Comparative Study of Ag and Cu Decorated Mesoporous Silica Nanoparticles for Adsorptive Desulfurization of Dibenzothiophene

Mesoporous SiO₂ nanoparticles and metal-decorated silica nanocomposites (SiO₂–Ag and SiO₂–Cu) were synthesized and evaluated for the adsorption removal of dibenzothiophene (DBT) from model fuel solutions. The structural and morphological properties of the synthesized materials were investigated using X-ray diffraction (XRD) and transmission electron microscopy (TEM). TEM analysis confirmed the formation of spherical mesoporous silica nanoparticles with highly ordered pore structures, while Ag and Cu nanoparticles were successfully dispersed on the silica surface without significant destruction of the mesoporous framework. Adsorption experiments demonstrated that metal decoration significantly enhanced the initial adsorption rate of DBT, with SiO₂–Ag and SiO₂–Cu achieving removal efficiencies of 44.2% and 42.9%, respectively, after 30 min, compared with only 9.3% for pure SiO₂. However, pure mesoporous SiO₂ exhibited the highest final adsorption efficiency, reaching 90.6% after 24 h, whereas SiO₂–Ag and SiO₂–Cu achieved 80.4% and 80.6%, respectively. The superior long-term adsorption performance of pure SiO₂ was attributed to its highly accessible mesoporous structure and larger effective surface area, while Ag and Cu nanoparticles provided rapid initial adsorption through enhanced metal–sulfur interactions with DBT molecules. The results demonstrate the important relationship between adsorption kinetics and pore accessibility in mesoporous silica-based adsorbents for desulfurization applications.