zr presented in Besides these, the peak intensities of carbon C 1s and O 1s in both the materials were observed in the range of 283–285 eV and 529–531 eV respectively. There was a slight shifting of the binding energies after impregnation of the metal which is in good agreement with the NIST database.2.37,54Contrary to this, the carbon composition of ZrAC was too low as compared to pristine activated carbon. Thus, the refined spectral analysis results by XPS, thereby concomitanted the EDX results suggesting the successful impregnation and enhancement of oxidizing surface of modified carbon using wet oxidation process for future use as an adsorbent. Further, the XPS spectra of ZrAC-post adsorption  resemble3.3.3.3.1.55,56 This increase in removal efficiency is attributed mainly due to electrostatic attraction between negatively charged sulfonate group (SO3−) of the RB19 and positively charged ZrAC and AC. RB19 is anionic dye species, so exists in the form of negatively charged ions when dissociated in water.59 So, the increase in pH leads to competition between the dye anions and hydroxyl ions for the adsorption sites. Other studies observed similar results.55,56The working solution pH plays a significant role in the adsorption process as it influences both the surface charge of the adsorbent and structure of dye molecules. The pH also affects the degree of ionisation of functional groups that adsorbents carry. In the present study, the effect of pH has been carried out by varying the solution pH from 2–11 using 0.1 N HCl and NaOH at a constant dose and dye concentration. The effect of pH on the removal of RB19 dye has been shown in Fig. S4.3.3.2.−1 to 500 mg L−1. Similarly, the adsorption capacity also showed the maximum adsorption capacity for ZrAC than AC. This rise in removal efficiency and adsorption capacity of ZrAC is mainly due to the higher oxidative functionality that readily uptake the dye molecules from the solution.A preliminary batch experiment has been conducted to investigate the performance of newly prepared ZrAC and to establish its viability in the wastewater treatment. The adsorption of the dye using AC and ZrAC are presented in R2. This indicates that the surface of the ZrAC seems to be energetically heterogeneous while adsorbing the dye molecules and the adsorption process follows the Freundlich isotherms during lower concentration range, followed by Langmuir isotherm at higher concentration range. The value of heterogeneity factor, n of sips isotherms is found to be greater than 1, suggesting some degree of heterogeneity of ZrAC-dye molecules. The monolayer adsorption capacity of ZrAC and AC were found to be 506.23 mg g−1 and 375.25 mg g−1 respectively. The maximum monolayer adsorption capacity of the ZrAC was compared with another developed adsorbent and presented in 57,58 This could be due to its developed meso–micropores structure on the surface of ZrAC and possible enhancement of oxidative functionalities and positive charge gained because of Zr(iv) that imparts the electropositive character to the activated carbon resulting into more uptake of anionic dye molecules. The RL values for both the adsorbent were found in between 0 to 1, thus indicating the favourable adsorption process. Hence it has been lastly corroborated that the textural and surface modification over ZrAC has been extended its applicability for the adsorption of reactive dyes . In this work, four desorbing agents were used to regenerate the spent adsorbent. The desorption efficiency of four eluents has been investigated and presented in −1 that changes to 86.49 mg g−1 after adsorption. This changes mainly attributed due to attachment of dye molecules over the adsorbent. Also, the XPS peak of ZrAC shows similar peaks of zirconium after the adsorption process [To regenerate the ZrAC and AC adsorbent, desorption study has been conducted for five cycles using NaOH as a desorbing agent and the results are presented in  process . Thus, c4.iv) impregnation on the surface. The physicochemical and structural results suggested that the modification of activated carbon leads to widening of the pores thereby results in the transformation of micropores into meso/macropores, due to the pore blocking and metal residing in and around the pores. The textural results further validated the structural transformation into eroded and heterogeneous surface upon modification. The modification process also enhanced the oxidative functionalities as well as Zr(iv) impregnation on AC, as observed in FTIR, XRD and XPS peaks. These modifications were validated with the experimental results, and it was observed that the maximum monolayer adsorption of ZrAC was found to superior than other developed adsorbent materials. The isothermal, kinetic and thermodynamics results corroborate that the adsorption process is favourable, endothermic and spontaneous in nature. The desorption and regeneration studies finally augmented the enhanced adsorption affinity of ZrAC towards RB19. Also, the stability of zirconium over activated carbon has been examined with ICP-MS and XPS, and it was found that the ZrAC has similar stability after adsorption cycles; thus, acclaimed its reusability. Henceforth, culminating the characterization and experimental results, it has been advocated that the ZrAC has the profuse capacity to be used as a future adsorbent for the removal of reactive blue 19 dye.In the present study, a novel material has been synthesized by using metal salt (zirconium oxychloride) as an impregnating metal on activated carbon. The developed material successfully gained the meso–microporous structures along with oxidative functionalization, because of Zr(There are no conflicts to declare.RA-010-C9RA10103A-s001


It was found that the local atomic pressure fluctuation of the Fe–Ni alloy nanowire surface became more prominent with an increase in the Ni content. At low temperature conditions (<50 K), the plastic deformation mechanism of the Fe–Ni alloy nanowires switched from the twinning mechanism to the dislocation slip mechanism with the increase in the Ni content from 0.5 at% to 8.0 at%. In the temperature range of 50–800 K, the dislocation slip mechanism dominated the deformation. Simulation results indicated that there was a significant linear relationship between the Ni content, temperature, and ultimate stress in the temperature range of 50–800 K. Our research revealed the association between the deformation mechanism and temperature in Fe–Ni alloy nanowires, which may facilitate new alloy nanowire designs.Fe–Ni alloy nanowires are widely used in high-density magnetic memories and catalysts due to their unique magnetic and electrochemical properties. Understanding the deformation mechanism and mechanical property of Fe–Ni alloy nanowires is of great importance for the development of devices. However, the detailed deformation mechanism of the alloy nanowires at different temperatures is unclear. Herein, the deformation mechanism of Fe–Ni alloy nanowires and their mechanical properties were investigated  Deformation mechanism and mechanical property of Fe–Ni alloy nanowires are investigated through molecular dynamics simulation method. Besides, the quantitative characterization and analysis of the mechanical properties of NWs also shed light on the understanding of theoretical properties of the corresponding bulk material.Magnetic nanowires (NWs) have attracted increasing attention for their distinctive propertiesin situ electron microscopy, have been developed to characterize the mechanical properties of NWs.12–18 The AFM-based three-point bending technique has been developed and widely applied in calculating the elastic modulus of NWs.19 The radial elasticity of the NWs could also be calculated through the resonance frequency and deflection changes by a contact resonance AFM measurement.20 By integrating a nanomanipulator system such as AFM21 and a micro-electromechanical device22 with the electron microscope (SEM or TEM), the in situ mechanical testing of the NWs and real-time observation of the deformation process was achieved. Despite the rapid development of nano-dimensional manipulation and characterization techniques in the past few decades, the experimental characterization of the mechanical properties of NWs is still a big challenge due to its small dimensions. The test condition is limited and unable to evaluate the mechanical properties under extreme environment.To date, several experimental methodologies, including atomic force microscope (AFM) and 18,23,24 Molecular dynamic simulation is widely used to study the elastic modulus, deformation-mechanism and failure behavior of metal NWs, including Au,25,26 Ag,27 Ni,28 Fe,29 Cu,30 Mo,31 W,32 and Ti.33 As an important magnetic material, Fe-based NWs have attracted considerable attention. Choudhary et al. investigated the effect of orientation on the deformation of body centered cubic (BCC) iron NWs under tensile loading; the results indicated that the deformation mechanism varied with crystal orientation.34 The <100>, <112>, and <102> oriented NWs deformed predominantly by the twinning mechanism, while the <110> and <111> oriented NWs deformed by a dislocation slip. Temperature and size also affected the deformation mechanism. As in ultrathin <100> BCC Fe NWs, deformation by slip dislocation dominates at small sizes and high temperatures, while twinning is promoted at large sizes and low temperatures.35 Zhang et al. explored the influence of a 5-fold twin boundary on the structural and mechanical properties of face center cubic (FCC) Fe NWs.36 The higher Young's modulus and higher critical stress upon loss of elasticity