壳聚糖/聚乙烯醇过滤膜的制备及其性能表征

以壳聚糖(CS)和聚乙烯醇(PVA)为膜原料,将其溶解于冰醋酸(HAc)、甘油和去离子水的混合液中,形成CS/PVA铸膜液,随后通过刮涂成膜的方式制备CS/PVA复合膜。实验结果表明:在膜的相分离过程中,CS/PVA在凝固浴中浸泡40 min,此时膜具有较为完整的表面结构及疏松的内部孔隙结构。其纯水通量为(90.56±3.92)L/(m^2·h),对牛血清蛋白的截留率可达(93.33±2.83)%。进一步利用此条件下的复合膜对分散黄、分散黑以及分散蓝3种染料进行过滤吸附性能测试,CS/PVA复合膜完整致密的表层结构对染料起到了有效的物理阻隔作用。除此之外,复合膜分子结构中的羟基基团能够与目标染料的氨基基团发生分子内氢键作用,而进一步提高过滤膜对染料的吸附能力。CS/PVA复合膜在130 min时对分散黄、分散黑以及分散蓝染料的过滤吸附逐渐趋于平衡(3种染料初始浓度均为0.1 g/L,过滤操作压力为0.15 MPa),其最终的平衡过滤吸附量分别为(294.42±1.34),(257.77±0.28),(210.74±1.06)mg/g。随后进行染料移除率实验,在NaOH溶液的作用下,CS/PVA复合膜的染料移除率可以达到96%,有利于膜的回收再利用。

Preparation and property characterization ofchitosan/polyvinyl alcohol filtration film

CS(chitosan)/PVA(polyvinyl alcohol)film was prepared by scraping,and then soaking it in a coagulation bath.The morphology and structure of CS/PVA films at different solidification time were investigated.Bovine serum albumin(BSA)and three different disperse dyes(disperse yellow,disperse black and disperse blue)were used as targets to investigate the filtration and adsorption performance of the CS/PVA film.The results show that the CS/PVA film can obtain a relatively complete surface structure and porous internal structure after soaking in coagulation bath for 40 min during the phase separation of film.The pure water flux of CS/PVA composite film is(90.56±3.92)L/(m^2·h)and the rejection of CS/PVA composite film for BSA is(93.33±2.83)%.The filtration and adsorption properties of CS/PVA composite film for disperse yellow,disperse black and disperse blue dyes were further investigated.The good filtration and adsorption capacity for disperse dyes is due to the complete and compact surface structure of CS/PVA composite film which provide an effective physical barrier to dyes.In addition,the hydroxyl group in the molecular structure of the composite membrane can interact with the amino group of the target dye to form intramolecular hydrogen bonds,which further improve the dye adsorption capacity of the filter membrane.At 130 min,the filtration and adsorption of disperse yellow,disperse black and disperse blue dyes tend to be balanced gradually(The initial concentration of dyes is 0.1 g/L and the operating pressure of filtration is 0.15 MPa),and the filtration and adsorption equilibrium are(294.42±1.34),(257.77±0.28),(210.74±1.06)mg/g,respectively.The dye removal rate of CS/PVA composite film can reach above 96%in NaOH solution,which is conducive to the reuse of the film.