Abstract

Cobalt is one of the most hazardous heavy metals present in the environment. Magnetic based nanoadsorbents were used for removal of Co(II) ions in this work. The characteristics results of FT-IR, XRD, TGA, and FE-SEM show that applied coatings were modified magnetite nanoparticles efficiently. The results of TEM indicate that magnetic nanoadsorbents were produced on the nanoscale with average particle sizes of 60±10 nm. Batch experiments were carried out to determine the removal efficiency of the nanoadsorbents. pH, temperature, contact time, adsorbent dose, shaking rate and the initial concentration of analyte were the studied parameters. At optimized conditions of operation parameters, the maximum removal percentage of 92% was obtained by using magnetite-citric acid as an adsorbent. Equilibrium data for Co(II) ions adsorption onto magnetite-citric acid were fitted well by Langmuir isotherm model and the maximum adsorption capacity for Co(II)ions was obtained 43.292 mg/g at 313 K. Also, thermodynamic parameters reveal the spontaneity, feasibility and endothermic nature of the Co(II) ions adsorption process. In addition, the cobalt ions can be desorbed from magnetite-citric acid nanoadsorbent by using nitric acid solution with 95% desorption efficiency and the magnetite-citric acid nanoadsorbent exhibits good recyclability.

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