were attributed to the twin boundary that suppressed the dislocation nucleation. Salje et al. reported the pseudo-elasticity and shape memory effect of α-Fe NWs under bending.37 They found that the nucleation of twins and nanoscale interfaces lead to pseudo-elasticity, which could be extended over a wide range of the wire diameter. Ackland et al. found that a totally different deformation mechanism applies for the tension and compression of the nanopillars of BCC Fe: dislocation glide in compression and twinning in tension, which is consistent with the experimentally-observed asymmetry in the nanopillar morphology.38 Dutta investigated the dislocation activities underlying the compressive deformation of BCC-iron nanopillars at a high strain rate. They found a direct correspondence between the bursts in dislocation activities and jerky deformation of the pillar.39 Temperature also has a pronounced effect on the deformation mechanism switch with the dislocation-plus-twinning mechanism shifting to completely dislocation-mediated mechanism as the temperature increases.Computational methods such as molecular dynamics simulation, Monte Carlo simulation and discreteness simulation methods provide an atomic-level insight of the mechanical properties of the NWs.40 As an important noble-metal-free alloy, the Fe–Ni alloys have shown outstanding soft magnetic properties.41 So far, little is known about the role and mechanisms of Ni effects on the microstructure evolution in the Fe–Ni alloy deformation process. Herein, we report a systematic study for the effect of composition and temperature on the deformation behavior of the Fex) to mimic infinitely long wires, and the other two directions in NWs were kept free.43 The Fe nanowires prepared through the electrochemical deposition generally adopt a [110] orientation for its lower surface energy. However, [110] and [111] are the hard magnetization axis and [200] is the easiest magnetization direction. Numerous efforts have been made to control the direction of Fe nanowires and achieved great experimental success.44 Thus, in this work, we modelled the nanowires with the [001] orientation along the wire for its better magnetic property and application potential. The interaction between the Fe–Ni atoms was described by the embedded-atom-method (EAM) potential developed by Bonny et al.45 Maxwell–Boltzmann distribution was applied to initiate the velocities of the atoms. Also, the leapfrog scheme was used for integrating the Newton's equations of motion. Prior to tension loading, the NWs were subjected to energy minimization using the conjugate gradient method; heated up to the desired temperature in a step-wise fashion and relaxed in the Nose/Hoover isobaric–isothermal ensemble (NPT) for 1000 ps. During energy minimization and relaxation, the side surfaces of those nanowires evolve and form several kinds of faces  ensemble.The molecular dynamics simulation was performed using the large-scale atomic/molecular massively parallel simulator (LAMMPS)trations . A perioof faces . The ten46 In alloy, different topological and chemical properties of the alloy elements are the main origin of a local atomic pressure. First, the different atomic sizes of the alloy elements will affect their packing scheme and efficiency. It is well known that in a system consisting of two types of elements the large one prefers to locate on the nanoalloy surface, while the small one prefers to locate in the core, for the strain induced by the size difference between the atoms.47 Second, different chemical properties also influence the atomic-level stress state for their different bonding capability and charge transfer interaction. The Fe–Ni alloy showed an increasing local atomic pressure fluctuation with the increase in the Ni concentration for larger lattice mismatch. At a low Ni concentration (0.5 at%), there is no significant relationship between the local atomic pressure and the Ni atom distribution  are shown in ribution . This maribution . Those hThe stress–strain curves of the Ni–Fe alloy nanowires with different Ni concentrations (0.5–8.0 at%) under tensile loading are shown in The test was first carried out at low temperature (1 K) to eliminate the influence of thermal vibrations . The You48 The Young's modulus and ultimate-stress dropped when more substitutional Ni atoms were added (0.5–8.0 at%). Note that there is a linear relationship between the ultimate stress and Ni concentrations from about 0.5 to 8.0 at%. Also, the elongations increase slightly with the addition of Ni (1.0–8.0 at%). The significantly different influence of the Ni concentration on the Young's modulus and ultimate-stress at two temperatures suggests that there are different mechanisms dominating the tensile deformation.The room temperature (300 K) stress–strain behaviour of the Ni–Fe alloy NWs with Ni concentration in the range of 0–8.0 at% are shown in 34 It is reported that nanowire orientation, size, temperature and strain rate could affect the deformation mechanism of the metal nanowire.34,35,49 Herein, according to the features, the deformation mechanisms of Ni–Fe alloy nanowires vary with the Ni concentration. The Ni–Fe alloy nanowires with a low Ni concentration (0.5 and 5.0 at%) deform mainly by twinning mechanism under tensile loading. It has been observed that a twin embryo was generated on the free surface of the alloy nanowire (0.5 at% Ni) at the strain of 8.58% and nanowire began yielding  to the twin induced enhancement. With the increase in the concentration of Ni, more defects were induced by the heteroatoms, which result in more partial dislocations to nucleate and emit form the free surface while yielding, followed by the formation of twin with small size. High density of the twin boundary results in strengthening of the nanowire.In order to understand the influence of the Ni concentration on their deformation behavior, atomic configurations of the Ni–Fe alloy nanowires at different strain were analyzed. yielding . Then, tyielding , but the52 The reduction of SFE is in favour of the emission of partial dislocations from the nanowire surface and twinning formation.53 The increase of dislocation and twinning density leads to the strengthening of the material. However, further increase in the amount of the Ni element will result in dislocation formed in small stress and slip, leading to decreased strength.54The atomic configuration of the Ni–Fe alloy nanowires with high Ni concentration (8.0 at%) was investigated to explore the decrease in the Young's modulus and ultimate-stress with the further increase in the Ni concentrations (6.0–8.0 at%). As shown in 55,56 We also found different mechanical behaviours and deformation mechanisms in the Fe–Ni alloy NWs at 1 K and 300 K, as described in the previous section. Herein, we further examined the temperature dependence of the ultimate stress up to 800 K with nine different Ni contents to provide a deeper insight into the mechanical property of the Fe–Ni alloy NW.Temperature has a profound influence on the phases, microstructure and mechanical behaviour of metals.T > 50 K). The result is consistent with Choudhary's report that ultrathin <100> BCC Fe NWs deform by the dislocation slip mechanism at high temperatures while twinning dominates at low temperatures.35Further investigation of the atomic configuration of the alloy NWs under tensile deformation at elevated temperature (50–800 K) showed that the dislocation slip is the dominant deformation mechanism in the Ni–Fe alloy tensile deformation at a high temperature (The dependence of the deformation mechanism on the Ni content and temperature could be attributed to the stacking fault energy.−2), the dislocation slip dominates the plasticity deformation of the alloys.57–60 With the increase in the Ni content or temperature, the deformation mechanism of the nanowires switch from twinning to dislocation slip.It is reported that for the alloys with small stacking energy twinning is more favourable to occur under external straining, and for the alloys with large stacking fault energy (>45 mJ mδY) has two trends: δY = A – BT or δY = A – BT0.5, where A and B are constants and T is the absolute temperature, depending on the interatomic potential model.61 Our simulation indicates that there is a linear relationship between the ultimate stress of Fe–Ni alloy NWs and temperature from about 50 K to 800 K (δ = A − BT), with a constant B of 0.00434, 0.00568, 0.00576, 0.00553, 0.00526, 0.00524, 0.00511, 0.00502, 0.00497, 0.00471 GPa and constant A of 6.30717, 7.94726, 7.84876, 7.64009, 7.39001, 7.30691, 7.14159, 7.0004, 6.87865, 6.64016 GPa for pure Fe, Fe – 0.5% Ni, Fe – 1.0% Ni, Fe – 2.0% Ni, Fe – 3.0% Ni, Fe – 4.0% Ni, Fe – 5.0% Ni, Fe – 6.0% Ni, Fe – 7.0% Ni, Fe – 8.0% Ni NWs, respectively.Generally, the temperature dependence of yield stress .Combining the linear relationship of ultimate stress-temperature and ultimate stress-Ni concentration, the influence of temperature and Ni concentration on the ultimate stress of Fe–Ni alloy NWs can been concluded as: T < 50 K) and low Ni content (C < 6.0 at%), while dislocation slip dominates at high temperatures (T > 50 K). The ultimate stress of the nanowires show a linear relationship with temperature and Ni concentration .Through molecular dynamic simulation, the influence of the Ni concentration and temperature on the deformation mechanism and mechanical properties of BCC Fe–Ni alloy nanowires under tension loading were systematically investigated. The results indicated that the Fe–Ni alloy nanowires with a diameter of 8.0 nm deform by twinning mechanisms at low temperatures (There are no conflicts to declare.


