Green Removal of Toxic Th(IV) by Amino-Functionalized Mesoporous TiO2-SiO2 Nanocomposite

Abstract

<em>Mesoporous TiO₂-SiO₂ nanocomposite (TS) was synthesized via sol-gel method and Amino-functionalized using 3-(aminopropyl) triethoxysilane. prepared amino-functionalized TiO₂-SiO₂ (NH₂TS) was evaluated for eliminating radioactive Th(IV) ion in comparison with (TS). The prepared nanocomposites were characterized using FT-IR, XRD, DSC-TGA, SEM, EDS, BET, and BJH analyses. DSC and TGA analyses revealed that the total organic content of the NH₂TS was at about 4%. According to the XRD patterns, synthesized nanocomposites exhibited only the crystalline anatase phase, and the sizes of the anatase crystallites in the prepared TS and NH₂TS calculated to be 10.4 and 14.1nm, respectively. Moreover, the pore diameters of TS and NH₂TS estimated to be 4.65 and 3.632 nm according to their BJH plot. The kinetic data of Th(IV) uptake process on both of two nanocomposites corresponded well to the pseudo-second-order equation. Adsorption thermodynamic parameters including the standard enthalpy, entropy, and Gibbs free energy revealed that the ion exchange reactions on both of NH₂TS and TS nanocomposites were endothermic and spontaneous processes. The results indicated that NH₂TS exhibited higher adsorption affinity toward Th(IV) compared to TS. Moreover, based on the Langmuir model, the maximum adsorption capacity of NH₂TS nanocomposite towards the Th (IV) was found to be 1000 mg/g.</em>