Tailoring structure–performance relationships in zeolite-NaX-modified PET–PSF membranes for high-efficiency and pressure-resilient heavy metal removal

Heavy metal pollution in industrial effluents continues to be a major obstacle to environmentally friendly water reuse. To effectively remove heavy metal ions from wastewater, a unique Zeolite-NaX-doped polyethylene terephthalate–polysulfone membrane (Zeolite-NaX@PET-PSF) was synthesized and tested for nanofiltration wastewater treatment. The resulting membrane demonstrated remarkable mechanical integrity, maintaining a stable permeate flux of about 16 ± 0.52 L m − 2 h − 1 at an operating pressure of 10 bars without collapsing structurally. Batch and filtration tests demonstrated excellent rejection of lead, chromium, and cadmium ions, with removal efficiency as high as 99%. Cobalt, mercury, and manganese had rejection rates of 55%, 75%, and 64%, respectively, which was due to their difficulty in removal. In all filtering cycles, near-total removal of Cd 2+ , Cr 3+ , and Pb 2+ was confirmed by inductively coupled plasma–optical emission spectrometry and surface composition of the treatment membrane using energy-dispersive spectroscopy. The hydrophilic change of the membrane surface and the production of nanoscale porosity were verified by complementary BJH, contact angle, XRD, FTIR, SEM/EDX, and TEM investigations. The Zeolite-NaX@PET-PSF composite membrane is a promising platform for advanced wastewater treatment targeting heavy metal contamination.