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

ABSTRACT 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.