BACKGROUND AND OBJECTIVES: The increase in industrial effluent discharges from sectors such as smelting, electroplating, pharmaceuticals, and ceramics has led to a rise in heavy metal presence in ecosystems, posing a growing environmental risk. In the search for increasingly efficient materials, there has been growing interest in using adsorbents derived from both biological sources and industrial waste, due to their low cost, availability, and effectiveness in removing heavy metals from aqueous environments. The objective of this study was to assess the potential of a modified adsorbent resin, synthesized from mineral coal waste originating in Cesar, Colombia, for the removal of cadmium and lead from aqueous solutions as a sustainable remediation strategy.METHODS: The coal waste was chemically modified using sodium hydroxide and carbon disulfide to synthesize the adsorbent resin. Batch adsorption experiments were conducted at potential of hydrogen levels ranging from 3 to 8 to evaluate the removal performance. The influence of potential of hydrogen on adsorption efficiency was investigated, and the experimental data were subjected to a comparative modeling approach. Adsorption equilibrium was assessed using the Freundlich, Langmuir, and Langmuir–Freundlich isotherms, while kinetic behavior was interpreted through pseudo-first- and second-order models.FINDINGS: The results demonstrated that the removal efficiencies varied with potential of hydrogen, reaching maximum values when it was adjusted to 6, with 98 percent for lead and 97 percent for cadmium. The adsorption process followed the Freundlich isotherm, suggesting a multilayer adsorption mechanism, and the pseudo-second-order kinetics indicated that chemisorption was the dominant mechanism.CONCLUSION: This study highlighted the potential of modified mineral coal waste as an effective adsorbent for the removal of cadmium and lead, offering a promising alternative for the treatment of industrial wastewater. In addition to its high performance, this strategy contributes to the valorization of solid waste from coal mining, promoting a circular economy and reducing the environmental impact associated with its disposal.