共存污染物对1,2,4-三氯苯在CTMAB-膨润土上吸附的影响

Influences of co-existing contaminants on the sorption of 1,2,4-trichlorobenzene by CTMAB-bentonite

基于污染物分子本身的特性,实验研究了2种典型的有机污染物———1,4-二氯苯和苯胺对1,2,4-三氯苯在CTMAB-膨润土上吸附的影响.分别用CTMAB-膨润土和预负载了共溶质1,4-二氯苯和苯胺的CTMAB-膨润土对1,2,4-三氯苯进行了等温吸附和动力学实验.结果表明,当固定共溶质初始浓度时,对于以上2种吸附体系,在主溶质浓度较低时,非极性共溶质1,4-二氯苯对1,2,4-三氯苯的吸附有抑制作用,浓度较高时抑制作用逐渐消失.而对于极性共溶质苯胺来说,则是在混合吸附体系中与1,4-二氯苯对1,2,4-三氯苯吸附等温线的影响一致,而对于预负载体系,苯胺则在整个浓度范围内促进1,2,4-三氯苯的吸附.对于改变共溶质初始浓度的混合吸附体系,随着共溶质浓度的逐渐增大,1,4-二氯苯对1,2,4-三氯苯的抑制作用逐渐增强,最终达到稳定;苯胺则是在较低浓度时抑制1,2,4-三氯苯的吸附,随后抑制作用逐渐减小,最后甚至促进了1,2,4-三氯苯的吸附.在竞争吸附动力学实验中,除了预负载苯胺的体系中共溶质不影响1,2,4-三氯苯吸附速率外,对于其它竞争吸附体系,1,2,4-三氯苯的吸附速率都有所下降.

Based on the properties of organic contaminants, two representative compounds, 1,4-dichlorobenzene （DCB） and aniline, were chosen to study the influences of them on 1,2,4-tfichlorobenzene （TCB） sorption by CTMAB-bentonite. Both isotherm and kinetics tests of TCB were conducted using fresh CTMAB-bentonite and CTMAB-bentonite preloaded with the representative compounds. In isotherm tests, the results showed that for both fresh and preloaded CTMAB-bentonites, DCB depressed TCB sorption in the lowest residual solution phase concentration ranges of that target solute investigated, while the suppression effect disappeared in its higher residual solution ranges. Aniline showed the same influence as DCB did on TCB sorption by fresh CTMAB-bentonite in isotherm tests. While, aniline enhanced the sorption capacity of TCB in the whole residual solution ranges of TCB in the preloading system. For fresh CTMAB-bentonite system, when co-contaminants concentrations were changed, aniline and DCB decreased TCB sorption at lower co-contaminants concentrations, whereas at the higher co-contaminants concentrations, the competition effect leveled off for DCB, while the TCB sorption was even enhanced for aniline. In kinetics tests, TCB sorption rate was lowered in all bi-solutes systems, except for CTMAB-bentonite preloaded with aniline, which had no influence on TCB sorption rate at all.