以不同比例聚乙二醇(PEG400)为添加剂,通过相转化法和界面聚合过程,成功制备了一系列以聚砜为支撑层的复合正渗透膜.对铸膜液的热力学和动力学分析表明,PEG400添加量越多,相转化速率越快,而相转化速率又影响了正渗透膜支撑层的形貌结构.在不同PEG400质量分数下,支撑层的接触角、孔隙率接近.RO测试结果发现,随着PEG400质量分数增加,复合正渗透膜纯水通量增大,当PEG400质量分数为8%时,正渗透膜的纯水渗透系数(A)值最大[16.2L/(m~2·h·MPa)],膜结构参数(S)值最小(516μm).在FO测试中发现,随着PEG400质量分数的增加,正渗透膜水通量(Jv)先增大后减小,在PEG400质量分数为8%时达到最大值,分别为12.5L/(m~2·h)(AL-FS模式,活性皮层面向料液)和23.8L/(m~2·h)(AL-DS模式,活性皮层面向驱动液).实验表明,8%的PEG400添加量可以最有效地降低支撑层的内浓差极化程度.
Effects of PEG400 concentration in the polysulfone (PSF) dope solution on the substrate morphology and performance of the thin-fi lm composite (TFC) forward osmosis (FO) membranes were investigated. Thermodynamic and kinetic analysis showed that the phase inversion was faster at higher PEG400 concentration. The contact angle and porosity of the PSF substrate at various PEG400 concentrations were similar,but the reverse osmosis (RO) water permeability of the TFC FO membraneincreased as the PEG400 increased. The structure parameter (S) decreased to 516 fj,m at PEG400 massfraction of 8% ? and then increased. The TFC FO membrane showed the highest FO water flux (/v) at 8 % PEG400 in both AL-FS mode [12. 5 L /(m2 h)] and A L -D S mode [23. 8 L /(m2 h)]. This means that the membrane with 8% PEG400 has the lowest internal concentration polarization.