Ionothermal synthesis of AlPO-34 membranes on macroporous α-Al2O3 supports without using organic template

Abstract

Continuous and compact AlPO-34 molecular sieve membranes were successfully synthesized on the outer surface of macroprous tube α-Al2O3 supports under secondary ionothermal growth with the proposed wetting seed layer. The recyclable ionic liquids (ILs) can both act as solvent media and the structure-directing agent (SDA) of the aiming topological structure of CHA, largely reducing the wastewater. Wetting the seed layer could accelerate the diffusion of ILs to the surface of the support and further increase the binding force between the membrane and the support. Compared with the open system, the closed system led to the achievement of the high-quality AlPO-34 membrane. The H2 permeance of the resulting membrane was 9.74 × 10−8 mol m−2 s−1 Pa−1 and the ideal selectivities of H2/CO2, H2/N2, H2/CH4, H2/C3H8 and H2/i-C4H10 were 7.48, 8.54, 14.67, 39.25 and 65.83, respectively, which were higher than Knudsen diffusion ratios. The obtained membrane was firstly explored for the PV dehydration of isopropyl alcohol (90 wt%)/water mixtures, exhibiting good performance with the separation factor of 147 and high water flux of 1.09 kg m−2 h−1.