Enhanced water purification performance of composite PVA–ZnO–Al2O3 hollow fiber membrane: A breakthrough approach for high-temperature stability, low-pressure water separation

[Display omitted] •Simple green synthesis of ZnO NP-incorporated ceramic HFMs with PVA coating.•Correlation of ZnO NP & PVA loadings towards HFMs porous media properties.•Optimal membrane evaluation for low-pressure natural seawater desalination.•Outstanding salt rejection in synthetic & untreated natural seawater conditions. This work describes the development of a composite Al2O3 hollow fiber combined with multiple-layer ZnO nanoparticles and PVA polymer as the active side for low-pressure saltwater purification. The composite membrane was evaluated with an active layer-facing salt solution, and slight suction condition was applied to the permeate inside the membrane lumen. Results show that varying nanoparticle layers to tune the porosity of the composite membrane influenced its morphology, porosity, and hydrophilicity. The effect of porosity tuning on the membrane characteristics and desalination performance was investigated. A salt rejection rate of >90 % was recorded for all 5 % PVA–ZnO–Al2O3 hollow fiber membranes with the highest salt rejection of 96.34 % and the water flux of 15.49 kg·m−2·h−1. The membrane was further tested with untreated natural seawater to demonstrate its ability to withstand continuous operation. The membrane has acceptable chemical stability when exposed to untreated natural seawater. The optimal PVA–ZnO–Al2O3 hollow fiber membrane exhibited efficient water phase change transfer and high salt rejection, making it a promising candidate for seawater purification.