Insight into the interfacial stability and reaction mechanism between gaseous mercury and chalcogen-based sorbents in SO2-containing flue gas

Qinyuan Hong; Haomiao Xu; Yong Liao; Wenjun Huang; Zan Qu; Naiqiang Yan

doi:10.1016/j.jcis.2020.05.072

Insight into the interfacial stability and reaction mechanism between gaseous mercury and chalcogen-based sorbents in SO₂-containing flue gas

J Colloid Interface Sci. 2020 Oct 1:577:503-511. doi: 10.1016/j.jcis.2020.05.072. Epub 2020 May 28.

Authors

Qinyuan Hong¹, Haomiao Xu², Yong Liao¹, Wenjun Huang¹, Zan Qu³, Naiqiang Yan³

Affiliations

¹ School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
² School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China. Electronic address: xuhaomiao@sjtu.edu.cn.
³ School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.

PMID: 32505831
DOI: 10.1016/j.jcis.2020.05.072

Abstract

Chalcogen-based materials have been confirmed to possess large adsorption capacities for gaseous elemental mercury (Hg⁰) from SO₂-containing flue gas. However, the interface reaction mechanisms and the interfacial stability are still ambiguous. Here, we selected some commonly used chalcogen-based sorbents (e.g., X, ZnX, CuX. X = S, Se) to investigate the in-depth reaction mechanisms. The adsorption capacities, structure effect on thermal and surface mercury stability, and interfacial reaction mechanism in the absence/presence of SO₂ were evaluated. The experimental results indicated that Cu-chalcogenide had higher Hg⁰ adsorption capacity and surface Hg-X bonding stability compared with zinc one, while they exhibited an opposite degree of thermal stability. Moreover, all the chalcogenides showed well SO₂ tolerance but with a slight difference. Chalcogenides with the same crystal structures, like ZnX or CuX, exhibited similar properties in stability and interfacial Hg⁰ and SO₂ reaction mechanism. X^- in chalcogenides have a better affinity to mercury, while in the Hg⁰ capture process, the existence of multivalent metal elements (like Cu²⁺ and Cu⁺) can faster the Hg⁰ oxidation for the further chemical-adsorption. This work provides a basic understanding of the application for efficiently enriching and recycling gaseous Hg⁰ from industrial SO₂-containing flue gas.

Keywords: Adsorption; Chalcogenides; Elemental mercury; SO(2) resistance; Structure effect.