Thallium removal from wastewater using sulfidized zero-valent manganese: Effects of sulfidation method and liquid nitrogen pretreatment. (March 2023)

• Record Type: Journal Article
• Authors: Shi, Zhengqin; Zhang, Ping; Li, Xiaohan; Zheng, Yijie; Huang, Juanxi; Wang, Yaxuan; Luo, Xiatiao; Zhang, Gaosheng; Xiao, Tangfu; Long, Jianyou; Li, Huosheng
• Is Part Of: Chemosphere. Volume 318(2023)
• Publication Date: 2023-03
• Subjects: Thallium -- Zero-valent manganese -- Sulfidation -- Heavy metal -- Liquid nitrogen; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2023.137971
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Zero-valent manganese (ZVMn) possesses high reducibility in theory, while sulfide exhibits strong affinity towards a variety of heavy metals owing to the low solubility of metal sulfides. Yet the performance and mechanisms on using sulfidized zero-valent manganese (SZVMn) to remove thallium (Tl) from wastewater still remain unclear. In this study, the performance of Tl(I) removal using SZVMn synthesized by borohydrides reduction followed by sulfides modification, with and without liquid nitrogen treatment, was compared and the mechanism behind was investigated. The results show that at a S/Mn molar ratio of 1.0, liquid nitrogen modified SZVMn (LSZVMn) possessed more interior channels and pores than SZVMn, with 65.3% higher specific surface area and 73.7% higher porosity, leading to 6.4–8.1% improvement in adsorption of Tl(I) at pH 4–10. LSZVMn showed effectiveness and robustness in Tl(I) removal in the presence of co-existing ions up to 0.1 M. The adsorption of Tl(I) conformed to the pseudo-1st-order kinetic model, and followed the Langmuir isothermal model, with the maximum Tl adsorption capacity of 264.9 mg·g −1 at 288 K. The mechanism of Tl(I) removal with SZVMn was found to include sulfidation-induced precipitation, manganese reduction, surface complexation, and electrostatic attraction. The liquid nitrogen pretreatment embrittled and cracked the outer shell of S/Mn compounds, resulted in a highly hierarchical structure, enhancing the manganese reduction and improving the Tl(I) removal. Based on the above results, the SZVMn and its liquid nitrogen-modified derivatives are novel and effective environmental materials for Tl(I) removal from wastewater, and the application of SZVMn to the removal of other pollutants merits investigation in future study. Graphical abstract: Image 1 Highlights: Sulfidized zero-valent manganese (SZVMn) is used for Tl removal for the first time. Liquid nitrogen-modified SZVMn (LSZVMn) at [S/Mn] = 1.0 improves Tl removal. Maximum Tl adsorption capacity of 264.9 mg⋅g −1 at 288 K is achieved. LSZVMn has better robustness in Tl removal in the presence of co-existing matrix. Tl is mainly removed via reduction, sulfide precipitation and surface complexation.