Abstract：Graphitic carbon nitride (GCN) was deposited on alumina hollow fibers by chemical vapor deposition for modification, and ZIF-8 membranes were prepared by in-situ crystallization on the modified supports. The effects of GCN loading temperature, loading amount, precursor type and the amount of sodium formate in the synthesis solution were investigated by X-ray diffraction (XRD), Fourier infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and gas permeation tests. It was found that the suitable temperature for loading GCN onto the alumina support surface was 350 ℃. The higher the temperature, the higher the C/N ratio of GCN on the support surface and the fewer N sites, which was less favorable for the in-situ crystallization of ZIF-8 membranes. At the same loading temperature, the longer the loading time, the higher the coverage (loading amount) of GCN on the alumina support. If the loading amount was too small, a dense membrane cannot be formed. Compared with melamine, using urea as the precursor for chemical vapor deposition, the loading amount decreased significantly under the same loading conditions, and finally a dense membrane could not be formed. The content of sodium formate in the synthesis solution was regulated and controlled, and the optimized formula of the synthesis solution was that the molar ratio of ZnCl2, Hmim (2-methylimidazole), HCOONa and CH3OH was 1:1.5:2.0:250. The obtained ZIF-8 membrane showed the H2 permeance of 6.11×10-7 mol/(Pa·s·m2), and the ideal separation selectivity of H2/N2 was 5.1.
YIN Zhengchi,WU Xiaoke,YANG Yanwei et al. Modification of Alumina Hollow Fibers and In-Situ Synthesis of ZIF-8 Membranes[J]. Chemical Reaction Engineering and Technology, 2023, 39(1): 1-10.
