Green Removal of Toxic Th(IV) by Amino-Functionalized Mesoporous TiO۲-SiO۲ Nanocomposite

Mesoporous TiO۲-SiO۲ nanocomposite (TS) was synthesized via sol-gel method and Amino-functionalized using ۳-(aminopropyl) triethoxysilane. prepared amino-functionalized TiO۲-SiO۲ (NH۲TS) 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 NH۲TS was at about ۴%. 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 NH۲TS calculated to be ۱۰.۴ and ۱۴.۱nm, respectively. Moreover, the pore diameters of TS and NH۲TS estimated to be ۴.۶۵ and ۳.۶۳۲ 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 NH۲TS and TS nanocomposites were endothermic and spontaneous processes. The results indicated that NH۲TS exhibited higher adsorption affinity toward Th(IV) compared to TS. Moreover, based on the Langmuir model, the maximum adsorption capacity of NH۲TS nanocomposite towards the Th (IV) was found to be ۱۰۰۰ mg/g.

کلیدواژه ها:

TiO۲-SiO۲ ، amino-functionalization ، Th (IV) ion removal ، Nanocomposite ، Gibbs free energy