Functional Polymeric and Ceramic Membrane-Based Catalysis for Advanced Water Treatment

Advanced oxidation processes (AOPs), driven mainly by hydroxyl (^•OH) and sulfate (SO₄ ^•-) radicals, can mineralize micropollutants or transform recalcitrant pollutants into biodegradable intermediates. However, heterogeneous AOPs often suffer from rapid quenching of reactive species and limited catalyst recyclability. This study critically assesses recent progress in membrane-based nanoconfined AOPs with a main objective of critically evaluating polymeric catalytic membranes vs. ceramic catalytic membranes. According to our literature survey, we identify ultrafast kinetics by polymeric catalytic membranes, particularly layered double hydroxide incorporated polymeric membranes with a k value of up to 240 000 min^-1; and angstrom-confined laminar membranes achieving millisecond-scale degradation, albeit with substantial flux-activity trade-offs. On the other hand, ceramic catalytic membranes are observed to maintain lower median flux (55 LMH) and lower median k values (0.88 min^-1). Importantly, they show predictable hydraulics, broader oxidant compatibility, robustness under harsh pH, and effective removal of mixed micropollutants via radical and non-radical pathways. Significant evidence was found for the restructuring of water under nanoconfinement, along with enrichment of reaction media, strengthening of oxidant adsorption, lowering activation barriers, and suppressing radical self-quenching. Future implementation will require integrated advances in membrane engineering, catalyst design, reactor/process integration, and scalable manufacturing of catalytic membranes.