Abstract

Activated carbon derived from polystyrene waste was evaluated as an adsorbent for the removal of the reactive dye Drimaren Red K-7B from aqueous solutions at different temperatures. The adsorption equilibrium was analyzed using Langmuir, Freundlich and Dubinin-Radushkevich models, with the latter providing the best fit (R²=0.97). Kinetic data followed the pseudo-second-order model at all temperatures (R²=0.99). The maximum adsorption capacity reached 35 mg/g at 20 °C. Thermodynamic analysis revealed negative Gibbs free energy values, confirming the spontaneous nature of the process, while positive enthalpy and entropy indicated an endothermic mechanism accompanied by increased interfacial disorder. These results demonstrate the potential of polystyrene-derived activated carbon as an efficient adsorbent for water treatment applications.