VII Simposio Internacional de Química 2019 "SIQ 2019" -VII Conferencia "Ciencias Químicas"

VII Simposio Internacional de Química 2019

SIQ 2019

ROLE OF AMINE SURFACE GROUPS IN CHLORDECONE AND β-HEXACHLOROCYCLOHEXANE ADSORPTION BY ACTIVATED CARBON: THEORETICAL STUDY

Resumen [ES]

Chlordecone (CLD) and hexachlorocyclohexane (HCH) are synthetic organochlorine compounds classified as persistent organic pollutants by the Stockholm Convention. When the technical HCH is used, β-hexachlorocyclohexane (β-HCH) is the most persistent isomer. Due to the persistence of these pollutants in the environment, the drinking water production plants have been equipped with filters of activated carbon (AC). In the present work, a theoretical study to evaluate the interaction between CLD and β-HCH with basic surface groups (SG) of AC, considering pH and hydration effect, was done, in order to better understand the adsorption process. Coronene was selected as AC model for the simulation of pesticides interaction with basic functional groups (primary, secondary and tertiary amine) attached to the edge of the coronene. Energetic and geometrical aspects of the interactions between CLD and β-HCH with SG on AC are analyzed by Multiple Minima Hypersurface methodology (MMH) using the semi-empirical Hamiltonian PM7. Furthermore, 16 distinctive structures obtained by MMH were re-optimized by Density Functional Theory, using the functional M06-2X and more rigorous characterized by Quantum Theory of Atoms in Molecules. As results, a greater association of both pesticides with the primary amine in comparison with the others, in the absence and presence of water molecules, was observed. Moreover, it was observed a weak association of the pollutants with the basic SGs. The interactions have dispersive nature between the chlorine atoms of the pesticides and the π-cloud of the functionalized coronene, evidencing a mechanism of physisorption of both pollutants in the basic ACs studied.

Resumen [EN]

Chlordecone (CLD) and hexachlorocyclohexane (HCH) are synthetic organochlorine compounds classified as persistent organic pollutants by the Stockholm Convention. When the technical HCH is used, β-hexachlorocyclohexane (β-HCH) is the most persistent isomer. Due to the persistence of these pollutants in the environment, the drinking water production plants have been equipped with filters of activated carbon (AC). In the present work, a theoretical study to evaluate the interaction between CLD and β-HCH with basic surface groups (SG) of AC, considering pH and hydration effect, was done, in order to better understand the adsorption process. Coronene was selected as AC model for the simulation of pesticides interaction with basic functional groups (primary, secondary and tertiary amine) attached to the edge of the coronene. Energetic and geometrical aspects of the interactions between CLD and β-HCH with SG on AC are analyzed by Multiple Minima Hypersurface methodology (MMH) using the semi-empirical Hamiltonian PM7. Furthermore, 16 distinctive structures obtained by MMH were re-optimized by Density Functional Theory, using the functional M06-2X and more rigorous characterized by Quantum Theory of Atoms in Molecules. As results, a greater association of both pesticides with the primary amine in comparison with the others, in the absence and presence of water molecules, was observed. Moreover, it was observed a weak association of the pollutants with the basic SGs. The interactions have dispersive nature between the chlorine atoms of the pesticides and the π-cloud of the functionalized coronene, evidencing a mechanism of physisorption of both pollutants in the basic ACs studied.

Sobre el ponente

Chayan Carmenate

Mr. Chayan Carmenate

InSTEC-UH Flag of Cuba
Información Práctica
Spanish / Español
No definido
30 minutos
No definido
Autores
Mr. Chayan Carmenate
Sarra Gaspard
Naddy Passe-Coutrin
Ulises Javier Jáuregui Haza
Kenia Melchor Rodríguez
Juan J. Gamboa Carballo
Palabras clave
activated carbon
amines
chlordecone
wastewater treatment
β-hexachlorocyclohexane