Design and synthesis of a novel polyoxovanadate–zeolite nanocomposite membrane for efficient desalination and heavy metal removal via forward osmosis

A novel thin-film nanocomposite (TFN) membrane was developed for desalination using the forward osmosis (FO) process. The membranes were modified with a polyoxovanadate/zeolite (POV/Z) nanocomposite, composed of (NH 4 ) 4 Na 2 (V 10 O 28 ).10H 2 O and zeolite X, embedded within the polyamide (PA) selective layer. The aim of this study was to design nanocomposites incorporating hydrophilic zeolite X particles with tailored pore structures to enhance desalination efficiency and fouling resistance. The addition of the hydrophilic polyoxometalate (POM), (NH 4 ) 4 Na 2 (V 10 O 28 ).10H 2 O, facilitated the formation of high-quality, defect-free TFN membrane surfaces exhibiting superior water flux and antifouling performance. Among the prepared membranes, TFN-PZ 2 (containing 0.05 wt% POV/Z) achieved the highest desalination performance in the FO process. Compared to conventional thin-film composite (TFC) and zeolite-modified TFN-Z 2 membranes, the TFN-PZ 2 membrane demonstrated a remarkable improvement in water flux and fouling resistance, confirming its potential as an optimal candidate for desalination applications. Furthermore, the TFN-PZ 2 membrane exhibited an impressive Cd 2+ rejection rate of 97.37%, indicating its strong capability for heavy metal removal.