Thermodynamic and Kinetic Aspects of Gold Adsorption in Micrometric Activated Carbon and the Impact of Their Loss in Adsorption, Desorption, and Reactivation Plants: Gold Adsorption in Micrometric Activated Carbon

Rodrigo Martinez Peñuñuri, Jose R. Parga-Torres, Jesus L Valenzuela-Garcia, Héctor J. Díaz-Galaviz, Gregorio González-Zamarripa, Alejandro Monserrat Garcia Alegria

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Abstract: The production and loss of fine particles of activated carbon (AC) loaded with gold in
the adsorption processes is a worldwide problem, mainly due to the behavior of increasing its
adsorption capacity with respect to the decrease in particle size, which becomes relevant to determine
the thermodynamic and kinetic activity of the gold adsorption and the economic impact of its loss,
with the escape towards the later stages of the system of adsorption, desorption, and reactivation
(ADR) plants of AC. Through the adsorption of gold in a synthetic medium with sodium cyanide
concentration, using different particle sizes, AC weights, and adsorption times, data were generated
for analysis by three different isotherm models, resulting in a better tendency for the Freundlich
isotherm, from which thermodynamic parameters of DG equal to 􀀀2.022 kcal/mol, DH equal to
􀀀16.710 kcal/mol, and DS equal to 􀀀0.049 kcal/molK were obtained, which shows that it is a
spontaneous, exothermic process with a lower degree of disorder. The kinetic analysis was performed
with two different models, from which the pseudo-second-order model was used due to a better
tendency and displayed a behavior that leaves open the interpretation of the increase in adsorption
with respect to the decrease in the AC particle size but demonstrated the importance of recovering
these particles in relation to their gold concentration and the economic impact from their poor
recovery, which, for this case study, amounted to ~0.3 million dollars per year.
Translated title of the contributionAspectos Cinéticos y Termodinámicos de la Adsorción de Oro en Carbón Activado Micrométrico y el Impacto de sus Pérdidas en Plantas de Adsorción, Desorción y Reactivación: Adsorción de Oro en Carbón Activado Micrométrico
Original languageAmerican English
Article number16-4961
Pages (from-to)1-20
Number of pages20
StatePublished - 1 Jul 2023

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