Synergistic oxidation-adsorption of As(III) via Zr/Fe prussian blue analogs composite membranes activated by peroxymonosulfate for sustainable water remediation

This study presents a Zr/Fe-PBAs@PDA/PEI-M composite membrane engineered for efficient arsenite (As(III)) removal via a synergistic adsorption-oxidation mechanism. A polytetrafluoroethylene (PTFE) membrane was functionalized with polydopamine/polyethyleneimine (PDA/PEI), enabling uniform deposition of zirconium-doped iron Prussian blue analogues (Zr/Fe-PBAs) with a mesoporous structure (3.6 nm pore size) and a face-centered cubic crystalline framework. Advanced characterization confirmed Zr⁴⁺ substitution at Fe sites and the formation of binuclear bidentate Fe²⁺/Fe³⁺-CN/Zr–O coordination complexes. This architecture facilitated dual As(III) remediation pathways: (1) Fe²⁺/Fe³⁺ redox cycling activated peroxymonosulfate (PMS), generating •OH, SO₄•⁻, O₂•⁻ and ¹O₂ for insitu oxidation; (2) Zr–O coordination selectively captured arsenic species. The membrane exhibited a high As(III) adsorption capacity (558.96 mg/m²) and 90 % removal efficiency (2.0 mg/L influent) under optimized conditions (30 kPa, pH ∼7.0) with minimal metal leaching (<0.12 mg/L Fe/Zr). It demonstrated strong resistance to cationic interference and retained 65 % efficiency after three cycles despite competitive anionic effects. Field validation using Pearl River water (0.5 mg/L effluent) confirmed 80 % removal, meeting Chinese discharge standards. This work presents a promising lattice-engineered strategy for activating PMS, enabling sustainable remediation of low-concentration As(III).