Inorganic Electrified Membrane: From Basic Science to Performance Translation

Decentralized water systems necessitate intensified, robust, and modular water treatment technologies for enhanced efficacy and resilience of the water purification process. Inorganic electrified membranes (IEMs) are gaining momentum in decentralized water systems by combining the versatility of electro-filtration processes with the favorable properties of inorganic materials, namely, strong mechanical strength, chemical stability, and hydrophilicity. This review quantitatively assesses three mainstream IEMs (i.e., Ti4O7, carbon, and metallic IEMs) from a fundamental perspective of the intrinsic electrochemical properties of the IEM materials and their translation into the IEM performances. We specifically (i) analyze the •OH production selectivity by Ti4O7 IEMs based on electrochemical thermodynamics and material science; (ii) differentiate degradation mechanisms of carbon IEMs in the context of various water matrices and propose strategies to address major concerns of avoiding membrane passivation and improving Faradaic efficiency of carbon IEMs; and (iii) highlight metallic IEMs doped with Ag or Pd, i.e., elucidate the combined sterilization mechanism by Ag-IEM via Ag+ dissolution and electro-phenomena, and unravel the unique hydrogenolysis ability of Pd-IEM for hydrodeoxygenation and persulfate electro-activation. We conclude by identifying the remaining obstacles of IEMs and present possible interdisciplinary approaches for IEM optimization.