An interlayer strategy to fabricate dense LTA membranes with high water vapor permeability on coarse alloy supports

Employing alloys as membrane support has shown promising industrial potential for application, because alloys exhibit excellent mechanical strength and ductility. However, alloys present intractable shortcomings, like large pore size and inadequate bonding strength, hindering membranes' formation and thereby limiting their widely use. In this work, a novel interlayer strategy was proposed to make a non-uniformly macroporous alloy suitable for zeolite membranes growth. Electroplated interlayers were firstly applied to refine supports' pore size distribution, leading to improved surface homogeneity and average pore size. Layered double hydroxide (LDH) interlayers were then incorporated to regulate the surface hydroxyl content, hydrophilicity, and roughness, thus promoting the Linde type A (LTA) zeolite hetero-nucleation. The obtained LTA/LDH/Ni–P/Alloy membranes presented a H2O/N2 selectivity of 107 and H2O permeability of 10,520 GPU (30 °C, 0.1 MPa, and a relative humidity of 90%), and its H2O permeability was much higher than conventional polymer membrane. Subsequently, the strategy showed its universality in the fabrication of CAU-1 membranes, a type of metal-organic frameworks (MOFs), where the as-synthesized sample displayed a dense morphology. The results of this study open new insights for the usage of cost-effective coarse alloy support and exploration of facile support modification methods.