Research On Physical And Desulfuization Property Of Ionic Liquid And Its Binary System

The rapid development of industry has brought great convenience for mankind,but also caused serious environmental pollution problems.The treatment of SO₂has become one of the most important tasks.Although SO₂removal can be performed by traditional desulphurization technology,it is easy to produce a large amount of solid waste,and the sulfur resources cannot be recycled.Ionic liquids have attracted more attention because of its low vapor pressure,non-volatilization and good recycling properties.In this paper,the density and viscosity of two kind of ionic liquids containing ether-chain(including[N_122,1O2][Tf₂N]and[N_122,1O2][BF₄])were studied.The coefficient of thermal expansion,molecular volumes,standard entropy,lattice energy were obtained according to the value of density and viscosity.The desulfurization performance of the two kind of pure ionic liquids was investigated.The saturated absorption capacity was 1.5mol SO₂/mol IL and 2.5 mol SO₂/mol IL,respectively.After five continuous adsorption-desorption cycles,the absorption performance of the ionic liquids remained constant,which illustrate that the ionic liquids have good recycling property.¹H NMR and FT-IR spectrum analysis indicated that their is a physical interactions existed between the ILs and SO₂at the experimental conditions.The density and viscosity of the binary system of ILs and molecular solvents（ethanol,propyl alcohol and water）were measured in the temperature range of 293.15 K-313.15 K.The influence of temperature and mole ratio of ionic liquid to molecular solvent on the density and viscosity of binary systems are discussed.The results indicated that the density and viscosity decrease with the increase of temperature under the same composition.At the same temperature,as the molar fraction of ionic liquid decreases,the density of the binary system decreases,while the viscosity of the binary system increases as the molar fraction of molecular solvent decreases.The thermodynamic properties of excess molar volume and apparent molar volume are calculated according to the density data.The results of viscosity indicated that the viscosity shows a decreasing trend with the increase of temperature under the same composition.At the same temperature,the viscosity of the binary system increases as the molar fraction of molecular solvent decreases.Through the viscosity data,the excess viscosity is calculated and correlated.In all binary systems,the desulfurization ability showed an upward trend as the content of ionic liquid increased.The desulfurization capacity of[N_122,1O2][Tf₂N]/ethanol is less than of the pure ILs.However,the desulfurization ability of[N_122,1O2][BF₄]/molecular solvent binary system are higher than that of the pure ILs.When the ionic liquid content was 95%in the binary system,the SO₂removal property reach the maximum value.