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| Comparison of Phenol Adsorption on Bentonite and Kaolinite Co-modified by BS-12 and Tween-80 |
| Received:May 20, 2015 |
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| KeyWord:combined modification;bentonite;kaolinite;BS-12;Tween 80;phenol;adsorption |
| Author Name | Affiliation | E-mail | | CUI Xiao-bo | College of Science, Northwest A&F University, Yangling 712100, China | | | MENG Zhao-fu | College of Natural Resource and Environment, Northwest A&F University, Yangling 712100, China | zfmeng1996@263.net | | YANG Ya-li | College of Science, Northwest A&F University, Yangling 712100, China | | | LI Wen-bin | College of Natural Resource and Environment, Northwest A&F University, Yangling 712100, China | | | DI Xin | College of Science, Northwest A&F University, Yangling 712100, China | | | WU Qiong | College of Natural Resource and Environment, Northwest A&F University, Yangling 712100, China | |
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| Abstract: |
| Clay minerals modified by different types of surfactants have showed enhanced capability of remediating soil or water polluted by heavy metals and organic substances. An experiment was designed to compare the adsorption of phenol on bentonite and kaolinite co-modified by dodecyl dimethyl betaine(BS-12)+ Tween80(Tw80, T) at different ratios of modifiers, ionic strength, temperature and pH using batch experiments. The adsorption mechanisms were explored by adsorption isotherms, temperature effects and thermodynamics. Results showed that CEC was the main factor influencing adsorption of phenol on co-modified clays. At the same ratio of the modifiers, bentonite with high CEC adsorbed more phenol than kaolinite with low CEC. The adsorption of phenol on modified bentonite and kaolinite showed consistent trends under different factors. The adsorption capacity of bentonite and kaolinite co-modified by BS-12+Tw80 was obviously higher than unmodified clays. It was found that the adsorption capacity of bentonite and kaolinite modified by 50BS+T increased with increasing Tw80 ratios, while that by 100BS+T decreased with increasing Tw80 ratios. The adsorption of phenol decreased with increasing temperature and pH, but increased with increasing ionic strength. Henry model very well described the adsorption of phenol. The adsorption of phenol on bentonite modified by BS+T was characteristized by enthalpy decreases and entropy increases, showing different forms of adsorption process, whereas the adsorption of phenol by kaolinite modified by BS+T was a hydrophobic adsorption process drived by enthalpy decreases. |
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