羧甲基壳聚糖/有机蒙脱土插层复合物对氯酚的吸附

Adsorption of Chlorophenols from Water by Carboxymethyl Chitosan/Organic Montmorillonite Intercalation Composites

本文使用溶液插层法制备羧甲基壳聚糖/有机蒙脱土(CMC/OMMT)复合物。以该复合物为吸附剂,去除水中的4-氯酚(4-CP)、2,4-二氯酚(DCP)及2,4,6-三氯酚(TCP)。考察了pH值对吸附性能的影响,并对其吸附动力学和吸附热力学特征进行了研究。结果表明,CMC/OMMT吸附4-CP、DCP和TCP的最适pH值分别为9、7和5。CMC/OMMT对氯酚类化合物的吸附过程符合拟二级动力学模型,且颗粒内扩散不是吸附速率的唯一控制步骤。CMC/OMMT对氯酚类化合物的吸附平衡最符合非线性Tempkin模型。热力学参数ΔGo、ΔHo及ΔSo表明该吸附过程是以物理吸附为主的放热反应。连续进行5次吸附/再生循环后,CMC/OMMT对4-CP、DCP和TCP的再生率分别为50.50%、46.76%和51.05%,表明该复合物具有较好的重复使用潜力。

Carboxymethyl chitosan/organic montmorillonite （CMC/OMMT） intercalation composites were prepared by polymer solution intercalation and used to remove 4-chlorophenol （4-CP）, 2,4-dichloro- phenol （DCP）, and 2,4,6-trichlorophenol （TCP） from water solution. The effects of pH of the solutionon the adsorption properties, adsorption kinetics and thermodynamics were investigated in detail. In the range of investigation, CMC/OMMT showed highest adsorption capacity at 9, 7 and 5 for 4-CP, DCP and TCP, respectively. The kinetic results showed that the adsorption process fitted by the pseudo-second-order e- quation and the intra-particle diffusion are not the only controlling step. The equilibrium data were best described by the nonlinear Tempkin model. The thermodynamic constants indicated that the adsorption process was feasible, spontaneous and exothermic. Desorption efficiency for 4-CP, DCP, and TCP of the recycled CMC/OMMT remained 50.50%,46.76%and 51.05%, respectively, even over five cycles using 1.5 tool · L-1 NaOH solution as desorption agent.