以多次原位水热法合成Ge-ZSM-5分子筛膜及其渗透蒸发性能的研究

摘要

On α-A12 O3 substrates,Ge-ZSM-5 membranes were prepared by multiple in situ crystallization method,and the synthesized membranes were used to separated acetic acid from acetic acid solution by pervaporation. The effects of crystallization time and Ge content in the synthesis mixture on the microstruc-ture and pervaporation performance were investigated. In the synthesis mixture with the molar composition of Ge(C2H5O)4∶SiO2∶TPAOH∶H2O =1∶x∶5. 13∶2 246(x =100,25),the membranes by three time crystallization were continuous and dense. When the membranes were used to separate acetic acid solution by pervaporation,the separation factor increased with the increasing of the temperature,while the flux kept constant. The membrane synthesized in the mixture with Si/Ge=25 and the crystallization of first time 24 h,second 18 h and third 12 h,exhibited the best separation performance with the separation factor of 2. 0 and the flux of 0. 8 kg/(m2·h),at 90 ℃,in separation 5% acetic acid solution.%在α-A12 O3载体上,通过多次原位水热合成制备Ge-ZSM-5分子筛膜,并利用渗透蒸发膜分离技术从乙酸/水溶液中分离乙酸。考察了晶化时间和合成液中 Ge含量对膜的结构和性能的影响。在溶胶物质的量组成为Ge(C2H5O)4∶SiO2∶TPAOH∶H2O=1∶x∶5.13∶2246(x=100,25)的合成液中,经过3次水热晶化,所得的膜均为致密膜,膜的分离因子随温度的升高而增加,渗透通量受温度影响不大。在Si/Ge=25的溶胶中,一次原位水热晶化24 h,二次原位水热晶化18 h,三次原位水热12 h合成的膜质量最优,对5%乙酸水溶液,在90℃时,分离因子可达2.0,此时渗透通量为0.8 kg/(m2·h)。