Preparation Of Oriented SAPO-34and LTA Molecular Sieve Membranes

Zeolites are inorganic microporous materials with intracrystaline nanoporous channelsand cages (diameter below2nm), which are based on TOn(T=Si, Al, P, etc.) tetrahedral bysharing bridging oxygen atoms. They are important for the applilcations in life andindustries. Firstly, zeolites can be used as adsorbents for purification and separation inindustrial production and environmental protection. Secondly, zeolites are importantcatalysts in petrochemical industry and fine chemical production. Thirdly, zeolites havebeen applied as ion-exchange materials during the production of detergent production andthe disposal of wastewaters. Moreover, functionalization of zeolites and other relatedresearches for more applications heve been scientific hot spots of inorganic synthesischemistry.With high chemical stabilities, excellent thermal stabilities and uniform nanoscalechannel systems, zeolites are promising membrane material. The pore diameters ofpolymer membranes in general are above1nm and have broad distributions. Zeolites havespecial channel systems with pores build up by6-24atoms in the range of0.3-1.24nm,endowing them the ability to separate small molecules like H2, CO2, H2O, ethanol and so on.So they are promising in extensive applications such as gas separation and dehydration oforganic solvents, etc.To realize and enhance the separation ability of zeolite membranes, the preparation ofthin, oriented and defects free membranes has always been people’s sought. Our research isalso dedicated to this objection, and includes two main contents:1. We applied SAPO-34lamellar seeds with thickness below50nm to make seedlayer by vaccum sucktion on alumina support. Then oriented SAPO-34membrane with thickness of3to5μm was prepared by secondary hydrothermal crystallization.Moreover, we altered amount of ingredients and applied different temperature andreaction time for condition optimization. XRD and SEM are the main characterizationmethods.2. We prepared mesoporous LTA zeolite membranes on alumina supports andinvestigated the impact of different amounts of mesopore-generating organic and otheringredients on mesopores and membranes. TEM, SEM, XRD and TG were used tocharacterize samples. Mesoporous LTA membranes with high pore ratios and surfaceroughness were synthesized.