摘要
为了探究阳离子型修饰剂修饰不同模式两性膨润土的热力学和表面特征,采用十二烷基三甲基溴化铵（DTAB,简写为DT）对不同十二烷基二甲基甜菜碱（BS-12,简写为BS）修饰模式膨润土进行复配修饰,研究其吸附热力学和温度效应,并分析BS和BS＋DT修饰土样总有机碳（TOC）含量和比表面积（S_（BET））、X射线衍射（XRD）、红外光谱（FTIR）、热重（TG）和扫描电镜（SEM）的特征。结果表明：DTAB吸附量、温度效应比（S_（40）/S_（20））的转折点均随膨润土表面BS疏水修饰的增强而减小。20～40℃范围内,CK（膨润土）对DTAB的吸附为增温正效应,不同模式BS膨润土对DTAB的吸附呈增温负效应。CK和不同模式BS膨润土对DTAB的吸附均属于自发反应。随BS疏水修饰的增强,反应自发性增强,且由吸热、熵增（CK）转为放热、熵减过程。随着BS和DT疏水修饰的增强,土样TOC含量、晶层间距（d_（001））均增大,而S_（BET）减小。TG、FTIR和SEM特征均证实了DTAB在BS膨润土表面的修饰。
Three different BS-12 modified amphiprotic bentonites were chosen to explore the impact of dodecyl trimethyl ammonium bro-mide（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）, S_（BET）（specific surfacearea）, 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（S_（40）/S_（20））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 S_（BET） 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.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2016年第10期1937-1944,共8页
Journal of Agro-Environment Science
基金
国家自然科学基金项目(41271244)
陕西省社会发展攻关项目(2013K13-01-05)
