Precursor-tuned nano-confined ferric hydroxy phosphate materials for enhanced synergistic fenton-like-adsorption of...

Although confined hydrated iron oxide (HFO) materials demonstrate adsorption and catalytic oxidation of water contaminants, their performance is fundamentally limited by precursor properties that are unmodifiable in conventional impregnation-precipitation synthesis. Here we use PO₄^3--assisted oxidation-polymerization to adjust the particle size and surface charge of ferric hydroxy phosphates (FHPs), followed by immobilization of the FHPs on polystyrene microspheres containing sulfonic acid group to prepare nano-confined FHP material. Nano-confined FHP material exhibits stronger catalytic oxidation activity and adsorption performance than confined HFO materials prepared by the impregnation-precipitation method, removing 96.49 % Cu²⁺ and 95.03 % EDTA from simulated wastewater. Removal efficiency remains above 95 % after eight cycles. Systematic evaluation revealed competitive ionic species exhibit a negligible impact on Cu-EDTA elimination efficiency, but the presence of humic acid decreases the removal efficiency of EDTA. Mechanistic investigations verified that the degradation process of EDTA predominantly involves ·OH and O₂^-· mediated decarboxylation pathways, while Cu²⁺ is removed by forming coordinate bonds with the oxygen-containing functional groups within the nano-confined FHP material. These findings establish a precursor-engineering paradigm for designing high-efficiency confinement materials targeting heavy metal organic complexes.