New insight into the mechanism of peroxymonosulfate activation by sulfur-containing minerals: Role of sulfur conversion in sulfate radical generation. (1st October 2018)

• Record Type: Journal Article
• Authors: Zhou, Yang; Wang, Xiaolei; Zhu, Changyin; Dionysiou, Dionysios D.; Zhao, Guangchao; Fang, Guodong; Zhou, Dongmei
• Is Part Of: Water research. Volume 142(2018)
• Page Start: 208
• Page End: 216
• Publication Date: 2018-10-01
• Subjects: Peroxymonosulfate -- Activation -- Pyrite -- Sulfur conversion -- Sulfate radicals; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2018.06.002
• Languages: English
• ISSNs: 0043-1354

Abstract

Abstract: Peroxymonosulfate (PMS) or persulfate activation by sulfur-containing minerals has been applied extensively for the degradation of contaminants; however, the role of sulfur conversion in this process has not been fully explored. In this study, pyrite (FeS2 )-based PMS activation process was developed for diethyl phthalate (DEP) degradation, and its underlying mechanisms were elucidated. PMS was found to be efficiently activated by FeS2 for DEP degradation and mineralization, achieving 58.9% total organic carbon removal using 0.5 g/L FeS2 and 2.0 mM PMS. Sulfides were the dominant electron donor for PMS activation, and mediated Fe(II) regeneration to activate PMS on the surface of FeS2 particles. Meanwhile, different sulfur conversion intermediates, such as S5 2−, S8 0, S2 O3 2−, and SO3 2−, were formed from the oxidation of sulfides by Fe(III) and PMS, and determined by X-ray photoelectron spectroscopy and in-situ attenuated total reflectance Fourier transform infrared spectroscopy analysis. SO3 2− was the dominant sulfur species responsible for sulfate radicals (SO4 − ) generation by activating PMS directly or activating Fe(III) to initiate a radical chain reaction, which was supported by the electron paramagnetic resonance results. This study highlights the important role of sulfur conversion in PMS activation by pyrite and provides new insights into the mechanism of oxidant activation by sulfur-containing minerals. Graphical abstract: Highlights: FeS2 -activated PMS efficiently for DEP degradation and mineralization. Sulfide electron donors mediated Fe(II) regeneration to activate PMS on FeS2 . Sulfur conversion plays an important role in SO4 − generation SO3 2− generated SO4 − by direct PMS or Fe(III) activation to initiate the reaction.