Self-confined growth of ZIF-8/MoS2-PA composite membranes for efficient and selective Pb(II) removal from complex water matrices

The development of high-performance membranes for heavy metal remediation remains a key challenge in advanced water treatment. In this work, a hierarchically structured composite membrane was fabricated via a self-confined growth strategy, in which Zn(OH) 2 nanostrands immobilized MoS 2 and directed the in-situ growth of ZIF-8, forming a defect-free interlayer for robust polyamide (PA) deposition. The resulting ZM15-PA membrane exhibits a highly hydrophilic surface with a contact angle of 31.5°, a strong positive surface charge under acidic conditions, and excellent water permeability reaching 83.5 L m -2 h -1 . Most notably, the membrane achieves an ultrahigh Pb(II) rejection rate of 99.2%, consistently reducing effluent concentrations to less than 10 μg L -1 , even in the presence of coexisting ions and dissolved organic matter. Mechanistic investigations reveal that Pb(II) removal is governed by synergistic mechanisms including electrostatic repulsion, molecular sieving, and coordination interactions involving Pb-S, Pb-O, and Pb-N bonds. Furthermore, the membrane demonstrates outstanding antifouling resistance, long-term operational stability, and antibacterial efficiency exceeding 99% under photo-Fenton conditions. These findings highlight the promise of self-confined growth strategies for stabilizing two-dimensional materials and developing multifunctional membranes for selective heavy metal removal in complex water matrices.