Patching NaA zeolite membrane by adding methylcellulose into the synthesis gel

•MC helped to synthesis compact and thin zeolite membrane;•First discussed the effects of temperature and pressure on membrane performance.

Uniform NaA zeolite membranes, with good permeation and separation performance were successfully synthesized with the assistance of methylcellulose (MC) via microwave heating (MH). The results of X-ray diffraction spectroscopy (XRD) and Scanning electron microscopy (SEM) showed that this strategy could not only reduce the crystal size, but also promote the patching of the defects in the substrate membrane with a slight increase of the membrane thickness. The gas permeation performance demonstrated that the NaA zeolite membranes with MC modification exhibited excellent H2 permeation, and their permselectivities of H2 over other small molecule gases were obviously larger than those corresponding Knudsen diffusion coefficients. The effects of temperature, pressure and binary mixtures of gases on gas permeation behavior were systemically studied. At 298 K and 0.1 MPa, the H2 permeation value of M6 membrane achieved as high as 4.23×10−6 mol m−2 s−1 Pa−1, meanwhile its permselectivity for H2 over CO2, N2 CO, CH4 and C3H8 was 6.31, 5.87, 7.98, 8.46 and 15.67, respectively.

Graphical abstractDownload high-res image (221KB)Download full-size imageThe addition of methylcellulose (MC) in synthesis gel promoted the defects in the substrate membrane be patched up by NaA zeolites and retard the thickening of NaA zeolite membrane.