New heterogeneous catalyst was synthesized via covalent anchoring of oxovanadium(IV) complex of 5,5′-dibromobis(salicyledene)diethylenetriamine (VO[5-Br(Saldien)]) on the surface of chloro-modified graphene oxide (GO@CTS). The structure of the catalyst was investigated using different characterization techniques such as XRD, SEM, EDX, FT-IR, TG, DTA and ICP-AES analyses. The synthesized heterogeneous oxovanadium(IV) was an efficient catalyst for high yield and selective oxidation desulfurization (ODS) of dibenzothiophene (DBT) as a model oil using H2O2 as oxidant and formic acid as a promoter. The effects of the catalyst mass, reaction temperature and time, formic acid/H2O2 ratio and molar ratio of H2O2 to the total amount of sulfur (O/S) on oxidation desulfurization activity were investigated. Moreover, the prepared catalyst can be easily separated from the reaction mixture and reused six times without a significant loss of catalytic activity and selectivity
