Adsorptive potential of ZnO/SiO2 nanorods prepared via the sol–gel method for the removal of Pb (II) and Cd (II) from petroleum refinery wastewater. Journal of Chemical Technology & Biotechnology,

Abstract

heavy metals, due to its excellent advantages of low cost, high efficiency and easy handling. This research looks into the pos sibility of using ZnO/SiO2 nanorods to remove Cd(II) and Pb(II) from refinery wastewater and their reusability. RESULTS: ZnO/SiO2 nanorods were synthesized via the sol–gel method. The analysis of ZnO/SiO2 shows the formation of a rod like structure and surface area of 33 m2 g−1 compared with the 0.3 and 8.620 m2 g−1 for ZnO and SiO2, respectively. Effects of adsorption contact time, adsorbent dosage and temperature were examined via batch adsorption. The result indicates that the ZnO/SiO2 rods exhibited higher adsorption removal efficiency of 85.06% and 84.12% for Pb(II) and Cd(II), respectively, com pared to Pb(II) (80.00% and 74.25%) and Cd(II) (76.48% and 70.99%) using ZnO and SiO2 nanoparticles. A thermodynamic study indicates that the adsorption process was endothermic. The data from the adsorption isotherm were well fitted to the Langmuir isotherm. The pseudo-second-order kinetic model best described the adsorption process. An adsorption–desorption study indi cated the adsorption to be concentration-dependent and maintained up to 80.65% and 76.90% for Pb(II) and Cd(II) after the fourth regeneration cycle. CONCLUSIONS: These findings demonstrated that ZnO/SiO2 nanorods are a better nanoadsorbent for the removal of Pb(II) and Cd(II) than ZnO and SiO2 nanoparticles due to their high adsorptive potential and stability. © 2022 Society of Chemical Industry.