Study on the Adsorption Behavior of Co(II), Pb(II) on Modified Sodium Trititanate Whisker and Its Application to Wastewater
The modification of sodium trititanate whisker surface was performed by means of impregnation procedure to fabricate the modified sodium trititanate whisker, which was characterized by scanning electron microscopy(SEM) and infrared spectroscopy(IR). Its adsorptive performance for Co(II), Pb(II) in a static system was investigated by inductively coupled plasma atomic emission spectrometry(ICP-AES). The main factors affecting adsorption and desorption of Co(II), Pb(II), the adsorptive capacity of Co(II), Pb(II) in optimal condition and adsorption isotherm and the influence of coexistent ions were examined. The comparative test for selectivity was done. The adsorptive rate for Co(II) and Pb(II) on 0.2500 g of modified sodium trititanate whisker at PH 5.0 was the best. Co(II), Pb(II) adsorbed on the modified sodium tretitanate whisker could be eluted with 10 mL of 3.0 mol/L HCl. The adsorptive performance of modified sodium trititanate whisker was better than that of unmodified sodium trititanate whisker. The sobent has been applied to the enrichment and separation of Co(II), Pb(II) in water sample to determine Co(II), Pb(II).
Novel modified pectin for heavy metal adsorption
Abstract Modified pectin cross-linked with adipic acid, was synthesized and used for heavy metal removal from wastewater. SEM and FTIR were used to investigate its structure and morphology. The modified pectin had a rough, porous phase covered with carboxy groups, resulting a high adsorption capacity. And at the room temperature, the saturated loading capacity for Pb 2+ , Cu 2+ and Zn 2+ reached 1.82 mmol/g, 1.794 mmol/g and 0.964 mmol/g, respectively. The results proved its potential application to remove of the heavy metal.
Methyl esterification divergently affects the degradability of pectic uronosyls in nonlignified and lignified maize cell walls.
Nonlignified cell walls from Zea mays (L.) cell suspensions were incubated with and without pectin methylesterase (PME) and a portion were artificially lignified to assess how methyl esters influence the release of pectic uronosyls and total sugars from cell walls by fungal enzymes. Treatment with PME reduced uronosyl concentrations from 97 to 92 mg/g, reduced uronosyl methylation from 57% to 21%, and increased Klason lignin concentrations in artificially lignified cell walls from 99 to 116 mg/g. Although PME treatment slightly enhanced uronosyl release from nonlignified cell walls, it reduced uronosyl release from artificially lignified cell walls by 55% after 4 h and by 7% after 72 h of enzymatic hydrolysis. Pectin hydrolysis in PME treated cell walls was probably impaired by enhanced benzyl ester cross-linking of uronosyls to lignin via quinone methide intermediates. Variations in uronosyl methylation had little effect on the overall release of total sugars from cell walls.