Degradation of 2,4-dichlorophenoxyacetic acid by anodic oxidation and electro-Fenton using BDD anode: Influencing factors and mechanism

• Published in: Separation and purification technology Vol. 230; p. 115867
• Main Authors: Cai, Jingju, Zhou, Minghua, Pan, Yuwei, Lu, Xiaoye
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 02-01-2020
• Subjects: 2,4-Dichlorophenoxyacetic acid; Anodic oxidation; BDD; Electro-Fenton; Modified graphite felt cathode; Anodic oxidation; Electro-Fenton; Modified graphite felt cathode; BDD; 2,4-Dichlorophenoxyacetic acid
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2019.115867

•2,4-D degradation was conducted by AO and EF with CB-GF.•2,4-D degradation obtained 53% MCE and 71.8 kWh/kg TOC Ec in EF.•The contribution of OH was increased to 92% compared with AO (57.5%).•EF using CB-GF was cost-effective for 2,4-D degradation.
The degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) was conducted by anodic oxidation (AO) with a boron-doped diamond (BDD) anode, and was greatly enhanced by combination with electro-Fenton (EF) using carbon black modified graphite felt (CB-GF) as cathode. A high current density, low initial pH and high concentration of Na2SO4 favored for the 2,4-D degradation by AO. In EF, 2,4-D degradation rate increased 8 times after using CB-GF cathode, obtaining a higher mineralization current efficiency (53%) and a lower energy consumption (71.8 kWh kg−1 TOC) due to the higher generation of H2O2. It indicated that the mainly contributing radicals for 2,4-D degradation by AO was OH (57.5%), while the contribution improved to 92% by EF. Compared with AO, EF was more efficient and complete for 2,4-D degradation, confirmed by the detection of the main degradation intermediates and short-chain carboxylic acids. This work demonstrated that EF using BDD anode and high-performance CB-GF cathode was efficient for 2,4-D degradation, which would be a promising electrochemical advanced oxidation process for organic wastewater treatment.