MOFs/biomass-derived carbon as a high-performance anode for phosphorus removal

Capacitive deionization (CDI) is considered an emerging electrochemical technology for phosphorus removal. Its high performance is strongly related to the electrode material. Metal-organic frameworks (MOFs)-derived carbon has been recognized as a promising phosphorus adsorbent, but the potential metal particle agglomeration, poor conductivity, and high cost largely thwarted its application. Fortunately, nitrogen (N) doping facilitates the dispersion of metal particles in the carbon matrix as well as enhances the conductivity. Herein, a strategy for fabricating MOF/biomass-derived zirconium-nitrogen co-doped carbon (N@Zr/C) electrode was developed through a carbonization step, which not only introduced N doping but also formed a stable carbon skeleton. Apparently, the experimental results demonstrated that the N and Zr sites could boost the physicochemical properties and conductivity, thus enhancing phosphorus removal. Under 1.2 V condition, the N@Zr/C electrode exhibited an optimal electrosorption capacity of 32.30 mg P/g. Meanwhile, the corresponding electrosorption was comprehensively clarified through Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). This study shows that the N@Zr/C electrode can be expected to achieve efficient phosphorus removal by CDI.