Highly ordered spherical SBA-15 catalysts for the removal of contaminants from the oil industry

- Facile synthesis of SBA-15 with spherical morphology and highly ordered structure.
- Fe catalyst prepared by impregnation and hydrophobized catalyst produced via CVD.
- Fe sites in the structure and on the surface of SBA catalyze oxidation reactions.
- Hydrophobization is essential for catalyst stability and activity.
- Promising results in quinoline and sulfide removal with hydrophobized catalyst.

Silica SBA-15 with spherical morphology was synthesized via the sol-gel method. Analysis by transmission electron microscopy showed that the SBA-15 presents highly organized structure with hexagonal cavities of about 6 nm in diameter. The synthesized SBA-15 was applied as catalyst support of iron nanoparticles with near 20 nm diameters (SBA/Fe - 9% Fe). These iron nanoparticles were used as catalysts for the chemical vapor deposition (CVD) process for carbon deposition on the surface of SBA-15 from ethanol, generating a more hydrophobic material, SBA/Fe/C, composed of 7% Fe and 5% C as a complex mixture of organized and disorganized carbon structures. The catalysts were employed in oxidation reactions of two contaminants of the oil industry: quinoline and sulfides. In quinoline oxidation experiments, it was observed that the material containing only iron (SBA/Fe) favors the formation of polymerization products, while SBA/Fe/C is selective for the oxidation reaction. In the sulfide oxidation, the catalyst SBA/Fe has shown to be unstable and did not react properly. On the other hand, the hydrophobized material SBA/Fe/C promoted the sulfide oxidation leading to the formation of polysulfides and sulfur oxides, non-hazardous species.

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