Mechanism of combination membrane and electro-winning process on treatment and remediation of Cu2+ polluted water body.
Mechanism of treatment and remediation of synthetic Cu2+ polluted water body by membrane and electro-winning combination process was investigated. The influences of electrolysis voltage, pH, and electrolysis time on the metal recovery efficiencies were studied. Relationship between trans-membrane pressure drop (DeltaP), additions ratio, initial Cu2+ concentration on operating efficiency, stability of membrane and the possibility of water reuse were also investigated. The morphology of membrane and electrodes were observed using scanning electron microscopy (SEM), the composition of surface deposits was ascertained using combined energy dispersive X-ray spectroscopy (EDX) and atomic absorption spectrophotometer. The results showed that using low pressure reverse osmosis (LPRO), Cu2+ concentration could increase from 20 to 100 mg/L or even higher in concentrated solutions and permeate water conductivity could be less than 20 microS/cm. The addition of sodium dodecy/sulfate sodium dodecyl sulfate improved Cu2+ removal efficiency, while EDTA had little side influence. In electro-reduction process, using plante electrode cell, Cu2+ concentration could be further reduced to 5 mg/L, and the average current efficiency ranged from 9% to 40%. Using 3D electrolysis treatment, Cu2+ concentration could be reduced to 0.5 mg/L with a current efficiency range 60%-70%.
Titanate Fibroin Nanocomposites: A Novel Approach for the Removal of Heavy-Metal Ions from water.
In this study, we report the fabrication of nanocomposites made of titanate nanosheets immobilized in a solid matrix of regenerated silk fibroin as novel heavy-metal-ion removal systems. The capacity of these nanocomposite films to remove lead, mercury, and copper cations from water was investigated, and as shown by the elemental quantitative analysis performed, their removal capacity is 73 mmol/g for all of the ions tested. We demonstrate that the nanocomposites can efficiently retain the adsorbed ions, with no release of titanate nanosheets occurring even after several exposure cycles to ionic solutions, eliminating the risk of release of potentially hazardous nanosubstances to the environment. We also prove that the introduction of sodium ions in the nanocomposite formulation makes the materials highly selective toward the lead ions. The developed biopolymer nanocomposites can be potentially used for the efficient removal of heavy-metal-ion pollutants from water and, thanks to their physical and optical characteristics, offer the possibility to be used in sensor applications.
Assessing Bioindication with Earthworms in An Intensively Farmed Rural Landscape (Yuanqiao and Daqiao Villages in Qianjiang Municipality, Located in Hubei Province, Subtropical China)
Earthworm species diversity, population density, biomass, age-structure, average individual weight, and pattern of distribution were studied in the agricultural landscape of two adjacent villages in Qianjiang Municipality located on the Jiang-Han plain, Hubei Province, China. We identified 16 earthworm species belonging to three families (Moniligastridae, Megascolecidae, and Lumbricidae). Among these, Amynthas hupeiensis and Metaphire guillelmi were the dominant species, and were recorded in significant numbers in different seasons and in the various land-use systems studied. The highest earthworm population density was found in June, before the hot summer, and averaged 23 ind. M−2, with a maximum of 239 ind. −2. Among the nine land-use systems distributed in the landscape, home gardens, intensively cropped commercial vegetable fields and their margins with weeds and bushes generally showed a higher earthworm population density, species diversity, and biomass compared with the other systems. These observa...