Spray-dispersion of ultra-small EMT zeolite crystals in thin-film composite membrane for high-permeability nanofiltration process

Abstract Thin-film composite (TFC) membranes show great potential in dye nanofiltration but their performance still required further improvement. In this work, ultra-small EMT zeolite nanocrystals were embedded into the interfacial polymerized polyamide (PA) layer supported on porous nylon via spray dispersion method and used in dye separation. Ultra-small nanosized EMT zeolite crystals with plate-like morphology were synthesized from organic-free precursor suspensions at ambient conditions (30 °C). The plate-like EMT nanocrystals were homogeneously dispersed in the thin-film nanocomposite (TFN) membranes, mitigating the formation of agglomerates during the interfacial polymerization. The TFN membrane prepared with 0.05 w/v % EMT nanocrystals had a water permeance up to 24.37 L m-2 h-1 bar-1, which is nearly 6 times higher than the pristine PA TFC membrane, and maintain the dye rejection (crystal violet) of 99.98 %. A new method for preparation of high quality TFN membranes containing zeolite nanocrystals was developed. The potential use of the TFN membranes with the ultra-small zeolite crystals for dye nanofiltration was demonstrated.