两步变温晶种法制备丝光沸石膜及其渗透汽化乙酸脱水性能

Preparation of mordenite membrane for pervaporation dehydration of acetic acid by a two-stage varying temperature crystallization hydrothermal method

在水热晶种法基础上采用两步变温晶化以高水硅比(n_(H_(2)O)/n_(SiO_(2)))稀溶液配方为合成液,研制用于渗透汽化(PV)乙酸脱水的丝光沸石膜(MOR膜),考察了变温晶化各段时间、水硅比与氟离子对MOR膜的形貌与分离性能的影响规律。结果表明:高温段晶化时间、水硅比与氟离子对MOR膜的形貌、结晶度和膜层厚度产生显著影响,并影响MOR膜渗透气化分离性能;在高温段(150℃)和低温段(120℃)的晶化时间分别为18和6 h,在水硅比为60且含氟离子体系中所制备的MOR膜的性能最佳,其对质量分数50%的乙酸水溶液的渗透通量和分离系数分别为1.45 kg·m^(-2)·h^(-1)和1 008。

Pervaporation(PV) has been favorably adopted in the industrial dehydration of various organic mixtures.In this work, mordenite membrane(MOR membrane) for PV dehydration of acetic acid was prepared by a two-stage varying temperature crystallization hydrothermal method from dilute synthesis solution with a high molar ratio of water to silica(n_(H_(2)O)/n_(SiO_(2))). The effects of varying temperature crystallization time, n_(H_(2)O)/n_(SiO_(2)), and the amount of fluorine ion on the morphology and separation performance of MOR membrane were investigated. The results showed that the above conditions have significant effects on the morphology, crystallinity, membrane thickness, and PV performance of the MOR membranes. The best performance MOR membrane was prepared at first-stage temperature(150 ℃, 18 h) and second-stage temperature(120 ℃, 6 h) with n_(H_(2)O)/n_(SiO_(2))=60. The permeation flux and separation coefficient of the mass fraction of 50% acetic acid aqueous solution were 1.45 kg·m^(-2)·h^(-1) and 1 008, respectively.