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Cu2+ adsorption and retardation effect of compound adsorbent by adding bacterium powder and amphoteric modified clay in active calcium silicate |
Received:September 26, 2017 |
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KeyWord:Saccharomyces cerevisiae;BS modified clay;Cu2+;adsorption amount;retardation |
Author Name | Affiliation | LI Wen-bin | College of Environmental Science and Engineering, China West Normal University, Nanchong 637009, China | DENG Hong-yan | College of Environmental Science and Engineering, China West Normal University, Nanchong 637009, China | LI Xue-lian | College of Environmental Science and Engineering, China West Normal University, Nanchong 637009, China | LIU Wei | Department of Natural Resource and Environment, Northwest A & F University, Yangling 712100, China | LEI Gang-gang | College of Environmental Science and Engineering, China West Normal University, Nanchong 637009, China | MENG Zhao-fu | Department of Natural Resource and Environment, Northwest A & F University, Yangling 712100, China Key Laboratory of Plant Nutrition and Agri-Environment in Northwest China, Ministry of Agriculture, Yangling 712100, China | LUO Chuan | College of Environmental Science and Engineering, China West Normal University, Nanchong 637009, China | WANG Teng | Department of Natural Resource and Environment, Northwest A & F University, Yangling 712100, China |
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Abstract: |
To study the adsorption characteristics and retardation effects of Cu2+ under different compound adsorbents mixed by bacterium powder, BS(BS-12, dodecyl dimethyl betaine) modified clay and active calcium silicate, Saccharomyces cerevisiae and BS-modified bentonite(Bentonite modified by modified ratio of 100% CEC of Bentonite) were mixed in active calcium silicate(CK), with a mass ratio of 10%, 20%, and 50% as the compound adsorbents(J-Ca and BS-Ca), and batch method was used to analyze the Cu2+ adsorption isotherms of the samples under different environmental conditions, such as under different pH and temperature values, also the Cu2+ retardation effects of the compound adsorbents were identified. The Cu2+ adsorption capacity of the J-Ca gradually decreased as the proportion of bacterium powder increased, whereas the adsorption of Cu2+ by the BS-Ca increased as the proportion of BS clay increased. The adsorption of Cu2+ by the J-Ca and BS-Ca in the same proportion of bacterium powder and BS clay decreased as follows:BS-Ca > CK > J-Ca. The adsorption of Cu2+ by the adsorbents was a spontaneous process that increased both enthalpy(except 50%BS-Ca) and entropy. Temperature had no significant effect on the Cu2+ adsorption of either the CK or the 10%J-Ca at 10~30℃ but did significantly affect the 25%J-Ca and 50%J-Ca. As the proportion of BS clay increased to 50%, the effect of temperature on the adsorption of Cu2+ by the BS-Ca changed from positive effect to negative effect. In addition, the adsorption of Cu2+ by the two materials increased with increasing pH.(3) In the saturated soil and column migration tests, the volume of penetrated Cu2+ increased as follows:25%J-Ca < CK < 25%BS-Ca. Meanwhile, the outflow concentration peak decreased as follows:25%J-Ca > CK > 25%BS-Ca. The adsorption rate of the CK, 25%J-Ca, and 25%BS-Ca were all above 95%, and the relative retardation factors of the materials were as follows:25%BS-Ca > CK > 25%J-Ca. |
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