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

Abstract

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.