Design of Phosphonated Imidazolium-Based Ionic Liquids Grafted on γ-Alumina: Potential Model for Hybrid Membranes

A critical review on graphene oxide membrane for industrial wastewater treatment

An important way to promote the environmental industry's goal of carbon reduction is to promote the recycling of resources. Membrane separation technology has unique advantages in resource recovery and advanced treatment of industrial wastewater. However, the great promise of traditional organic membrane is hampered by challenges associated with organic solvent tolerance, lack of oxidation resistance, and serious membrane fouling control. Moreover, the high concentrations of organic matter and inorganic salts in the membrane filtration concentrate also hinder the wider application of the membrane separation technology. The emerging cost-effective graphene oxide (GO)-based membrane with excellent resistance to organic solvents and oxidants, more hydrophilicity, lower membrane fouling, better separation performance has been expected to contribute more in industrial wastewater treatment. Herein, we provide comprehensive insights into the preparation and characteristic of GO membranes, as well as current research status and problems related to its future application in industrial wastewater treatment. Finally, concluding remarks and future perspectives have been deduced and recommended for the GO membrane separation technology application for industrial wastewater treatment, which leads to realizing sustainable wastewater recycling and a nearly "zero discharge" water treatment process.

Recent advances in NMR spectroscopy of ionic liquids

This review presents recent developments in the application of NMR spectroscopic techniques in the study of ionic liquids. NMR has been the primary tool not only for the structural characterization of ionic liquids, but also for the study of dynamics. The presence of a host of NMR active nuclei in ionic liquids permits widespread use of multinuclear NMR experiments. Chemical shifts and multinuclear coupling constants are used routinely for the structure elucidation of ionic liquids and of products formed by their covalent interactions with other materials. Also, the availability of a multitude of NMR techniques has facilitated the study of dynamical processes in them. These include the use of NOESY to study inter-ionic interactions, pulsed-field gradient techniques for probing transport properties, and relaxation measurements to elucidate rotational dynamics. This review will focus on the application of each of these techniques to investigate ionic liquids.

Controlled grafting of dialkylphosphonate-based ionic liquids on γ-alumina: design of hybrid materials with high potential for CO2 separation applications

In this work we provide a detailed study on grafting reactions of various dialkylphosphonate-based ILs. Special attention has been devoted to a comprehensive investigation on how the nature of the anion and the organic spacer composition (hydrophilic or hydrophobic groups) could impact the grafting densities and bonding modes of phosphonate-based ILs anchored to γ-alumina (γ-Al₂O₃) powders. For the first time, the bonding of phosphonate-based ILs with only surface hexacoordinated aluminum nuclei was established using both solid-state ³¹P–²⁷Al D-HMQC and ³¹P NMR experiments. It has been demonstrated that the grafting of dialkylphosphonate-based ILs is competing with a hydrolysis and/or precipitation process which could be attractively hindered by changing the anion nature: bis(trifluoromethane)sulfonylimide anion instead of bromide. In additon, independently of the chosen spacer, similar reaction conditions led to equivalent grafting densities with different bonding mode configurations. The CO₂ physisorption analysis on both pure ILs and grafted ILs on alumina powders confirmed that the initial sorption properties of ILs do not change upon grafting, thus confirming the attractive potential of as-grafted ILs for the preparation of hybrid materials in a form of selective adsorbers or membranes for CO₂ separation applications.

Grafting of diethylphophonate-based ILs onto γ-Al₂O₃ powder in solvothermal condition was achieved on mesoporous γ-alumina powder and membrane (A = organic spacer).