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

摘要

A novel desulfurization process of gasoline was realized via sodium metaborate (NaBO_2) electroreduction with pulse voltage using a boron-doped diamond (BDD) thin film electrode under mild conditions. The results of cyclic voltammetry and ~(11)boron (B) nuclear magnetic resonance (NMR) confirmed that NaBO_2 was converted into sodium borohydride (NaBH_4) by electroreduction and the electroreduction voltage ranged from -1.2V 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 chro-matography/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.