Enhancing and optimization for efficient removal of nickel ions by modified activated carbon

) of 0.92. The maximum removal capacity achieved was 210 mg/g under optimal conditions: 150 min contact time, pH 1, a low adsorbent dose of 0.2 g/L, and initial Ni (II) concentration of 125 mg/L. The adsorption isotherm analysis indicates that the Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) models adequately describe the adsorption of Ni(II) onto MAC. The D-R model results further suggest that the adsorption process is mainly controlled by chemisorption, potentially through ion-exchange mechanisms. These findings demonstrate that MAC, along with the proposed predictive models, offers a promising approach for optimizing Ni (II) removal efficiency in wastewater treatment applications.