Development of a water-selective zeolite composite membrane by a new pore-plugging technique

A new membrane preparation method based on mechanical pore-plugging of the supports with appropriate sized seeds followed by secondary zeolite growth by hydrothermal synthesis was optimized for the production of hydroxy-sodalite (hydroxy-SOD) membranes. A series of parameters were investigated during membrane production, including seed loading, presence of Teflon on the coarse side of the support, top-layer orientation in the autoclave, autoclave agitation, synthesis time and temperature, membrane post-synthesis treatment, and nature and pore size of the support (TiO2/SS, SS, Al2O3 and ZrO2/TiO2). Zeolite seeds and synthesized membranes were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and gas permeation. The gas permselective separation ability of these membranes was demonstrated from H2, N2, CO2 and H2O permeation tests at temperature up to 250 °C. The membranes fabricated with the optimized parameters achieved H2O/N2, H2O/CO2, and H2O/H2 ideal gas permselectivities of 5.1, 4.8 and 1.4 at 250 °C, while providing a high water permeance (ΠH2O of 1.26 × 10−7 mol Pa−1 m−2 s−1) at the same temperature. [Display omitted] •Synthesis of new hydrophilic pore-plugged SOD zeolite membranes for in-situ water removal.•Development of new reverse cross flow filtration seeding technique on asymmetric support.•Optimization of operational parameters and evaluation of gas permeation up to 250 °C.