Synthesis and structural properties of ZnO and diatomite-supported ZnO nanostructures

Zinc oxide (ZnO) and diatomite-supported ZnO nanostructures were prepared using a direct precipitation and co-precipitation method, respectively. The morphologies of the prepared nanostructures were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The surface charge of the samples was assessed by zeta potential measurements. The XRD results showed that the size of the prepared nanoparticles were 18 nm, which was consistent with TEM consequences. The FT-IR spectrum clearly indicated the formation of an interfacial chemical bond between Zn and O of prepared samples but ZnO characteristic peaks shifted to lower wave numbers at about 467 cm-1 for diatomite-supported ZnO. Characterization exhibited that the ZnO particles were successfully distributed in the diatomite support. Prepared nanoparticles have potential for different applications owing to processing facility and more economical reagents. © 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.Firat University Scientific Research Projects Management Unit: 2012 NBE 015This project was supported by Ege University Scientific Research Project Unit Project No. 2012 NBE 015 . -

Sorption of Th(IV) onto ZnO nanoparticles and diatomite-supported ZnO nanocomposite: kinetics, mechanism and activation parameters

WOS: 000384108400003In this study, for the first time ZnO nanoparticles and diatomite-supported ZnO nanocomposite have been utilized as adsorbent for the removal of Th(IV) ions from aqueous solutions under different experimental conditions. The Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D-R) isotherms were used to analyze the equilibrium data. The sorption equilibrium data were fitted well to the Langmuir isotherm with maximum sorption capacities values was found to be 1.105 mmol/g and 0.320mmol/gfor ZnO nanoparticles and diatomite-supported ZnO nanocomposite, respectively. Pseudo-first and pseudo-second order equations, Intraparticle diffusion and Bangham's models were considered to evaluate the rate parameters and sorption mechanism. Sorption kinetics were better reproduced by the pseudo-second order model (R-2 > 0.999), with an activation energy (E-a) of +99.74kJ/mol and +62.95kJ/mol for ZnO nanoparticles and diatomite-supported ZnOnanocomposite, respectively. In order to specify the type of sorption reaction, thermodynamic parameters were also determined. The evaluated Delta G* and Delta H* indicate the non-spontaneous and endothermic nature of the reactions. The results of this work suggest that both of the used materials are fast and effective adsorbents for removing Th(IV) from aqueous solutions and chemical sorption plays a role in controlling the sorption rate.Ege UniversityEge University [2012 NBE 015]This project was supported by Ege University Scientific Research Project Unit Project No. 2012 NBE 015. The research for this paper was carried out at the Institute of Nuclear Sciences, Ege University, Bornova-Izmir, within the frame of ERASMUS Program