S-SRT and SBRcontrol that simulated the short sludge retention time and conventional biological phosphorus removal processes, respectively, were set up to treat real domestic sewage for 120 d. SBRS-SRT achieved an efficient COD (91.5 ± 3.5%), S-SRT indicated the washout of nitrifiers. The dominant phosphorus accumulating organisms Tetrasphaera and Hydrogenophaga, which were enriched with the shortened sludge retention time, was in line with the excellent phosphorus performance of SBRS-SRT. The calculated methanogenic efficiency of SBRS-SRT increased significantly, which was in line with the higher sludge yield. This study proved that the short sludge retention time is a promising and practical approach to integrate biological phosphorus removal in A-stage when re-engineering a biological nutrient removal process.The increasing concerns on resource and energy recovery call for the modification of the current wastewater treatment strategy. This study synthetically evaluates the feasibility of the short sludge retention time approach to improve the energy recovery potential, but keeping steady biological phosphorus removal and system stability simultaneously. SBR The vast amounts of energy and material consumption caused by the huge scale and number of constructed wastewater treatment plants (WWTPs) has attracted society’s concerns. Thus, technologies that focused on energy saving or recovery ,2, resouGenerally, the first stage is the extremely high load biosorption of the biological concentration of sewage with minimum organic oxidation degradation. The concentrated sludge is anaerobically digested for the recovery of energy content from sewage organics. Subsequently, a low load biological stage follows the first stage, operated to ensure the removal of dissolved organics and ammonia. This is the so-called A-B process due to the two-stage operation model . Thus, bTo meet the strict discharge standards, enhanced biological phosphorus removal (EBPR) processes, such as anaerobic/anoxic–oxic (AO), anaerobic–anoxic–oxic (AAO), or their modified operation mode, are widely applied in WWTPs . GeneralY or obsY) or the ratio of the mixed liquor volatile suspended solids (MLVSS) and the mixed liquor suspended solids (MLSSs) [The high-rate activated sludge technology  was employed as an A-stage for partial organic carbon capture, mainly based on bio-sorption in the typical A-B stage process . However (MLSSs) ,16. Gene (MLSSs) , and thecontrol and SBRS-SRT) are set up and operated for 120d. The oxic phase duration of SBRcontrol is adjusted (from 1.5 h to 2.5 h) to achieve efficient phosphorus and ammonia removal, while the SRT of SBRS-SRT is adjusted from 5 d to 3 d. The overall COD, phosphorus removal efficiencies, and operational stabilities of the two SBR systems are studied; the microbial community and structures are measured to analyze the primary driving force corresponding to the reactors’ operations. Two AnSBR are also set up to anaerobically digest WAS from the two SBR systems treating sewage. This study proves the feasibility of short-time EBPR as a practical tool for the modification of conventional biological phosphorus removal processes into the A-stage towards improving the energy recovery potential.The main objects of this study are to investigate the stability and the methane production potential of short-SRT EBPR systems acting as the A-stage. Two sequencing batch reactors . The collected sludge was passed through 20 mesh sieves to remove large particles and then, the MLSSs were measured. Certain volumes of sludge were inoculated to maintain the initial MLSS concentrations of the two experimental SBRs as 4.0 g/L. Mechanical stirring was employed to maintain the suspension of the mixed liquor. Two air diffusers were set at the bottom of each SBR and connected with a glass rotameter to control the aeration intensity at 0.8 L/min. The oxygen concentration was measured daily. Additionally, the dissolved oxygen concentration of the two experimental SBRs was maintained above 3.0 mg/L. Each SBR was equipped with an air pump. All phases of each SBR were managed by time controllers. The detailed operational strategies of the two SBRs are shown in Two SBR reactors were operated for four cycles per day. In each cycle, the incoming influent and discharge of effluent were both 4.5 L  to maintain the hydraulic retention time as 12 h. The SRT of the SBRhttp://www.majorbio.com/) on 1 December 2021.Sludge samples (100 mL) were collected from the two SBRs on the last day of each operation stage, and the inoculum WAS was sampled as a control. Metagenomic DNAs were extracted by using the 3S DNA isolation kit for Environmental Samples  following the manufacturer’s instructions. The primers 338F (ACTCCTACGGGAGGCAGCA) and 806R (GGACTACHVGGGTWTCTAAT) were employed for PCR performances, executed in TransStart Fastpfu DNA Polymerase 20 μL reaction systems through 27 time cycles. The high-throughput sequencing analysis of DNA samples was carried out by a commercial service and conducted based on the online data processing developed by the Shanghai Major Biomedical Science and Technology Ltd.   was calculated by Equation (1) in this study.dischargeV (L) is the volume of discharged WAS; tS (g/L) is the concentration of MLSS or MLVSS in SBRs at time t; infV (L) is the volume of influent sewage per day; infCOD (mg/L) and effCOD (mg/L) are the concentrations of COD in influents and effluents of SBRs.As the energy or resource recovery is mainly based on the collected WAS, the accumulated WAS discharge per unit of total) of the two experimental SBRs were calculated according to Equations (2) and (3) as follows:biogas is the total volume of generated biogas at time t; Rmethane is the volume ratio of methane in generated biogas; SWAS is the concentration of inflow WAS corresponded to biogas production; and MPaverage is the average methanogenic efficiency of specified operation duration. obsY of the same specified operation duration was calculated according to Equation (1), and CODR is the average COD removal efficiency.The methanogenic efficiency (MP) of WAS and total methane recovery potential  of the two SBRs during each stage are shown in S-SRT decreased with the decrease in SRT, as shown in S-SRT, which was not consistent with the study in [S-SRT remain slightly higher than SBRcontrol . This phenomenon might be caused by the difference and instability of sewage quality. However, a higher MLVSS/MLSS was beneficial to the sequential AD treatment of WAS [The operational stability was assessed by the measurements of MLSS, MLVSS, SVI, and study in . As showt of WAS .control significantly decreased when the duration of the oxic phase was extended from 2 h to 2.5 h, while the SV30 remained relatively stable with the shortening of SRT in SBRS-SRT. The SVI of both experimental SBRs remained around 50 mL/g, indicating the excellent sedimentation capacity of the activated sludge in this study. It was notable that the SVI of SBRS-SRT was higher than SBRcontrol during operation stage III. It might be due to the high organic substance content and also indicated the higher metabolic activity of the activated sludge in SBRS-SRT.The SV30 and SVI were measured to assess the sedimentation performance of the activated sludge in the experimental reactors and the results are shown in control and SBRS-SRT is demonstrated in obsY of MLSS and MLVSS were calculated by Equation (1), and the effluent MLSS or MLVSS was not included to represent the total feedstock of the subsequent WAS disposal processes realistically in this study. The extension of the oxidation duration slightly affected the obsY of the SBRcontrol, which were 0.4257 g/gCOD (obs-MLSS-Yh2.5) and 0.3808 g/gCOD (obs-MLSS-Yh2) when the oxic phase durations were 2 h and 2.5 h, respectively. The shortening of SRT from 4 d to 3 d increased the obsY from 0.4223 g/gCOD (obs-MLSS-Yd4) to 0.4849 g/gCOD (obs-MLSS-Yd3). The obs-MLSS-Yd3 of SBRS-SRT was 27.3% higher than the obs-MLSS-Yh2 of the SBRcontrol and the obs-MLVSS-Yd3 was 35.2% higher than obs-MLVSS-Yh2.5, indicating that more removed COD was converted into WAS. The high accumulation of WAS production of SBRS-SRT at SRT 3 d indicates the outstanding COD capture capacity of SBRS-SRT. It was beneficial to increase the energy recovery potential of the subsequent WAS AD process.The accumulated