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Article

Simultaneous Kinetics of Selenite Oxidation and Sorption on δ-MnO2 in Stirred-Flow Reactors

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College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
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Hubei Research Centre for Environment Pollution and Remediation, Wuhan 430070, China
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School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan 430070, China
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Department of Environmental Engineering Design, Hubei Urban Construction Design Institute Co., Ltd., Wuhan 430051, China
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CAS Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China
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Chenzhou Dongjiang Lake Water Environmental Protection Bureau, Chenzhou 423000, China
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Department of Civil and Environmental Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
*
Author to whom correspondence should be addressed.
Academic Editor: Paul Tchounwou
Int. J. Environ. Res. Public Health 2021, 18(6), 2902; https://doi.org/10.3390/ijerph18062902
Received: 21 February 2021 / Revised: 9 March 2021 / Accepted: 10 March 2021 / Published: 12 March 2021
Selenium (Se) is an essential and crucial micronutrient for humans and animals, but excessive Se brings negativity and toxicity. The adsorption and oxidation of Se(IV) on Mn-oxide surfaces are important processes for understanding the geochemical fate of Se and developing engineered remediation strategies. In this study, the characterization of simultaneous adsorption, oxidation, and desorption of Se(IV) on δ-MnO2 mineral was carried out using stirred-flow reactors. About 9.5% to 25.3% of Se(IV) was oxidized to Se(VI) in the stirred-flow system in a continuous and slow process, with the kinetic rate constant k of 0.032 h−1, which was significantly higher than the apparent rate constant of 0.0014 h−1 obtained by the quasi-level kinetic fit of the batch method. The oxidation reaction was driven by proton concentration, and its rate also depended on the Se(IV) influent concentration, flow rate, and δ-MnO2 dosage. During the reaction of Se(IV) and δ-MnO2, Mn(II) was produced and adsorbed strongly on Mn oxide surfaces, which was evidenced by the total reflectance Fourier transform infrared (ATR-FTIR) results. The X-ray photoelectron spectroscopy (XPS) data indicated that the reaction of Se(VI) on δ-MnO2 produced Mn(III) as the main product. These results contribute to a deeper understanding of the interface chemical process of Se(IV) with δ-MnO2 in the environment. View Full-Text
Keywords: selenium; oxidation; adsorption; manganese oxide; simultaneous kinetics selenium; oxidation; adsorption; manganese oxide; simultaneous kinetics
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MDPI and ACS Style

Li, Z.; Yuan, Y.; Ma, L.; Zhang, Y.; Jiang, H.; He, J.; Hu, Y.; Yuan, S.; Ginder-Vogel, M.; Tu, S. Simultaneous Kinetics of Selenite Oxidation and Sorption on δ-MnO2 in Stirred-Flow Reactors. Int. J. Environ. Res. Public Health 2021, 18, 2902. https://doi.org/10.3390/ijerph18062902

AMA Style

Li Z, Yuan Y, Ma L, Zhang Y, Jiang H, He J, Hu Y, Yuan S, Ginder-Vogel M, Tu S. Simultaneous Kinetics of Selenite Oxidation and Sorption on δ-MnO2 in Stirred-Flow Reactors. International Journal of Environmental Research and Public Health. 2021; 18(6):2902. https://doi.org/10.3390/ijerph18062902

Chicago/Turabian Style

Li, Zheyong, Yajun Yuan, Lin Ma, Yihui Zhang, Hongwei Jiang, Jiqiang He, Yifan Hu, Shoushu Yuan, Matthew Ginder-Vogel, and Shuxin Tu. 2021. "Simultaneous Kinetics of Selenite Oxidation and Sorption on δ-MnO2 in Stirred-Flow Reactors" International Journal of Environmental Research and Public Health 18, no. 6: 2902. https://doi.org/10.3390/ijerph18062902

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