Co-degradation of ammonia nitrogen and 4-chlorophenol in a photoelectrochemical system by a tandem reaction of chlorine and hydroxyl radicals

• Published in: Chemical engineering science 2020-11, Vol.226, p.115813, Article 115813
• Main Authors: Zhang, Jun, Zheng, Jili, Yang, Wei
• Format: Article
• Language: English
• Subjects: 4-Chlorophenol; Ammonia nitrogen; Chlorine ion; Chlorine radical; Photoelectrochemical
• ISSN: 0009-2509; 1873-4405
• DOI: 10.1016/j.ces.2020.115813

[Display omitted] •Co-degradation of ammonia nitrogen and 4-chlorophenol removal was realized.•Chlorine ion from 4-chlorophenol degradation was used for ammonia nitrogen removal.•Ammonia nitrogen removal efficiency was improved by adding 4-chlorophenol.•Cl was the dominating active radical for NH4+ degradation in the PEC system. A photoelectrochemical system was proposed for simultaneous ammonia nitrogen (NH4+) and 4-chlorophenol (4-cp) removal. In the system, 4-cp was degraded by photogenerated holes (h+) and hydroxyl radicals (HO) on the photoanode, in which chlorine ion (Cl−) was generated as a degradation product. Significantly, chlorine radical (Cl) yielded from Cl− oxidization by h+ is the main radical specie contributing to the degradation of NH4+. Therefore, the as-proposed system can achieve the co-degradation of 4-cp and NH4+ with an improved degradation efficiency of NH4+. The developed co-degradation system had a high NH4+ removal rate of 95% within 2.5 h, 62% higher than traditional NH4+ degradation system without the use of 4-cp. These results suggested that the as-proposed system can provide an efficient and viable avenue for the co-degradation of 4-cp and NH4+.