Efficient removal of uranium by hydroxyapatite modified kaolin aerogel

[email protected] aerogel (HKLA) was first prepared via a combination of coprecipitation and freeze-drying-calcination method to capture uranium from water. Characterization results demonstrated that the introduction of hydroxyapatite (HAP) could improve the adsorbent stability, change the surface morphology and bring abundant groups, which were in favor of the uranium removal. In comparison with kaolin (KL), the removal rate (93.4%), removal capacity (401.6 mg g−1) (t = 24 h, pH = 5.0, T = 298 K and m/V = 1.0 g L−1) and removal equilibrium time of uranium on HKLA all showed a great improvement. Pseudo-second-order and Langmuir model were more suitable to describe the uranium removal behavior on HKLA, illustrating that the uranium ions were immobilized on HKLA via chemical adsorption. Meanwhile, high temperature was conducive to the uranium removal on HKLA, indicating that the removal process was a spontaneous endothermic reaction. Furthermore, HKLA showed excellent anti-ion interference ability, recyclability, cyclic stability and dynamic adsorption performances. On the basis of the analysis of SEM, BET, XRD, FTIR and XPS, uranium was loaded on HKLA through complex reaction, chemical adsorption, electrostatic adsorption and ion exchange. Therefore, HKLA was a promising candidate for the removal of uranium from wastewater.