Design And Synthesis Of Guanidinium-based Functionalized Ionic Liquids Immobilised On Siliga Gel And The Sorption Performance Of SO₂

The emission of SO₂ in the process of industrial production seriously causes the environment pollution.The calcium treatment technology widely used in industrial flue gas desulfurization is not only unable to utilize the resources of sulfur,but also produces a large number of solid wastes that are difficult to handle.Ionic liquids have become an effective SO₂ remover because of their low vapor pressure,good thermal stability,recycle and the designability of structural.The study of SO₂ absorption by ionic liquids has been drawn extensive attention.Guanidinium-based ionic liquids interact well with SO₂ and are often used as SO₂ absorbent.The functional group with specific interaction with SO₂ can be introduced into the ionic liquid structure and form the functional ionic liquid,which may further improve its absorption capacity for SO₂.In this thesis,ether groups are introduced into guanidinium-based ionic liquids,and the functionalionicliquids[1,1,3,3-tetramethylguanidinium][Poly?ethylene glycol?bis?carboxymethyl?ether]?[TMG][PBE]?is designed and synthesized.The ionic liquid is characterized by ¹HNMR and FTIR.[1,1,3,3-tetramethylguanidinium][Suberic acid]?[TMG][SUB]?is synthesized to verify the effect of ether groups on the desulfurization performance of ionic liquids.In order to further investigate the effect of the number of ether groups in the structure of ionic liquids on the desulfurization performanceofionicliquids,[1,1,3,3-tetramethylguanidine methoxypolyethyleneglycols][Poly?ethyleneglycol?bis?carboxymethyl?ether]?[TMG-MPG][PBE]?and[1,1,3,3-tetramethylguanidinemethoxypolyethyleneglycols][Br]?[TMG-MPEG][Br]?aresynthesized.Theabsorptionandregenerationof[TMG-MPEG][Br]and[TMG-MPG][PBE]are compared at different conditions that adsorbing the pure SO₂ at 20?-50?and adsorbing the different partial pressure SO₂ at20?.It shows that the saturated absorption amount of[TMG-MPEG][Br]is0.714gSO₂/gILandthatof[TMG-MPEG][PBE]is0.926gSO₂/gIL.Both[TMG-MPEG][Br]and[TMG-MPEG][PBE]have good regeneration ability by 5 times absorption desorption cycle experiments.When the ionic liquid is used for the removal of the gas SO₂,the gas-liquid contact method is often used for absorption.However,due to the high viscosity and high price of the ionic liquid,the liquid distribution is difficult,the mist entrainment is serious,and the desulfurization cost is high.In order to make up these shortcomings,the ionic liquid can be fixed on the porous solid material,so that the contact area of the two phases is increased,and the influence of the above mass transfer problem is overcome to the greatest extent.At the same time,the amount of the ionic liquid is greatly reduced,and the cost is reduced.There are more advantages in industrial applications.In this paper,four kinds of ionic liquids are immobilized on silica gel by impregnation method,and[TMG-MPEG][Br]-SiO_2,[TMG-MPEG][PBE]-SiO_2,[TMG][SUB]-SiO₂ and[TMG][PBE]-SiO₂ desulfurization materials are prepared and characterized.It is found that the channels of the four desulfurization materials are relatively regular,and the pore structure is stable,which is suitable for SO₂ adsorption.The desulfurization performance and regeneration ability of desulphurization materials with different loading ratios are discussed at different conditions that adsorbing the pure SO₂ at 20?-50?and adsorbing the different partial pressure SO₂ at 20?.It is found that the sulfur capacities of the four desulfurization materials are higher than those of pure ionic liquids and blank silica gel.The[TMG-MPEG][Br]-SiO_2,[TMG-MPEG][PBE]-SiO₂and[TMG][PBE]-SiO₂desulphurizationmaterialsstillshowgoodadsorptionpropertiesafterfive adsorption-desorption cycles.This work provides the experimental basis for the design of functional ionic liquids and the industrial application of desulfurization materials supported with ionic liquids.