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

This study aims to enhance the adsorption capacity of activated carbon (AC) and optimize the cumulative effect of various operational parameters on the removal of Ni (II) ions, providing a comprehensive understanding of the removal process. Activated carbon was modified using the Fenton oxidation process to produce modified activated carbon (MAC). The functional groups and morphological features of MAC were characterized using FTIR spectroscopy, particle size analysis, high-resolution scanning electron microscopy (HRSEM), and surface area measurements. To optimize the removal efficiency, response surface methodology (RSM) was employed using a central composite design (CCD). The predicted removal capacities showed good agreement with experimental values, with a determination coefficient (R²) 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.