Study of cerium adsorption in graphene oxide decorated with ZnO by X Ray Fluorescence

Abstract

With the goal of recover strategic materials contained in spent electronic and electric devices; this work focuses on the recovery of Ce from Ce synthetic solutions, by using graphene oxides-based (GO) adsorbent materials. Graphene oxide is synthesized by the Hummers' method and decorated with zinc oxide (ZnO-GO). After that, adsorption experiments at pH 2 and 6 were carried out using Ce(NO3)3 aqueous solutions with concentrations of 100-1000 mg/L. Compounds of GO and ZnO-GO with and without Ce were analysed by Raman where changes of GO structure were observed; by FTIR spectroscopy, after decoration, the reduction of COOH, C=O, C-OH and C-O groups were observed and after the adsorption the decrease of COOH and C-O groups as well as the presence of NO3 and CH2CH3 groups were detected. TEM micrographs show particles adsorbed in GO sheets, and XRF analysis helped to quantify cerium from solutions after adsorption. The ZnO-GO, obtained at pH 6, has higher Ce adsorption (3837.5 mgce/mgads) and highest percentage of Ce removal (43% of cerium); It concludes that ZnO improve the Ce adsorption, however, the adsorption mechanisms of Ce onto the graphene network are unknown, and Zn-Ce ion exchange was found depending on the pH.