Material-Efficient Synthesis of Polymer Membrane-Immobilized Metal Oxides for Advanced Oxidation Processes: Catalytic...

A unique all-in-one synthesis is presented for membrane-immobilized transition metal oxides, integrating into a single process: metallic nanoparticle synthesis within a polymer dope solution, porous support membrane formation via film casting and polymer precipitation, and aqueous room-temperature oxidation using atmospheric oxygen. This approach achieves near-perfect metal utilization and enables synthesis of different metal oxides under identical conditions. As-prepared CrO₂, MnO₂, FeOOH, CoOOH, Ni(OH)₂, CuO, and ZnO are benchmarked in advanced oxidation processes (AOPs) for water treatment at neutral pH and with NaCl and NaHCO₃. Tetracycline, diclofenac, cefalexin, and p-nitrophenol are tested as organic pollutants and persulfate (S₂O₈ ^2-), hydrogen peroxide (H₂O₂), and sulfite (SO₃ ^2-) as oxidants. Key reactivity trends and performance indicators across diverse catalyst-oxidant-pollutant systems are identified. The role of catalyst-oxidant affinities is elucidated, showing how Lewis acid-base interactions at the metal oxide surface impact metal cation leaching and resistance to interference from dissolved anions during oxidant activation. Furthermore, a novel theoretical framework is introduced that links the material properties of metal oxides to their catalytic oxidant activation mechanisms. Building on this framework, a mathematical model is established that predicts the catalytic activity of metal oxides in AOPs across various conditions, providing a new strategy for rational catalyst design.