Synthesis Of Metal Organic Framework Materials And Its Adsorptive Desulfurization Performance For Model Oil

Gasoline combustion releases a large amount of sulfur oxide?SO_x?which seriously harms the ecological environment and human health.Therefore,deep desulfurization of gasoline has attracted great attention around the world.Adsorption desulfurization?ADS?has been extensive studied in recent years due to its advantages of low cost,mild conditions,simple operation and the ability to protect octane number from loss in deep desulfurization.Metal-organic framework materials?MOFs?has been widely used in adsorption desulfurization due to its large specific surface area,high porosity and easy modification.In this paper,two methods,loading phosphor-tungstic acid?PTA?onto MOFs in-situ synthesis and preparation optimization of MOFs by deep solvent,were used to modulate the acid sites,morphologies and structures of MOFs.And their adsorption desulfurization properties of model oil were studied.The main research contents and conclusions are displayed as follows:?1?The PTA@MOF-808 adsorbents were successfully prepared by loading phosphor-tungstic acid?PTA?onto MOF-808 through in-situ synthesis method.The adsorbents were characterized by XRD,FT-IR,N₂ adsorption-desorption,and SEM methods.Adsorption desulfurization properties of PTA@MOF-808 were investigated.The experimental results showed that the PTA could introduce new acid sites to improve the adsorption capacity and selectivity of adsorbent on thiophene organic sulfur,and shorten the adsorption equilibrium time from 30 min to 5 min.The optimal adsorption conditions were shown as follows:10 g model oil of 200 ppm S,50 mg adsorbent,adsorption temperature 30?,adsorption time 5 min.Under the adsorption conditions,the maximum adsorption capacity of 20 wt.%PTA@MOF-808 for thiophene?TP?,benzo-thiophene?BT?and dibenzothiophene?DBT?were 18.5,25.4and 34.9 mg·g^-1,respectively.This was mainly due to the higher selectivity of PTA to DBT and the stronger interaction between DBT and metal active center Zr⁴⁺.In addition,the adsorption of BT follows the quasi-second-order kinetic model and includes physical adsorption and chemical adsorption.?2?HKUST-1 was prepared by different deep eutectic solvent?acidic Ch Cl/CH₃COOH and alkaline Ch Cl/m-Urea?and hydrothermal method?Et OH/H₂O?.The structure and morphology of HKUST-1 was characterized by FT-IR,XRD and Raman.The experimental results showed that the optimal conditions were as follows:10 g model oil of 500 ppm S,0.1 g absorbent,adsorption temperature 30?,and adsorption time 120 min.Under this condition,the adsorption capacity to DBT was as follows:HKUST-1?Ch Cl/m-Urea?(46.8 mg·g^-1)?HKUST-1?Et OH/H₂O?(46.8 mg·g^-1)>HKUST-1?Ch Cl/CH₃COOH?(45.7 mg·g^-1),which was consistent with the sequence of specific surface area and pore volume.Desulfurization capacity of HKUST-1 synthesized by three solvents on three model oils were DBT>BT>TP.This reason was the strong soft hard acid base interaction between Cu²⁺and DBT.In addition,the kinetic analysis of DBT adsorption on HKUST-1 indicates that the quasi-secondary kinetic model can reasonably describe the adsorption process,and chemical adsorption is dominant at this time.