Efficient immobilization and detoxification of gaseous elemental mercury by nanoflower/rod WSe2/halloysite composite: Performance and mechanisms

Xuelei Duan; Yuan Li; Changxian Zhao; Yiwen Shen; Qi Guo; Zhihao Huang; Dexu Shan; Yue Gao; Kegang Zhang; Jianbo Shi; Jingfu Liu; Yongsheng Chen; Chun-Gang Yuan

doi:10.1016/j.jhazmat.2023.131898

Efficient immobilization and detoxification of gaseous elemental mercury by nanoflower/rod WSe₂/halloysite composite: Performance and mechanisms

J Hazard Mater. 2023 Sep 15:458:131898. doi: 10.1016/j.jhazmat.2023.131898. Epub 2023 Jun 20.

Authors

Xuelei Duan¹, Yuan Li¹, Changxian Zhao¹, Yiwen Shen¹, Qi Guo¹, Zhihao Huang¹, Dexu Shan¹, Yue Gao¹, Kegang Zhang¹, Jianbo Shi², Jingfu Liu², Yongsheng Chen³, Chun-Gang Yuan⁴

Affiliations

¹ Hebei Key Lab of Power Plant Flue Gas Multi-Pollutants Control, Department of Environmental Science & Engineering, North China Electric Power University, Baoding 071000, China.
² State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P. O. Box 2871, Beijing 100085, China.
³ Department of Civil & Environmental Engineering, Georgia Institute of Technology, Atlanta, GA, USA.
⁴ Hebei Key Lab of Power Plant Flue Gas Multi-Pollutants Control, Department of Environmental Science & Engineering, North China Electric Power University, Baoding 071000, China; MOE Key Laboratory of Resources and Environmental Systems Optimization, College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, China. Electronic address: cgyuan@ncepu.edu.cn.

PMID: 37354718
DOI: 10.1016/j.jhazmat.2023.131898

Abstract

Gaseous mercury pollution control technologies with low stability and high releasing risks always face with great challenges. Herein, we developed one halloysite nanotubes (HNTs)-supported tungsten diselenide (WSe₂) composite (WSe₂/HNTs) by one-pot solvothermal approach, curing Hg⁰ from complicated flue gas (CFG) and reducing second environment risks. WSe₂ as a monolayer with nano-flower structure and HNTs with rod shapes in the as-prepared sorbent exhibited outstanding synergy efficiency, resulting in exceptional performance for Hg⁰ removal with high capture capacity of 30.6 mg·g^-1 and rate of 9.09 μg·g^-1·min^-1, which benefited from the high affinity of selenium and mercury (1 ×10⁴⁵) and the adequate exposure of Se-terminated. The adsorbent showed beneficial tolerance to high amount of NO_x and SO_x. An online lab-built thermal decomposition system (TPD-AFS) was employed to explore Hg species on the used-sorbent, finding that the adsorbed-mercury species were principally mercury selenide (HgSe). Density functional theory calculations indicated that the hollow-sites were the major adsorption sites and exhibited excellent selectivity for Hg⁰, as well as HgSe generation needed to overcome the 0.32 eV energy barrier. The adsorbed mercury displayed high environmental stability after the leaching toxicity test, which significantly decreased its secondary environmental risks. With these advantages, WSe₂/HNTs possess enormous potential to achieve the effective and permanent immobilization of gaseous mercury from CFG in the future.

Keywords: Detoxification; Flue gas; Hg(0); Immobilization; Tungsten diselenide.