Catalytic membrane with dual-layer structure for ultrafast degradation of emerging contaminants in surface water treatment

The catalytic membrane-based oxidation-filtration process integrates physical separation and chemical oxidation, offering a highly efficient water purification strategy. However, the oxidation-filtration process is limited in practical applications due to the short residence time of milliseconds within the catalytic layer and the interference of coexisting organic pollutants in real water. Herein, a dual-layer membrane containing a top selective layer and a bottom catalytic layer was fabricated using an in situ co-casting method with a double-blade knife. Experimental results demonstrated that the selective layer rejected macromolecular organic pollutants, thereby alleviating their interference with bisphenol A (BPA) degradation. Concurrently, the catalytic layer activated peracetic acid oxidant and achieved a high BPA degradation exceeding 90 % in milliseconds with reactive oxygen species (especially •OH). The finite-element analysis confirmed a high-concentration reaction field occupying the pore cavity of the catalytic layer, enhancing collision probability between reactive oxygen species and BPA, i.e., the nano-confinement effect. Additionally, the dual-layer membrane achieved a long-term stable performance for emerging contaminant degradation in surface water treatment. This work underscores a novel catalytic membrane structure design for high-performance oxidation-filtration processes and elucidates its mechanisms underlying ultrafast degradation. [Display omitted] •The MnO2-PVDF membrane was synthesized in situ by a co-casting method.•The MnO2-PVDF/PAA system could intercept large molecular pollutants and oxidize small molecular pollutants.•The toxicity of the intermediate degradation products of pollutants was reduced after degradation.•The MnO2-PVDF/PAA system had ultrafast degradation of emerging contaminants in surface water.