聚丙烯酸-聚乙烯醇共混膜分离甲醇-碳酸二甲酯共沸体系

采用涂敷法制备了聚丙烯酸(PAA)-聚乙烯醇(PVA)共混膜，将其用于渗透汽化法分离甲醇(MeOH)-碳酸二甲酯(DMC)共沸物，考察了共混比例、热处理条件对甲醇分离性能的影响. 渗透汽化实验结果表明，随着热处理时间延长或热处理温度提高，分离因子先升高后降低，而渗透通量则逐渐减小；随着共混膜中PAA/PVA比例增加，分离因子先升高后降低，而渗透通量先减小后增大；当PAA/PVA质量比为7/3、热处理时间为60 min、热处理温度为150℃时，选择性最佳，在料液组成为70%(w) MeOH-30%(w) DMC及70℃的操作温度下，甲醇的分离因子为9.5(透过侧MeOH浓度为95.5%, w)，渗透通量为360 g/(m2×h).

Pervaporation Performance ofPoly(acrylic acid)-Poly(vinyl alcohol) Blend Membrane for Separation of Methanol-Dimethyl Carbonate Azeotrope

Poly(acrylic acid)-poly(vinyl alcohol) (PAA-PVA) blend membrane was prepared by coating method for separating methanol -dimethyl carbonate (MeOH-DMC) azeotrope by pervaporation, and the influences of mass ratio of PAA to PVA, and heat treatment conditions on pervaporation performance of the membrane were investigated. The experimented results of pervaporation showed that as the heat treatment time and temperature increased, the separation factor of MeOH increased first and then decreased, but the flux decreased gradually, as PAA/PVA ratio increased, the separation factor increased first and then decreased, but the flux decreased first and then increased. For separating MeOH-DMC azeotrope of 70%(w) MeOH at 70℃, the PAA-PVA blend membrane with a mass ratio of PAA to PVA at 7/3 and heated at 150℃ for 60 min had the highest selectivity, the separation factor of MeOH was 9.5 (MeOH in the permeate side of 95.5%, w), the flux 360 g/(m2×h).