Bio-engineered sodium alginate-polyoxometalate hybrid: A green dual-function catalyst for ultra-efficient desulfurization with inherent self-demulsification in real diesel

This study innovatively synthesizes a bio-based poly(ionic liquid), namely GH.ALG, from renewable sodium alginate-an abundant, biodegradable marine biomass-thus avoiding reliance on petrochemical feedstocks. A heterogeneous catalyst, GH.ALG@POM, is fabricated by anchoring polyoxometalates (POMs) onto the GH.ALG, integrating POMs， robust oxidative capacity with the desulfurization and self-demulsuification properties of GH.ALG. Under optimized conditions (0.2 g catalyst, O/S molar ratio 7, 70 °C), GH.ALG@POM demonstrates exceptional desulfurization performance without the need for adding auxiliary extractants during the reaction stage: the desulfurization rate reaches 99.72 % for DBT, 85.79 % for 4,6- 4,6-DMDBT, and 55.35 % for BT. Notably, the catalyst retains over 95 % activity after five consecutive cycles. Applied to real diesel, it reduces sulfur content from 2.172 wt% to 0.1983 wt%, with a 90.87 % removal rate. Mechanistic studies reveal superoxide radicals (·O₂ − ) as the main reactive species driving the desulfurization process. This study pioneers a new approach for biomass-based catalyst design, offering a sustainable and scalable deep desulfurization solution-one that aligns with green chemistry principles by minimizing toxicity, utilizing renewable feedstocks, and integrating oxidation and extraction into a single step without the need for additional chemical additives.