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| Secondary Modification Mechanisms of BS-12 Modified Bentonite with DTAB and Phenanthrene Adsorption by Combinedly Modified Bentonite |
| Received:April 01, 2015 |
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| KeyWord:combined modification;ion exchange;hydrophobic bonding;adsorption |
| Author Name | Affiliation | E-mail | | LI Wen-bin | Department of Natural Resource and Environment, Northwest A&F University, Yangling 712100, China | | | YANG Shu-ying | Department of Science, 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 | | CUI Xiao-bo | Department of Science, Northwest A&F University, Yangling 712100, China | | | LIU Wei | Department of Natural Resource and Environment, Northwest A&F University, Yangling 712100, China | | | BAI Dan | Department of Natural Resource and Environment, Northwest A&F University, Yangling 712100, China | |
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| Abstract: |
| Combinedly modified clays have enhanced adsorption of pollutants. In the present study, we investigated combined modification mechanisms of BS-12 modified amphoteric bentonite using DTAB, and examined the phenanthrene adsorption by combinedly modified clays. Ion exchange and hydrophobic bonding mode were determined by the changes in "SDC" curves and the model fitting results. Results showed that ion exchange and hydrophobic bonds coexisted in combined modification of BS-12-bentonite with DTAB. Hydrophobic bonding began to appear at DTAB rate of 31.15%, 17.26% and 2.40% CEC for 25%, 50%, and 100% BS-12 bentonite, respectively. Phenanthrene adsorption increased with increasing modification ratios for single modified(BS-12) and combined modified clays(25% BS-12+DTAB and 50%BS-12+DTAB). However, the adsorption by 100% BS-12+DTAB showed little difference. Adsorption of phenanthrene by original and BS-12 modified bentonite was profoundly influenced by ionic strength, with the maximum observed at 0.1 mol·L-1, whereas no difference in phenanthrene adsorption was found on BS-12 and DTAB combinedly modified bentonite. The adsorption of phenanthrene on combinedly modified clays was dependent on the ratios of both BS-12 and DTAB, and the saturated adsorption of phenanthrene on clay surface. |
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