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| Surface characteristics and CrO42- adsorption of kaolin with different modification |
| Received:November 15, 2015 |
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| KeyWord:modified mode;kaolin;surface characteristics;CrO42-;adsorption capacity |
| Author Name | Affiliation | E-mail | | LI Wen-bin | Department of Natural Resource and Environment, Northwest A & F University, Yangling 712100, 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 | zfmeng@hotmail.com | | WU Qiong | Department of Natural Resource and Environment, Northwest A & F University, Yangling 712100, China | | | ZHAO Yun-fei | Department of Natural Resource and Environment, Northwest A & F University, Yangling 712100, China | | | REN Shuang | Department of Natural Resource and Environment, Northwest A & F University, Yangling 712100, China | | | YU Lu | Department of Natural Resource and Environment, Northwest A & F University, Yangling 712100, China | | | GUO Hui | Department of Natural Resource and Environment, Northwest A & F University, Yangling 712100, China | | | ZHOU Chun-yan | Department of Natural Resource and Environment, Northwest A & F University, Yangling 712100, China | |
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| Abstract: |
| Modified minerals have enhanced surface and thus adsorption. In this study, surface characteristics and CrO42- adsorption of kaolin under different modification were examined at various pH and temperature. Dodecyl trimethyl ammonium bromide(DTAB) was used to modify 15%, 30% and 60% BS-12(Dodecyl dimethyl betaine) pre-modified kaolin. Results showed that:TOC content was hydrophobic >hydrophobic and ion exchange >ion exchange modifications for BS-12 and BS+DTAB modified samples. The interlayer spacing in different modified kaolin had no significant variation, but was all greater to different extent than that of the original(CK). The specific surface area of different modified kaolin decreased with increasing hydrophobic modification. Adsorption of CrO42- on BS-12 kaolin was greatly improved after co-modification with DTAB. Henry model fitting proved that kaolin modified with hydrophobic substance had enhanced adsorption capacity for CrO42-, which increased with increasing hydrophobic ratios. When temperature increased from 10 to 30℃, the adsorption capacity for CrO42- was increased by more than 5% on CK and by 1.4%~3.7% on BS-12 modified kaolin, but was reduced by 5.4%~7.2% on 15%, 30% and 60% BS+DTAB modified kaolin. Increasing pH from 4 to 10 decreased the adsorption capacity for CrO42- on all modified kaolin. |
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