Adsorptive removal of uranium from aqueous solution using magnetic hydroxyapatite

High efficiency and easy separation adsorbents are important for the treatment of uranium-containing wastewater, but still face challenges. In this paper, a new effective adsorbent for uranium removal from wastewater, i. e., PEG-beta-CD-nHA@Fe3O4 composite, was synthesized by hydrothermal reaction using iron doping and in-situ coprecipitation method, in which polyethylene glycol (PEG) and beta-cyclodextrin (beta-CD) were used as double templates to mediate the synthesis process. The results showed that the morphology and magnetic property of the composite were significantly improved. The adsorption capacity reached 928.46 mg/g, and the composite could be quickly magnetically separated after U(VI) adsorption. U(VI) adsorption performance was obviously affected by adsorbent dosage, pH, contact time and U(VI) concentration. Pseudo-second-order (PSO) and Sips models could accurately fit adsorption experimental data, indicating that it was chemisorption, in which -OH and PO43played an important role. U(VI) ions were adsorbed and fixed through complexation, precipitation and ion exchange. The results indicated that PEG-beta-CD-nHA@Fe3O4 composite was a green, efficient and easily separated adsorbent for U(VI) removal.