Sustainable Development of Functionalized Cobalt Oxide Nanoparticles with Effective Cu(II) Sorbent Properties

The present work reports the solution combustion synthesis of negatively charged cobalt oxide nanoparticles (CONPs) using glycine as a fuel. The morphology, composition, crystallinity, and surface characteristics of synthesized CONPs were confirmed. The particles were oval in shape with an average size of 10 ± 2 nm and negatively charged functional groups (C-H and N = N = N) on their surface. Batch experiments were performed to estimate the optimum values of parameter to estimate the maximum Cu(II) adsorption of CONPs, which was found to be 523 ± 12.72 mg g⁻¹. The acid treatment achieved regeneration of loaded CONPs, and their sustainability was checked by performing adsorption–desorption experiments up to 4 cycles. The obtained results showed only a 14.4% reduction in adsorption capacity up to 4 cycles. Further, the diversified application of CONPs was examined by exposing them to synthetically prepared textile industry effluent containing multiple metal ions. The batch study data were fitted to various isotherm and kinetic models to understand the adsorption kinetics. The possible mechanism for the adsorption of Cu(II) onto CONPs has also been discussed. The antimicrobial assay results advocated that the disposal of CONPs is harmless to the ecosystem.