Modification Of MOFs Derived Porous Carbon And Its Oxidative Desulfurization Performances

The existence of organic sulfide and its derivatives in fuel oil is a great threat to the ecological environment and human health.The deep desulfurization of fuel oil has become a particularly urgent project.Among many desulfurization technologies,oxidative desulfurization is considered as one of the most promising desulfurization strategies because of its mild operating conditions and high removal efficiency for aromatic sulfur compounds.The key technology of oxidative desulfurization is the preparation of high-efficient catalysts.Thus,to meet the goal of high-efficient desulfurization,metal organic frameworks(MOFs)derived porous carbons as oxidative desulfurization catalysts with excellent texture properties and well dispersed metal active sites were designed and constructed.Firstly,a series of porous carbon HPW@ZC catalysts were prepared by direct calcination and isovolumetric impregnation methods with zeolites based imidazolium ester framework material ZIF-8 as precursor and phosphotungstic acid(HPW)as active component.And,X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),transmission electron microscopy(TEM),scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS)and low-temperature N2 adsorption-desorption were used to characterize samples' physico-chemical properties.The results illustrated that the HPW loaded on ZC900 retained its complete Keggin structure.Benefiting from the optimization investigating of the experimental parameters,the optimal desulfurization conditions were confirmed as follows: HPW loading amount was 40%,reaction temperature was 60 °C,O/S=6.Under the optimum experimental conditions,the catalyst40%HPW@ZC900 presented 100% desulfurization rate within 90 min and the desulfurization rate was only decreased by 9.7% after five cycle experiments.Second,through employing in-situ synthesis method,a series of MIL@ZIF-HPW-x composite materials were synthesized by ZIF-8 coating MIL-101(Fe)and HPW,which were used as precursors to prepare porous carbon MZC-W-x catalysts by a direct calcination strategy.The characterization results depicted that the catalyst contained?-Fe2O3,WO3 and uniformly distributed metal active sites.Benefiting from the optimization investigating of the experimental parameters,the optimum desulfurization conditions are: HPW doping amount was 80 mg,reaction temperature was 60 °C,O/S=6.Under the optimum experimental conditions,MZC-W-80 catalyst showed 98.9%desulfurization efficiency within 60 min,and the desulfurization rate was only decreased by 7.1% after five cycle experiments.Finally,based on the analysis and discussion of oxidative desulfurization mechanism,it was concluded that the excellent oxidative desulfurization performance s benefited from the synergistic effects of catalyst,H2O2 and methanol.In addition,GC-MS technology showed that the conversion process from DBT to DBTO2 was not one-step direct conversion,and DBTO was the intermediate product in the conversion process.