阴-阳离子改性凹凸棒石对水溶液中双酚A的吸附机制

Adsorption mechanism of bisphenol A in aqueous solution using anionic-cationic surfactant modified attapulgite

以阴、阳离子表面活性剂十二烷基硫酸钠(SDS)和十六烷基三甲基溴化铵(HDTMAB)为改性剂,超声制备了阴-阳离子改性凹凸棒石.采用静态吸附法研究了双酚A在阴-阳离子改性凹凸棒石上的吸附特性以及动力学和热力学过程,并分析了其可能的吸附机理.结果表明:在所研究的配比范围内,阴、阳离子表面活性剂未产生协同增溶作用;双酚A在阴-阳离子改性凹凸棒石上的吸附符合准二级动力学方程,其吸附速率受边界层扩散和颗粒内扩散共同控制;Lang-muir等温吸附方程能较好地描述吸附等温线,表面吸附作用在吸附过程中占主导地位;吸附过程为熵减自发放热过程,以物理吸附为主,表现为氢键力、范德华力、疏水作用力和偶极间作用力等多种作用力的协同作用.

Using anionic surfactant sodium dodecyl sulfate （SDS） and cationic surfactant hexadecyl trimethylammonium bromide （HDTMAB） as modifiers, the adsorbent of attapulgite supported an- ionic-cationic surfactant was prepared through ultrasonic treatment. The adsorption characteristics, thermodynamics and kinetics of the adsorption of bisphenol A （BPA） in aqueous solution were stud- ied by using static experiments, and the possible adsorption mechanism was proposed. The results show that there is no significant synergism for the mixed surfactants within the experimental ratio range. The adsorption kinetics of BPA on the adsorbent are in agreement with the pseudo-second-or- der rate equation, and the adsorption rate was controlled by intra-particle diffusion and extra-particle diffusion. Meanwhile, the adsorption isotherms can be described by using the Langmuir isotherm model, and surface adsorption plays a leading role in the process of BPA adsorption into organic-at- tapulgite. The adsorption accompanied by a decrease in entropy is a spontaneous and exothermic process, mainly dominated by the physical interaction which is expressed as the collaborative effects of hydrogen bond forces, van der Waals forces, hydrophobic bond forces and dipole bond forces an SO on.