# Ionic Liquids Hybridization for Carbon Dioxide Capture: A Review
## 4 Application of ILs Hybrid Material in Carbon Dioxide
### ILs/Mof
A total of seven [BMIM] ILs coupled with various anions, [PF\({}_{6}\)]\({}^{-}\), trifluorometanesulfonate [CF\({}_{3}\)SO\({}_{3}\)]\({}^{-}\), methylsulfate [MeSO\({}_{4}\)]\({}^{-}\), methanesulfonate [MeSO\({}_{3}\)]\({}^{-}\), hexafluoroantimonate [SbF\({}_{6}\)]\({}^{-}\) and octysulfate [CoSO\({}_{4}\)]\({}^{-}\), were selected to combine with Cu-BTC. The results indicated the gas uptake for simulation conducted by using Dreiding force field was in a good agreement with experimental work for all gases. The study was further explored by synthesis of new combination of Cu-BTC/ILs to confirm the transferability of this approach on other composites. Two [BMIM] ILs with dibutylphosphate [DBP]\({}^{-}\) and dicyanamide [DCA]\({}^{-}\) were selected to be combined with Cu-BTC. Before undergoing an adsorption test, both materials were characterized. Analysis on XRD revealed the crystal structure of Cu-BTC was preserved upon the introduction of ILs. In terms of gas separation performance, both materials showed better selectivity in CO\({}_{2}\)/CH\({}_{4}\), CO\({}_{2}\)/N\({}_{2}\) and CH\({}_{4}\)/N\({}_{2}\) compared to pristine MOF low pressure conditions (0.5-10 bar). The result was also in agreement with simulation data obtained by using a Dreiding force field. This shows that the type of computational method that was proposed initially is reliable for gas uptake prediction. However, in terms of surface area and porosity obtained from BET, it had been determined that the CO\({}_{2}\), CH\({}_{4}\) and N\({}_{2}\) adsorption by hybrid materials were lower than pristine Cu-BTC. [PERSON] and co-workers synthesized MOF/IL hybrid materials by combining two MOFs, UiO-66 and Nu-1000 with AAILs [41]. The AAILs were [EMIM][Gly] and [EMIM][Phe]. The experimental work was accompanied by simulation in order to obtain better understanding due to the inconsistent results on CO\({}_{2}\) uptake by both studies. The XRD pattern showed undisrupted MOF framework for all concentrations of IL loading (5, 10 and 30 vol%). Moreover, the addition of ILs into MOF led to a reduction in material surface area and pore volume. Regardless of the amount of AAILs added, the CO\({}_{2}\) uptake of hybrid material was lower than pristine MOF. This could possibly be due to pores blocking caused by the presence of ILs, thus preventing the entrance of CO\({}_{2}\) in MOF framework. A study on pore size distribution (PSD) revealed the accumulation of AAILs occurred greatly on one channel of MOF, mainly in pore windows which directly affected the number of active sites for CO\({}_{2}\) adsorption. The authors also conducted a study by employing GCMC simulation for Nu-1000/[EMIM][Gly] in which two models were adopted, namely, random and blocked. For pristine Nu-1000, both models showed good agreement with experimental work. However, for Nu-1000/[EMIM][Gly], the CO\({}_{2}\) capture demonstrated by simulation showed opposite outcome with experimental result. While the experimental results indicate the opposite trend, both models suggest that Nu-1000/[EMIM][Gly] exhibits a greater CO\({}_{2}\) uptake compared to pristine Nu-1000. Additionally, it was identified that blocked models produced closer outcome to experimental result, thus confirming the existence of block pore in MOF. However, this finding could differ depending on ILs and MOF types. In 2019, [PERSON] et al. conducted a study on ILs impregnation onto ZIF-8 for CO\({}_{2}\)/CH\({}_{4}\) separation [110]. A total of 10 ILs with different alkyl chains and anion were selected to be loaded into ZIF-8. Textural analysis on ZIF-8/ILs materials revealed a reduction in total pore volume and surface areas compared to pristine MOF due to blockage effect caused by IL incorporation. However, the values for total pore volume and surface area are almost similar for all hybrid materials resulting from similar ILs' molar composition impregnated into ZIF-8. The XRD pattern of ZIF-8/ILs indicates no structural changes occurred when compared to pristine ZIF-8.