Aminopropiltrimetoksisilan ile Fonksiyonelleştirilmiş Silika Nanoparçacıklarındaki Amin Gruplarının Kuantifikasyonu: Sentez, Boyut Kontrolü ve Nadir Toprak Metalleri için Sorbent Olarak Uygulaması

Abstract

SiO₂ nanopartikülleri, tetraetil ortosilikat konsantrasyonu, amonyak ve sıcaklık gibi farklı değişken koşullar altında Stöber yöntemi kullanılarak sentezlendi ve bu sayede ayarlanabilir boyutlar elde edildi. Ardından, 3-aminopropiltrimetoksi silan (APTMS) silika yüzeyine aşılanarak SiO₂–APTMS nanopartikülleri oluşturuldu. FTIR, TGA ve XPS analizleri, aminopropil gruplarının yüzeye başarıyla aşılandığını doğruladı. Kantitatif analizler ise hem ninhidrin testi hem de termogravimetrik ölçümlerle gerçekleştirildi. Ninhidrin testi, yüzeydeki erişilebilir amin gruplarını seçici bir şekilde ortaya koyarken; TGA, 3,4 ila 9,6 molekül·nm⁻² arasında değişen aşılanma yoğunluklarıyla toplam organik yüklemeyi belirledi. Fonksiyonelleştirilmiş SiO₂–APTMS nanopartikülleri, nadir toprak elementleri (La³⁺, Nd³⁺, Dy³⁺, Er³⁺) için adsorban malzemeler olarak daha ayrıntılı biçimde incelendi. Adsorpsiyon deneyleri, 100 dakika içinde hızlı bir emilim gerçekleştiğini ve yaklaşık 200 dakikada dengeye ulaşıldığını gösterdi. Bu elementler arasında Dy³⁺ en yüksek adsorpsiyon kapasitesine (~0,63 mmol·g⁻¹) sahip olduğu gözlendi. Sonuçlar, aminopropil gruplarının başarılı şekilde yüzeye aşılandığını ve miktarının doğrulandığını gösterdi. Ayrıca, SiO₂–APTMS nanopartiküllerinin sulu çözeltilerden nadir toprak elementlerinin geri kazanımı için umut verici bir potansiyele sahip olduğu ortaya kondu.

Keywords

• silika nanoparçacık
• kuantifikasyon
• organosilan
• spektroskopi
• nadir toprak elementi

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

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

• silica nanoparticles
• quantification
• organosilane
• spectrocopy
• rare earth elements

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