Ultra-deep desulfurization via reactive adsorption on peroxophosphomolybdate/agarose hybrids

- Amphiphilic polyoxometalates were loaded on agarose to obtain C16PMo(O2)2/agarose.
- C16PMo(O2)2/agarose showed high affinity to non-polar sulfur and to H2O2.
- This catalyst realizes the oxidation-adsorption desulfurization with high efficiency.
- This system beneficial to the energy saving and environmental protection.
- C16PMo(O2)2/agarose has good stability and regeneration in the ODS.

A catalyst system composed of peroxophosphomolybdates as catalytic center and agarose as matrix material had been designed. The [C16H33N(CH3)3]3[PO4{MoO(O2)2}4]/agarose (C16PMo(O2)2/agarose) hybrid was found to be active for oxidation desulfurization (ODS) of dibenzothiophene (DBT) or real fuel into corresponding sulfone by H2O2 as an oxidant, while the sulfur content could be reduced to 5 ppm. The higher activity comes from its components including [PO4{MoO(O2)2}4] catalytic sites, the hydrophobic quaternary ammonium cation affinity to low polarity substrates, and agarose matrix affinity to H2O2 and sulfone. During the oxidative reaction, the mass transfer resistance between H2O2 and organic sulfurs could be decreased and the reaction rate could increase by the assistance of agarose and hydrophobic tails of [C16H33N(CH3)3]3[PO4{MoO(O2)2}4]. Meanwhile, the oxidative products could be adsorbed by agarose matrix to give clean fuel avoiding the post-treatment. In addition, the hybrid was easily regenerated to be reused.