Modeling static and dynamic adsorption of gold cyanide on activated carbons obtained from different agricultural residues

Adsorption of gold cyanide complex onto three various types of activated carbons has been investigated based on both batch and dynamic approaches. These activated carbons have been obtained from different agricultural residues including coconut-shell (CAC), peach-core (PAC) and walnut-shell (WAC). Linear and nonlinear regression methods were applied to verify the agreement of the batch and continuous adsorption models with the experimental data. Batch equilibrium experiments were analyzed using well known isotherm models including, Langmuir, Freundlich, Temkin and Dubinin–Radushkevich with the Freundlich model suggested the best fit. Also, Pseudo First Order (PFO) and Pseudo Second Order (PSO) models were used to study the batch adsorption kinetics. The results revealed that PSO, Type(ΙΙ) is in better agreement with the kinetic data (R2 > 0.99 & HYBRID < 0.4). Thomas column adsorption model was also applied for modeling of the breakthrough curves. The modeling results revealed that except for continuous mode which lineaer method best fits the adsorption data (R2 > 0.84 & HYBRID < 0.7), the nonlinear regression method is a better way to estimate the isotherm and kinetic parameters.

Keywords:

Activated carbon , Gold cyanide , Adsorption , Nonlinear regression