Water disinfection by the UVA/electro-Fenton process under near neutral conditions: Performance and mechanisms

• Published in: Chemosphere (Oxford) Vol. 308; p. 136488
• Main Authors: Chen, Xiongjian, Chen, Ziyu, Lin, Chun-Yan, Chen, Riyao, Huang, Peiwen, Jin, Yanchao
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2022
• Subjects: Boron-doped diamond anode; Disinfection; Electro-fenton; Nitrilotriacetic acid; Ultraviolet A; Disinfection; Nitrilotriacetic acid; Ultraviolet A; Electro-fenton; Boron-doped diamond anode
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2022.136488

An efficient and thorough water disinfection is critical for human health. In this study, UVA-LEDs, nitrilotriacetic acid (NTA) and a boron-doped diamond anode were respectively used as the UVA source, the iron chelator and the anode for the UVA/electro-Fenton (E-Fenton) reaction to treat wastewater. The disinfection performance of the UVA/E-Fenton had been investigated. The mechanisms of the E. coli inactivation had been clarified. The results showed that complete disinfection (about 5.6-log removal) could be achieved within 50 min at a certain condition due to the synergistic effort of the UVA, anodic oxidation and the electro-Fenton. The quenching experiments and the electron paramagnetic resonance (EPR) detection indicated that •OH, •O2− and 1O2 play important roles for inactivating E. coli. The results of SEM images and genomic DNA electrophoresis suggested that both the cell structure and the DNA had been thoroughly destroyed during the UVA/E-Fenton process. Increasing the UVA irradiation, oxygen bubbling could improve the disinfection rate, while it also would increase the energy consumption. The appropriate Fe and NTA ratio was 1:2 to realize an efficient Fenton reaction under near neutral condition. Complete disinfection was also achieved within 50 min when it used for treating real wastewater. Thus, the UVA/E-Fenton process is a satisfied way for water disinfection. [Display omitted] •Both the cell structure and the bacterial genomic DNA was completely destroyed.•Disinfection was achieved by the synergetic effort of UVA, BDD and electro-Fenton.•Complete disinfection was achieved within 50 min under certain conditions.•It revealed a satisfied performance in real wastewater disinfection.