Highly efficient removal of aqueous Hg(II) by FeS micro-flakes

Mingling Xiao; Xiaofang Lai; Jun He; Jiahao Huang; Zhenhua Tang; Ruiwen Wu; Jikang Jian

doi:10.1016/j.scitotenv.2023.162013

Highly efficient removal of aqueous Hg(II) by FeS micro-flakes

Sci Total Environ. 2023 Apr 20:870:162013. doi: 10.1016/j.scitotenv.2023.162013. Epub 2023 Feb 3.

Authors

Mingling Xiao¹, Xiaofang Lai², Jun He³, Jiahao Huang¹, Zhenhua Tang¹, Ruiwen Wu¹, Jikang Jian⁴

Affiliations

¹ School of Physics and Optoelectronic Engineering, Guangdong University of Technology, Guangzhou 510006, China.
² School of Physics and Optoelectronic Engineering, Guangdong University of Technology, Guangzhou 510006, China. Electronic address: zhujilai@163.com.
³ School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, China.
⁴ School of Physics and Optoelectronic Engineering, Guangdong University of Technology, Guangzhou 510006, China. Electronic address: jianjikang@126.com.

PMID: 36737015
DOI: 10.1016/j.scitotenv.2023.162013

Abstract

FeS (mackinawite) is known to be effective in the sorption of aqueous Hg(II). However, FeS nanoparticles are apt to aggregate and easy to be oxidized, which limits their wide applications. Here, we have synthesized FeS micro-flakes which can be uniformly dispersed in water without aggregation. Owing to the good stability and dispersibility, FeS micro-flakes exhibit high efficiency in the removal of Hg(II) from water. The sorption of Hg(II) on the FeS micro-flakes is more consistent with the pseudo-second-order kinetic model and Langmuir model, indicating that the sorption of Hg(II) is mainly monolayer sorption dominated by chemical sorption. The maximum sorption capacity is 2680 mg/g at pH 5.6 and 30 °C, significantly higher than those of FeS nanoparticles and other Hg(II) scavengers. The pH studies indicate that FeS (0.31 g/L) can effectively remove >97.6 % of 200 mg/L Hg(II) in the pH range of 2-12 at 30 °C. Powder X-ray diffraction, elemental and sorption analyses suggest that Hg(II) is removed via chemical precipitation and surface adsorption. This study demonstrates the potential and viability of FeS micro-flakes for efficient removal of aqueous Hg(II).

Keywords: FeS micro-flakes; Mercury; Sorption capacity; Sorption mechanism; pH.