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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