To develop a highly ion-conductive polymer electrolyte, we copolymerized methacrylonitrile (MAN) with ethylene glycol dimethacrylate (EGDMA) in propylene carbonate that contained tetraethylammonium tetrafluoroborate (TEATFB), changing the TEATFB concentration and the MAN/EGDMA molar ratio. We characterized the obtained polymer gel electrolytes with complex impedance analysis and cyclic voltammetry, intending to apply them to electric double-layer capacitors. The ionic conductivities of the polymer gel electrolytes were dependent on the TEATFB concentration, the temperature, and particularly the crosslinking degree. The polymer gel electrolytes in this system exhibited high room-temperature conductivities (Ͼ10 Ϫ3 S/cm). Furthermore, these polymer electrolytes showed good electrochemical stability windows ranging from Ϫ4.0 to ϩ4.0 V versus Ag.

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An esr study has been carried out for reactions of electrons with acrylic acid (AA) in a variety of irradiated frozen solutions. The electron adducts of acrylic acid [CEL-CH-COOH]" were found to be formed in some matrices, such as 2-methyltetrahydrofuran (MTHF), triethylamine (TEA), and 3-methylhexane (MHX). The hyperfine couplings to the end CH2 protons (oq 13 G) are consistent with the INDO MO calculation made for the delocalized anion w radical. The post-irradiation thermal annealing of the frozen MTHF-AA solutions at 97°K resulted in protonation of the electron adducts to form the hydrogen addition radical [CH3-CH-COOH]. The same conversion was also observed in the TEA matrices at around 115°K, while no conversion was observed in the MHX matrices. The radical conversion seems to be associated with the molecular reorientations in the matrices which were found from the sudden change of the line width in the wide-line nmr measurements of frozen MTHF. On the other hand, the hydrogen addition radicals were found immediately after irradiation in some matrices containing polar protons such as alcohols and alkaline aqueous solutions. It is concluded that the electron adducts of acrylic acid can be stabilized either in a molecular anion or in its protonated form, depending upon the nature of the matrix molecules and that the hydrogen addition radicals are formed from the polar proton transfer to the electron adducts. A model of proton transfer from protonated cations via the hydrogen bond is proposed for protonation of the electron adducts in the MTHF and TEA matrices.

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Regeneration of adsorbents for reuse is crucial for reducing operating costs and maintaining sustainable systems. Few researchers have studied the regeneration of sorbents without using chemical solvents or appropriate methods. The purpose of this study was to evaluate the feasibility of the sonochemical technique (ST) for the regeneration of granular activated carbon (GAC), a mixed cation and anion resin (DOWEX MB-50), and an anion resin (IRA910) for the removal of per- and polyfluoroalkyl substances (PFAS). The ST was performed at 120 kW, and the power density was 250 W L−1 for 30 min. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were used to examine physicochemical properties of the spent adsorbents. The removal efficiency of the spent adsorbent regeneration occurred in the following order: DOWEX > GAC > IRA910. As the PFAS-adsorbed adsorbents disappeared in the spectrum, the FTIR results showed the existence of a sulfonic group that is similar to the peaks of virgin sorbents. However, this method affected the morphology of GAC and IRA910 but not DOWEX MB-50. Consequently, the ST is a potential alternative to chemical regeneration for DOWEX MB-50 resins. It is also a potential method for an eco-friendly approach to regenerate PFAS-adsorbed materials.