WAS discharged from SBRS-SRT and SBRcontrol was 5 d and 10 d, respectively, during the initial 21 d to accumulate PAOs and to acclimate to the operation mode for the start-up. The nutrient removal efficiencies of SBRS-SRT and SBRcontrol EBPR reactors were shown in S-SRT and SBRcontrol under each stage were 90.0 ± 3.9% and 90.7 ± 5.4%, 91.1 ± 3.2% and 90.7 ± 3.5%, 92.0 ± 3.8% and 91.5 ± 3.5%, respectively (p > 0.05), as shown in S-SRT negligibly, while the extension of the oxic phase duration slightly enhanced the COD removal efficiency of SBRcontrol, as shown in S-SRT.The SRT of the SBRcontrol was adjusted and extended to achieve efficient ammonia removal. The ammonia removal performances of the two experimental SBRs are shown in p < 0.05, S-SRT. An SRT around 4.3 d and a low dissolved oxygen were beneficial for the nitrification and the accumulation of AOBs [S-SRT accounted for the inefficient ammonia removal. The activity of the AOBs was inhibited when the SRT of the SBR system was 3.5 d [S-SRT offered a lower ammonia removal efficiency, which was mainly by microbial assimilation.Ammonia removal was the premise step that supplied  of AOBs . The shoas 3.5 d . The nitas 3.5 d . Howevercontrol and the SBRS-SRT removed S-SRT was above 95% under both SRT 4 d and 3 d, as shown in S-SRT and the SBRcontrol. Furthermore, TP was the control target specified in effluent discharge standards. The average TP removal efficiencies of the SBRS-SRT were 93.8 ± 3.9% and 93.5 ± 3.47% at SRT 4 d and 3 d, respectively, as shown in S-SRT was adapted to the autotrophic nitrogen removal processes and the additional chemical phosphorus removal section was non-essential.Both the SBRSludge was sampled on day 0 (inoculum), day 21 (SRT10d1 and SRT5d), day 84 (SRT10d2 and SRT4d), and day 120 (SRT10d3 and SRT3d) from two operated experimental SBRs for high-throughput sequencing analysis, and the average length of OTU was 416 with a coverage above 99% in this study. The analysis of microbial diversity and community structure was conducted after data extraction flat. The indexes that reflected microbial diversity are shown in Thiothrix, which is a typical filamentous bacterium, results in bulking the sludge in conventional activated sludge systems [Thiothrix was detected in the short-sludge-age or ultra-short SRT EBPR systems reported by [Thiothrix was increased to 1.86% in SBRS-SRT after 120 d operation due to the shortening of SRT, but it remained stable and lower than 1% in the SBRcontrol. The disagreement between the enrichment of filamentous bacteria and the good settling ability of sludge in SBRS-SRT was mainly due to the relatively low abundance of Thiothrix (ranged as the twelfth most abundant bacteria in the sample SRT3d) and the quality of the influent. However, the results suggest that the SBRS-SRT had the risk of sludge bulking.The abundance of functional bacteria related to phosphorus removal and system stability is shown in  systems . Thiothrorted by ,15. The Nitrospira and norank_Nitrosomonadaceae were both zero in the samples SRT4d and SRT3d, as shown in S-SRT completely, which is in agreement with the poor ammonia removal performance of SBRS-SRT. Tetrasphaera is an important PAO [Candidatus_Accumulibacter in the EBPR process [Tetrasphaera was the dominant PAO in both the SBRS-SRT and SBRcontrol, while the abundances of Candidatus_Accumulibacter and Dechlorimonas [Tetrasphaera in the sample collected from SBRS-SRT at SRT 3 d was almost seven times higher than the inoculum (6.29% vs. 0.81%). The shortening of SRT was beneficial for the enrichment of Tetrasphaera. The abundance of Tetrasphaera in the samples collected from the SBRcontrol decreased from 12.22% to 3.56% when the duration of the oxic phase extended from 2 h to 2.5 h. The extension of the oxic phase improved the ammonia removal that resulted in the enhanced competition of the carbon source between denitrification and phosphorus release in the anaerobic phase. This might cause the reduction in PAO Tetrasphaera. Hydrogenophaga [Flavobacterium [S-SRT and SBRcontrol, respectively. The abundance of the main glycogen accumulating organisms (GAO) Candidatus_Competibacter [S-SRT.Only a few sequences were detected and the sequence numbers of tant PAO  and has  process . Tetrasporimonas  were lowenophaga ,26 and Facterium  were reptibacter  increasecontrol and AnSBRS-SRT) treated WAS from the corresponding two SBR is demonstrated in S-SRT treated WAS was significantly higher than the AnSBRcontrol. The WAS average methanogenic efficiency decreased from 166.7 ± 54.7 mL CH4/gSS to 136.0 ± 53.2 mL CH4/gSS when the SRT of SBRS-SRT shortened from 4 d to 3 d. This result was consistent with the decrease in MLVSS/MLSS ratios (from 60.2% to 54.0%), as previously discussed. However, the average methanogenic efficiency of the WAS collected from the SBRS-SRT (SRT 3 d) was 54.1% higher than the methanogenic efficiency of the WAS collected from the SBRcontrol (the oxic phase duration as 2.5 h), as shown in obsY and comparable COD removal efficiency into an account, the methane recovery potential of SBRS-SRT at SRT 3 d was 95.1% higher than the SBRcontrol with the oxic phase duration as 2.5 h, according to Equations (2) and (3). The S-SRT approach was an effective and promising selection for the enhancement of energy recovery.The methane production and methanogenic efficiency of two AnSBRs  and the removal efficiencies were 91.5 ± 3.5%, 95.4 ± 3.8%, and 93.5 ± 3.7%, respectively, at a SRT of 3 d. The SBRS-SRT remained steady sludge settleability, which was comparable with the SBRcontrol (p > 0.05). The ammonia in sewage was retained with an ammonia removal efficiency of 15.7 ± 7.7% indicated the wash-out of nitrifiers in SBRS-SRT when the SRT was shorter than T4 d. The enrichment of Tetrasphaera and the stable abundance of filamentous bacteria were the source force that maintained the stability of the SBRS-SRT. The methanogenic efficiency increased by 95% when the SRT of SBRS-SRT was 3 d compared with SBRcontrol as its oxic phase duration was 2.5 h. This study proved that the S-SRT EBPR was a promising and practical A-stage selection that maximally utilized the biological phosphorus removal function when shifting a conventional WWTP into a “source and energy recovery factory” operated as an A-B stage process.Two EBPR SBR systems were set up to treat real domestic sewage and two AnSBRs were conducted to compare the methanogenic efficiencies of the generated (or collected) WAS from the two systems. A


Restoring UBE3A levels is a potential disease-modifying therapy for AS and has recently entered clinical trials. There is paucity of data regarding the molecular changes downstream of UBE3A hampering elucidation of disease therapeutics and biomarkers. Notably, UBE3A plays an important role in the nucleus but its targets have yet to be elucidated. Using proteomics, we assessed changes during postnatal cortical development in an AS mouse model. Pathway analysis revealed dysregulation of proteasomal and tRNA synthetase pathways at all postnatal brain developmental stages, while synaptic proteins were altered in adults. We confirmed pathway alterations in an adult AS rat model across multiple brain regions and highlighted region-specific differences. UBE3A reinstatement in AS model mice resulted in near complete and partial rescue of the proteome alterations in adolescence and adults, respectively, supporting the notion that restoration of UBE3A expression provides a promising therapeutic option. We show that the nuclear enriched transketolase (TKT), one of the most abundantly altered proteins, is a novel direct UBE3A substrate and is elevated in the neuronal nucleus of rat brains and human iPSC-derived neurons. Taken together, our study provides a comprehensive map of UBE3A-driven proteome remodeling in AS across development and species, and corroborates an early UBE3A reinstatement as a viable therapeutic option. To support future disease and biomarker research, we present an accessible large-scale multi-species proteomic resource for the AS community ( UBE3A-ATS), while the maternal copy remains functional. In most AS cases, genetic defects of the maternal allele led to a complete UBE3A loss of function in neurons , 2120, 2Proteins corresponding to all components of the proteasome were altered from birth and persistent to adulthood. We