含氟体系下高性能丝光沸石分子筛膜的制备及其性能

采用热涂-浸渍法在大孔α-Al2O3载体上形成薄且致密的晶种层,然后在不添加有机模板剂的含氟条件下二次水热生长法制备了高性能丝光沸石分子筛膜,考察了NaF含量、硅/铝比对丝光沸石分子筛膜形貌和性能的影响.将摩尔组成为6Na2O:1.2Al2O3:30SiO2:780H2O:1.5NaF条件下合成的丝光沸石分子筛膜用于渗透汽化分离91.5%乙醇/水体系,在渗透汽化温度70°C、真空度为400Pa条件下,分离因子和通量分别达到了6872和0.51kg/(m2·h);另外,在分离异丙醇/水、乙酸/水体系时,渗透侧水浓度达到了100%(在色谱检测极限范围内),该分离系数是目前报道的丝光沸石分子筛膜分离的最佳值,并在乙酸浓度为1mol/L的乙醇水溶液中表现出良好的耐酸性.该膜有望作为膜反应器在乙酸乙酯等酯类的生产中大大提高转化率.

Preparation and Performance of Mordenite Zeolite Membrane Using Fluoride Route

High performance mordenite zeolite membranes in fluoride media with organic-free template were prepared on macroporous α-Al2O3 tubes by secondary growth.The seeding method was used hot dip-coating and could form a thin and compact layer.The effects of NaF content and Si/Al ratio on the morphology and pervaporation properties of the as-synthesized membranes were studied.The prepared membranes with a molar composition 6Na2O:1.2Al2O3:30SiO2:780H2O:1.5NaF for pervaporation experiments were carried out at 70℃and vacuum pressure 400 Pa in a 91.5% EtOH/H2O system.The results indicated that the separation factor reached 6872 with flux 0.51 kg/(m2·h).The H2O concentration of permeation side for pervaporation of IPA/H2O,acetic acid/H2O systems can reach 100% (limit in GC detection).The membranes almost keep high selectivity as before after acid test with 1mol/L acetic acid in the H2O/EtOH system.The membranes may have potential applications as membrane reactors in acetic ether production with a higher transformation ratio.