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Assessment of Ag Nanoparticles Interaction over Low-Cost Mesoporous Silica in Deep Desulfurization of Diesel
- Source :
- Catalysts, Vol 9, Iss 8, p 651 (2019)
- Publication Year :
- 2019
- Publisher :
- MDPI AG, 2019.
-
Abstract
- Chemical interactions between metal particles (Ag or Ni) dispersed in a low-cost MCM-41M produced from beach sand amorphous silica and sulfur compounds were evaluated in the deep adsorptive desulfurization process of real diesel fuel. N2 adsorption-desorption isotherms, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM) and scanning transmission electron microscopy coupled to energy-dispersive X-ray spectroscopy (STEM-EDX) were used for characterizing the adsorbents. HRTEM and XPS confirmed the high dispersion of Ag nanoparticles on the MCM-41 surface, and its chemical interaction with support and sulfur compounds by diverse mechanisms such as π-complexation and oxidation. Thermodynamic tests indicated that the adsorption of sulfur compounds over Ag(I)/MCM-41M is an endothermic process under the studied conditions. The magnitude of ΔH° (42.1 kJ/mol) indicates that chemisorptive mechanisms govern the sulfur removal. The best fit of kinetic and equilibrium data to pseudo-second order (R2 > 0.99) and Langmuir models (R2 > 0.98), respectively, along with the results for intraparticle diffusion and Boyd’s film-diffusion kinetic models, suggest that the chemisorptive interaction between organosulfur compounds and Ag nanosites controls sulfur adsorption, as seen in the XPS results. Its adsorption capacity (qm = 31.25 mgS/g) was 10 times higher than that obtained for pure MCM-41M and double the qm for the Ag(I)/MCM-41C adsorbent from commercial silica. Saturated adsorbents presented a satisfactory regeneration rate after a total of five sulfur adsorption cycles.
Details
- Language :
- English
- ISSN :
- 20734344
- Volume :
- 9
- Issue :
- 8
- Database :
- Directory of Open Access Journals
- Journal :
- Catalysts
- Publication Type :
- Academic Journal
- Accession number :
- edsdoj.35bd7b628eea4acabd6d6431c65671d0
- Document Type :
- article
- Full Text :
- https://doi.org/10.3390/catal9080651