Bio-regeneration of π-complexation desulfurization adsorbents

The coupling of adsorption desulfurization and biodesulfurization is a new approach to produce clean fuels. Sulfur compounds are firstly adsorbed on adsorbents, and then the adsorbents are regenerated by microbial conversion. pi-Complexation adsorbent, Cu(I)-Y, was obtained by ion exchanging Y-type zeolite with Cu2+ and then by auto-reduction in helium at 450 degrees C for 3 h. Dibenzothiophene (DBT) was used as a model compound. The effects of cell concentration, volume of oil phase, the ratio of aqueous phase to adsorbent on DBT desorption by a bacterium were studied. The amounts of DBT desorbed and 2-HBP produced can be apparently increased with addition of n-octane. BIDS activity can be improved by increasing cell concentration and the ratio of water-to-adsorbent. 89% of DBT desorbed from the adsorbents can be converted to 2-HBP within 6 h and almost 100% within 24 h, when the volume ratio of oil-to-water was 1/5 mL/mL, the cell concentration was 60 g (.) L-1, and the ratio of adsorbent-to-oil was 0.03 g (.) mL(-1). The amount of 2-HBP produced was strongly dependent on the volume ratio of oil-to-water, cell concentration and amount of adsorbent. Adsorption capacity of the regenerated adsorbent is 95% that of the fresh one after being desorbed with Pseudomonas delafieldii R-8, washed with n-octane, dried at 100 degrees C for 24 h and auto-reduced in He.