Triple-Janus porous electrode for electrostatic filtration of complex wastewater

Diverse contaminants (oil-in-water (O/W) emulsions, microparticles, bacteria) coexist in wastewater. Although electrostatic separation of O/W emulsions using hydrophilic/hydrophobic Janus porous electrodes has been reported, these approaches exhibit limited removal of fouling-inducing impurities, including bacteria and particulate matter. Here, we report an electroactive triple-Janus porous electrode (TJPE) that integrates asymmetric porosity, wettability, and electrical conductivity within a single membrane, enabling stable electrostatic filtration of multicomponent wastewater. The TJPE establishes electrostatic emulsion repulsion, depth-selective particle interception, and intrinsic antibacterial activity within a single electroactive architecture. Under an applied electric field, the TJPE achieves 99.9% oil rejection with a high permeate flux of 1929 L·m^-2·h^-1, while simultaneously removing 99.3% of microscale particles and inactivating bacteria. Importantly, the spatial decoupling of contaminant capture from the conductive interface prevents electrode fouling and catastrophic failure, enabling stable operation under complex feed conditions. Extended operation tests demonstrate sustained performance over 24 h with stable flux and > 99.6% oil rejection, while Ag leaching remains low (18.41 ppb), well below regulatory limits. Electrochemical analyses further confirm stable charge transport and interfacial electrostatic behavior at the TJPE interface. This work establishes a Janus electroactive membrane architecture for integrated, fouling-resistant electrostatic filtration, providing a new design framework for multicomponent wastewater treatment.