Removal of Rhodamine 6G in the absence of UV radiation using ceria nanoparticles (CeO2-NPs)

Abstract

In this work, the capacity to removal rhodamine 6 G (R6 G), in the absence of UV radiation, using cerium dioxide nanoparticles (CeO2-NP) was determined. The synthesized NPs were characterized by X-ray powder diffraction (XRD) and X-ray photoelectron (XPS), Raman and photoluminiscence spectroscopies. The results indicated that CeO2 powders had a crystallite size between ∼ 12 and ∼ 14 nm. The presence of the peroxide species (O22-) η2, superoxide (O2-) η1, adsorbed species O2δ (0 < δ < 1) over the surface of the ceria nanoparticles was demonstrated in the Raman spectra. Additionally, the ability of the CeO2-NPs synthesized to interact with organic molecules was determined by evaluating the removal of the R6 G dye. The results of these tests showed substantial dye removal by the as-synthesized CeO2-NPs at pH∼9.1 (∼87 % within 120 min). The kinetic adsorption of the R6 G by these NPs was suitably described by a pseudo-second-order equation.