本研究调查了溶剂后处理对聚酰胺基薄膜复合材料(TFC)膜的影响,专门检查对商业纳滤(NF)和反渗透(RO)膜的影响。Na2SO4截留率和纯水渗透率(PWP)的增加被认为是输出参数。后处理溶液和TFC膜的聚酰胺层之间的汉森溶解度参数(HSP)的差异,用Ra表示,很好地适应于理解在处理时通过膜的水渗透的增强。将Ra值为4的二甲基甲酰胺、Ra值为8.3的乙腈和Ra值为12.7的乙醇的水溶液用作后处理溶液。我们的实验设计,基于响应面法的Box-Behnken设计,包含变量,例如溶液中溶剂的浓度(%v/v),Ra值,和治疗时间(S)。我们的发现表明后处理对TFC膜的影响不受Ra值的支配。值得注意的是,在用乙腈水溶液后处理的同时,80%v/v持续30s,对NF膜有相当大的影响(PWP增强124.5%;Na2SO4截留率降低3.5%),其对RO膜的影响可以忽略不计。几个因素解释了这种差异,包括复合聚合物的HSP模型的局限性,PWP或脱盐率作为溶胀指标的不准确性,不同膜的聚酰胺层的HSP值的变化,以及在支撑膜和聚酰胺层之间的界面中的可能的改变。总之,我们的研究提供了对溶剂和复合膜之间复杂相互作用的见解,表明单独的HSP不是预测聚酰胺基TFC膜的后处理效果的决定性因素。
This study investigates the impact of solvent post-treatment on polyamide-based thin film composite (TFC) membranes, specifically examining the effect on commercial nanofiltration (NF) and reverse osmosis (RO) membranes. Na2SO4 rejection and increase in pure water permeance (PWP) were considered as the output parameters. The disparity in Hansen solubility parameters (HSP) between the post-treatment solution and the polyamide layer of the TFC membrane, denoted by Ra, is well adapted to understand the enhancement in water permeance through the membranes upon treatment. Aqueous solutions of dimethylformamide with a Ra value of 4, acetonitrile with a Ra value of 8.3, and ethanol with a Ra value of 12.7 were used as the post-treatment solutions. Our experimental design, based on the Box-Behnken design of Response Surface Methodology, incorporates variables such as the concentration of the solvent in the solution (% v/v), Ra value, and treatment time (s). Our findings demonstrate that the effect of post-treatment on the TFC membranes is not governed by the Ra value. Notably, while the post-treatment with the aqueous solution of acetonitrile, 80% v/v for 30 s, had considerable effects on NF membranes (124.5% enhancement in PWP; reduction of 3.5% in Na2SO4 rejection), its impact on RO membranes was negligible. Several factors explain this discrepancy, including the limitations of the HSP model for composite polymers, the inaccuracy of the PWP or salt rejection as a swelling indicator, variations in the HSP values of the polyamide layers for different membranes, and possible modifications in the interface between the support membrane and the polyamide layer. In summary, our study provides insights into the complex interactions between solvents and composite membranes, indicating that HSP alone is not a decisive factor in predicting post-treatment effects on polyamide-based TFC membranes.