荷正电聚酰胺有机/无机杂化复合纳滤膜的制备和脱盐性能研究

Preparation and desalination performance of positively charged polyamide hybrid composite nanofiltration membranes

以聚砜(PSF)超滤基膜为支撑层,将氨基化多壁碳纳米管(MWCNTs-NH_2)分散在聚乙烯亚胺(PEI)水溶液中得到水相溶液,与间苯二甲酰氯(IPC)和均苯三甲酰氯(TMC)的混合有机相溶液进行界面聚合反应,制备了荷正电氨基化多壁碳纳米管/聚酰胺/聚砜(MWCNTs-NH_2/PA/PSF)有机-无机杂化复合纳滤膜,并确定了最佳的MWCNTs-NH_2质量分数为0.16%。优化制备条件所制得的MWCNTs-NH_2/PA活性层厚度为155 nm,较PA活性层薄。在0.4 MPa、室温下,对1 000 mg/L MgCl_2水溶液的截留率为93.0%,通量为13.9 L/(m^2·h)。该种荷正电的聚酰胺杂化复合纳滤膜对不同无机盐有不同的截留性能,可应用于海水淡化的预处理、硬水软化、饮用水净化等。

The aqueous phase is formed by dispersing aminated multi-walled carbon nanotubes（ MWCNTs-NH_2） in the polyetherimide aqueous solution,and the organic phase is formed by mixing both isophthaloyl dichloride（ IPC） and trimesoyl chloride（ TMC） in hexane. Then the positively charged polyamide（ PA） hybrid composite nanofiltration membranes are fabricated through making the aqueous solution and the organic phases perform interfacial polymerization on the surface of polysulfone（ PSF） ultrafiltration membrane.The optimal concentration of MWCNTs-NH_2 is determined as 0. 16%.The thickness of active layer of MWCNTs-NH_2/PA/PSF composite nanofiltration membrane prepared under optimal conditions is 155 nm,thinner than that of PA active layer.Under 0. 4 MPa and ambient temperature,the rejection rate and the permeate flux of the prepared membranes against 1,000 mg·L^（-1） MgCl_2 aqueous solution are 93. 0% and 13. 9 L/（ m^2·h）,respectively. This positively charged PA hybrid composite nanofiltration membrane shows different rejection performances for different types of inorganic electrolytes,and can be applied to the pretreatment of seawater desalination,water softening,purification of drinking water,etc.