Plasma Treatment of Silver Impregnated Mesoporous Aluminosilicate Nanoparticles for Adsorptive Desulfurization

We report a regenerable adsorbent for the removal of refractory organosulfur compounds from fossil fuels. The material is composed of well dispersed silver nanoparticles confined within the mesochannels of aluminum doped MCM-41 nanoparticles. With an average initial desulfurization capacity of 15 mg S.g(-1), 79% desulfurization capacity is retained after six cycles for the removal of dibenzothiophene from n-decane. The addition of intraframework aluminum to form a mesoporous aluminosilicate nanoparticle (MASN) aids in the retention and dispersion of silver ions within the mesochannels (Ag-MASN). The nanoparticles are subsequently reduced by glow discharge plasma treatment in argon (PT-Ag-MASN). The size dispersion, surface area, and structural integrity were characterized by scanning electron microscopy, annular dark-field scanning transmission electron microscopy (ADF-STEM), nitrogen adsorption analysis (BET), and powder X-ray diffraction. Silver nanoparticle formation within the mesochannels of MASN was confirmed by ADF-STEM and diffuse reflectance UV-vis spectroscopy. Model fuel testing revealed that PT Ag-MASN had the highest regeneration capacity after six cycles compared to non-plasma-treated (Ag-MASN) and aluminum-free materials (Ag-MSN and PT-Ag-MSN). Initial testing of the military jet fuel JP-8 also shows a high desulfurization capacity of 41 mg S.g(-1).