Improvement of stability and reduction of energy consumption for Ti-based MnOx electrode by Ce and carbon black co-incorporation in electrochemical degradation of ammonia nitrogen

Abstract

Ti-based electrode coated with MnOx catalytic layer has presented superior electrochemical activity for degradation of organic pollution in wastewater, however, the industrial application of Ti-based MnOx electrode is limited by the poor stability of the electrode. In this study, the novel Ti-based MnOx electrodes co-incorporated with rare earth (Ce) and conductive carbon black (C) were prepared by spraying-calcination method. The Ti/Ce:MnOx-C electrode, with uniform and integrated surface and enhanced Mn(IV) content by C and Ce co-incorporation, could completely remove ammonia nitrogen (NH4+-N) with N2 as the main product. The cell potential and energy consumption of Ti/Ce:MnOx-C electrode during the electrochemical process was significantly reduced compared with Ti/MnOx electrode, which mainly originated from the enhanced electrochemical activity and reduced charge transfer resistance by Ce and C co-incorporation. The accelerated lifetime tests in sulfuric acid showed that the actual service lifetime of Ti/Ce:MnOx-C was ca. 25 times that of Ti/MnOx, which demonstrated the significantly promoted stability of MnOx-based electrode by Ce and C co-incorporation. HIGHLIGHTS The Ti-based MnOx electrodes co-incorporated with Ce and C were prepared and served as electrocatalysts to remove ammonia nitrogen.; The cell potential and energy consumption of Ti/Ce:MnOx-C was reduced by 35% compared with Ti/MnOx, originating from the enhanced activity and reduced resistance.; The service lifetime of Ti/Ce:MnOx-C was improved by 25 times compared with Ti/MnOx, demonstrating the promoted stability.;

Keywords

• ammonia nitrogen (nh4+-n)
• electrochemical oxidation
• mnox
• ti-based electrodes
• wastewater remediation