New Insights into H2S Adsorption on Graphene and Graphene-Like Structures: A Comparative DFT Study

Azam Salmankhani,Sajjad Habibzadeh,Alain Celzard,Alain Celzard,Mohammad Reza Ganjali,Mohammad Reza Ganjali,Vanessa Fierro,Vanessa Fierro,Mohammad Reza Saeb,Amin Hamed Mashhadzadeh,Amin Hamed Mashhadzadeh,Amin Esmaeili,Zohre Karami,Vahid Vatanpour

doi:10.3390/c6040074

Abstract

The efficient removal of pollutants from different environments has been one of the great challenges for scientists in recent years. However, the understanding of the mechanisms underlying this phenomenon is still the subject of passionate debates, mainly due to the lack of experimental tools capable of detecting events at the atomic scale. Herein, a comparative theoretical study was carried out to capture the adsorption of H2S on metal oxide surfaces such as zinc oxide (ZnO) and beryllium oxide (BeO), as well as graphene and Ni-decorated graphene. A simulation based on density-functional theory (DFT) was carried out by adopting General Gradient Approximation (GGA) under the Perdew–Burke–Ernzerhof (PBE) function. The calculations quantified H2S adsorption on the considered metal oxide sheets as well as on the non-decorated graphene having a physical nature. In contrast, H2S adsorbed on Ni-decorated graphene sheet gave an adsorption energy of −1.64 eV due to the interaction of S and Ni atoms through the formation of a covalent bond, proof of chemisorption. It seems that the graphene sheet decorated with Ni atoms is a more suitable adsorbent for H2S molecules than BeO, ZnO, or non-decorated graphene, providing a theoretical basis for future studies.

Highlights

H2 S is one of the air pollutants released during various processes such as petroleum refinery, natural gas and biogas processing, coking plants, wastewater treatment units, etc. [1,2]
With respect to the H2 S molecule were evaluated by density-functional theory (DFT) calculations. These properties were compared to the adsorption properties of pristine and Ni-decorated graphene sheets
The results showed that the H2 S molecule physically adsorbs on beryllium oxide (BeO) and zinc oxide (ZnO) surfaces with adsorption energies of −0.144 and −0.376 eV, respectively

Summary

Introduction

H2 S is one of the air pollutants released during various processes such as petroleum refinery, natural gas and biogas processing, coking plants, wastewater treatment units, etc. [1,2]. C 2020, 6, 74 toxic compound has raised global concerns in recent decades due to its harmful effects on the environment as well as on human health [3,4]. Even at low concentrations, H2 S can seriously affect the nervous system, causes a feeling of weakness, coughing, and runny nose. At higher concentrations, the consequences would be even worse, which could lead to visceral injury, coma, acidosis, and death [5,6]. H2 S can cause corrosion of process equipment, contaminate pipelines, and affect product quality [7]. Excess H2 S in the environment and atmosphere can lead to acid rains and cause serious damage to crops and infrastructure [8,9]

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