螯合凝胶的制备及其从水溶液除镉性能研究

Study on Preparation of Chelating Gel and Its Performance of Removing Cadmium from Aqueous Solution

摘要:

镉污染是当今重金属污染中面积最广、危害最大的重金属元素之一，对水体镉污染处理方法的研究也一直是热点研究课题。本文研究了依据Mannich反应，以聚丙烯酰胺凝胶(PAM-Gel)为骨架，接枝三乙烯四胺，得到了螯合接枝凝胶。当PAM-Gel:甲醛:三乙烯四胺物料配比为1:2.4:2.5，pH = 11，反应时间为2 h + 2 h，反应温度为50℃时，得到最佳接枝效果。并研究了该凝胶及从水溶液中去除Cd²⁺的最佳条件。结果表明，当镉含量为10 mg/L时，在pH = 4~8，固液比(w/v)为1:166，振荡时间为40 min时，去除率可达到98%以上。静态法测得凝胶对镉的饱和吸附量为42.3729 mg/g，除镉效果明显。获得了一种新的、低成本的从镉废水中去除镉的材料和方法。

Abstract: Cadmium pollution has been one of heavy metal elements which have most widely pollution area in the heavy metal pollution, and researed on treatment of cadmium pollution from aqueous solution also is a hot spot. In this paper, according to the Mannich-Reaction, a kind of chelating polyacrylamide gel (PAM-Gel) grafted with triethylene- tetramine was prepared by using polyacrylamide (PAM) as skeleton. The best grafting degree obtained when molar ratio of PAM-Gel:formaldehyde:TETA is 1:2.4:2.5, pH = 11, reaction time is 2 h + 2 h, reaction temperation is 50˚C. And the optimum of Cd²⁺ removal from aqueous solution was experimented. The results show that for the cadmium concen- tration of 10 mg/L the optimum of cadmium (II) removal is obtained at pH = 4 - 8, oscillating for 40 min and using a solid-liquid ratio (w/v) 1:166. At these conditions, the removal rate can be above 98%. And the saturated adsorption capacity was recorded being 42.3729 mg/g by static method. Thus, a new and low-cost material and method to remove cadmium from aqueous solution is obtained.