The Performance Of Modified Y Zeolites And Copper Supported Carbon Spheres For Removing Sulfur Compounds In Gasoline/diesel Oil

As the combustion of sulphur-containing compounds pose a serious threat to the environment,the production of ultra-low-sulfur gasoline and diesel has become a general trend in the development of clean fuels in the world.Finding more economically viable ultra-deep desulphurization method is one of the most pressing issues in clean fuel production.The adsorptive desulfurization has been considered as an efficient and economical technology due to its low energy consumption,the ambient operation temperature and atmospheric pressure and extensive sources of sorbents.In this paper,the adsorptive removal of benzothiophene in model diesel by NaY and NiY zeolites were studied by a method of combining experimental research with mathematical model calculation.The appropriate adsorption temperature for the removal of benzothiophene in model diesel on NaY and NiY zeolites is 50 ^oC,and the adsorption equilibrium can be achieved in 60 min.Compared with Langmuir and Freundlich models,Toth model is more appropriate to depict the isotherm equilibrium adsorption process of benzothiophene on NaY and NiY zeolites,indicating that the adsorption of benzothiophene on NaY and NiY zeolites is heterogeneous.Thermodynamic studies demonstrate that the adsorption process is exothermal and spontaneous.Investigation of adsorption kinetics shows that the adsorption of benzothiophene on NaY and NiY zeolites follows the pseudo-n order rate expression with n of 1.45 and 1.67,respectively.Using phenolic resin as carbon precursor,copper supported carbon spheres adsorbents were prepared by the chelation of alginic acid with Cu²⁺and subsequent carbonization process.The in-situ supporting of active component copper was realized,and the pore properties and surface chemical properties of carbon spheres were further adjusted by nitric acid oxidation.The surface morphology,pore structure and surface chemical properties of copper supported carbon spheres were characterized by SEM-EDS,N₂ sorption-desorption,FT-IR and Boehm titration.The specific surface area,pore volume,pore size and the concentration of oxygen functional groups of carbon spheres are increased by nitric acid oxidation treatment for 60 min.The adsorption capacity of Cu-AC-60 carbon spheres treated by oxidation for 60 min is1.69 times and 1.82 times that of Cu-AC-0 without oxidation for thiophene and benzothiophene in model gasoline/diesel oil.Correlation of adsorption capacities with pore properties and surface chemical properties of carbon spheres indicates that the increase in specific surface area and pore volume of the micropores and the increase in content of carboxyl and phenolic hydroxyl groups are more helpful to the increase in the sulfur adsorption capacity.The adsorption capacity of Cu-AC-60 adsorbents for thiophene and benzothiophene can reach 70.27%and 72.18%of the initial sulfur capacity after five times adsorption-regeneration cycles,indicating that Cu-AC-60 has better regeneration performance.The adsorptive removal of thiophene sulfide by copper supported carbon spheres is realized by combining acid-base interaction with?-complexation.