In-situ synthesis of Al2O3-TiO2 nanocomposite with enhanced adsorption performance to uranium(VI) from aqueous solution

• Al 2 O 3 -TiO 2 nanocomposite was in-situ prepared for the romoval of U(VI). • Al 2 O 3 -TiO 2 showed high adsorption capacity (586.7 mg g −1 ). • The adsorption efficiency of Al 2 O 3 -TiO 2 reached 98% within 60 min. • The interaction mechanism between U(VI) and Al 2 O 3 -TiO 2 was further explored. In this study, Al 2 O 3 -TiO 2 nanocomposite was in-situ fabricated using cross-linking-freeze-drying technology for the separation of U(VI). Al 2 O 3 -TiO 2 nanocomposite exhibited an excellent removal property for U(VI) with a removal efficiency of 97.5% and a maximum adsorption capacity of 586.7 mg g −1 , which exceeded those of other TiO 2 -based adsorption materials. After five cycles, the removal percentage for U(VI) on Al 2 O 3 -TiO 2 nanocomposite still maintained more than 90.0%. The study of isotherm and kinetic demonstrated that the removal behavior of Al 2 O 3 -TiO 2 nanocomposite for U(VI) was monolayer chemisorption. Furthermore, the results of pH zpc , BET, SEM, FTIR and XPS analysis manifested that the interactions between Al 2 O 3 -TiO 2 nanocomposite and U(VI) included electrostatic interaction, surface complexation, oxygen vacancy chemistry and redox reactions. In one word, Al 2 O 3 -TiO 2 nanocomposite was a potential candidate as adsorbent in U(VI)-bearing wastewater remediation owing to its simple preparation method and the excellent removal properties.