Hydrated electron based photochemical processes for water treatment. (15th October 2022)

• Record Type: Journal Article
• Authors: Zhao, Yunmeng; Zhang, Chaojie; Chu, Liquan; Zhou, Qi; Huang, Baorong; Ji, Ruixin; Zhou, Xuefei; Zhang, Yalei
• Is Part Of: Water research. Volume 225(2022)
• Publication Date: 2022-10-15
• Subjects: Hydrated electron -- Photochemical processes -- Water treatment -- Perfluorinated compounds -- Disinfection by-products; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2022.119212
• Languages: English
• ISSNs: 0043-1354

Abstract

Highlights: Characteristics of various eaq − based photochemical processes are outlined. The identification methods of eaq − are summarized. Experimental parameters affecting contaminant degradation are analyzed. Degradation efficiency of contaminants by photo-induced eaq − are presented. Research prospects of eaq − based photochemical processes are proposed. Abstract: Hydrated electron (eaq − ) based photochemical processes have emerged as a promising technology for contaminant removal in water due to the mild operating conditions. This review aims to provide a comprehensive and up-to-date summary on eaq − based photochemical processes for the decomposition of various oxidative contaminants. Specifically, the characteristics of different photo-reductive systems are first elaborated, including the environment required to generate sufficient eaq −, the advantages and disadvantages of each system, and the comparison of the degradation efficiency of contaminants induced by eaq − . In addition, the identification methods of eaq − (e.g., laser flash photolysis, scavenging studies, chemical probes and electron spin resonance techniques) are summarized, and the influences of operating conditions (e.g., solution pH, dissolved oxygen, source chemical concentration and UV type) on the performance of contaminants are also discussed. Considering the complexity of contaminated water, particular attention is paid to the influence of water matrix (e.g., coexisting anions, alkalinity and humic acid). Moreover, the degradation regularities of various contaminants (e.g., perfluorinated compounds, disinfection by-products and nitrate) by eaq − are summarized. We finally put forward several research prospects for the decomposition of contaminants by eaq − based photochemical processes to promote their practical application in water treatment. Graphical abstract: Image, graphical abstract