observed a consistent increase in abundance of several proteasome interacting proteins , as well as of proteins belonging to the 11S and 19S regulatory subunits  PSMD11,.p value < 0.05) and found 63 proteins that fulfilled these criteria  and that there was large overlap in the alterations in the hippocampus and cortex , with YARS, WARS and GARS decreased, and MARS, VARS, AIMP1 and AIMP2 increased in AS compared to controls in both mice and rats  and across brain regions , and rat hippocampus , while diverging in AS cerebellum . Of interest, the synaptic proteins GAD2, ACHE, PLCXD3, and GRK2, were decreased in AS in all brain regions and across species, while PSD, DLG4, PLCB1, and VPS11, were increased in AS compared to controls. Others such as MAP1A, PCLO, PTPRF, STX1A, showed brain region- or species-specific differences , AS (Ube3aStop/p+), and UBE3A reinstatement mice  were injected with tamoxifen at either P21 or P56, corresponding to juvenile and adult developmental stages, and sacrificed at P84 to compare rescue at the two time points  derived AS patient neurons , 28, 29 To identify in a more systematic way additional proteins that are changed between species in an UBE3A-dependent manner, we calculated the overlap of increased (fold change > 0.25 log2) or decreased (fold change < −0.25 log2) protein abundance in the AS condition compared to controls in mouse, rat, and human patient neurons from a previous study . We founConsistently, across AS patient neurons, and AS mouse and rat brains, TKT was robustly altered. Distinct from other enzymes in the pentose phosphate pathway, TKT has been previously reported to be enriched in the nucleus of non-neuronal cells, and to contain a nuclear localization signal . SimilarE. coli [E. coli cells were transformed with plasmids encoding UBE3A  and other components needed for ubiquitination, ubiquitin, and TKT or RING1B. RING1B is a well-established target of UBE3A and serves as positive control [C817S  labeled specific antibodies. PLA signal was located in both cytoplasm and nuclei of neurons, and nuclear signal was significantly decreased upon treatment with UBE3A KD ASO compared to NT controls .In this study, we performed a global analysis of UBE3A-driven temporal and spatial remodeling of the rodent proteome. Together with our previous proteomic analysis of AS patient derived neurons , we highThe most striking changes observed in the AS proteome in all species and across all developmental stages, was the upregulation of proteasomal subunits and ARS. It has been reported previously that UBE3A can directly interact with the 26S proteasome and regulate turnover of proteasomal subunits , 35, 36.Our study represents the first proteomic study of AS rat brain tissue , in whicRestoring UBE3A expression is a promising therapeutic strategy for AS currently undergoing clinical trials . In a conditional AS mouse model harboring an inducible maternal UBE3A allele, age-dependent rescue of specific behavioral phenotypes was demonstrated after UBE3A reinstatement , 9. StriIn a previous study, proteomic analysis of patient derived iPSC neuronal cultures and after UBE3A reinstatement using ASOs revealed a set of human specific UBE3A targets, including the GAG domain containing protein PEG10 . In addiNotably, TKT; a rate limiting enzyme of the pentose phosphate pathway; showed consistent cross species and UBE3A-dependent changes. Intriguingly, TKT localization in both human neurons and rat brain tissue was found to be predominantly nuclear, even though the PPP takes place in the cytosol . In thisMice were housed in individually ventilated cages  in a barrier facility. All animals were kept at 22 ± 2 °C with a 12 h dark and light cycle, and provided with mouse chow (801727CRM(P) from Special Dietary Service) and water ad libitum. All animal experiments were conducted in accordance with the European Commission Council Directive 2010/63/EU .Total protein profiling of rat and mouse tissue was performed at Biognosys AG  using Biognosys’ Hyper Reaction Monitoring (HRM™) label-free discovery proteomics workflow.All measurements were performed in a randomized and blinded fashion and balanced for genotype age and treatment condition at Biognosys prior to sample preparation. All.raw files will be made available on Massive server: Massive ID: MSV000087972. Proteomic analysis of angelman rodent models.For detailed methods on sample preparation, HPRP fractionation, library generation, and acquisition, see HRM mass spectrometric data were analyzed using Spectronaut Pulsar software . The false discovery rate on peptide and protein level was set to 1%, data was filtered using row based extraction. The assay library (protein inventory) generated in this project combined with the ones from MCP  was useFor bioinformatics analyses of proteomic data see n = 3 animals per group) and hiPSC lysates (n = 3 independent differentiations per group) was analysed by automated capillary western blotting . All experimental steps were carried out according to the manufacturer’s instructions. For brief overview of experimental procedure see The investigators were not blind to the genotypes during analysis and acquisition of capillary western blotting data. Protein expression of putative UBE3A targets in mouse brain , UBE3a  and Map2  and DAPI as previously described .n = 2 independent differentiations) was performed to distinguish neuronal from non-neuronal cells. Replicates from two independent differentiations were combined for data analysis. Statistical analysis was performed with GraphPad Prism Software (version 8) using Kruskal–Wallis test followed by Dunn’s post hoc test.Images were acquired on a Leica TCS SP5 confocal microscope. Automated quantification of nuclear UBE3A and TKT expression was performed by using DAPI staining as a mask and measuring the integrated density of fluorescence in each cell (ImageJ). Manual thresholding of HuC/D staining in each independent experiment (® GlutaNeurons (FUJIFILM Cellular Dynamics) were seeded according to the manufacturer’s instructions. Cells were treated for 7 days with 5 μM ASO. PLA was performed using the Duolink® In Situ Green Kit (Sigma-Aldrich) according to the manufacturer’s instructions. Antibodies: anti-TKT , anti-UBE3a , anti-mCherry , anti-ZsGreen1  and anti-Tau (2E9) Alexa Fluor® 647 . Images were acquired by a Perkin Elmer Opera Phenix plus high-content confocal imaging system with a 63x water objective and analysis was done using Harmony high-content analysis software 5.1. For each pair, six wells with 5′000–10′000 nuclei each were counted.Human iCellBrain tissue was fixed with 4% PFA and prepared for cryosectioning. Immunohistochemical staining for Tkt , Ube3a , and NeuN  in rat brain tissue was performed as previously described with more details in Images were acquired on a Leica TCS SP8 confocal microscope. Z-stack projections were performed using the ‘sum of slices’ command on FIJI (ImageJ). Automated quantification of nuclear UBE3A and TKT expression was performed by using DAPI staining as a mask and measuring the integrated density of fluorescence in each cell. Manual thresholding of NeuN staining was performed and kept consistent across animals to distinguish neuronal from non-neuronal cells. Statistical analysis was performed with GraphPad Prism Software (version 8) using using Kruskal–Wallis test followed by Dunn’s post hoc test.Supplementary Table 1Supplementary Table 2Supplementary Table 3Supplementary Table 4Supplementary Table 5Supplementary Table 6Supplementary Table 7Supplementary Table 8Supplementary Table 9Supplementary FiguresSupplementary MethodsSupplementary Table Descriptions


