PVA/PES复合膜的制备及其渗透汽化脱盐性能研究

Preparation of PVA/PES pervaporation composite membranes for desalination

以聚醚砜(PES)超滤膜为基底,戊二醛为表面粘合剂,将由4-磺基邻苯二甲酸(SPTA)交联得到的聚乙烯醇(PVA)涂覆到PES表面得到了磺化PVA/PES复合膜。利用傅里叶变换红外光谱仪(FT-IR)、热失重分析仪(TGA)表征不同交联剂含量PVA膜的交联程度以及热稳定性,通过电子扫描显微镜(SEM)对复合膜的形貌进行表征。研究了交联剂含量对PVA/PES复合膜渗透汽化脱盐性能的影响,结果表明:随着交联剂含量的增加,致密膜的溶胀度先减小后增加,而水接触角先增加后减小;当交联度为15%时,复合膜的渗透汽化性能最优;性能最优复合膜的纯水通量在70℃时达到24.32 L/(m^2·h),在处理质量分数为3.5%Na Cl水溶液时的水通量达到13.27 L/(m2·h),对盐的截留率高达99.88%。

Sulfonated-poly（ vinyl alcohol）（ PVA）/polyethersulfone（ PES） composite membranes have been fabricated.Specifically,a commercial PES ultrafiltration membrane was first soaked in a glutaraldehyde solution and then coated with a thin layer of PVA which was mixed with sulfophthalic acid（ SPTA） as a crosslinking agent.SPTA not only serves as the crosslinker but also increases the hydrophilicity of the PVA layer.The physiochemical properties of the composite membranes were characterized using FT-IR、TGA、SEM、contact angle and swelling degree measurements.The experimental results showed that as the amount of SPTA increased,the swelling degree of the dense PVA films first decreased and then increased,whilst the water contact angles first increased and then decreased.The best separation performance was obtained when the crosslinking degree was 15%.The membrane exhibited a water flux of 24.32 L /（m^2·h） for pure water,and 13.27 L/（m^2·h） for 3.5% mass fraction of NaCl solution with a salt rejection to Na Cl of 99.88% at 70 ℃.