Methacrylic acid was used together with a molecular imprinting technique to modify chitosan. In addition, the adsorption kinetics and adsorption isotherms were recorded and the results were analyzed to investigate rep...Methacrylic acid was used together with a molecular imprinting technique to modify chitosan. In addition, the adsorption kinetics and adsorption isotherms were recorded and the results were analyzed to investigate reparative adsorption for Cr（VI） from the polluted Xiangjiang River water. A comparative X-ray analysis shows that the degree of crystallization in the imprinted polymer was significantly weakened, the area of the non-crystalline region was larger. There were more adsorption sites in the imprinted polymer, and the adsorption capacity towards Cr（VI） was increased. The adsorption capacity of the imprinted polymer towards Cr（VI） increased with time and reaches saturation after 8 h. The optimal adsorption time was 4-8 h after the adsorption starting and the optimal pH value for the solution was in the range of 4.5-7.5. When the chitosan reaches saturation, the adsorption capacity achieves a state of equilibrium, and the maximum Cr（VI） extraction rate reaches 33.7%. Moreover, the adsorption capacity of the imprinted polymer towards Cr（VI） increases with increasing chitosan concentration. In this situation, the Cr（VI） extraction rate shows little variation, and the maximum removal rate can reach 98.3%. Furthermore, the Cr（VI） extraction rate increases with an increase in the degree of deacetylation in the chatoyant and chitosan, with the best adsorption effect corresponding to 90% deacetylation. Fitting the adsorption data to the quasi first- and second-order kinetic models yields correlation coefficients of 0.9013 and 0.9875, respectively. The corresponding rate constants for the two models are 0.0091 min-1 and 7.129 g/（mg.min）, respectively. Hence, the adsorption using Cr（VI）-imprinted chitosan is more consistent with the second-order kinetics. Comparing the data to Freundlich and Langrnuir adsorption isotherms shows that the latter has a better linear fit and a maximum adsorption capacity of 15.784 mg/g.展开更多
[ Objective] The research aimed to study Cr wastewater treatment by steel slag. [ Method] Steel slag was used as adsorbent to remove Cr from wastewater, and influence factors of the Cr wastewater treatment by steel sl...[ Objective] The research aimed to study Cr wastewater treatment by steel slag. [ Method] Steel slag was used as adsorbent to remove Cr from wastewater, and influence factors of the Cr wastewater treatment by steel slag were studied. [ Result] Removal rate of Cr（VI） by steel slag was quite low, and the highest removal rate only reached 8.9%. Cr （III） removal by steel slag was quite effective. For 50 ml of Cr（VI） solution （100 mg/L）, after reduction, 0.30 g of steel slag （100 meshes） was added to oscillate for 35 min, and total Cr removal rate was up to 90%. Cr adsorption by steel slag was an exothermal process, and physical adsorption was dominant. Steel slag was suitable for treating acidic Cr wastewater, and its adsorption process on Cr followed Frenndlich isothermal adsorption model. [ Conduslon] It could reach the aim of ＂waste treat- ment by waste＂ bv usin~ steel slaq to treat Cr wastewater.展开更多
基金Project(41271332)supported by the National Natural Science Foundation of ChinaProject(2010YBB186)supported by the Social Science Foundation of Hunan Province,Chian
文摘Methacrylic acid was used together with a molecular imprinting technique to modify chitosan. In addition, the adsorption kinetics and adsorption isotherms were recorded and the results were analyzed to investigate reparative adsorption for Cr（VI） from the polluted Xiangjiang River water. A comparative X-ray analysis shows that the degree of crystallization in the imprinted polymer was significantly weakened, the area of the non-crystalline region was larger. There were more adsorption sites in the imprinted polymer, and the adsorption capacity towards Cr（VI） was increased. The adsorption capacity of the imprinted polymer towards Cr（VI） increased with time and reaches saturation after 8 h. The optimal adsorption time was 4-8 h after the adsorption starting and the optimal pH value for the solution was in the range of 4.5-7.5. When the chitosan reaches saturation, the adsorption capacity achieves a state of equilibrium, and the maximum Cr（VI） extraction rate reaches 33.7%. Moreover, the adsorption capacity of the imprinted polymer towards Cr（VI） increases with increasing chitosan concentration. In this situation, the Cr（VI） extraction rate shows little variation, and the maximum removal rate can reach 98.3%. Furthermore, the Cr（VI） extraction rate increases with an increase in the degree of deacetylation in the chatoyant and chitosan, with the best adsorption effect corresponding to 90% deacetylation. Fitting the adsorption data to the quasi first- and second-order kinetic models yields correlation coefficients of 0.9013 and 0.9875, respectively. The corresponding rate constants for the two models are 0.0091 min-1 and 7.129 g/（mg.min）, respectively. Hence, the adsorption using Cr（VI）-imprinted chitosan is more consistent with the second-order kinetics. Comparing the data to Freundlich and Langrnuir adsorption isotherms shows that the latter has a better linear fit and a maximum adsorption capacity of 15.784 mg/g.
文摘[ Objective] The research aimed to study Cr wastewater treatment by steel slag. [ Method] Steel slag was used as adsorbent to remove Cr from wastewater, and influence factors of the Cr wastewater treatment by steel slag were studied. [ Result] Removal rate of Cr（VI） by steel slag was quite low, and the highest removal rate only reached 8.9%. Cr （III） removal by steel slag was quite effective. For 50 ml of Cr（VI） solution （100 mg/L）, after reduction, 0.30 g of steel slag （100 meshes） was added to oscillate for 35 min, and total Cr removal rate was up to 90%. Cr adsorption by steel slag was an exothermal process, and physical adsorption was dominant. Steel slag was suitable for treating acidic Cr wastewater, and its adsorption process on Cr followed Frenndlich isothermal adsorption model. [ Conduslon] It could reach the aim of ＂waste treat- ment by waste＂ bv usin~ steel slaq to treat Cr wastewater.
