基于低温等离子体基膜改性的高脱盐性反渗透复合膜的制备

Preparation of high desalting reverse osmosis composite membrane based on low temperature plasma modification of support membrane

为了改善反渗透聚砜(PS)基膜的亲水性,增加基膜与皮层间的结合力,提高反渗透复合膜脱盐性,本研究采用丙烯酸(AA)为接枝单体,对PS膜进行低温等离子体引发接枝聚合改性,将改性后的基膜通过界面聚合制备反渗透复合膜.通过均匀试验方法研究改性条件并利用SPSS软件对反渗透复合膜截留率进行回归分析,建立显著性回归方程.根据截留率高低对回归方程进行寻优处理,得出最优改性参数并进行试验验证.得到优化改性参数为:放电电流4 A,放电时间7 min,接枝液体积分数70%,接枝时间180 min,验证结果表明,基膜改性后制备的反渗透复合膜截留率达到95.83%,较未改性基膜制备的复合膜截留率提高了36.24%.

In this work,polysulfone(PS)membrane was modified by low temperature plasma surface initiation of graft polymerization to prepare reverse osmosis composite membrane by interfacial polymerization.Acrylic acid(AA)was used as the grafting liquid to improve the hydrophilicity of the PS membrane,so as to increase the adhesion between the support membrane and the skin layer and improve the desalting property of the reverse osmosis composite membrane.The uniform design was used to study the modification conditions.The SPSS software was used to analyze the salt rejection of the reverse osmosis composite membrane and establish a significant regression equation.According to the magnitude of the salt rejection,the regression equation was optimized,and the optimal mixture ratio of the modification was obtained and tested.The equation was optimized and the optimization parameters were as follows:the discharge current was 4 A,the discharge time was 7 min,the concentration of the grafting solution was 70%,and the grafting time was 180 min.The final verification test showed that the rejection rate of the reverse osmosis composite membrane prepared after the modification of the support membrane reached 95.83%,which was 36.24%higher than that of the unmodified membrane.