Enhanced Removal of Acid Orange 7 onto Layered Interleaved Symmetrical 3D Flower-like CeO2 with Y(III) Doping

Abstract

CeO2 has a potential application in the purification of organic dye wastewater because of the abundant oxygen vacancy (VO) defects in its crystals. In this study, a cubic CeO2 microsphere with layered interleaved symmetrical 3D flower-like morphology was synthesized, and its adsorption capacity for acid orange 7 (AO7) was further enhanced by Y doping. The impact of varying amounts of Y ions on the phase composition, lattice parameters, and morphology of the product was investigated, revealing that 4 mol.% was determined as the doping level limit of Y ions in CeO2 crystals. XPS, Raman, and H2−TPR techniques were employed to compare surface species changes before and after 4 mol.% Y doping in the CeO2 crystals, including O−Ce(III), O−Ce(IV), O−Y(III), and VO correlation, yielding a rough quantitative assessment of these species. The 4 mol.% Y-doped CeO2 (2.0 g/L) demonstrated the highest removal rate for 20 mg/L of AO7 dye within just 20 min to reach adsorption–desorption equilibrium, half the time required by undoped CeO2, achieving an impressive adsorption rate of 94.6%, compared to only 69.5% for undoped CeO2 at 20 min. The adsorption capacity of undoped CeO2 was enhanced by 19.05% through the doping of 4 mol.% Y, achieving a value of 16.56 mg/L. The feasibility of enhancing the adsorption capacity of CeO2 by Y doping provides a reference for the application of CeO2 and other metal oxides.