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| Thermodynamics and surface characteristics of DTAB and BS-12 co-modified bentonites |
| Received:April 06, 2016 |
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| KeyWord:DTAB;BS-12;bentonite;thermodynamics;surface characteristics |
| Author Name | Affiliation | E-mail | | LI Wen-bin | Department of Natural Resource and Environment, Northwest A & F University, Yangling 712100, China | | | LIU Wei | 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 | | REN Shuang | Department of Natural Resource and Environment, Northwest A & F University, Yangling 712100, China | | | FU Qian | Department of Natural Resource and Environment, Northwest A & F University, Yangling 712100, China | | | XU Shao-e | Department of Biological and Agriculture Engineering, University of Arkansas, Fayetteville 72707, US | |
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| Abstract: |
| Three different BS-12 modified amphiprotic bentonites were chosen to explore the impact of dodecyl trimethyl ammonium bromide(DTAB or DT) re-modification on thermodynamics and surface characteristics of BS-12 bentonites. Their adsorption thermodynamic properties and temperature effects were studied. In addition, TOC(total organic carbon), XRD(x-ray diffraction), SBET(specific surface-area), FTIR(fourier transform infrared spectroscopy), TG(thermogravimetry) and SEM(scanning electron microscope) characteristics of different modified bentonites were analyzed. Results showed that:adsorption amount of DTAB and turning point of temperature effect(S40/S20) decreased with increasing hydrophobic property of BS bentonite. CK(bentonite) presented positive temperature effect on DTAB adsorption from 20℃ to 40℃, while BS bentonites showed negative temperature effect; DTAB adsorption on CK and different BS bentonites were a spontaneous process. With enhanced hydrophobic property of BS-12 bentonite, the adsorption spontaneity was promoted and the reaction changed from endothermic and entropy increase process to exothermic and entropy decrease process; TOC content and interlayer spacing increased, but SBET decreased in different BS+DT modified bentonites with enhanced hydrophobic modification by BS+DT. FTIR, TG and SEM results all proved the modification effects of DTAB on BS bentonites. |
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