Enhanced leachability of gold and silver in cyanide media : effect of alkaline pre-treatment of jarosite minerals

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Computational Studies of Binding Energies and Structures of Methylamine on Functionalized Activated Carbon Surfaces

Empirical force fields and density functional theory (DFT) were used to study the binding energies and structures of methylamine on the surface of activated carbon (ACs). This is a first step in studying the adsorption of alkyl amines on the surface of functionalized ACs. The force fields used were Dreiding (DFF), Universal (UFF) and Compass (CFF) models. The generalized gradient approximation with Perdew Wang 91 (PW91) functional was used for DFT calculations. In addition to obtaining the amine-carboxylic acid adsorption energies, the results were used to establish reliability of the empirical models for these systems. CFF predicted a binding energy of (-9.227 kcal/mol) which agreed with PW91 at (-13.17 kcal/mol), compared to DFF (0 kcal/mol) and UFF (-0.72 kcal/mol). However, the CFF binding energies for the amine to ester and ketone disagreed with PW91 results. The structures obtained from all models agreed with PW91 results

Computational Studies of Binding Energies and Structures of Methylamine on Functionalized Activated Carbon Surfaces

Empirical force fields and density functional theory (DFT) were used to study the binding energies and structures of methylamine on the surface of activated carbon (ACs). This is a first step in studying the adsorption of alkyl amines on the surface of functionalized ACs. The force fields used were Dreiding (DFF), Universal (UFF) and Compass (CFF) models. The generalized gradient approximation with Perdew Wang 91 (PW91) functional was used for DFT calculations. In addition to obtaining the amine-carboxylic acid adsorption energies, the results were used to establish reliability of the empirical models for these systems. CFF predicted a binding energy of (-9.227 kcal/mol) which agreed with PW91 at (-13.17 kcal/mol), compared to DFF (0 kcal/mol) and UFF (-0.72 kcal/mol). However, the CFF binding energies for the amine to ester and ketone disagreed with PW91 results. The structures obtained from all models agreed with PW91 results