A novel desulfurization process of gasoline via sodium metaborate electroreduction with pulse voltage using a boron-doped diamond thin film electrode

A novel desulfurization process of gasoline was realized via sodium metaborate (NaBO2) electroreduction with pulse voltage using a boron-doped diamond (BDD) thin film electrode under mild conditions. The results of cyclic voltammetry and 11boron (B) nuclear magnetic resonance (NMR) confirmed that NaBO2 was converted into sodium borohydride (NaBH4) by electroreduction and the electroreduction voltage ranged from −1.2 V to −1.8 V. The factors that influenced desulfurization efficiency were investigated and the desulfurization efficiency reached more than 95% for model gasoline and more than 97% for real gasoline. The components of model gasolines before and after desulfurization were analyzed by gas chromatography/mass spectrometer (GC/MS) and the elements content of electrolytes and digestion solution of precipitate were determined by inductively coupled plasma (ICP). Results indicated that reductive desulfurization process mainly involved the cleavage of C–S bond and the hydrogenation of C–C double bond and B recycle was realized at the same time as desulfurization. Consequently, possible desulfurization mechanism was proposed. Desulfurization kinetics showed a pseudo-first-order toward thiophene or benzothiophene. All these results indicated that the gasoline desulfurization process via sodium metaborate electroreduction with pulse voltage using a BDD thin film electrode was feasible.