Electrodeposition of FeOOH nanosheets on carbon felt for enhanced sulfamerazine removal via visible light-assisted electro-Fenton process

How to accelerate the Fe(III)/Fe(II) cycle to improve •OH generation is of significance for heterogeneous electro-Fenton (hetero-EF) cathode. In this work, FeOOH nanosheets modified carbon felt (FeOOH/CF) were prepared by in-situ electrodeposition and used as a hetero-EF cathode for enhanced sulfamerazine (SMR) removal via visible light-assisted electro-Fenton (vis-EF) process. Material characterization results suggested that the interaction between FeOOH and CF was strengthened via the formation of Fe-O-C bonding due to the special electrodeposition method. As expected, the as-prepared cathode exhibited excellent EF catalysis ability and visible light activation. With visible light assistance, the SMR removal rate for FeOOH/CF-40 was as high as 92.41%, which was increased by 110% compared with the pristine EF process. In addition, the applicable pH range could be expanded to a mild condition for FeOOH/CF cathode via the vis-EF process. Only 0.13% of total electrodeposited Fe was leached to the solution, indicative of good stability. Mechanism analysis revealed that the enhanced electron transfer via Fe-O-C bonding can significantly promote Fe(III)/Fe(II) cycle under visible light irradiation, thus activating the in-situ generated H2O2 to produce abundant •OH. These findings proved FeOOH/CF would be a promising hetero-EF cathode for practical water treatment with solar energy assistance.