Functional organosilanes-modified silica nanosorbents for the removal of rare earth ions from aqueous solution and investigations on their adsorption

18th International Nanoscience and Nanotechnology Conference (NanoTR-18), İstanbul, Türkiye, 26 - 28 Ağustos 2024, ss.105

The demand for rare earth elements (REEs) has increased over the last thirty years due to their critical

use in car catalysts (Ce), hybrid vehicles (Dy, La, Nd), green energy technologies like wind turbines

(Pr, Nd, Sm, Dy), batteries (La), and fluorescent lamps (La, Gd, Tb, Eu, Yb) [1]. The most effective

nanomaterials for sequestrating the REEs are based on silicon dioxide (SiO2), titanium dioxide (TiO2),

and carbon-based nanostructures. Among these sorbents, SiO2-based nanostructures offer excellent

efficiency and high adsorption ability due to their large specific surface area [2].

In this study, silica nanosorbents prepared via the sol-gel method were functionalized with organosilane

derivatives, including (CH2)3NH2, (CH2)3NH(CH2)2NH(CH2)3, -(CH2)3OCH2-C(OH)-CH2-NH-(CH2)3,

-(CH2)2P(O)(OH)2, and (CH2)3-N-[(CH2)2-OH], using a grafting technique. This functionalization aims

to differentiate their adsorption affinity towards REEs. The resultant nanosorbents were further

characterized using dynamic light scattering (DLS), transmission electron microscope (TEM), X-ray

photoelectron spectroscopy (XPS), and thermal gravimetric analysis (TGA). To explore their adsorption

behaviours, complexometric titrations with EDTA were performed to analyse adsorption kinetics and

isotherms. The titrations provided insights into the rate of the adsorption and the adsorption capacity

under different conditions. The adsorption experiments demonstrated medium to high capacity

depending on the REE ions (La3+, Nd3+, Dy3+, and Er3+). The results reveal that the organosilanemodified

silica nanosorbents are effective in capturing these ions, making them promising candidates

for REE sequestration applications. This project (221N430) was supported by the 2531 TUBITAKDAAD

bilateral cooperation support program.