Comparative Evaluation of Strong Base Anion Exchange Resin and Activated Carbon for Gold Cyanide Recovery Using Isotherm Modelling

Abstract

This study presents a comparative evaluation of strong base anion (SBA) exchange resin and activated carbon (AC) for the adsorption of gold cyanide complex ions, Au(CN)??, from cyanide leach solutions. Batch adsorption experiments were conducted at varying dosages, and the equilibrium data were analysed using non-linear Langmuir, Freundlich, and Sips isotherm models. The SBA resin exhibited a significantly higher maximum adsorption capacity and stronger binding affinity (q?=68.94mg/g, K?=3.16 L/mg) than activated carbon (q?= 34.11mg/g, K?= 0.18 L/mg). Model fitting revealed that the Langmuir and Sips models best described the SBA resin's adsorption behaviour (R² = 0.9673, RMSE = 3.49), suggesting monolayer adsorption on a homogeneous surface. In contrast, activated carbon exhibited lower adsorption performance, characterised by greater surface heterogeneity (n = 0.92), as indicated by the Sips model (R² = 0.9427, RMSE = 2.07). These findings confirm that SBA resin provides superior adsorption efficiency, selectivity, and surface uniformity, making it a more promising material for gold recovery, especially in low-concentration or complex cyanide leach systems, compared to activated carbon