交联壳聚糖凝胶溶胀性能及Ni(Ⅱ)吸附效果研究

Study on the Swelling Property and Adsorption of Ni(Ⅱ)on Cross-linked Chitosan Gel

以壳聚糖为原料,戊二醛为交联剂制备交联壳聚糖凝胶,并对凝胶的溶胀性能及Ni^(2+)吸附效果进行研究。实验结果表明,交联剂用量越大,交联密度越高,但是凝胶网络弹性降低,溶胀性变差;弱酸至中性条件有利于凝胶的溶胀,交联改性能降低壳聚糖的溶胀热敏温度,降低后期吸附Ni^(2+)的能耗。用1%的戊二醛交联壳聚糖处理20、40 mg/L Ni^(2+)电镀废水,投加60 mg交联改性壳聚糖,在30℃、p H=7条件下吸附3 h,吸附率分别达96.9%和92.4%,吸附过程可用一级动力学模型进行模拟。废水经过二次吸附后出水水质均能达到0.01 mg/L Ni^(2+)的《污水综合排放标准》(GB3838)标准,交联改性壳聚糖的重复使用性好,多次循环使用后依然具有很好的吸附效果。

Cross-linked chitosan gel was prepared using chitosan as raw material and glutaraldehyde as crosslinking agent, and the swelling property of the gel and the adsorption effect of Ni2. were studied. The results showed that, with the increase of crosslinking agent amount, the crosslinking density increased, the elasticity of the gel network decreased, and the swelling property became worse. The results also revealed that weak acid to neutral conditions were beneficial to gel swelling, crosslinking modification could reduce the swelling thermally sensitive temperature of chitosan and energy consumption in the later absorption of Ni^2＋. Removal rate of Ni^2＋ were about 96.9% and 92.4% when using 1% glutaraldehyde cross-linked chitosan to treat the electroplating wastewater with the Ni^2＋ concentration of 20 mg/L and 40 mg/L, and the added amount of crosslinked modified chitosan, temperature, pH value and absorption time were 60 mg, 30 ℃ ,7 and 3 h, respectively. The adsorption kinetics showed that the isothermal adsorption process can be simulated by the first order kinetics model. The effluent quality can reach 0.01 mg/L through secondary adsorption,which can reach the standard of integrated wastewater discharge （GB3838）. The reusability of crosslinked modified chitosan is good, and it still has a good adsorption effect after repeated cycles.