超支化聚酰胺纳滤膜的制备及其吸附性能研究∗

摘要

以端氨基超支化聚酰胺为水相单体,对苯二甲酰氯为油相单体,采用界面聚合法通过控制单体浓度制备出具有荷负电特征的超支化聚酰胺纳滤膜.该膜对1000 mg/L NaCl、Na2 SO4、MgCl2、MgSO4的脱除顺序为Na2 SO4＞MgSO4＞MgCl2＞NaCl,对硫酸钠的脱除率为73．5％.在明确该膜分离特征的基础上,着重考察了操作压力、Mg 2＋浓度等因素对纳滤膜吸附镁离子性能的影响.结果表明,增大操作压力和进料液浓度均有助于缩短膜吸附达到平衡的时间,且吸附量略有增大；动力学模拟结果表明该膜的吸附动力学比较符合准一级动力学模型；并且理论分析初步表明镁离子主要吸附在膜表面及孔内部.%A negatively charged nanofiltration membrane was prepared by interfacial polymerization of amino-ter-minated hyperbranched polyamide (monomer in aqueous phase)with 1 ,4-benzenedicarbonyl dichloride (mono-mer in oil phase)at certain concentration.The salts rejection order of this membrane for 1 000 mg/L NaCl, Na2SO4,MgCl2 and MgSO4 was MgCl2> MgSO4> Na2SO4> NaCl and the rejection coefficient of Na2SO4was 73.5%.The effects of the operation pressure and the concentration of Mg2+ on the Mg2+ adsorption of the mem-brane were investigated.The results indicated that adsorption equilibrium time could be reduced by increasing the operation pressure or increasing the CMg2+ in feeding solution which can also enhance the adsorption capacity of the membrane for Mg2+.Pseudo-first-order kinetics model provided better fit to the adsorption data,howev-er,which needs some modification.The data analysis also indicted that most Mg2+ deposited on the surface of the membrane and existed in the membrane pore.