These results revealTPB–TFB COF thin films as promising candidates for organicelectronics and catalysis and provide insights into the rational designof highly crystalline porous materials for efficient and long-rangecharge transport.Two-dimensional covalentorganic frameworks (2D COFs) representa family of crystalline porous polymers with a long-range order andwell-defined open nanochannels that hold great promise for electronics,catalysis, sensing, and energy storage. To date, the development ofhighly conductive 2D COFs has remained challenging due to the finiteπ-conjugation along the 2D lattice and charge localization atgrain boundaries. Furthermore, the charge transport mechanism withinthe crystalline framework remains elusive. Here, time- and frequency-resolvedterahertz spectroscopy reveals intrinsically Drude-type band transportof charge carriers in semiconducting 2D COF thin films condensed by1,3,5-tris(4-aminophenyl)benzene (TPB) and 1,3,5-triformylbenzene(TFB). The TPB–TFB COF thin films demonstrate high photoconductivitywith a long charge scattering time exceeding 70 fs at room temperaturewhich resembles crystalline inorganic materials. This correspondsto a record charge carrier mobility of 165 ± 10 cm In this regard, recently developed crystallinemolecular semiconductors4 exhibit charge mobilities exceeding10 cm2 V–1 s–1.Conventional amorphoussemiconducting polymers exhibit localizedcharge transport properties with reported state-of-the-art chargecarrier mobility on the order of 1 cm10 and optoelectronics.16 As salient characteristics, 2D COFs possess 2D polygon sheets alongthe x–y plane mimicking thegraphene lattice and layer-stacked architectures along the z-direction resembling layered van der Waals materials.Although their long-range-ordered frameworks hold great promise forelectronics,23 2D COFs with high charge carrier mobility comparable to that ofinorganic semiconductors remain scarce, and the underlying chargetransport mechanism has remained largely elusive.Two-dimensional covalent organic frameworks (2D COFs) with periodicnanochannels, abundant active sites, high chemical and thermal stability,and tailorable topologies have emerged recently as promising alternativeelectronic materials for solid electrolytes20 manystudies have been committed to tuning their charge transport propertiesby exploiting various subunits,24 linkages,27 and topologies.28 One representativestudy by Yaghi and co-workers29 demonstratedimpressive charge mobilities of 8.0 and 3.1 cm2 V–1 s–1 in boronate ester and imine-linked porphyrin-based2D COFs by integrating flash photolysis time-resolved microwave conductivitymeasurements (FP-TRMC) with time-of-flight (TOF) transients at differentbias voltages. Follow-up works developed high-mobility 2D COFs byemploying macromolecular building blocks,30 exploring π-conjugated linkages,31 regulating orientations,33 and doping.35 For instance, Dalapati et al.28 integrated a hexabenzocoronene (HBC) building block intothe backbone of an imine-linked triangular COF, achieving a chargemobility of 0.7 cm2 V–1 s–1. Moreover, utilizing π-conjugated linkages, Guo et al.26 reported a charge mobilityup to 4.2 cm2 V–1 s–1 in a phenazine-linked 2D COF using FP-TRMC combined with TOF transientsat different bias voltages. Recently, Wang et al.31 have disclosed a record device-relevant mobility of ∼5cm2 V–1 s–1 in field-effecttransistors based on π-conjugated pyrazine-linked 2D COFs bythe condensation of zinc-phalocyanine and tert-butylpyrene-tetraone.The mobility was further improved up to 22 cm2 V–1 s–1 by molecular iodine doping.34 Despite the impressive progress in developing high-mobility2D COFs, the reported mobilities are far lower than those of theirmetal-based 2D counterparts, that is, 2D metal–organic frameworks(2D MOFs) with a record mobility over 200 cm2 V–1 s–1, as reported by Dong et al.36 Furthermore, according to recent spectroscopicstudies,37 photogeneratedcharge carriers in 2D COFs are subject to the strong spatial confinement,likely originating from their small grain sizes. This is in starkcontrast to the fully delocalized, band-like charge transport reportedin the π–d conjugated porous Fe3(THT)2(NH4)3 MOFs.36 Finally, photogenerated charge carriers in allthe 2D COFs reported till now37 exhibit short lifetimes on the order of sub-10 ps, likely due tocharge trapping at defects. The charge localization and short carrierlifetime impede 2D COFs toward advanced electronics and optoelectronics,which calls for fundamental understanding of their intrinsic chargetransport and recombination mechanisms.Since theadvent of 2D COFs,2 V–1 s–1 in highly crystalline TPB–TFB COF thin films at room temperature,comparable to mobilities in inorganic semiconductors. Along with theband-like transport nature, the observed high mobility also originatesfrom the largely reduced scattering events as demonstrated by thelong charge scattering time of up to 70 fs. This value is superiorto that of the previously reported 2D COFs, whose scattering timesrange from 30 to 50 fs (with non-Drude transport characteristics).39 Temperature-dependentTHz photoconductivity measurements confirm the band-like charge transportin TPB–TFB COF thin films, by showing a negative temperaturedependence of the mobility. Furthermore, there remains considerableroom for further enhancing the mobility, as impurity scattering playsa nontrivial role in limiting the charge mobility. Our results areof importance for 2D COFs toward electronics, as they not only unveilthe intrinsic charge transport mechanism in 2D COFs but also demonstratethe possibility of producing 2D COFs with high mobilities and therelevance of highly crystalline TPB–TFB COF thin films fororganic electronics.Here, we report thefirst observation of band-like transport inhighly crystalline 2D TPB–TFB COF thin films. Terahertz (THz)spectroscopy reveals the Drude response of photogenerated charge carriers,typical of band transport, with a charge scattering time of up to70 fs. Our studies unveil an intuitive but critical parameter to ensurelong-range, delocalized charge transport: crystallinity. Remarkably,our results disclose an exceptionally high charge mobility of 165± 10 cm41 driven by the condensation of C3-symmetric1,3,5-tris(4-aminophenyl)benzene (TPB) and C3-symmetric 1,3,5-triformylbenzene (TFB) monomers.As schematically depicted in –1. Powder X-ray diffraction (PXRD) pattern of the TPB–TFB COFpowder ,(110), (200), and (001) facets, respectively. The strong reflectionat 2θ = 5.6° indicates a structural periodicity of d = 2π/q ∼1.6 nm  well reproduces the experimentallyobserved PXRD profile, as evidenced by their negligible difference rather than the simulated AB-stacking one in terms of the peak positions and intensities. The 2D X-ray scatteringpattern of the thin film (q/q ∼ 0.12) is smaller than thatof the powder (Δq/q ∼0.14). A further significant decrease in the innermost reflectionpeak widths is observed for a 200 nm thick thin film . According to the Scherrer equation,Δq/q is inversely proportionalto the crystallite size. These results, therefore, suggest that thecrystallite size in thin films is larger than that in the powder.We synthesizeimine-linked 2D hexagonal TPB–TFB COFs viaa facile and mild solvothermal polymerization approach6 nm see 1a. Assumhin film 1d not on42 . Figure S3b visualizesa stacked-layer structure with an interlayer distance of 3.6 Å, in good agreement with thePXRD data. Moreover, TEM images with periodic patterns at differentintervals are obtained and reproduced well by the simulations generatedfrom the AA-stacking TPB–TFB COF . These results indicate a face-to-face arrangementof the discrete 2D COF sheets, forming periodically ordered and unidirectionalhexagonal π-columns along the out-of-plane direction . The average pore size is calculatedas 1.7 nm using the nonlocal density functional theory (NLDFT) method. mh) and electron mass (me) inferred from the energy band diagram are2.04 m0 and 1.26 m0, respectively, giving rise to a reduced electron–holemass of m* = 0.78 m0 (with m0 representing the electron rest mass).The formation of TPB–TFBCOF is further confirmed by high-resolutiontransmission electron microscopy (HR-TEM). 