Quantification of Amine Groups in Aminopropyltrimethoxysilane-Functionalized Silica Nanoparticles: Synthesis, Size Control, and Application as Sorbents for Rare Earth Metals

Authors : Seda Demirel Topel

Pages : 665-673

Doi:10.19113/sdufenbed.1798410

View : 56 | Download : 457

Publication Date : 2025-12-25

Article Type : Research Paper

Abstract :SiO2 nanoparticles were prepared using the Stöber method under different variable factors, such as concentration of tetraethyl orthosilicate, ammonia, and temperature, which yielded tunable sizes, and accordingly, 3-aminopropyltrimethoxysilane (APTMS) was grafted onto the silica surface to yield SiO2-APTMS nanoparticles. FTIR, TGA, and XPS confirmed the grafting of aminopropyl groups, while quantitative analysis was carried out using both the ninhydrin assay and thermogravimetric measurements. Ninhydrin selectively revealed the presence of accessible surface amines, whereas TGA provided the total organic loading, with calculated grafting densities ranging from 3.4 to 9.6 molecules.nm⁻². The functionalized SiO₂–APTMS nanoparticles were further examined as sorbent materials for rare earth elements (La³⁺, Nd³⁺, Dy³⁺, Er³⁺). Adsorption studies demonstrated a rapid uptake within 100 min and reached an equilibrium at ~200 min. Dy³⁺ exhibited the highest capacity (~0.63 mmol·g⁻¹) among those elements. The results demonstrated the successful surface modification and quantification of aminopropyl groups, as well as the promising potential of SiO₂–APTMS nanoparticles for rare earth recovery from aqueous solutions.
Keywords : silika nanoparçacık, kuantifikasyon, organosilan, spektroskopi, nadir toprak elementi

ORIGINAL ARTICLE URL