【摘要】 采用两性表面修饰剂十二烷基二甲基甜菜碱(BS-12)和阳离子表面修饰剂十六烷基三甲基溴化铵(CTMAB)复配修饰膨润土,通过批处理法研究了不同修饰比例、温度、pH和离子强度等条件下,复配修饰膨润土对苯酚的吸附规律和热力学特征,并探讨了其吸附机制。结果表明,CTMAB复配修饰显著增强了两性修饰膨润土对苯酚的吸附能力,30℃时吸附量呈现100BS+100CT(100%BS-12+100%CTMAB)>100BS+50CT(100%BS-12+50%CTMAB)>50BS+100CT(50%BS-12+100%CTMAB)>100BS+150CT(100%BS-12+150%CTMAB)>50BS+50CT(50%BS-12+50%CTMAB)>100BS+25CT(100%BS-12+25%CTMAB)>50BS+150CT(50%BS-12+150%CTMAB)>50BS+25CT(50%BS-12+25%CTMAB)>100BS(100%BS-12)>50BS(50%BS-12)>CK(原土)的顺序。当CTMAB复配修饰比例在0~100%CEC时,两性复配修饰土样对苯酚的吸附量随着修饰比例的增大而升高,而在100%~150%CEC阶段,吸附量则随CTMAB修饰比例的增大有所降低;修饰土样对苯酚吸附量随着温度、pH的升高而降低,在低浓度范围内,随着离子强度的增大而升高。Henry模型适用于描述苯酚在供试土样的吸附,供试土样对苯酚的吸附属于自发的物理吸附过程,吸附呈现焓减、熵增特征。更多还原

【Abstract】 Modified bentonites have been used as an adsorbent for environmental remediation. An experiment was designed to examine the adsorption of phenol on bentonites modified by a mixture of amphoteric modifier, dodecyl dimethyl betaine(BS-12), and cationic modifier,hexadecyltrimethylammonium bromide(CTMAB)as influenced by modifier ratios, ionic strength, temperature and pH. Adsorption capacity of phenol on bentonites was in order of 100BS+100CT(100%BS-12+100%CTMAB)>100BS+50CT(100%BS-12+50% CTMAB)>50BS+100CT(50%BS-12+100%CTMAB)>100BS+150CT(100%BS-12+150%CTMAB)>50BS+50CT(50%BS-12+50%CTMAB)>100BS+25CT(100%BS-12+25%CTMAB)>50BS+150CT(50%BS-12+150%CTMAB)>50BS+25CT(50%BS-12+25%CTMAB)>100BS(100%BS-12)>50BS(50%BS-12)>CK(unmodified soil). This revealed that the adsorption of phenol on modified bentonites increased with increasing CTMAB ratios at 0~100% of CEC, while decreased slightly at CTMAB ratios greater than 100% of CEC. The phenol adsorption was reduced by elevated temperature and pH, but increased with ionic strength at low concentration ranges. Henry equation could best describe the phenol isotherms. The adsorption of phenol on amphoteric-cationic modified bentonites is a spontaneous physical adsorption process characteristized by both enthalpy decreases and entropy increases.更多还原