42 S3a. Figu42 S3a. Figu42 S3a. FiguSupporting Information). In a typical OPTP measurement, as schematicallyshown in E).The pump-induced, relative change in the transmitted THz electricfield, −ΔE/E, is linearlyproportional to Δσ.43 Followingoptical excitations, photogenerated charge carriers in the TPB–TFBCOF thin film  and thus a low density of charge carriers n. This directly provides the first indication of a large μin the TPB–TFB COF thin film. As for the charge carrier lifetime,further extending the pump–probe delay window reveals that the photoconductivity decays in a biexponential fashioncharacterized by fast and slow relaxation components with time constantsof t1 = 10 ± 1 ps and t2 = 131 ± 10 ps, respectively. The fast and slowrelaxation components can be tentatively assigned to trapping andelectron–hole recombination processes, respectively. The weightedfast and slow relaxation components yield an averaged charge carrierlifetime of t ∼ 40 ps, significantly longerthan that of the other COFs characterized by the same technique,39 where the photoconductivitybecomes negligible within sub-10 ps. To explore the role of crystallinityin determining the charge transport properties, we compare thin-filmphotoconductivity with that of the TPB–TFB COF powder (thesample morphology that has been extensively used in previous photoconductivitymeasurements). Under the same absorbed photon density, the TPB–TFBCOF powder  spectroscopy (see details in the Supporting Information). As shown in 47 and can be well described bythe Drude model, following eq p, ε0, ω, and τ represent the plasmafrequency, vacuum permittivity, angular frequency, and charge scatteringtime, respectively. Furthermore, the charge carrier density can beobtained from the inferred plasma frequency by eq N and e stand for the charge carrier densityand elementary charge, respectively.To further confirm the high mobility of photogeneratedcharge carriersin TPB–TFB COF thin films and investigate their transport mechanism,we performed frequency-resolved complex photoconductivity [Δσ(ω)]measurements at varied pump–probe delays  using THz time-domain spectroscopy . As shown in N follows the same trend with −ΔE/E (and thus Δσ) during the photoconductivitydecay, indicating that the decrease in N is responsiblefor the decay of Δσ, as consequences of the trapping andelectron–hole recombination processes. Furthermore, the inferredτ is almost unchanged at the four pump–probe delays,as displayed in N in the measured charge carrier density range (∼3–5× 1016 cm–3). Using τ̅=72 fs and m* = 0.78 m0 obtained from the DFT calculation, we infer the mobility of photogeneratedcharge carriers in TPB–TFB COF thin films to be 165 ±10 cm2 V–1 s–1, followingμ = eτ̅/m*. Tothe best of our knowledge, our results represent the first observationof the Drude transport of charge carriers in 2D COFs. Furthermore,the estimated mobility constitutes a record high in COFs and is almostone order of magnitude higher than the other reported conductive 2DCOFs48 (see Table S5). Note that the obtained mobility combines the contributionsof in- and out-of-plane conduction. Further efforts to control thelayer orientation of 2D COFs, for example, by pre-organizing themon the water surface by exploiting the π–π interactionand hydrophobicity of monomers49 and choosingsuitable substrates for COF growth,41 arerequired to disentangle the in- and out-of-plane conduction by THzspectroscopy. Such experiments are critical for providing insightsinto the potential anisotropic charge transport properties of 2D COFs.The intrinsically high charge mobility and the Drude-type charge transportobserved here indicate that band transport prevails in the TPB–TFBCOF thin films. The relatively long charge carrier lifetime and outstandingmobility facilitate the efficient and long-range transport of chargecarriers in TPB–TFB COF thin films and lead to a diffusionlength exceeding 100 nm (see details in SectionS9). The superior chargetransport properties of TPB–TFB films over other molecularand polymeric materials (see Table S6) make them promising candidatesfor organic electrodes, electronics, and catalysis.The Drude fits to Δσ(ω)at different pump–probedelays depict the evolution of microscopic charge transport properties. The charge scattering time exhibits a weak temperaturedependence, increasing slightly with a decrease in T. Such dependence is qualitatively in line with band transport, asfreezing out phonons at lower T reduces charge scattering.Impurity scattering likely weakens the temperature dependence of themobility.51 The presenceof defects is further evidenced by a correlation between the chargescattering time and charge carrier lifetime in our samples: comparedto sample A used for the OPTP studies . As such, despite being already high, the estimated mobility representsthe lower bound that appears to be limited by defects and may be furtherimproved by, for example, passivating defects by doping and screeningof charged impurities through dielectric engineering.52 Furthermore, we expect that further enhancement of the charge transportproperties can be achieved by increasing the conjugation within thelayers and incorporating donor–acceptor structures into thebackbones to enable the synthesis of 2D COFs promising for advancedoptoelectronic applications.To providefurther insights into the charge transport mechanismin the TPB–TFB COF thin films, we perform temperature-dependentfrequency-resolved photoconductivity measurements spanning from 278to 78 K. As shown in shown in 2, we not2 V–1 s–1 for 2D COFs. The outstanding mobility, togetherwith the much-enhanced charge carrier lifetime compared to other 2DCOFs (∼40 vs sub-10 ps), enables relativelyefficient and long-range charge transport that holds great promisefor organic optoelectronics, green catalysis, and chemiresistive sensing.Our results not only provide insights into the intrinsic charge transportmechanism in 2D COFs but also demonstrate the possibility of producinghigh-mobility 2D COFs through the rational design of their chemicalstructures and fine control of their crystallinity.In summary, we report the first observation of Drude-type bandtransport of photogenerated charge carriers in 2D COFs and revealthe critical role of crystallinity in determining the charge transportproperties. The highly crystalline TPB–TFB COF thin films exhibita long scattering time beyond 70 fs at room temperature, correspondingto a record mobility of 165 ± 10 cm


Hot deformation was carried out with uniaxial compression of cylindrical specimens on a Gleeble 3800 thermomechanical simulator. It is shown that the flow stress increased with a decrease in the deformation temperature and an increase in the strain rate. The shape of the stress-strain curves indicates that, at high temperatures and low strain rates, the hot deformation of AISI 321 steel was accompanied by dynamic recrystallization. The passage of dynamic recrystallization was confirmed by microstructural studies. Hyperbolic sine type of constitutive equation with deformation activation energy Q = 444.2 kJ·mol−1 was established by analyzing the experimental flow stresses. The power-law dependences of the critical strain necessary for the onset of dynamic recrystallization and the size of recrystallized grains on the Zener–Hollomon parameter were established. The value of the parameter Z = 5.6 × 1015 was determined, above which the dynamic recrystallization was abruptly suppressed in the steel under study. It is speculated that the suppression of dynamic recrystallization occurs due to dispersed precipitates of titanium carbonitrides.In this study, the hot deformation behavior of austenitic Ti-modified AISI 321 steel with a relatively high content of carbon (0.07 wt.%) and titanium (0.50 wt.%) was studied in the temperature range of 1000–1280 °C and strain rates in the range of 0.01–1 s Austenitic stainless steels are widely used in the chemical industry, thermal and nuclear power, and medical and cryogenic engineering . The proHot deformation of steels is accompanied by softening processes: dynamic recovery and recrystallization ,6,7,8. TThe study of deformation behavior and structure evolution during hot deformation of austenitic stainless steels was mainly carried out on AISI 316 and AISI 304 steels ,16,17,18−1. Results showed that the main restoration process in the temperature range of 800–950 °C is dynamic recovery −1. Resulrecovery , a methorecovery  investigrecovery ,23,24,25cated in ,23,24,25cated in  also stucated in , hot rolcated in , the reacated in  do not eThe aim of the present study was to investigate the processes of hot deformation of AISI 321 steel containing 0.07% carbon and 0.5% titanium in the range of temperatures and strain rates typical for rolling operations in the production of seamless pipes. For the most complete dissolution of titanium carbonitrides, the preheating temperature of the samples (1280 °C) was chosen to be equal to the heating temperature of the billet in the production process.The chemical composition of the austenitic stainless steel used in the present study is shown in −1, 0.1 s−1, and 1 s−1. During the test, the true strain ε, the true stress σ, and the current