Phenol degradation in iron-based advanced oxidation processes through ferric reduction assisted by molybdenum disulfide. (January 2023)

• Record Type: Journal Article
• Authors: You, Yingying; He, Zhen
• Is Part Of: Chemosphere. Volume 312:Part 1(2023)
• Publication Date: 2023-01
• Subjects: Advanced oxidation process -- Fe redox cycle -- Molybdenum disulfide -- Persulfate -- Phenol; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2022.137278
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: In the iron-based advanced oxidation processes (AOPs), direct use of Fe III can be more convenient than Fe II but the reduction of Fe III to Fe II is a rate-limiting step. Introducing co-catalysts with abundant reducing sites to Fe-based AOPs can be an efficient way to accelerate the Fe redox process. Herein, molybdenum disulfide (MoS2 ) was used to enhance the catalytic performance of Fe 3+ /persulfate (PS) for phenol removal. In the Fe 3+ /MoS2 /PS system, 99.6 ± 0.1% of phenol was removed in 60 min, comparable to that of the Fe 2+ /PS/MoS2 system (99.1 ± 0.3%). With the help of MoS2, 99.3 ± 4.2% of Fe 3+ was transformed to Fe 2+ in 10 min, and the Fe 2+ /Fe ratio was able to be maintained at 70.0 ± 1.4% after 60 min. The rapid and complete reduction of Fe 3+ with MoS2 made it possible to replace Fe 2+ by Fe 3+, which is easier to store, transport, and use. The decrease in XPS peak area percentage of Mo(IV) and the lower valent S after reaction revealed that MoS2 acted as an electron provider in the Fe redox cycle. Quenching experiment results indicated that the phenol removal was highly depended on the surface-bound radicals, including both SO4 − and OH. Those results have demonstrated that ferric salts can be directly used in the Fe-based AOPs and the redox cycle could be sustained with the assistance of MoS2 . Graphical abstract: Image 1 Highlights: The fast reduction of Fe 3+ to Fe 2+ is accomplished in the presence of MoS2 . Fe 3+ based AOP has comparable phenol degradation to Fe 2+ based AOPs. Continuous Fe redox cycle is achieved with stable Fe 2+ concentration under excess PS. MoS2 plays the role of an electron provider in the Fe redox cycle reaction.