Effect of Ultrasonic Irradiation on Preparation and Properties of Ionogels

Abstract

Silica-gel matrices containing ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate viz. ionogels have been synthesized using one-pot nonhydrolytic sol-gel method and taking tetraethyl orthosilicate (TEOS) as starting precursor. Effect of ultrasonic irradiation on pore parameters of ionogels and vibrational properties of the IL upon confinement in the porous matrix has been investigated. The synthesized gels have been characterized by BET, DSC, TGA, and FTIR. BET analysis shows some changes in the pore parameters due to ultrasonic irradiation. DSC results indicate shift in glass transition temperature upon confinement of the IL. The FTIR spectra show changes in vibrational bands on confinement, particularly, the bands related to the imidazolium ring; aliphatic chain and anionPF6 −of the IL are found to shift upon confinement in porous silica matrix obtained due to ultrasonic irradiation. Ultrasonic irradiation has been found to affect the gelation dynamics and kinetics and pore parameters.

Low Frequency Ultrasound Enhanced Dual Amination of Biochar: A Nitrogen-Enriched Sorbent for CO2 Capture

“…Upon further increase of the sonication time, cavitation disarranged the orientation of the layered structure of biochar, consequently blocking the pores and reducing the adsorption capacity. Similar phenomena were observed by Verma et al and Hamdaoui et al Furthermore, it is observed from Table that both surface area (based on CO 2 and N 2 analysis) and pore volume of biochar were decreased by amine functionalization, indicating that amines physically loaded on the solid support formed a layer that blocked some of the pores. Similar observations have also been reported by Yue et al and Teng et al where they used TEPA-grafted mesoporous silica and KOH-amine modified silica, respectively, for CO 2 adsorption.…”

“…Q700), typically with 3 g of biochar in 250 mL of water for 30 s. The duration was selected based on the optimum value obtained from a previous study . Longer duration of sonication promotes intensified cavitation that could disarrange the orientation of the layered structure of biochar, consequently blocking the pores and reducing the adsorption capacity. , The ultrasonically modified biochar was then subjected to chemical modification with simple or blended amines, using either EDC–HOBt or KOH activation. The details of the chemical activation procedures are discussed in the following sections.…”

Nanoconfined Ionic Liquids

“…Compared to the intensive studies related to the structure and dynamic properties of ILs confined in silica, the role of confinement on the thermal stability of IL has been less investigated. ,− ,,,,,,, TGA is often carried out in air or an inert atmosphere of nitrogen to understand such properties. A general conclusion drawn from the previous work is that the thermal decomposition of most commonly used imidazolium ILs confined in silica occurs in a much easier way than the bulk ILs.…”

“…The only difference between these two samples was the further depressed onset decomposition temperature of [BMIm]­[PF 6 ]/SiO 2 (221 °C) . The onset decomposition temperature of [BMIm]­[PF 6 ] decreased to ∼170 °C when confined in silica gel . In the case of a [BF 4 ]-based IL, such as [EMIm]­[BF 4 ], a decrease in the onset temperature of ca.…”

Removal of Confined Ionic Liquid from a Metal Organic Framework by Extraction with Molecular Solvents

“…However, the resulting hybrid materials represent an almost unexplored area. To date, most investigations have focused on ILs in inorganic porous matrices such as SiO 2 , TiO 2 , and SnO 2 as well as organic porous matrices such as carbon nanotubes, graphene, and porous carbon . The hybrid material is known as an ionogel, in which the IL is kept inside the porous skeleton.…”