Nano-sphere RuO2 embedded in MOF-derived carbon arrays as a dual-matrix anode for cost-effective electrochemical wastewater treatment

Xiangyang Zhang; Kelong Ao; Walid A Daoud

doi:10.1016/j.scitotenv.2022.161126

Nano-sphere RuO₂ embedded in MOF-derived carbon arrays as a dual-matrix anode for cost-effective electrochemical wastewater treatment

Sci Total Environ. 2023 Mar 20:865:161126. doi: 10.1016/j.scitotenv.2022.161126. Epub 2022 Dec 29.

Authors

Xiangyang Zhang¹, Kelong Ao¹, Walid A Daoud²

Affiliations

¹ Department of Mechanical Engineering, City University of Hong Kong, Tat Chee Avenue, Hong Kong, China.
² Department of Mechanical Engineering, City University of Hong Kong, Tat Chee Avenue, Hong Kong, China. Electronic address: wdaoud@cityu.edu.hk.

PMID: 36587675
DOI: 10.1016/j.scitotenv.2022.161126

Abstract

The electrodes' activity, surface area and cost hinder the deployment of electrochemical wastewater treatment. Using an economical microfiber-based carbon felt (CF) substrate, we design RuO₂ nanospheres confined by Co_xO cooperated carbon nanoarrays (RuO₂-Co_xO@TCF) to augment noble metal utilization and thus reduce the catalyst cost. RuO₂-Co_xO@TCF anode with vertical diffusion channels exhibits rapid generation ability of oxidizing species particularity in the presence of Cl^- ions, which play a crucial role in azo bond cleavage and benzene ring chlorination of methyl orange. As a result, the catalyst shows 99.5 % color removal and ∼ 70 % mineralization efficiency at a concentration of 60 ppm. In synthetic dyeing wastewater, RuO₂-Co_xO@TCF delivers a stable total organic carbon (TOC) removal throughout ten cycling tests. Moreover, the electricity consumption of RuO₂-Co_xO@TCF is far below the reference anode, showing great promise for dye degradation and remediation of industrial wastewater.

Keywords: Carbon felt; Dual-matrix Co(x)O‑carbon array; Electrochemical wastewater treatment; Oxidizing species.