MBfR中疏水性PVDF中空纤维膜表面改性研究

Study on the surface modification of hydrophobic PVDF hollow fiber membrane for MBfR

针对膜生物膜反应器(membrane biofilm reactor,MBfR)研究中疏水微孔膜供氧能力不足、耐污染性较差等问题,以壳聚糖(CS)和均苯三甲酰氯(TMC)为水、油两相单体,采用界面聚合法对自制疏水性聚偏氟乙烯(PVDF)中空纤维膜进行表面改性,采用正交实验法针对水相及油相单体浓度、界面聚合时间及热处理温度等参数对改性PVDF复合膜性能的影响进行系统研究,以氧传质性能为评价指标优化表面改性条件,并选取牛血清白蛋白(BSA)、腐殖酸(HA)、海藻酸钠(SA)为典型有机污染物,考察改性PVDF膜的抗污染能力.结果表明,在最佳表面改性条件TMC质量分数0.35%,CS质量分数0.30%,界面聚合时间15min,热处理温度70℃时,改性PVDF膜与原膜具有相似的机械强度,氧气传质性能提高(氧总转移系数为原膜的1.8倍),亲水性增强(接触角自原膜69.8°降至39.9°),并具有优于原膜的抗污染能力.

In order to overcome some disadvantages of hydrophobic hollow fiber membrane used in the MBfR,such as insufficient oxygen supply capacity and poor antifouling properties,an interfacial polymerization method was used to study the surface modification of self-made hydrophobic polyvinylidene fluoride（PVDF）hollow fiber membrane,Chitosan（Cs）was selected as the aqueous phase monomer,together with trimesoyl chloride（TMC）as oil phase monomer.Orthogonal experimental method was chosen to study the effects of the monomer concentrations in the water and oil phases,interfacialpolymerization time and heat treatment time on the performance of composite membrane systematically.Bovine serum albumin（BSA）,humic acid（HA）and sodium alginate（SA）were used as the typical organic pollutants in order to investigate the anti-pollution ability of the modified membranes.The results showed that the modified membrane had a similar mechanical strength compared with the original membrane,when the mass fraction of TMC and CS was 0.35% and 0.30% respectively,interfacial polymerization time was 15 min and heat treatment temperature was 70 ℃,the oxygen transfer coefficient of the modified membrane was increased（oxygen transfer coefficient was 1.8times than the original membrane）,the surface hydrophilicity of the modified membrane was improved（contact angle decreased from 69.8°of the original membrane to 39.9°）,the anti-fouling ability of the modified membrane was superior to that of the original membrane.