溴化十四烷基吡啶对膨润土吸附萘的增强效应及机理

研究了溴化十四烷基吡啶(MPB)对膨润土吸附萘的增强效应、机理及影响因素,试图为有机膨润土在污染环境修复中的应用提供新的技术路线.结果表明,MPB能显著增强膨润土对萘的吸附作用,增强效应及机理与MPB浓度有关.当MPB平衡浓度(X)在0～1/10CMC之间,MPB几乎全部被膨润土吸附,对萘产生分配作用,其表观分配系数(K_d^*)随MPB加入量的增大而急剧增大;当X在1/10CMC～ICMC之间,由于表面活性剂的吸附作用及其单体的增溶作用,K_d^*值则缓慢减小;当X大于1CMC,由于增加的表面活性剂主要起胶束增溶作用,K_d^*值则急剧减小.引入了标化表观分配系数(K_oc^*)探讨萘在表面活性剂-膨润土-水体系中的吸附机理,其倒数(1/K_oc^*)与X呈线性关系;由线性斜率和截距可求得K_oc、K_mn、K_mc参数.

Enhanced Sorption of Naphthalene into Bentonites in Water Containing Myristylpyridinium Bromide and Its Mechanism

The influence of myristylpyridinium bromide (MPB) on sorption behavior of naphthalene into two bentonites in aqueous solution and its mechanism were investigated. The apparent sorption coefficients (Kd*) of naphthalene on two bentonites with surfactant was dependent on MPB equilibrium concentration (X). When X was less than 1/10CMC, the Kd* value increased rapidly with increasing MPB primary concentration (X0) that was mainly contributed to increasing the organic carbon contents (foc) of bentonites for partitioning naphthalene. The Kd* value decreased slowly with increasing X0 when X was intermediate 1/10CMC and 1 CMC, because the adding MPB increased foc for sorption naphthalene was less than MPB monomer for enhancement solubility of naphthalene. Then The Kd* value decreased sharply with increasing X0 when X was larger than 1 CMC, which resulted from that the addition of MPB only increased micelle concentration for enhancement solubility of naphthalene. The mechanism was explained by apparent partition coefficient normalized by foc(i. e. Koc*) for the first time. The relationship of 1/Koc* and X was linear. The value of Koc, Kmn and Kmc can be calculated from the intercept and slope of the linear, which will provide theoretical gist for organobentonite applied on organic contaminant remediation.