Graphene Oxide/Polyvinyl Alcohol/Fe ₃O ₄ Nanocomposite: An Efficient Adsorbent for Co(II) Ion Removal

Abstract

In this work, an effective nanocomposite-based adsorbent directed to adsorb cobalt (Co ²⁺) ion was successfully synthesized from graphene oxide (GO), polyvinyl alcohol (PVA), and magnetite (Fe ₃O ₄) nanoparticles via a coprecipitation technique. The synthesized GO/PVA/Fe ₃O ₄ nanocomposite was applied for Co ²⁺ ion removal with the optimized working conditions including 100 min of contact time, 0.01 g of adsorbent dosage, pH of 5.2, and 50°C of temperature. The investigation of adsorption kinetics showed that the adsorption of Co ²⁺ ion onto the GO/PVA/Fe ₃O ₄ nanocomposite followed the pseudo-second-order kinetic model with the rate constant k ₂ being 0.0026 (g mg ⁻¹·min ⁻¹). The Langmuir model is suitable to describe the adsorption of Co ²⁺ ion onto the GO/PVA/Fe ₃O ₄ nanocomposite with the maximum sorption capacity ( q _max) reaching 373.37 mg·g ⁻¹. The obtained results also indicated that the GO/PVA/Fe ₃O ₄ nanocomposite can adsorb/regenerate for at least 5 cycles with a little reduction in removal efficiency. Therefore, we believe that the GO/PVA/Fe ₃O ₄ nanocomposite could be used as a potential adsorbent for heavy metal treatment in terms of high adsorption capacity, fast adsorption rate, and recyclability.