Ionothermal synthesis of LTA-type aluminophosphate molecular sieve membranes with gas separation performance

• Published in: Microporous and mesoporous materials 2016-07, Vol.228, p.45-53
• Main Authors: Li, Xiaolei, Li, Keda, Tao, Shuo, Ma, Huaijun, Xu, Renshun, Wang, Bingchun, Wang, Ping, Tian, Zhijian
• Format: Article
• Language: English
• Subjects: Aluminophosphate; Gas separation; Ionothermal synthesis; LTA membrane
• ISSN: 1387-1811; 1873-3093
• DOI: 10.1016/j.micromeso.2016.03.026

LTA-type aluminophosphate molecular sieve membranes with gas separation performance were ionothermally synthesized by using δ-alumina substrates as both the supports and the aluminum sources. The effects of the synthesis parameters, such as the concentrations of H3PO4, TAMOH, and HF, and the detailed formation process of the membrane were thoroughly investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). Furthermore, the subsequent membrane syntheses by using recycled mother liquids were also studied. The results demonstrated that continuous and compact LTA molecular sieve membranes can be prepared over a relatively wide range of the synthesis composition. The membranes prepared with fresh and recycled mother liquids exhibit the same crystallinity, morphology and the gas separation performance. Typically, for single-component gases at 293 K, the ideal separation factors of H2/CO2, H2/O2, H2/N2, and H2/CH4, are 10.9, 8.1, 6.8, and 4.8, respectively, which suggests the good gas separation performance of the membranes. [Display omitted] •LTA-type aluminophosphate membranes were ionothermally synthesized.•The δ-alumina substrate played a dual role as both the substrate and the Al source.•Continuous LTA membranes can be prepared over a wide synthesis range.•The mother liquids can be recycled and reused.•The LTA membranes displayed molecular sieving effect in gas separation.