Removal efficiency of heavy metals, oily in water, total suspended solids, and chemical oxygen demand from industrial petroleum wastewater by modern green nanocomposite methods

Abstract

In the present work, we discuss the concern over heavy metals, such as As(III), Bi(II), Cd(II), Cr(VI), Mn(II), Mo(II), Ni(II), Pb(II), Sb(III), Se(-II), Zn(II), and the degradation of oil in water (OIW) saturated with hydrocarbons, total suspended solids (TSS), and chemical oxygen demand (COD) in petroleum wastewater, which pose a significant threat to aquatic and terrestrial life. To address this issue and preserve biodiversity, researchers conducted a study on the synthesis and characterization of ZnO@CuO nanocomposite (NC) using Mentha pulegium L leaf extract. The characterization techniques employed included UV-Vis spectrophotometry, FTIR spectroscopy, X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Thermogravimetric Analysis (DSC–TGA), and Zeta potential. The results showed that the ZnO@CuO NC achieved 100% removal efficiency under optimal conditions. Furthermore, the kinetics of the removal process were well described by both the first and second-order kinetic models. The isotherm studies of heavy metals, OIW, TSS, and COD revealed that the adsorption process followed well the Langmuir isotherm model. Overall, this study highlights the potential of green-synthesized ZnO@CuO NPs as effective adsorbents for the remediation of heavy metals and pollutants in petrochemical wastewater.