Mesoporous CeO2 on HA Nanobundle for Selective Adsorption and Separation of Anionic Dyes

The presence of dye pollutants poses a serious environmental hazard, leading to an increasing urgency for the efficient separation of dye wastewater. In this study, by in situ growing mesoporous CeO 2 particles (CeO 2 MP) on the surface of hydroxyapatite nanobundle (HAnB), a novel adsorbent material (CeO 2 MP@HAnB) with separation function was synthesized and characterized by SEM, EDS, XPS, FT-IR, XRD, BET, and Zeta potential. Methyl blue (MeB) was selected as the representative of anionic dyes to evaluate the adsorption properties of CeO 2 MP@HAnB. It was worth noting that CeO 2 MP@HAnB exhibited excellent activity for the adsorption of MeB, reaching 86.27% adsorption rate within 0.5 min, and the adsorption rate was still 80.00% after 6 cycles. It was found that the process of MeB adsorption by CeO 2 MP@HAnB was more suitable for the Elovich and Freundlich isotherm model. In combination with kinetic, thermodynamic, BET, FT-IR, and potentiometric tests, the adsorption of CeO 2 MP@HAnB on pollutants was analyzed and summarized as a pore-filled multilayer adsorption with chemical, hydrogen bonding, and electrostatic interactions as the main mechanisms. Concurrently, CeO 2 MP@HAnB exhibited high separation efficiency and repeatability for mixtures of dyes containing MeB. The separation efficiency of MeB got to 97.97% from the mixture of MeB and methyl orange (MO). In summary, we provided a novel and efficient strategy for the synthesis of separating adsorbent. And CeO 2 MP@HAnB was expected to be applied to the efficient purification of dyes in wastewater, contributing to a safer water environment.