7th ISF

CHEM040 - A Study of Mercury Behaviors and Reactions to Investigate the Formation Toxic and Corrosive Species by Utilizing Molecular Dynamics Simulation and Quantum Chemistry Simulation

Although a very small amount of mercury is found in crude oil and natural gas, it causes significant harm to their transportation systems both in short and long terms. In the short term, the presence of mercury contaminates crude oil and natural gas, which requires additional treatment for its removal; in the long term its leftover in the transportation pipeline can cause steel embrittlement, one of the major concerns for pipeline's corrosion. However, mercury's behaviour and its reaction in the gas pipelines are yet to be investigated. In this work, we mainly focus on the investigation of the behaviour and reactions of mercury species using molecular dynamics and quantum chemistry simulation. In the molecular dynamics part, the self-diffusion coefficient of Hg0 and (CH3)2Hg in 300 K, 350 K, and 400 K in water and crude oil environment are determined. The results reveal that elemental mercury can diffuse better than dimethyl mercury, and mercury can diffuse better in water than in crude oil because of the higher viscosity. In the quantum chemistry part, reactions of mercury compounds, namely (CH3)2Hg, CH3HgCl, and CH3HgI, were investigated by Density Functional Theory (DFT). The transition state and activation energy were calculated using the Nudged Elastic Band Method (NEB). The calculations were integrated with the Solvation Model Based on Density (SMD). The results reveal that the impact of solvents lowered overall energy, and polar solvents tend to have lower energy than non-polar solvents

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