The high price and toxicity of ionic liquids(ILs) have limited the design and application of supported ionic liquid membranes(SILMs) for CO_2 separation in both academic and industrial fields. In this work, [Choline][Pro]/polyethylene glycol 200(PEG200) mixtures were selected to prepare novel SILMs because of their green and costeffective characterization, and the CO_2/N_2 separation with the prepared SILMs was investigated experimentally at temperatures from 308.15 to 343.15 K. The temperature effect on the permeability, solubility and diffusivity of CO_2 was modeled with the Arrhenius equation. A competitive performance of the prepared SILMs was observed with high CO_2 permeability ranged in 343.3–1798.6 barrer and high CO_2/N_2 selectivity from 7.9 to 34.8.It was also found that the CO_2 permeability increased 3 times by decreasing the viscosity of liquids from 370 to38 m Pa·s. In addition, the inherent mechanism behind the significant permeability enhancement was revealed based on the diffusion-reaction theory, i.e. with the addition of PEG200, the overall resistance was substantially decreased and the SILMs process was switched from diffusion-control to reaction-control.
Tengteng FanWenlong XieXiaoyan JiChang LiuXin FengXiaohua Lu
Halogen bonding interactions between several halogenated ion pairs and CO2 molecules have been investigated by means of density functional theory calculations. To account for the influence of solvent environment, the implicit polarized continuum model was also employed. The bromide and iodide cations of ionic liquids (ILs) under study can interact with CO2 molecules via X O interactions, which become much stronger in strength than those in the complexes of iodo-perfluorobenzenes, very effective halogen bond donors, with CO2 molecules. Such interactions, albeit somewhat weaker in strength, are also observed between halogenated ion pairs and CO2 molecules. Thus, the solubility of CO2 may be improved when using halogenated ILs, as a result of the formation of X O halogen bonds. Under solvent effects, the strength of the interactions tends to be weakened to some degree, with a concomitant elongation of intermolecular distances. The results presented here would be very useful in the design and synthesis of novel and potent ILs for CO2 physical absorption.
LI HaiYingLU YunXiangZHU XiangPENG ChangJunHU JunLIU HongLaiHU Ying
Vapor pressures were measured for acetonitrile+1-butyl-3-methylimidazolium chloride([C4mim][Cl]),+1-butyl-3-methylimidazolium tetrafluoroborate([C4mim][BF4])and+1-hexyl-3-methylimidazolium chloride([C6mim][Cl])at temperatures of 313 to 353 K by a quasi-static method.The experimental data for the binary systems were correlated by the non-random two liquid(NRTL)equation with an average absolute relative deviation(AARD)of within 1.84%.The results indicate that the three ionic liquids(ILs)can result in a negative deviation from the Raoult's law for the binary solutions containing acetonitrile,and the affinity between ILs and acetonitrile molecules follows the order[C4mim][BF4]+acetonitrile N[C4mim][Cl]+acetonitrile N[C6mim][Cl]+acetonitrile.
Mesoporous TiO_2-B/anatase microparticles have been in-situ synthesized from K_2Ti_2O_5 without template.The TiO_2-B phase around the particle surface accelerates the diffusion of charges through the interface,while the anatase phase in the core maintains the capacity stability.The heterojunction interface between the main polymorph of anatase and the trace of TiO_2-B exhibits promising lithium ion battery performance.This trace of 5%(by mass) TiO_2-B determined by Raman spectra brings the first discharge capacity of this material to 247 mA · h ·g^(-1),giving 20%improvement compared to the anatase counterpart Stability testing at 1 C reveals that the capacity maintains at 171 mA·h·^(-1),which is better than 162 mA·h·g^(-1) for single phase anatase or 159 mA·h·g^(-1) for TiO_2-B.The mesoporous TiO_2-B/anatase rnicroparticles also show superior rate performance with 100 mA·h·g^(-1) at 40 C,increased by nearly 25%as compared to pure anatase.This opens a possibility of a general design route,which can be applied to other metal oxide electrode materials for rechargeable batteries and supercapacitors.
