Enhanced transformation of organic pollutants by mild oxidants in the presence of synthetic or natural redox mediators: A review.

Yang Song, Jin Jiang, Wen Qin, Juan Li, Yang Zhou, Yuan Gao

Journal: Water research 2021;189():116667

PMID: 33271411

Full Text on Elsevier Science View on PubMed

Abstract

Synthetic or natural mediators (Med) can enhance the transformation of different types of organic pollutants by mild oxidants, which has been extensively studied in literature. This enhancing effect is attributed to the following two steps: (i) mild oxidants react with Med forming Med with higher reactivity, and then (ii) these organic pollutants are more readily transformed by Med. The present work reviews the latest findings on the formation of Med from the reactions of synthetic (i.e., 2,2'-azino-bis(3-ethylbenzothiazoline)-6-sulfonate (ABTS) and 1-hydroxybenzotriazole (HBT)) or natural mediators (i.e., syringaldehyde (SA), acetosyringone (AS), p-coumaric acid, and catechol) with mild oxidants such as laccase, manganese oxidants including permanganate (Mn(VII)) and MnO, and ferrate (Fe(VI)), as well as the transformation of organic pollutants including phenols, amines, polycyclic aromatic hydrocarbons (PAHs), organic dyes, pulp, and perfluoroalkyl acids (PFAAs) by Med. First, reaction kinetics and mechanisms of the oxidation of synthetic or natural mediators by these mild oxidants were summarized. Reactivity and pathways of synthetic Med including ABTS, ABTS, HBT or natural Med including phenoxy radicals and quinone-type compounds reacting with different organic pollutants were then discussed. Finally, the possibilities of engineering applications and new perspectives were assessed on the combinations of different types of mild oxidants with synthetic or natural mediators for the treatment of various organic pollutants.

Address: School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, Guangdong, China.; Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, Guangdong, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, Guangdong, China. Electronic address: [email protected].; Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, Guangdong, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, Guangdong, China.

DOI: 10.1016/j.watres.2020.116667