Investigation on mercury removal and recovery based on enhanced adsorption by activated coke

Donghai An; Xiaofei Sun; Xingxing Cheng; Lin Cui; Xiaoyang Zhang; Yongchun Zhao; Yong Dong

doi:10.1016/j.jhazmat.2019.121354

Investigation on mercury removal and recovery based on enhanced adsorption by activated coke

J Hazard Mater. 2020 Feb 15:384:121354. doi: 10.1016/j.jhazmat.2019.121354. Epub 2019 Sep 30.

Authors

Donghai An¹, Xiaofei Sun¹, Xingxing Cheng², Lin Cui¹, Xiaoyang Zhang¹, Yongchun Zhao³, Yong Dong⁴

Affiliations

¹ National Engineering Laboratory for Coal-fired Pollutants Emission Reduction, Shandong University, Jinan, Shandong 250061, China.
² National Engineering Laboratory for Coal-fired Pollutants Emission Reduction, Shandong University, Jinan, Shandong 250061, China. Electronic address: xcheng@sdu.edu.cn.
³ State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, Hubei, China.
⁴ National Engineering Laboratory for Coal-fired Pollutants Emission Reduction, Shandong University, Jinan, Shandong 250061, China. Electronic address: dongy@sdu.edu.cn.

PMID: 31615709
DOI: 10.1016/j.jhazmat.2019.121354

Abstract

This work is to systematically study the mercury-removal behavior of activated coke (AC), regeneration of spent AC by microwave treatment and subsequent recycling of Hg⁰. The powdery (AC) was obtained under coal-fired hot gas conditions in a drop-tube reactor. The adsorption mechanism and capacity of the AC for Hg⁰ removal in a H₂O + SO₂ + O₂ atmosphere were investigated. The regeneration of the AC by microwave heating and recovery of Hg⁰ were studied. The results showed that this AC preparation method can greatly simplify the process, and the AC's large surface area, developed pore structure, and abundant functional groups played a key role in the adsorption of Hg⁰. The adsorption mechanism and the optimum reaction conditions were determined, with a highest average Hg⁰-adsorption efficiency of 91% obtained at 70 °C in 3 h. Desorption of Hg⁰ was also studied, in which the alkaline-functional-group content and pore structure were enhanced, and S was detected by X-ray photoelectron spectroscopy in microwave-regenerated AC, which could improve the Hg⁰ removal efficiency increased to 96% after five adsorption/desorption cycles. The Hg⁰ could subsequently be recovered from the desorbed gas by condensation with an efficiency of 87.4% using ice-water.

Keywords: Activated coke; Adsorption; Mercury; Recovery; Regeneration.

Publication types

Research Support, Non-U.S. Gov't