Phosphotungstic acid immobilized on amino functionalized spherical millimeter-sized mesoporous γ-Al2O3 bead and its superior performance in oxidative desulfurization of dibenzothiophene

• Spherical millimeter-sized mesoporous γ-Al2O3 beads are selected as catalyst carrier.
• Surface of the beads is functionalized with amino groups.
• Phosphotungstic acid is stably anchored on the beads via electrostatic interaction.
• The obtained materials show excellent oxidative desulfurization for DBT.
• Remarkable advantages are witnessed for the obtained materials.

The composite material HPW/NH2–Al2O3 was successfully prepared by immobilization of phosphotungstic acid H3PW12O40 (HPW) on the surface of amino functionalized spherical millimeter-sized mesoporous γ-Al2O3 beads (NH2–Al2O3), that featured high specific surface area, remarkable enhanced mechanical strength, chemical stability and low cost. This composite material was characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), Brunner−Emmet−Teller (BET) and mechanical strength measurements. The experimental results showed that introduction of NH2 group in between HPW and Al2O3 surface not only provide strong binding sites for catalytic centers HPW to get high dispersion on the carrier surface but also prevent HPW from structural decomposition. As a consequence, the prepared HPW/NH2–Al2O3 exhibited excellent catalytic performance in the oxidative desulfurization of model oil composed of dibenzothiophene (DBT) and n-octane. The 350 ppmwS of sulfur content in 20 mL of n-octane can be dropped down to 2.8 ppmwS in 2 h using 60 mg of HPW/NH2–Al2O3 catalyst under the optimal conditions. Remarkably, the catalyst can be conveniently recycled by simple decantation method. After 10 times recycling, the oxidation desulfurization efficiency just dropped down slightly from 99.2% to 98.6%. The results indicate that synthesized HPW/NH2–Al2O3 beads have great potential as a catalyst in oxidative desulfurization for special practical applications.

Phosphotungstic acid immobilized on amino functionalized spherical millimeter-sized mesoporous γ-Al2O3 beads possesses high potentials for practical oxidative desulfurization of dibenzothiophene.Figure optionsDownload as PowerPoint slide