Enhanced Treatment of p-Nitrophenol and Coking Wastewater through Electrochemical and Electrochemical-Ozonation Coupling Process Utilizing a Novel Ti4O7 Reactive Electrochemical Membrane Anode

Organic pollutants in water could be removed by electrochemical treatment using a reactive electrochemical membrane (REM) with Magnéli phase Ti4O7, yet it is challenging to design suitable porosity to realize effective mass transfer and enhance the reactivity. Here, a novel Ti4O7 REM was prepared by a spark plasma sintering (SPS) method, which showed excellent electrochemical reactivity and mass transfer rate for organic pollutants in water. Compared to other Ti4O7 REMs, the novel Ti4O7 REM achieved a 140~9000-fold decrease in charge transfer resistance and a 5~110-fold increase in mass transfer rate. The p-nitrophenol in water can be completely removed in the REM system, with a maximum total organic carbon (TOC) removal rate of 85%. Then the REM system obtained an amazing removal rate of TOC (50.1%) and UV254 (89.6%) in the electrochemical treatment of real coking wastewater. In addition, to further enhance the removal efficiency, a coupled oxidation process with the novel Ti4O7 REM and O3 aeration was investigated. The TOC removal rate and energy consumption were 57.1% and 165.2 kWh (kg TOC)-1 at the optimal conditions within a short treating time. Our findings highlighted an innovative REM for a broad range of potential environmental applications.