Adsorptive removal of radioactive isotopes of cobalt and zinc from water and radioactive wastewater using TiO2/Ag2O nanoadsorbents

The metal oxides nanoparticles, nano titanium oxide (NTiO2), nano silver oxide (NAg2O) and nano titanium oxide-coated-silver oxide (NTiO2-NAg2O) were synthesized and compared to their removal performances of cobalt (II), zinc (II), and their radioactive isotopes from water and radioactive wastewater using batch and column techniques. The three synthesized nanoparticles were characterized by Fourier Transform infrared analysis, scanning electron microscope, high resolution transmission electron microscope, X-ray diffraction, thermal gravimetric analysis and surface area determination. Determination of the surface area of nanomaterials was accomplished using BET method. The nanoparticles were found in the range 16-32 nm for NAg2O, 35-46 nm for NTiO2 and 63-91 nm for NTiO2-NAg2O based on SEM analysis. The different experimental controlling parameters were investigated to identify the optimum operating conditions. The collected results revealed that NAg2O exhibited the optimum pH conditions to remove Co(II) and Zn(II) at pH 7.0 and 60 min contact time. The adsorption isotherm data were evaluated, and fitted well with the Langmuir and Freundlich models. NAg2O was found highly efficient in the removal of Co(II), and Zn(II) from aqueous solution under the optimized experimental parameters followed by NTiO2-NAg2O and NTiO2 in the same order. The performance of NAg2O, NTiO2 and NTiO2-NAg2O nanoadsorbents for the removal of cobalt (II), zinc (II) from tap water and their radioactive isotopes (Co-60 and Zn-65) from radioactive wastewater samples were studied and compared by the micro column system. The results confirmed the validity and efficiency of these nanoadsorbents as remediation materials for the target purposes.