Graphene Oxide/Polyvinyl Alcohol/FeO Nanocomposite: An Efficient Adsorbent for Co(II) Ion Removal.

In this work, an effective nanocomposite-based adsorbent directed to adsorb cobalt (Co) ion was successfully synthesized from graphene oxide (GO), polyvinyl alcohol (PVA), and magnetite (FeO) nanoparticles via a coprecipitation technique. The synthesized GO/PVA/FeO nanocomposite was applied for Co 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 ion onto the GO/PVA/FeO nanocomposite followed the pseudo-second-order kinetic model with the rate constant k being 0.0026 (g mg·min). The Langmuir model is suitable to describe the adsorption of Co ion onto the GO/PVA/FeO nanocomposite with the maximum sorption capacity ( ) reaching 373.37 mg·g. The obtained results also indicated that the GO/PVA/FeO nanocomposite can adsorb/regenerate for at least 5 cycles with a little reduction in removal efficiency. Therefore, we believe that the GO/PVA/FeO nanocomposite could be used as a potential adsorbent for heavy metal treatment in terms of high adsorption capacity, fast adsorption rate, and recyclability.