Multifunctional cobalt oxide nanocomposites for efficient removal of heavy metals from aqueous solutions.

In this study, co-precipitation synthesis of natural clay (NC) with CoO nanoparticles (NPs) is carried out to elaborate the super NC@CoO nanocomposites with admirable salinity confrontation, environmental stability and reusability, to eliminate heavy metal pollution such as toxic Pb(II) and Cd(II) ions. The advantages of using the NC@CoO adsorbent are easy synthesis and biocompatibility. In addition, NC@CoO can keep an excellent adsorption capacity by taking into account various environmental parameters such as the pH solution, NC@CoO dose, adsorption process time and the initial heavy metals concentration. Furthermore, FTIR, XRD, TGA, SEM-EDS, TEM and AFM analyses were performed to confirm NC@CoO nanocomposites synthesis and characterisation. The adsorption efficiencies of Pb(II) and Cd(II) ions by NC@CoO nanocomposites were demonstrated to be up to 86.89% and 82.06% respectively. Regarding the adsorption from water onto the NC@CoO nanocomposites, kinetics data were well fitted with PSO kinetic model, whereas a good agreement was found between the equilibrium adsorption and theoretical Langmuir isotherm model leading to maximum adsorption capacities of 55.24 and 52.91 mg/g, for Pb(II) and Cd(II) respectively. Monte Carlo (MC) simulations confirmed the spontaneous of this adsorption based on the negative values of E. The MC simulations were performed to highlight the interactions occurring between heavy metal ions and the surface of NC@CoO nanocomposites, these were well correlated with the experimental results. Overall the study showed that NC@CoO nanoadsorbents have strongly versatile applications and are well designed for pollutant removal from wastewater due to their unique adsorptive properties.