Hydrogen chloride adsorption on large defective PAHs modeling soot surfaces and influence on water trapping: A DFT and AIMD study

Abstract

DFT calculations both at 0 K in energy optimization procedure and at finite temperature in ab initio molecular dynamics (AIMD) calculations are used to characterize the adsorption of the hydrogen chloride molecule on a carbonaceous cluster in which a carbon vacancy has been created by removing one carbon atom. This aims at modeling the defective surface of the small graphitic basic structural units that constitute soot nanoparticles, as experimentally evidenced. The results show that HCl can be easily dissociated at the vacancy site of the surface, resulting in the formation of a chlorinated site at the carbonaceous surface, which could have different structures depending on the thermodynamics of the reactions. Then, the resulting chlorinated carbonaceous surfaces are used as model substrates to characterize the first stages of the adsorption of water molecules on chlorinated soot. It is thus shown that adsorbed chlorine atoms may act as an efficient nucleation center for water trapping at the surface of soot. These results represent a new step towards a better understanding of the soot behavior in industrial or domestic fire situations, as well as in marine atmospheric environment where oxidant and chlorinated species are ubiquitous.

The Dynamics of Per- and Polyfluoroalkyl Substances (PFAS) at Interfaces in Porous Media: A Computational Roadmap from Nanoscale Molecular Dynamics Simulation to Macroscale Modeling

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Elucidating the Sorption Mechanisms of Environmental Pollutants Using Molecular Simulation

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Ion Pairing in HCl–Water Clusters: From Electronic Structure Investigations to Multiconfigurational Force-Field Development

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