Grafting cellulose acetate with ionic liquids for biofuel purification membranes : Influence of the anion

Fast Track to Acetate-Based Ionic Liquids: Preparation, Properties and Application in Energy and Petrochemical Fields

Acetate-based ionic liquids (AcILs), as a kind of typical carboxylate-based ILs, display excellent structure tunability, non-volatility, good solubility to biomass, and favorable adsorption capacity, etc. These unique characteristics of AcILs make them important candidates for a range of applications in the field of energy and in the petrochemical industry. This paper intends to provide a comprehensive overview of recent advances in AcILs, including pure AcILs, AcIL-based multi-solvents, and AcIL-based composites, etc. Preparation methods, with one- and two-step synthesis, are reviewed. The relationship between properties and temperature is discussed, and some physical and thermodynamic properties of different AcILs are summarized and further calculated. The applications of AcILs in the fields of biomass processing, organic synthesis, separation, electrochemistry, and other fields are reviewed based on their prominent properties. Thereinto, the dual functions of AcILs as solvents and activators for biomass dissolution are discussed, and the roles of AcILs as catalysts and reaction mediums in clean organic synthesis are highlighted. Meanwhile, the reaction mechanisms of AcILs with acid gases are posed by means of molecular simulation and experimental characterization. Moreover, AcILs as electrolytes for zinc batteries, supercapacitors, and electrodeposition are particularly introduced. Finally, the future research challenges and prospects of AcILs are presented.

Preparation of Alkaline Polyelectrolyte Membrane Based on Quaternary Ammonium Salt-Modified Cellulose and Its Application in Zn-Air Flexible Battery

In this study, a type of alkaline solid polyelectrolyte (ASPE) membrane was developed via the introduction of microcrystalline cellulose (MCC) and its modified product (QMCC) into the polyvinyl alcohol (PVA) matrix. In this process, green NaOH/urea-based solvent was used to achieve a good dispersion of MCC in the PVA matrix; meanwhile, the OH^- groups in the NaOH/urea-based solvent provided an alkaline environment for good ion conductivity. Compared to the MCC-incorporated ASPE, further improved conductivity was achieved when the MCC was modified with quantitative quaternary ammonium salt. TGA showed that the addition of QMCC improved the water retention of the matrix, which was beneficial to the OH^- conduction in the system. Compared to the control (50 mS cm^-1), a maximum conductivity of 238 mS cm^-1 was obtained after the incorporation of QMCC in the PVA matrix. Moreover, the tensile strength of the polymer electrolyte were also significantly increased with the addition of QMCC. Finally, this developed ASPE membrane was used in assembling a flexible Zn-air battery and showed a promising potential in the development of flexible electronic devices.

Water Vapour Promotes CO2 Transport in Poly(ionic liquid)/Ionic Liquid-Based Thin-Film Composite Membranes Containing Zinc Salt for Flue Gas Treatment

A poly(ionic-liquid) (PIL) matrix can be altered by incorporating additives that will disrupt the polymer chain packing, such as an ionic liquid (IL) and inorganic salts to boost their exploitation as materials for membrane production to be used in CO2 capture. Herein, potential of PIL/IL/salt blends is investigated on the example of poly(diallyldimethyl ammonium) bis(trifluoromethylsulfonyl)imide (P[DADMA][Tf2N]) with N-butyl-N-methyl pyrrolidinium bis(trifluoromethylsulfonyl)imide ([Pyrr14][Tf2N]) and zinc di-bis(trifluoromethylsulfonyl)imide (Zn[Tf2N]2). Composite material with IL and a higher amount of Zn2+ showed an increase in the equilibrium CO2 sorption capacity to 2.77 cm3 (STP)cm −3 bar−1. Prepared blends were successfully processed into thick, dense membranes and thin-film composite membranes. Their CO2 separation efficiency was determined using ideal and mixed-gas feed (vol% CO2 = 50 , dry and with 90% relative humidity). The dominant role of solubility in the transport mechanism is confirmed by combining direct gravimetric sorption measurements and indirect estimations from time-lag experiments. The maximum incorporated amount of Zn2+ salts increased equilibrium solubility selectivity by at least 50% in comparison to the parent PIL. All materials showed increased CO2 permeance values by at least 30% in dry conditions, and 60% in humidified conditions when compared to the parent PIL; the performance of pure PIL remained unchanged upon addition of water vapor to the feed stream. Mixed-gas selectivities for all materials rose by 10% in humidified conditions when compared to dry feed experiments. Our results confirm that the addition of IL improves the performance of PIL-based composites due to lower stiffness of the membrane matrix. The addition of Zn2+-based salt had a marginal effect on CO2 separation efficiency, suggesting that the cation participates in the facilitated transport of CO2.