Highly Porous Ti4O7 Reactive Electrode Membranes for Water Filtration

Previous work has demonstrated the effectiveness of Ti₄O₇ ceramic reactive electrochemical membranes (REMs) for contaminant oxidation and fouling prevention during water filtration, where contaminants/foulants are destroyed via electrochemical anodic oxidation at the surface of the membrane. However, these studies used low-porosity rigid ceramic REMs with limited configurations. To expand the potential applications of Ti₄O₇ REMS, in this study, highly porous and flexible REMs were fabricated via a simultaneous electrospinning/electrospraying (E/E) technique. The resulting membranes from this method produced a network of poly(sulfone) (PSU) nanofibers and Ti₄O₇ particles with intimate contact between both materials throughout the porous matrix, where changing the various electrospinning and electrospraying parameters and solution properties allows for membranes with various porosities, fiber sizes, and particle sizes. To date, few studies have explored the E/E method to develop membranes for water purification and to our knowledge previous studies have not utilized the E/E method to develop REMs. Characterization of the E/E REMs was performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermal gravimetric analysis (TGA). The electrochemical properties and water filtration performance of these E/E REMs were evaluated using electrical impedance spectroscopy (EIS), cyclic voltammetry (CV), and membrane filtration studies. Filtration results demonstrate that E/E REMs exhibited a significantly higher water flux than previously investigated rigid REMs along with an order of magnitude higher contaminant removal rate.