ZSM-5 Zeolite Nanosheet-Based Membranes on Porous Polyvinylidene Fluoride for High-Flux Desalination

A submicrometer-thick molecular sieve zeolite nanosheet laminated (ZNL) membrane has been synthesized on macroporous polyvinylidene fluoride (PVDF) substrate via the simplistic vacuum filtration-coating method. The membrane has been demonstrated with extraordinary water flux (similar to 11 kg/m(2).h) and salt rejection (similar to 99.9%) in pervaporation (PV) desalination of a multicomponent brine with 22 wt % of total dissolved salts (TDS) including Li+, Na+, K+, Mg2+, Cl-, and SO42-, etc. The desalination of high-salinity brines is critical to treatment and beneficial use of many industrial produced waters. The large aspect ratios (>100) and preferable b-orientation of the densely layered nanosheets make the solution dewatering rate surpass the ion diffusion rates in the nanoscale internanosheet spaces. This unique transport behavior effectively prevents the dissolved salts from migrating through the ZNL layer and stabilizes the water flux and ion rejection rates. The supported multilayered ZNL membrane, which is interlocked by the substrate-type PVDF binder, exhibits structure and performance stability in PV desalination of high-TDS brines.

Automated summary

A submicrometer-thick molecular sieve zeolite nanosheet laminated (ZNL) membrane has been synthesized on a macroporous polyvinylidene fluoride (PVDF) substrate, demonstrating extraordinary water flux and salt rejection in pervaporation desalination of high-salinity brines containing multiple ions. The densely layered nanosheets with large aspect ratios effectively prevent salt migration, resulting in stable performance in high-TDS brine desalination.