Preparation Of Modified HMS Molecular Sieve And Its Catalytic Performance On Oxidation Desulfurization Reaction

These days,environmental protection is one of the hot issues in society,and the sulfur compounds in gasoline combustion will cause serious air pollution.To achieve the depth of oil desulfurization,reducing the sulfur content in gasoline is a task which brooks no delay.The hydrodesulfurization process for the removal of thiophenic compounds must be carried out under more severe operating conditions,and the production cost will be increased.Oxidation desulfurization is a kind of deep desulfurization technology with wide application prospect,which can be used as a follow-up process of hydrodesulfurization.Molecular sieve has become a key research of oxidative desulfurization catalysts because of its large specific surface area and tunable pore size.In this paper,a series of modified HMS oxidation desulfurization catalysts were prepared and characterized by means of XRD,FT-TR,SEM,TEM,N2 adsorption desorption,UV-Vis.The catalytic performance of various catalysts was tested through the oxidative desulfurization?ODS?of thiophene?Th?in model oil.The main research contents were as follows:?1?The HPW-NH₂-HMS catalysts were prepared by using Fe-HMS functionalized with amino groups as carrier and phosphotungstic acid as active component.The characterization results showed that the mesoporous structure of HMS zeolite and the Keggin structure of phosphotungstic acid were retained.And the effects of reaction time,H2O2/S molar ratio,catalyst dosage,and reaction temperature on the desulfurization ratewere investigated as well.The experimental results indicated that under the optimal conditions(reaction temperature,60 ?;H2O2/S molar ratio,8;catalyst dosage,0.1 g·?10mL?^-1;reaction time,120 min),the desulfurization rate of 25%HPW-NH₂-HMS reached up to 93.89%.The dynamic experiment results showed that the oxidation reaction of thiophene was a first-order reaction and the reaction activation energy was 31.9 KJ/mol.?2?Fe/Ti-HMS,Cu/Ti-HMS and Zn/Ti-HMS catalysts were successfully prepared by ultrasonic impregnation and characterized.The analysis results showed that the obtained Ti-HMS molecular sieves had the typical mesoporous structure and metal species dispersed on the surface of Ti-HMS carriers in the form of metallic oxides.The experimental results indicated that metal species effectively improved the catalytic performance,which decreased in the order of Zn/Ti-HMS > Cu/Ti-HMS > Fe/Ti-HMS.?3?Cu²⁺/Fe-HMS of heterogeneous Fenton-like catalyst was prepared by complexation Cu²⁺with amino groups grafted on the surface of Fe-HMS.The characterization results showed that Fe successfully entered into the framework of molecular sieve,and the specific surface area,pore volume and pore size of the catalyst were reduced after surface grafting of amino group and complexation of copper ions.This catalyst performed better than Fe-HMS.This could mainly be attributed to the adsorption effect of the Cu²⁺.The surface of copper ion and iron skeleton showed synergistic effect,the copper ions adsorbed thiophene molecules onto the surface of the catalyst,and the skeleton iron catalyzed the hydroxyl radical production.The two kinds of reactants accumulated continuously on the surface of the catalyst,which greatly improved the desulfurization rate.