Metal/Al₂o₃-reduced Graphene Oxide Preparation And Adsorptive Desulfurization Performance For Diesel Oil

In recent years,with the continuous improvement of social productivity,people pay more and more attention to the environmental pollution,especially air pollution.Among the variety of pollutants,SO_x emissions from the combustion of sulfur compounds contained in diesel oil have received wide attention.Therefore,many studies have focused on ultra-deep desulfurization technology,which could produce“zero”sulfur fuels.Among several effective desulfurization processes,selective adsorption desulfurization provides a promising approach for the removal of thiophene and its derivatives from hydrocarbon fuels with the potential to realize low sulfur levels under normal pressure and temperature conditions.In this work,firstly,graphene oxide?GO?was prepared by“improved method”.Secondly,surface of GO was modified by boehmite to prepare a kind of composite support with large specific surface area and suitable chemical activity.The influences of different preparation conditions on the specific surface area,pore structure and crystal structure of the composite were studied and the mechanism for the formation of boehmite-reduced graphene oxide?Boehmite-RGO?composite was discussed.Thirdly,MO/?-Al₂O₃-RGO?M=Cu or Ni?adsorbents with different MO mass fraction were synthesized to investigate their effects on the adsorbents specific area,pore structure,crystal structure and their active phase dispersion conditions.Finally,the adsorptive desulfurization performances of the prepared adsorbents were evaluated using static adsorption method under ambient conditions,as well as the regeneration performances of them were estimated.The results indicated that GO was partially reduced during the hydrothermal treatment and the interlayer d-spacing was decreased owing to the occurrence of heat decarboxylation reaction.Compared with that of graphite,the ratio of length to thickness of RGO has greatly improved during secondary stacking process and its surface has fold structure,leading to a large specific surface area of 313.0 m²/g.Boehmite was anchored on the GO surface by dehydration condensation between partial Al-OH with-OH and-COOH of GO,enlarging the interlayer d-spacing of RGO and preventing the formation of the interlayer lattice of RGO.Although the structural integrity of RGO was influenced,the laminated mesoporous structure of RGO could still be maintained as a whole.The BET areas of prepared Boehmite-RGO composites have been increased.The surface area reaches a maximum of 378.6 m²/g when the prepare conditions are:pH value of 7 and mass ratio of Al₂O₃ to GO of 6 for the initial mixture of GO-Al-Cl-NH₃-H₂O,which is 20.8%higher than that of RGO?313 m²/g?.For the MO/?-Al₂O₃-RGO adsorbents prepared,the active components were highly dispersed on the surface of composite support in the form of[Al-O-M-O-Al].The results of static adsorption desulfurization suggest that the adsorption capacity reaches to the maximum values of 6.0 mg S/g and 5.9 mg S/g when the loading amounts of active component are:2 wt.%CuO and 3 wt.%NiO,respectively,and the saturated adsorption capacities of them are obviously enhanced in comparison with that of pure RGO?3.9 mg S/g?.The results of adsorption capacities for regenerated adsorbents also show that the regeneration performance of MO/?-Al₂O₃-RGO adsorbents is much more practical than that of the pure RGO adsorbent.