| In recent years, it is particularly important to study the capture of greenhouse gas CO2 which leads to greenhouse effect threatening people’s health and living environment. As a kind of green CO2 absorber, ionic liquids has attracted a wide spread attention of researchers due to designability, thermal stability, non-toxic, and involatile. Immobilized ionic liquids in porous material can not only effectively reduce the amount of the ionic liquids and promote mass transfer as well as increase CO2 absorption capacity, but also realize the gas separation with fixed bed or fluidlized bed and easy to recycle. This paper is aimd at preparation of immobilized ionic liquid with high fixing amount, large sepcific surface and pore volume using different immobilized methods and investigates the effect of different operating conditions on the immobilization as well as evaluates ionic liquid’s adsorbability ofCO2. The main works focused on the following several aspects:1. Two imidazolium ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate [Bmim]BF4 and 1-butyl-3-methyllimidazolium hexafluorophosphate [Bmim]PF6 were synthesized by the tranditional two-step method. The pure of intermediates [Bmim]Br, two target ionic liquid [Bmim]BF4 and [Bmim]PF6 were 99%、92%'98% respectively.2. Ionic liquid [Bmim]BF4 was immobilized in the mesoporous silica SBA-15 by the dipping-evaporation method and dipping-filtration method. Supported ionic liquid prepared by the later method had larger specific surface area and volume under the same ionic liquid fixing amount comparing with the one preared by the former method. The ionic liquid fixing rate reached to as high as 33.58% when selecting acetone as dispersant, ionic liquid and carrier quality ratio as 6:1 and dipping 9 hours. Investigated the CO2 adsorption performance of SBA-15 with different fixing amount of ionic liquid, the results showed that the maximum adsorption amount of CO2 were 34.80 mg·g-1 (dipping-evaporation method) and 40.26 mg·g-1(dipping-filtration method) respectively.3. Supercritical Fluid Deposition(SFD) method could successfully immobilize ionic liquid [Bmim]BF4 on the SBA-15 by using organic solvent(methanol, acetone and ethanol) as the co-solvent, ordered mesoporous material SBA-15 as the carrier and ionic liquid [Bmim]BF4 as the precursor and could keep porous characteristic well when campared with tranditional dipping-evaporption and diping-filtration method. The adsorption amount of CO2 could reach to 51.31 mg·g-1. The influence of deposition pressrue, tempreture and deposition time on fixing amount were studied in the preparation process of prepared [Bmim]BF4@SBA-15 by SFD method. The results showed that the fixing amount increased with the increasment of deposition pressure and the deposition tempreture had little influence on the fixing amount Moreover, the ionic liquid fixing amount increased when extended the deposition time and tend to achieve balance after 12h.4. The CO2-organic solvent-[Bmim]BF4 ternary system thermodynamics were studied, found that the expansion degree of organic solvent were change with the exist of [Bmim]BF4, and the system was composed of the [Bmim]BF4-rich phase and CO2-rich phase. In addition, the SFD method could also be applied to the mesoporous silical material KIT-6 with complex 3d channel and mesoporous silical material MCM-41 with smaller pore. |
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