PDA/PIP二胺混合聚酰胺复合纳滤膜制备及性能表征

Preparation and characterization of PDA/PIP mixtures polyamide composite nanofiltration membranes

以聚砜超滤膜为基膜,通过间苯二胺(PDA)、哌嗪(PIP)与均苯三甲酰氯(TMC)界面聚合制备复合纳滤膜.研究了不同PDA/PIP比例下复合纳滤膜的分离性能、接触角、功能层化学结构及表面形貌特征,分析探讨了界面聚合条件对膜性能的影响.结果表明:随着PDA/PIP混合体中PDA含量的减小,功能层聚集态逐渐从部分结晶向无定形状态转变,导致膜面粗糙度及接触角减小,膜通量上升而截留率下降;PDA/PIP质量比为25/75时膜性能最佳,最佳聚合条件为:PDA、PIP和TMC浓度分别为0.5 wt%、1.5 wt%、和0.1 wt%,反应时间60 s,热处理温度及时间为80℃和3 min.最佳条件下所得纳滤膜对四种无机盐的截留效率为Mg SO4>Na2SO4>Mg Cl2>Na Cl;相应通量大小为:Na Cl>Mg Cl2>Na2SO4>Mg SO4.

Polyamide thin-film composite NF membrane was prepared by interfacial polymerization of 1,3-phenylenediamine（PDA）, piperazine（PIP） and trimesoyl chloride（TMC） on polysulfone（PSF） ultrafiltration membrane. The separation properties, contact angle, structure of the active layer polymer and the surface morphology of the composite membranes which prepared with different mass ratio of PDA/PIP, were systematically investigated. And the effect of interfacial polymerization conditions on the performance of composite membrane were carried out. The results showed that the shape of active layer has changed gradually from partially crystalline to amorphous state with the decrease of PDA in the PDA/PIP mixtures, which resulted in decreasing the roughness and contact angle of membrane surface. Moreover, the decrease of PDA led to the improvement of the pure water flux, accompanied by a decreased salt rejection of composite membrane. The optimum PDA/PIP mass ratio is 25/75 when the optimum polymerization conditions are as follows： the concentration of PDA and PIP is 0.5 wt % and 1.5 wt %, respectively, while the concentration of TMC is 0.1 wt %; reaction time is 60 s, curing temperature and curing time is 80 ℃ and 3 min, respectively. The rejection order of composite membrane prepared in the optimized condition to four salt solution was Mg SO4〉Na2SO4〉Mg Cl2〉Na Cl, while the flux order was Na Cl〉Mg Cl2〉Na2SO4〉Mg SO4.