title: Theoretical study of γ-hexachlorocyclohexane and β-hexachlorocyclohexane isomers interaction with surface groups of activated carbon model.
abstract: Activated carbon (AC) is employed in drinking water purification without almost any knowledge about the adsorption mechanism of persistent organic pollutants (POPs) onto it. Hexachlorocyclohexane (HCH) is an organochlorinated contaminant present in water and soils of banana crops production zones of the Caribbean. The most relevant isomers of HCH are γ-HCH and β-HCH, both with great environmental persistence. A theoretical study of the influence of AC surface groups (SGs) on HCH adsorption is done in order to help to understand the process and may lead to improve the AC selection process. A simplified AC model consisting of naphthalene with a functional group was used to assess the influence of SGs over the adsorption process. The Multiple Minima Hypersurface (MMH) methodology was employed to study γ-HCH and β-HCH interactions with different AC SGs (hydroxyl and carboxyl) under different hydration and pH conditions. The results obtained showed that association of HCH with SGs preferentially occurs between the axial protons of HCH and SG's oxygen atom, and the most favorable interactions occurring with charged SGs. An increase in carboxylic SGs content is proposed to enhance HCH adsorption onto AC under neutral pH conditions. Finally, this work presents an inexpensive computer aided methodology for preselecting activated carbon SGs content for the removal of a given compound.
authors.affiliation: Instituto Superior de Tecnología y Ciencias Aplicadas, La Habana, A.P. 6163, Cuba. Electronic address: victorero@instec.cu.
authors.forename: Carlos
authors.initials: C
authors.lastname: Enriquez-Victorero
authors.affiliation: Instituto Superior de Tecnología y Ciencias Aplicadas, La Habana, A.P. 6163, Cuba. Electronic address: danielhv@instec.cu.
authors.forename: Daniel
authors.initials: D
authors.lastname: Hernández-Valdés
authors.affiliation: Laboratorio de Química Computacional y Teórica, Facultad de Química, Universidad de La Habana, 10400 La Habana, Cuba. Electronic address: tuti@fq.uh.cu.
authors.forename: Ana Lilian
authors.initials: AL
authors.lastname: Montero-Alejo
authors.affiliation: Laboratoire COVACHIM M2E, EA 3592, Université des Antilles et de la Guyane, BP 250, 97157 Pointe à Pitre Cedex, Guadeloupe. Electronic address: adurimel@univ-ag.fr.
authors.forename: Axelle
authors.initials: A
authors.lastname: Durimel
authors.affiliation: Laboratoire COVACHIM M2E, EA 3592, Université des Antilles et de la Guyane, BP 250, 97157 Pointe à Pitre Cedex, Guadeloupe. Electronic address: sgaspard@univ-ag.fr.
authors.forename: Sarra
authors.initials: S
authors.lastname: Gaspard
authors.affiliation: Instituto Superior de Tecnología y Ciencias Aplicadas, La Habana, A.P. 6163, Cuba. Electronic address: ulises@instec.cu.
authors.forename: Ulises
authors.initials: U
authors.lastname: Jáuregui-Haza
mesh_terms: D000327:Adsorption; D003198:Computer Simulation; D001556:Hexachlorocyclohexane / Q000737:chemistry*; D007536:Isomerism; D008958:Models, Molecular; D008968:Molecular Conformation; D012997:Solvents / Q000737:chemistry; D013499:Surface Properties; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
chemical_list: D012997:Solvents; D014867:Water; D001556:Hexachlorocyclohexane; C023888:beta-hexachlorocyclohexane
keywords: Activated carbon; Adsorption; Hexachlorocyclohexane; Lindane; Multiple minima hypersurface; Surface groups