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| Effect of addition of different compositely modified amphipathic maifanites on Cu2+ adsorption by purple soil |
| Received:June 28, 2018 |
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| KeyWord:composite modification;maifanite;purple soil;Cu2+ pollution;adsorption amount |
| Author Name | Affiliation | E-mail | | LI Wen-bin | College of Environmental Science and Engineering, China West Normal University, Nanchong 637009, China | | | XIE Jia | 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 | dhongyan119@163.com | | HE Hai-xia | College of Environmental Science and Engineering, China West Normal University, Nanchong 637009, China | | | ZHU Lang | College of Environmental Science and Engineering, China West Normal University, Nanchong 637009, China | | | KANG Le | College of Environmental Science and Engineering, China West Normal University, Nanchong 637009, China | | | LIU Wei | College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China | | | MENG Zhao-fu | College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China
Key Laboratory of Plant Nutrition and Agri-Environment in Northwest China, Ministry of Agriculture and Rural Affairs, Yangling 712100, China | |
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| Abstract: |
| To explore the effect of addition of different compositely modified amphipathic clays on Cu2+ adsorption by purple soil, 50% and 100% CEC of anionic polyacrylamide (APAM, abbreviated as PA), citric acid (CA), ethylenediamine tetraacetic acid (EDTA, abbreviated as ED), and sodium dodecyl sulfate (SDS, abbreviated as SD) were used to compositely modify 50% CEC of lauryl dimethyl betaine (BS-12 or BS) -modified maifanite. Subsequently, the different compositely modified maifanites were added to purple soil (PS) with a mass ratio of 1% to form four types of mixed soil samples, such as PS50BS+PA (addition of 1% 50BS+PA-modified maifanite into PS, similarly hereinafter), PS50BS+CA, PS50BS+ED, and PS50BS+SD. The adsorption isotherms and thermodynamic characteristics of Cu2+ on the various mixed samples were studied by batch treatment, and the adsorption effects of pH values, temperatures and ion strengths were evaluated. The results showed the following. The adsorption isotherms of Cu2+ on the mixed samples were all "L" type and accorded with the Langmuir model. The maximum adsorption amount of Cu2+ on the mixed samples changed between 94.90 mmol·kg-1 and 144.80 mmol·kg-1, and presented the trend of PS50BS+PA > PS50BS+CA > PS50BS+SD > PS50BS+ED > PS50BS > PS. At the same composite modification mode, Cu2+ adsorption showed a good adsorption amount at the composite modification ratio of 100%. In the range of 20~40℃, the adsorption amount of Cu2+ on the tested soils increased with the increase in temperature, except that on PS50BS+PA and PS50BS+SD, and the increasing range was 8.29%~15.99%. Within the pH range of 3~5, Cu2+ adsorbed by each mixed soil increased with the increase in pH. The adsorption amount of Cu2+ on the mixed soils (except that on PS50BS) decreased with the increase in ionic strength, which was the highest at 0.01 mol·L-1. The adsorption of Cu2+ on the mixed samples (except that on PS50BS+PA and PS50BS+SD) was a spontaneous and entropy increasing process, and the process showed an endothermic reaction. |
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