<p>Thiosulfate and bromide are promising substitutes of cyanide in gold (Au) leaching from ore, offering lower toxicity and favorable kinetics. The aim of this study is to evaluate the adsorption behavior of activated carbon (AC) in three cyanide-free leaching systems. The innovative concept of this research is to study the adsorption of Au on coconut shell-derived AC using two optimized ore (110 ppm of Au content) leaching solutions from previous studies: (i) thiosulfate system—1 M of sodium thiosulfate reagent (Na₂S₂O₃), 2 M of ammonia (NH₄OH, 28%), and 0.01 M of copper sulfate pentahydrate (CuSO₄·5H₂O); (ii) bromide system—0.4 M of sodium bromide (NaBr, 99%), 1 M of hydrochloric acid (HCl, 37 %), and 0.7 M of sodium hypochlorite (NaClO, 5.25 %). Additionally, the adsorption behavior of these alternatives is compared with a standard solution to assess their feasibility. The maximum adsorption capacity reached 0.5 mg Au/g AC in the thiosulfate system and 4.094 mg Au/g AC in the bromide system. The results show that Au adsorption in the thiosulfate solution is most consistent with the Freundlich isotherm model, while the bromide solution follows the Langmuir model. Kinetic studies show agreement with a pseudo-second-order model for both systems. In particular, bromide showed superior performance when paired with AC, highlighting its potential as an effective leachate for cyanide-free Au recovery. These results underscore the promise of bromide in advancing environmentally friendly Au extraction methods.</p> Graphical Abstract <p></p>