有机铵盐改性蒙脱土、海泡石吸附去除水中苯、甲苯和乙苯等污染物的研究

本文用两种有机铵——十六烷基三甲基溴化铵(CTMAB)和十六烷基吡啶(CPB)与两种粘土——蒙脱土和海泡石进行反应,使有机铵阳离子取代粘土中阳离子,形成有机改性粘土。用此改性粘土作为吸附剂去除水中苯、甲苯和乙苯三种污染物,静态吸附实验的平衡时间为2h,吸附容量约为5～10mg/g(平衡浓度以10ppm计),远远大于粘土原土的吸附容量。获得这样效果的主要原因是有机铵的脂肪链端改变了粘土的亲水性能,使得粘土表面憎水。同时X衍射实验数据还显示了粘土层间间距因有机铵的嵌入而大幅度撑开,被吸附的有机物分子进入粘土层间又使得其层间间距进一步增大。这表明改性粘土吸附水中有机污染物的机理包括两个方面:一是改性粘土利用有机铵的非极性脂肪链端萃取有机物分子;二是粘土层间对有机物的进一步吸附。

Adsorption of Benzene,Toluene and Ethylbenzene in Water by Aliphatic Amines,Modified Montmorillonite and Meerschaum

Organo-clays may be used to adsorb organic contaminants in water.Montmorillonite and meerschaum are treated by Cetyltrimethylammonium bromide (CTMAB) and Cetylpyridinium bromide (CPB) and used as adsorbents to remove benzene, toluene and ethylbenzene in water. The adsorption capacity is studied by batch experiments. It is shown that equilibrium time of adsorption is about 2 hours and capacity about 10 mg/g. The mechanism of the raising of adsorption capacity is studied by X- ray differential (XRD). Results demonstrate that the interlamellar space of the clay is enlarged by the aliphatic amines, and further extented by the organic contaminants. It seems to be the fact that the enlargement of interlamellar space and extraction of the aliphatic amine molecules raise the adsorption capacity on benzene, toluene and ethylbenzene.