表面活性剂复配修饰添加不同含量蒙脱石的黄棕壤对苯酚的吸附作用

在两性修饰剂十二烷基二甲基甜菜碱(BS-12)和阳离子型表面修饰剂十六烷基三甲基溴化铵(CTMAB)复配修饰膨润土吸附苯酚最佳修饰比例的基础上,通过添加膨润土改变2种黄棕壤中的蒙脱石含量(分别为6%和43%),利用X射线衍射和有机碳含量表征了蒙脱石含量对BS+CTMAB复配修饰黄棕壤性质的影响.同时,采用批处理法研究了蒙脱石含量对BS-12+CTMAB复配修饰黄棕壤吸附苯酚能力的影响,对比了不同温度、p H和离子强度下吸附的差异,并探讨了影响机制.结果表明,CTMAB复配修饰增加了BS-12修饰土样的TOC含量并增强了土样对苯酚的吸附能力,且苯酚在复配修饰土中的解吸程度均高于CK、BS-12和CTMAB修饰土;随着黄棕壤中蒙脱石含量的增大,BS-12、CTMAB修饰和BS-12+CTMAB复配修饰土蒙脱石层间距、TOC含量和对苯酚吸附能力整体上均呈增加趋势;单因素对各修饰土样吸附苯酚的影响程度上,温度、p H逐渐减小,离子强度逐渐增大;蒙脱石含量决定的TOC是影响修饰土样对苯酚吸附能力大小的关键因素,修饰土样对苯酚的吸附依然以分配作用为主.

Adsorption of phenol on amphoteric-cationic modified yellow brown soil by adding montmorillonite

Based on the best modification ratio of phenol adsorption on bentonites modified by an amphoteric modifier of dodecyl dimethyl betaine (BS-12) and a cationic modifier of hexadecyltrimethyl ammonium bromide (CTMAB), an experiment was designed to add bentonites to change the clay mineral composition of yellow brown soils, which contain 6% and 43% montmorillonite, respectively. X-ray diffraction and organic carbon contents were detected to investigate the influence of montmorillonite on the properties of co-modified yellow brown soils, Batch experiments were conducted to evaluate the impacts of montmorillonite on the phenol adsorption of amphoteric-cationic modified yellow brown soils,the difference of phenol adsorption was contrasted under different temperature, pH and ionic strength. In the meanwhile, the related adsorption mechanism was also explored. Results showed that total organic carbon content and adsorption capacity of phenol all increased with combined modification,and the desorption of phenol on co-modified yellow brown soils was higher than CK, BS-12 and CTMAB modified yellow brown soils. With the increase of montmorillonite content, montmorillonite interlayer spacing, total organic carbon content and adsorption capacity of amphoteric, cationic and co-modified soils all increased. In addition, the impact of temperature and pH decreased, while the impact of ionic strength increased with increase of montmorillonite content. TOC, decided by montmorillonite content, was the key factor for phenol adsorption on modified yellow brown soils, and distribution played a leading role on the adsorption process.