N,N′-双(3-氨丙基)甲胺为单体制备荷正电复合纳滤膜及其脱盐性能

Preparation and desalting performance of positively charged composite nanofiltration membrane with N,N′-bis(3-aminopropyl)methylamine as a monomer

以N,N′-双(3-胺丙基)甲胺为水相单体,均苯三甲酰氯为油相单体,采用界面聚合的方法制备了荷正电复合纳滤膜.通过在水相里添加二乙烯三胺,调节并最终优化该纳滤膜对硫酸镁的截留率.该复合纳滤膜对不同盐溶液的截留率顺序为MgCl_2>MgSO_4>NaCl>Na_2SO_4,其中MgCl_2的截留率可保持在98%左右;MgSO_4的截留率可以通过二乙烯三胺调节从75%上升至98%;一价阳离子盐(Na_2SO_4与NaCl)的截留率较低.通过扫描电子显微镜、衰减全反射红外光谱仪和X射线光电子能谱对典型的纳滤膜的结构进行了表征,表明形成明显的聚酰胺功能层.利用Zeta电位仪表征其表面荷电性质,用接触角测量仪测定膜表面的亲水性.

A positively charged composite nanofiltration membrane was prepared via interracial polymerization with N, NCbis（3-aminopropyl） methylamine as an aqueous phase monomer and trimesoyl chloride as an oil phase monomer. To adjust and finally optimize rejection rate of magnesium sulfate of the nanofiltration membrane, diethylenetriamine was added into the aqueous phase. The rejection rates of different inorganic salt by the composite nanofiltration membrane were MgCl2 〉 MgSO4 〉 NaCl 〉Na2SO4, and the rejection rate of MgCl2 could be maintained at about 98%. The rejection rate of MgSO4 rose from 75% to 98% by adjusting the dosage of diethylenetriamine. The rejection rates of monovalent cation salt such as Na2SO4 and NaCl were small. The structures of some representative nanofiltration membranes were characterized by scanning electron microscopy, attenuated total reflection infrared spectroscopy and X-ray photoelectron spectroscopy, it clearly indicated the formation of a polyamide function layer. Zeta potential was used to characterize the surface charge, meanwhile, hydrophilic property of membrane surface was measured by using a contact angle measuring instrument.