Roles of humic substances redox activity on environmental remediation

• Published in: Journal of hazardous materials Vol. 435; p. 129070
• Main Authors: Peng, Xiong-Xin, Gai, Shuang, Cheng, Kui, Yang, Fan
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 05.08.2022
• Subjects: arsenic; chromium; Environmental Pollutants; Environmental remediation; Environmental Restoration and Remediation; Ferric Compounds; Functional groups; Humic substances; Humic Substances - analysis; ionic strength; mercury; Oxidation-Reduction; photocatalysis; pollution; Reactive oxygen species; Redox process; redox reactions; remediation; silver; toxicity; Environmental remediation; Reactive oxygen species; Redox process; Humic substances; Functional groups
• ISSN: 0304-3894; 1873-3336; 1873-3336
• DOI: 10.1016/j.jhazmat.2022.129070

Humic substances (HS) as representative natural organic matters and the most common organic compounds existing in the environment, has been applied to the treatment and remediation of environmental pollution. This review systematically introduces and summarizes the redox activity of HS for the remediation of environmental pollutants. For inorganic pollutants (such as silver, chromium, mercury, and arsenic), the redox reaction of HS can reduce their toxicity and mobilization, thereby reducing the harm of these pollutants to the environment. The concentration and chemical composition of HS, environmental pH, ionic strength, and competing components affect the degree and rate of redox reactions between inorganic pollutants and HS significantly. With regards to organic pollutants, HS has photocatalytic activity and produces a large number of reactive oxygen species (ROS) under the light which reacts with organic pollutants to accelerate the degradation of organic pollutants. Under the affection of HS, the redox of Fe(III) and Fe(II) can enhance the efficiency of Fenton-like reaction to degrade organic pollutants. Finally, the research direction of HS redox remediation of environmental pollution is prospected. [Display omitted] •The redox activity of humic substances for environmental remediation is reviewed.•The redox mechanism of humic substances and environmental pollutants is discussed.•The factors affecting the oxidation-reduction rate of humic substances are described.•The future perspectives and challenges of humic substances in the application of environmental remediation are pointed out.