Process Research On Desulfurization Performance Of Supported Ionic Liquids

Excessive emission of sulfur dioxide has caused serious problems and is harmful to human health and the environment.The traditional flue gas desulfurization treatment method has various inherent defects,including the generation of by-products,the volatilization of solvents,high operating costs,and high energy consumption.Therefore,it is of great significance to develop a new absorbent with high efficiency,green,recycling for sulfur dioxide absorption.Ionic liquids are used for sulfur dioxide capture due to their low vapor pressure,high thermal stability and adjustable structure.However,ionic liquids have high viscosity and have high mass transfer resistance when used in adsorption processes.It will affect the absorption efficiency and absorption effect,and to some extent hinder its industrial application process.Supporting ionic liquid into the carrier material can reduce these defects.Considering the cost of industrial application,this study uses activated carbon as the carrier material,selects two cheap alcohol amine ionic liquids to load on the activated carbon,prepares supported ionic liquids(SILs),and conducts flue gas desulfurization experiments under different conditions,the study have shows that the adsorption of SO₂ by SILs is a fast and efficient process,and the prepared two supported alcoholamine ionic liquids have good SO₂desulfurization ability,and the adsorption equilibrium is reached within 30 minutes,which is comparable to pure ionic liquids,it saves about 60?70%of the time,reduces the viscosity of the pure ionic liquid and enhances the mass transfer effect;among them,the molar absorption of ILs in TC-AC-1/4 and TL-AC-1/4 can reach 7.33 mol/mol and 2.27mol/mol respectively;After five consecutive adsorption-desorption cycles of SILs,their excellent adsorption performance has not changed significantly,and their saturated adsorption capacity remains above 90%.It shows that SILs have good cycle performance and good industrial application prospects.For the two kinds of activated carbon-supported alcoholamine ionic liquids,chemical adsorption is the main reason for the absorption of SO₂,but physical adsorption cannot be ignored.However,the synergy between the structure of different ILs and AC in SILs has different effects on the adsorption of SO₂.In addition,the choice of ionic liquids with different cation structures will reflect the different interactions with sulfur dioxide.In order to further explain the adsorption mechanism,we selected activated carbon materials to support-NH₂functional ionic liquids[APMIM][Br]and conventional imidazole ionic liquids[BMIM][Br]to prepare SILs.It was found that the two kinds of SILs had a good desulfurization ability for SO₂,and the maximum molar absorption of ILs in APMIM-AC-1/4 and BMIM-AC-1/3 could reach 3.05mol/mol and 1.67 mol/mol,respectively;After five successive adsorption-desorption cycles,the adsorption capacity of APMIM-AC on SO₂ is weaker than that before regeneration,and the capacity decreases by about 22%;However,For BMIM-AC,its excellent adsorption capacity has not changed significantly,which is related to the adsorption mechanism of IL in SILs,APMIM-AC not only has physical adsorption of SO₂,but also with the occurrence of chemical adsorption,such as N-H bond participates in the reaction,and a new bond N-S bond is formed,while the adsorption process of BMIM-AC on SO₂ only has physical adsorption,which is only controlled by weak interactions,such as hydrogen bonds,van der Waals forces,and Coulomb interactions.As we all know,the actual flue gas components are complex,generally including N₂,O₂,CO₂,H₂O,etc.Therefore,this article takes SILs as the research object,and investigates the influence of single component and dual component on the desulfurization performance of SILs.The result shows that the single component of flue gas has an inhibitory effect on the absorption of SO₂.When CO₂ and O₂ are introduced at the same time,the desulfurization performance of SILs is inhibited.But when H₂O and O₂ coexist,which promotes the adsorption of SO₂ on SILs.SILs have great industrial application prospects,but a lot of work needs to be done before the supported ionic liquids are applied to SO₂ capture.For example,in the actual flue gas conditions,it is of great significance and value to develop new functional ionic liquids to absorb a large amount of sulfur dioxide.In addition,in order to find the best carrier material of ionic liquid as desulfurizer,more efficient and low-cost mesoporous materials need to be considered.