Abstract: The trimethylammonium anion exchange resin was synthesized by the reaction of trimethylamine with chloracetylated polystyrene instead of chloromethylated polystyrene, and characterized by FT-IR spectrometry. Its microstructure and elements were also analyzed. The static adsorption properties of resin to Cr(VI) were studied. The results indicated that the adsorption increased with the decrease of pH and its highest adsorption capacity was 117 mg/g. The adsorption isotherms approximately fitted the Langmuir or Freundlich equation within the experimental range of concentrations, the correlative coefficients were 0.9988 and 0.9769. Besides, the kinetics of adsorption was mainly controlled by liquid film diffusion, and it fitted well into the Boyd liquid film diffusion model. The thermodynamic equilibrium functions were calculated, DG0<0, DH0=-3648.16 J/mol, DS0=3.98 J/(K×mol), so the anion exchange process was exothermic, spontaneous and entropy increasing. Using 5% NaOH nearly 96% Cr(VI) from the resin can be recovered.

Key words: chloracetylated crosslinked polystyrene, strongly alkaline anion exchange resin, chromiun, adsorption kinetics, adsorption thermodynamics

摘要： 用氯乙酰化聚苯乙烯树脂代替传统的氯甲基化聚苯乙烯树脂，通过与三甲胺反应得到一种新型的三甲铵型强碱性阴离子交换树脂，对该树脂进行了红外光谱表征、元素分析及微孔结构的测定，同时研究了其对Cr(VI)的静态吸附性能. 结果表明，该树脂对Cr(VI)的吸附量随pH的降低而增加，pH=2时最大吸附量达117 mg/g. 吸附过程在实验浓度范围内符合Langmuir和Freundlich方程，相关系数分别为0.9988和0.9769. 动力学研究表明，吸附过程符合Boyd液膜扩散方程，相关系数为0.9927. 热力学函数DG0<0，表明该吸附过程为自发过程；DH0=-3648.16 J/mol，说明该吸附过程为放热过程，同时DS0=3.98 J/(K×mol)，说明吸附过程熵增加占主导作用. 吸附后用5%的NaOH可以将Cr(VI)洗脱，洗脱率达96%以上.

关键词: 氯乙酰化聚苯乙烯, 强碱性离子交换树脂, 铬, 吸附动力学, 吸附热力学