孔径分布对超高交联树脂吸附己内酰胺的影响

Influence of pore size distribution on adsorption of caprolactam by crosslinked resin

以氯甲基苯乙烯树脂(CMPS)为原材料,通过控制Friedel-Crafts反应条件合成了一系列超高交联树脂并用于吸附水溶液中的己内酰胺。结果表明,A-8-12树脂对己内酰胺表现出优异的吸附性能,其对己内酰胺的吸附量是商业树脂H-103的1.4倍,且吸附量不受pH变化和干扰离子的影响,在经过5次吸附-脱附后,A-8-12树脂仍有良好的吸附性能。吸附动力学分析结果表明,A-8-12树脂和H-103树脂对己内酰胺的吸附均符合准一级动力学模型,A-8-12树脂颗粒内扩散速率是H-103树脂的1.8倍,这归因于其在2~4 nm的孔径范围内具有较大的比表面积和孔体积。吸附等温线、热力学表征结果表明,A-8-12对己内酰胺的吸附符合Freundlich模型,吸附过程是一个自发的物理放热反应。

A series of hyper-crosslinked resin is synthesized from chloromethyl polystyrene(CMPS)resin through controlling the conditions of Friedel-Crafts reaction,and used to adsorb caprolactam in aqueous solution.Results show that A-8-12 resin exhibits exceptional adsorption performance for caprolactam,its adsorption capacity to caprolactam is 1.4 times that of the widely used H-103 resin.The adsorption capacity is not affected by changes in pH or interfering ions.Even after undergoing 5 cycles of adsorption-desorption,A-8-12 resin remains consistent and excellent adsorption performance.It is indicated from adsorption kinetics analysis that the adsorption of caprolactam by A-8-12 resin and H-103 resin both conforms to the pseudo-first-order kinetic model.The intra-particle diffusion rate of A-8-12 resin is 1.8 times that of H-103 resin,which is attributed to its large specific surface area and pore volume within the pore size range of 2-4 nm.It is shown from adsorption isotherm and thermodynamic characterization that the static adsorption of caprolactam by A-8-12 resin conforms to Freundlich model,indicating a spontaneous physical exothermic reaction.