First-principles studies of HF and HCl adsorption over graphene
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ORIGINAL PAPER
First-principles studies of HF and HCl adsorption over graphene Jiwei Ran 1 & Xingguang Hao 1 & Kai Li 1 & Chi Wang 2 & Xin Song 1 & Xin Sun 1
&
Ping Ning 1,3
Received: 28 February 2020 / Accepted: 31 August 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract In this paper, the adsorption characteristics of HF and HCl over graphene were studied by the first-principles method. The results showed that the adsorption of HCl over graphene was a weak chemical adsorption, while HF was a weak physical adsorption. The density of states showed that HCl and graphene at − 4.3 eV are relative to the Fermi level. At the same time, there is no obvious change and hybridization between HF-graphene system near the Fermi level. Furthermore, when HCl and HF molecules adsorbed over the graphene simultaneously, two optimal adsorption structures would be chosen to investigate how HCl and HF molecules jointly affected adsorption properties. The result showed that two gas molecules adsorbed over graphene could enhance the adsorption effect and influenced electronic distribution. Keywords Density functional theory . Graphene . Density of states
Introduction Hydrogen chloride (HCl) and hydrofluoric acid (HF) are the pollutants widely exist in the environment, mainly from coalfired flue gas, copper smelting flue gas, and waste combustion gas [1, 2]. Although the contents of HCl and HF are lower than those of sulfur and nitrogen pollutants, it has serious corrosion effects on the equipment. Therefore, the removal of HCl and HF from tail gas is of great significance for the purification and utilization of gasification products. At present, the methods for removing these two gases in the mixed gas include the following: physical adsorption separation of
Jiwei Ran and Xingguang Hao contributed equally to this work. Jiwei Ran and Xingguang Hao are joint first authors. * Xin Sun [email protected] * Ping Ning [email protected] 1
Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
2
Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500, China
3
National-Regional Engineering Center for Recovery of Waste Gases from Metallurgical and Chemical Industries, Kunming University of Science and Technology, Kunming 650500, People’s Republic of China
activated carbon, other dechlorinating agents, chemical absorption separation of dechlorinating agents, and defluorinating agents [3–6], because wet absorption has the disadvantages of large floor area, high equipment requirements, high cost, and easy to cause secondary pollution. Therefore, dry adsorption is a more effective way of adsorption. At present, activated carbon fiber (ACF) and molecular sieve catalysts are mostly used for dichlorination in industry [7, 8]. Yang [7] used PAN-ACF as catalyst for this kind of reaction shows obvious advantages, the selectivity is over 99%, the conversion rate is much higher than that of ACF catalysts, the tempera
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