HDTMA改性沸石对水中铬酸盐的吸附

Adsorption of Chromate Onto HDTMA-Modified Zeolite in Water

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 3 0℃ ,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

The zeolite (Ca-type) was modified by hexadecyltrimethylammonium (HDTMA). The results show that the optimum modifying temperature is 30°C, the optimum HDTMA's concentration is 1.5%. In addition, the effect of pH, HDTMA-zeolite amount and shaking time on the adsorption were investigated. The adsorption isotherm and the mechanism for the adsorption were investigated respectively. The results indicated that pH has no influences on the adsorption, and the adsorption efficiency increases with the extension of shaking time and the addition of HDTMA-zeolite amount. The adsorption isotherm appears in double S shape. The mechanism for the adsorption is: ion exchange and the formation of precipitation of HDTMA-Cr (VI) complex salt perform the adsorption.