Review on the degradation of chlorinated hydrocarbons by persulfate activated with zero-valent iron-based materials. (19th January 2023)

• Record Type: Journal Article
• Authors: Chen, Zhiguo; Cao, Wenqing; Bai, He; Zhang, Rong; Liu, Yiyun; Li, Yan; Song, Jingpeng; Liu, Juncheng; Ren, Gengbo
• Is Part Of: Water science and technology. Volume 87:Number 3(2023)
• Page Start: 761
• Page End: 782
• Publication Date: 2023-01-19
• Subjects: chlorinated hydrocarbons -- nZVI modification -- persulfate -- zero-valent iron; Water -- Pollution; Sewage -- Purification; Water quality management; Periodicals; 628.168
• DOI: 10.2166/wst.2023.009
• Languages: English
• ISSNs: 0273-1223

Abstract

Abstract: Chlorinated hydrocarbons (CHCs) are often used in industrial processes, and they have been found in groundwater with increasing frequency in recent years. Several typical CHCs, including trichloroethylene (TCE), 1, 1, 1-trichloroethane (TCA), carbon tetrachloride (CT), etc., have strong cytotoxicity and carcinogenicity, posing a serious threat to human health and ecological environment. Advanced persulfate (PS) oxidation technology based on nano zero-valent iron (nZVI) has become a research hotspot for CHCs degradation in recent years. However, nZVI is easily oxidized to form the surface passivation layer and prone to aggregation in practical application, which significantly reduces the activation efficiency of PS. In order to solve this problem, various nZVI modification solutions have been proposed. This review systematically summarizes four commonly used modification methods of nZVI, and the theoretical mechanisms of PS activated by primitive and modified nZVI. Besides, the influencing factors in the engineering application process are discussed. In addition, the controversial views on which of the two (SO4 · - and ·OH) is dominant in the nZVI/PS system are summarized. Generally, SO4 · - predominates in acidic conditions while ·OH prefers neutral and alkaline environments. Finally, challenges and prospects for practical application of CHCs removal by nZVI-based materials activating PS are also analyzed. HIGHLIGHTS: The mechanism of zero-valent iron-based activated persulfate was systematically summarized. The dominant free radical in the process of CHCs degradation by modified zero-valent iron activated persulfate was summarized and analyzed. Various influencing factors of zero-valent iron activated persulfate were analyzed. Graphical Abstract