Chloride adsorption on Fe- and Al-(hydr)oxide: estimation of Gibbs free energies
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Springer New York LLC
Facultad de Ciencias Básicas
Facultad de Ciencias Básicas
Abstract
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In this study, we used chemical quantum methods to analysis the adsorption of chloride on Al and Fe-(hydr)oxide clusters. Inner and outer sphere complexes were the generating complexes during the adsorption process on variably charged Al- and Fe-(hydr)oxide clusters. For the chloride adsorption on Al-(hydr)oxide, the outer sphere complexes—H-bonded—were favored for all clusters, while the adsorption modes as inner sphere complexes—BB or MM—were not favored. It was found, that the H-bonded complex on neutral clusters was the most thermodynamically favored with an adsorption energy of − 63.4 kJ/mol. For iron clusters, thermodynamic favorability was observed for both outer (− 70.5 kJ/mol) and inner monodentate (− 65.8 kJ/mol) sphere complexes. These theoretical results indicated that the thermodynamic favorability of chloride adsorption on Fe and Al-(hydr)oxide was directly related to positive surface charge. © 2018 Springer Science+Business Media, LLC, part of Springer Nature
Keywords
Adsorption; Al-(hydr)oxide; Bidentate complex; Chloride; Fe-(hydr)oxide; Gibbs free energy; H-bonded complex; Monodentate complex, Adsorption; Aluminum; Chemical analysis; Chlorine compounds; Free energy; Gibbs free energy; Hydraulic servomechanisms; Spheres; Bidentate complexes; Chloride; Chloride adsorption; H-bonded complexes; Inner sphere complexes; Monodentate complexes; Outer-sphere complexes; Positive surface charge; Aluminum compounds