Comparison of the Efficiency of Activated Carbon Prepared from Oak Cap and Activated Carbon Modified with Magnetite Nanoparticles on Removal of Cadmium in Aqueous Solution

The removal of cadmium from water sources is necessary due to the inherent degradability and biocompatibility. The aim of this study was to evaluate and compare the performance of activated carbon produced from oak cap before and after modification with magnetic nanoparticles, as adsorbents for the removal of cadmium. The effect of contact time (5 to 120 minutes), adsorbent dose (1 to 15 g/l), pH (2 to 8), and cadmium concentration (5-50 mg/l) was investigated. The adsorption behavior of cadmium was evaluated using Freundlich and Langmuir models. The effect of time was described via kinetics models. Chemical composition and surface characteristics of adsorbent evaluated using X-ray diffractometry analysis (XRD) and scanning electron microscopy (SEM). Findings: The removal efficiency of conventional and modified activated carbon produced from oak caps under the constant conditions of pH of 8, contact time of 30 minutes, adsorbent dose of 5 g/l, and cadmium concentration of 30 mg/l was 81.13 and 91.32 percent, respectively. Study of isotherm results showed that conventional activated carbon produced from oak caps had a correlation coefficient of 0.98 with Langmuir model, but modified activated carbon with magnetic nanoparticles followed Freundlich model with a correlation coefficient of 0.943. The results of kinetics showed that both sorbent followed the pseudo-second order kinetics, and their equilibrium time was 30 minutes. The activated carbon prepared from oak caps pulp is able to remove cadmium from aqueous solutions, and can be used as a low-cost adsorbent material for treatment of water resources contaminated with cadmium. Moreover, modification with magnetite nanoparticles significantly increases the absorption efficiency.