temperature of the sample T were recorded.The samples in the form of cylinders with 15 mm length and 10 mm diameter were cut out of the tube after piercing, in the radial direction. Hot deformation was carried out using a uniaxial compression test on a simulator of thermomechanical processes, Gleeble 3800. The temperature of the sample during the test was measured using a thermocouple welded to its central part. Before deformation, the samples were heated to a temperature of 1280 °C and held for 10 min. Notably, 1280 °C is a typical temperature for heating cast blanks before subsequent hot deformation. Afterward, the sample was cooled to the deformation temperature, held at this temperature for 3 min, and deformed. The deformation was carried out at temperatures of 1000 °C, 1100 °C, 1200 °C, and 1280 °C with a strain rate of 0.01 sTo study the structure formed during hot deformation, samples were quenched via a water jet after the deformation was completed. Microstructural studies were performed using an optical microscope C. Zeiss Observer. The slots made from the longitudinal section of the samples were subjected to electrolytic etching in a 4% solution of nitric acid. The grain size was determined using the intersection method.T and strain rate Z, because an increase in temperature accelerates the thermally activated processes of dynamic recovery and dynamic recrystallization, and a decrease in the strain rate provides more time for their implementation. At relatively low temperatures and high strain rates , a work-hardening stage was observed on the flow curves, after which the flow stress reached a constant (steady-state) level −1 and 1 s−1 have such a shape. The shape of flow curves shows that the hot deformation was accompanied by a dynamic recovery process—namely, the process of dynamic softening, which consists of the redistribution and annihilation of part of the dislocations. The work-hardening rate decreased monotonically with the increase in the strain and became zero when a balance was reached between the rate of generation and annihilation of dislocations, due to the dynamic recovery.The flow stresses decrease with a decrease in the parameter Z parameter (relatively high temperatures and low strain rates) have the form of curves with a maximum, indicating that hot deformation was accompanied by dynamic recrystallization. As shown in −1 have this shape. The formation of new recrystallized grains first led to a decrease in the strain work-hardening rate and the achievement of the peak value of the flow stress The stress curves obtained during tests with low values of the The results of the microstructural studies are consistent with the shape of flow curves . During −1 also indicates the passage of dynamic recrystallization. However, with an increase in the strain rate to 0.1 s−1, the time to complete the dynamic recrystallization was not enough, so some elongated non-recrystallized grains remained in the microstructure (The shape of the flow curve (with a stress peak) at a temperature of 1100 °C and a strain rate of 0.01 structure d.Based on the flow curves at a temperature of 1000 °C, the flow stress monotonically increased to a steady level, i.e., there were no signs of dynamic recrystallization. The microstructure in x; To find the relationship between the Zener–Hollomon parameter and peak or steady-state stresses, the empirical Sellars–Tegart expression  is widelFrom Equation (2), it is derived thatUnknown parameters in Equations (2) and (3) were found by regression analysis of experimental stresses The flow stresses accuracy .A, n, and Q changes by no more than 5 kJ/mol.A similar regression discrepancy can be obtained with slightly different sets of parameters n (5.442) and the activation energy Q (444.2 kJ/mol) obtained by us lie within the ranges of values (4.5–6.1) and (433–465 kJ/mol), respectively, published earlier for AISI 321 steels with slightly different contents of carbon and titanium. However, all of the above estimates of the activation energy significantly exceed the value of the activation energy of self-diffusion of iron atoms in austenite (280 kJ/mol), which determines the rate of dislocation climb in the processes of dynamic recovery and the rate of migration of grain boundaries in the processes of dynamic recrystallization. One of the reasons for this discrepancy is the fact that Equations (2) and (3) do not take into account the temperature dependence of the elastic modulus of the material. Therefore, in [n close to 5, according to some authors, will indicate that the mechanism that controls hot deformation is glide and climb of dislocations [Q the “apparent” activation energy.The exponent fore, in ,30, it iocations ,32. HoweZ  relates the peak strain lization  as follok in Expression (5) for austenitic AISI 321 steel is 0.69 [The coefficient Z parameter has a linear form , which limits the area of full dynamic recrystallization in our investigation.The horizontal dotted line in  studies b,c. The Z region , the portion of dynamically recrystallized grains decreased sharply , only narrow bands of very small recrystallized grains along the boundaries of large elongated grains are visible in microstructure photographs  and (9) extrapolated to the high  sharply d. With atographs a. From t−1  was accompanied by complete dynamic recrystallization [It should be noted that in AISI 321 steel with a lower content of carbon (0.04%) and titanium (0.32%), deformation at a temperature of 1000 °C with strain rates in the range of 0.01–1 sThis circumstance suggests that the reason for the suppression of dynamic recrystallization in our AISI 321 steel with a high content of carbon (0.07%) and titanium (0.50%) can be dispersed particles of titanium carbonitrides Ti, which precipitate before and/or in the process of hot deformation and suppress the growth of new grains.As shown in , the traZ > 15.75 requires further research. Nevertheless, it can be argued that, for guaranteed refinement of the grain structure of AISI 321 steel due to dynamic recrystallization, the temperature of hot deformation should not be lower than 1100 °C.Elucidation of the true reasons for the suppression of dynamic recrystallization of the steel under study in deformation modes with the parameter log D of dynamically recrystallized grains as a function of the Zener–Hollomon parameter. For this purpose, the graph of the logarithm of experimental grain sizes versus log Z was plotted  dynamic recrystallization, the sizes of small grains formed along the boundaries of large deformed grains are determined with a significant error; however, it can be argued that their corresponding points lie significantly below the regression line. Expression (10) is valid in the region of full dynamic recrystallization and makes it possible to determine the temperature range and the rate of hot deformation, which ensures obtaining grains of the required size in a completely recrystallized microstructure.−1. The main results are as follows:(1)Z was 444.2 kJ/mol. The flow stresses decreased with a decrease in the Z parameter, i.e., with an increase in temperature and a decrease in the strain rate.The apparent activation energy of hot deformation in the Zener–Hollomon parameter (2)Z < 15.65 or Z < 5.6 × 1015. The size of recrystallized grains is a power function of the Zener–Hollomon parameter and decreases with increasing temperature and increasing strain rate.The hot deformations were accompanied by full dynamic recrystallization if log (3)Z > 15.65, a sharp suppression of dynamic recrystallization was observed. The reason for the suppression of dynamic recrystallization in AISI 321 steel can be dispersed particles of titanium carbonitrides Ti, which precipitate before and/or during hot deformation and hinder the growth of new grains.In deformation modes with parameters log (4)The analytical expressions obtained in this research for flow stresses, the critical deformation of the onset of dynamic recrystallization, and the size of recrystallized grains are suitable for use in finite element modeling of hot deformation processes in the steel under study.The hot deformation behavior of austenitic AISI 321 steel with a relatively high content of carbon (0.07 wt.%) and titanium (0.50 wt.%) was studied in the temperature range of 1000–1280 °C and strain rates in the range of 0.01–1 s