The effect of the addition of 1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim][BF4]) on the formation rates of CO2 hydrates was investigate. The isothermal and isobaric methods were used to measure the formation rates of CO2 hydrates. As compared to those of pure water, the data of phase equilibrium changed greatly. The effects of pressure, temperature, and the concentration of [C4mim][BF4] aqueous solution on the formation rates of CO2 hydrates were investigated. With a constant concentration of [C4mim][BF4], the rate of gas consumption was enhanced with the lowering of experimental temperature. However, a decrease in pressure exerted an opposite effect on the rate of gas consumption. Moreover, the addition of [C4mim][BF4] raised the equilibrium pressure of hydrate formation at the same temperature.
Qi ChenYong YuPeng ZengWei YangQianqing LiangXiaoming PengYansheng LiuYufeng Hu
Ionic liquids (ILs) have been regarded as the potential novel solvents for improved analytical-and process-scale separation methods. The development of methods for the recovery of ILs from aqueous solutions to escape contamination and recycle samples will ultimately govern the viability of ILs in the future industrial applications. Therefore, in this paper a new method for separation of ILs from their dilute aqueous solutions and simultaneously purification of water was proposed on the basis of the CO2 hydrate formation. For illustration, the dilute aqueous solutions with concentrations of ILs ranging from 2×10-3 mol% to 2×10-1mol% were concentrated.The results show that the separation efficiency is very impressive and that the new method is applicable to aqueous solutions of both hydrophobic and hydrophilic ILs.Compared to the literature separation method based on the supercritical CO2,the new method is applicable to lower concentrations,and more importantly, its operation condition is mild.
Xiaoming PengYufeng HuYansheng LiuChuanwei JinHuaijing Lin
