HDTMA改性沸石对水中铬酸盐的吸附

摘要

The zeolite(Ca-type) was modified by hexadecyltrimethylammonium(HDTMA) .The results show that the optimum modifying temperature is 30 ℃, the optimum H D TMA's concentration is 1.5%.In addition, the effect of pH，HDTMA-zeolite amoun t and shaking time on the adsorption were investigated. The adsorption isotherm and the mechanism for the adsorption were investigated respectively. The results indicate d that pH has no influences on the adsorption, and the adsorption efficiency inc r eases with the extension of shaking time and the addition of HDTMA-zeolite amo u nt. The adsorption isotherm appears in double S shape. The mechanism for the ads orpt ion is: ion exchange and the formation of precipitation of HDTMA-Cr (VI) complex salt perform the adsorption.%采用十六烷基三甲基溴化铵(HDTMA)对Ca型沸石进行了改性。结果表明，最适合的改性温度为30℃,改性剂HDTMA溶液质量分数为1.5%。又考察了pH、改性沸石用量及振荡时间对HDTMA-沸石吸附去除水中铬酸盐效果的影响。测定了吸附等温线并探讨了吸附机理。结果表明，pH对吸附没有显著影响，随着改性沸石用量的增加、振荡时间的延长，铬酸盐的去除率升高。改性沸石对水中铬酸根离子的等温吸附曲线呈双“S”型。吸附机理为：一是通过离子交换而吸附；二是通过在沸石表面形成HDTMA-阴离子络合物沉淀而吸附。