A binder-free electrode for efficient H2O2 formation and Fe2+ regeneration and its application to an electro-Fenton process for removing organics in iron-laden acid wastewater

• Published in: Chinese chemical letters Vol. 33; no. 2; pp. 920 - 925
• Main Authors: Wei, Ziliang, Xu, Haolin, Lei, Zhenchao, Yi, Xiaoyun, Feng, Chunhua, Dang, Zhi
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.02.2022; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters,Ministry of Education,School of Environment and Energy,South China University of Technology,Guangzhou 510006,China
• Subjects: Acid wastewater treatment; Binder-free electrode; Fe2+ regeneration; N-doped carbon nanotubes; Oxygen reduction reaction; N-doped carbon nanotubes; Fe2+ regeneration; Binder-free electrode; Acid wastewater treatment; Oxygen reduction reaction; Fe2+regeneration
• ISSN: 1001-8417; 1878-5964
• DOI: 10.1016/j.cclet.2021.07.006

The electro-Fenton process, with its capacity for in-situ H2O2 formation and Fe2+ regeneration, is a striking alternative to the traditional chemical-Fenton process. However, the frequent requirement of extra binders for electrode fabrication leads to low catalyst utilization, a complex fabrication process, and weak conductivity. Herein, a three-dimensional (3D) porous electrode was fabricated in-situ on a Ni foam (NF) substrate integrated with nitrogen-doped carbon nanotubes (N@C) derived from carbonization of zeolitic imidazolate framework-8 (ZIF-8) without any binder. The resulting 900/N@C-NF cathode (synthesized at 900 °C) was high in surface area, N content, and degree of graphitization, achieved high performance of H2O2 production (2.58 mg L−1 h−1 H2O2/mg catalyst) at -0.7 V (vs. SCE), and enabled prompt regeneration of Fe2+. The electro-Fenton system equipped with the 900/N@C-NF cathode was effective in removing a diverse range of organic pollutants, including rhodamine B (RhB), phenol, bisphenol A (BPA), nitrobenzene (NB), and Cu-ethylenediaminetetraacetic acid (EDTA), and significantly attenuating the concentration of chemical oxygen demand (COD) in the real acid wastewater, exhibiting superior activity and stability. This binder-free and self-supporting electro-Fenton cathode was thus shown to be an attractive candidate for application to wastewater treatment, particularly those rich in organics, acids, and Fe3+/Fe2+. We demonstrate a binder-free and self-supporting electrode for efficient H2O2 formation and Fe2+ regeneration, which can be applied to the electro-Fenton process for treating wastewater effluents, particularly those rich in organics, acids, and Fe3+/Fe2+. [Display omitted]