壳聚糖交联β-环糊精对水中铬酸盐的吸附研究

Research on the adsorption of chromate on CTS-CD in aqueous solution

以戊二醛为交联剂,通过在壳聚糖分子链上引入β-环糊精,制备出壳聚糖交联β-环糊精高聚物(CTS-CD),并研究了CTS-CD对水中铬酸盐的吸附性能.实验结果表明,在pH=5、318 K的条件下,CTS-CD对铬酸盐的饱和吸附容量为105 mg·g-1;吸附过程符合Lagergren二级动力学模型,吸附速率常数随温度的升高而增大,其表观活化能为32.2 kJ·mol-1;吸附等温模型符合Langmuir等温式,为单分子层吸附;吸附铬酸盐的ΔH、ΔS、ΔG分别为40.6 kJ·mol-1、158 J·mol-1·K-1、-9.54 kJ·mol-1,表明CTS-CD对水中铬酸盐的吸附主要为化学吸附.

Chitosan-β-cyclodextrin polymer( CTS-CD),a kind of natural polymer,was synthesized by immobi-lizing β-cyclodextrin( β-CD) onto the molecular structure of chitosan by the cross-linking function of glutar-aldehyde. The adsorption properties of chromate on CTS-CD in drinking water were investigated. The experiment results showed that at 318 K,pH of 5,the saturated adsorption capacity of chromate on CTS-CD was 105 mg·g-1.Furthermore,the adsorption process fitted pseudo-second-order kinetics model and the adsorption rate constant increased with the temperature. The apparent activation energy of the adsorption was 32. 2 kJ·mol-1. The adsorption pattern fitted Langmuir isotherms,which was monomolecular layer adsorption. ΔH,ΔS and ΔG of the adsorption were 40.6 kJ·mol-1,158 J·mol-1·K-1and-9.54 kJ·mol-1,respectively.The experimental results showed that the adsorption was mainly chemical adsorption.