Polyaniline-derived mesoporous carbon electrode for selective and efficient ammonium removal with in a flow-electrode capacitive deionization system

As an emerging technology for wastewater treatment, Flow-electrode Capacitive Deionization (FCDI) has the advantages of no pollution and low energy consumption. In this study, we obtained a mesoporous carbon named Polyaniline-Derived Mesoporous Carbon (PDMC) with remarkable specific surface area (2728 cm3·g−1) and high specific capacitance (126.63 F·g−1) by carbonizing polyaniline and treating the obtained carbon with KOH. In the FCDI system, we found that PDMC exhibited ammonium removal under the conditions of 1.2 V of voltage, feed water flow rate of 10 ml·min−1, and flow-electrode content of 5 wt%, at which time the average ammonium removal rate and removal efficiency could reach 40.95 mg·m−2·min−1 and 87.3%, respectively. In addition, we conducted continuous cycling experiments and found that the FCDI system could maintain relatively stable results after multiple operations. Finally, the ammonium removal effect and selectivity of PDMC were demonstrated in simulated municipal wastewater experiments. Our study identified a high-performance mesoporous material that can be used in the FCDI system with a simple synthesis method to achieve efficient ammonium removal. This work opens up a new path for ammonium removal by FCDI.