Elemental Mercury Adsorption by Cupric Chloride-Modified Mesoporous Carbon Aerogel

Dongjing Liu,Jiang Wu,Cheng Lu

doi:10.3390/colloids2040066

Dongjing Liu, Jiang Wu + Show 1 more

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https://doi.org/10.3390/colloids2040066

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Abstract

Mesoporous carbon aerogels (MCA) synthesized via aqueous polymerization of resorcinol and formaldehyde were modified by copper chloride and applied for adsorption removal of elemental mercury (Hg0) at a low temperature. The sorbents were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), nitrogen adsorption/desorption isotherms, and X-ray photoelectron spectroscopy (XPS) techniques. The results show that CuCl2-modified MCA exhibited good ability for Hg0 adsorption in the 40–160 °C temperature range, with Hg0 removal efficiency all above 95.0%. The Hg0 removal efficiency first increased and then decreased with the elevation of reaction temperature. It performed optimally at 80 °C with the highest Hg0 removal efficiency of 98.7%. XPS results indicate that covalent chlorines (C-Cl groups) play an important role in elemental mercury adsorption process. Hg0 is firstly captured in the form of oxidized mercury (Hg2+) and then reacts with C-Cl groups to form HgCl2.

Highlights

Mercury is one of the most toxic heavy metal elements in the environment due to its high volatility, long persistence, and strong bioaccumulation property [1]
Adsorption removal of elemental mercury by using solid sorbents is a viable method with respect to mercury emission control of coal-fired power plants [5]
CuCl2-modification is found to be effective for mercury adsorption, and the chlorine ions contained in CuCl2 are favorable for Hg0 oxidation in chlorine-free flue gas [13]

Summary

Introduction

Mercury is one of the most toxic heavy metal elements in the environment due to its high volatility, long persistence, and strong bioaccumulation property [1]. On account of its low aqueous insolubility and high vaporability, elemental mercury (Hg0) capture from flue gas is considered the hardest and most urgent work in the mercury emission control of coal-fired power plants [4]. Adsorption removal of elemental mercury by using solid sorbents is a viable method with respect to mercury emission control of coal-fired power plants [5]. Most of them exhibit limited mercury adsorption capacity and poorer Hg0 removal efficiency at low temperatures under flue gas free of HCl [10]. Yang et al [14] developed a CuCl2-modified magnetosphere for elemental mercury removal. It performed optimally at 150 ◦C with the highest Hg0 metal oxide additives. CofuH06gM0 CcaAp,tuCreuo18vMerCCAu,Cla2n-md odCiufi3e0dMMCCAA disenalostoe adthderesMseCdAaccmoroddiinfigedto tbhye XCPuSCal2nawlyistihs remsoulatsr. cCoun0c6eMntCraAti,oCnus1o8fM0.C0A6,,0a.n18d, Canud300M.3C0Amdoel/nLo,treetshpeecMtiCveAlym. odified by CuCl2 with molar concentrations of 0.06, 0.18, and 0.30 mol/L, respectively

Results and Discussions

Catalyst Synthesis and Characterization

Conclusions