Defects reparation and surface hydrophilic modification of zeolite beta membranes with spherical polyelectrolyte complex nanoparticles via vacuum-wiping deposition technique

The elimination of defects in zeolite membranes is of vital importance to achieve superior separation performances. A facile and versatile strategy was proposed to repair defects in zeolite membranes via vacuum-wiping deposition (VWD) with spherical polyelectrolyte complex (PEC) nanoparticles as the filler, realizing defects reparation and surface hydrophilic modification of zeolite beta membranes simultaneously. The repaired zeolite beta membrane was applied to the separation of methanol/methyl tert-butyl ether (MeOH/MTBE) mixture. By manipulating the deposition of PEC nanoparticles, the repaired zeolite beta membrane exhibited a significantly enhanced separation factor of 489.8 and a high flux of 4.1 kg m(-2) h(-1) with a satisfactory operation stability. Compared with other defect-patching methods of zeolite membranes, VWD technique with spherical PEC nanoparticles could endow the repaired zeolite beta membrane with a remarkable enhancement of separation selectivity and a low loss of permeation flux. Meanwhile, the repaired zeolite beta membrane showed the highest flux and comparable MeOH concentration in permeate in comparison with state-of-the-art membranes. The above results suggest that VWD technique with spherical PEC nanoparticles as the filler exhibits great potential of being developed as a versatile defect-patching strategy to fulfil widespread applications of zeolite membranes.