RESUMO
In recent years, iron-based ionic liquids (e.g. BmimFeCl4, Fe-IL) have been widely used in the catalytic oxidation removal of hydrogen sulfide owing to their excellent redox reversibility and stability. Nevertheless, the high viscosity and poor Fe3+ activity of BmimFeCl4 limit its large-scale industrial application. The addition of aprotic organic solvents to BmimFeCl4 is an effective strategy to enhance its mass transfer efficiency and catalytic oxidation desulfurization performance. In this work, the effects of two kinds of aprotic organic solvents, weak polar polyether alcohols (NHD, PEG200) and strong polar amides (DMAC, DMF, and NMP), on the density, viscosity, conductivity and ferric activity of Fe-IL were investigated. The Eyring equation fitted well for the relationship between the viscosity and the temperature of the composites. When the mass ratio of BmimFeCl4 to solvent was 7 : 3 at 298.2 K, the viscosity of BmimFeCl4/DMAC and BmimFeCl4/NHD was 8.67 mPa s and 27.19 mPa s, respectively. The excess molar volume (VE) and viscosity deviation (Δη) of the two composite systems were calculated and fitted using the Redlich-Kister equation. The study of VE implies that DMAC has stronger solvation to the BmimFeCl4 ion pairs, and NHD could cause a more obvious volume shrinkage. For the composites investigated, Δη of BmimFeCl4/DMAC is negative while that of BmimFeCl4/NHD is positive, showing that DMAC could significantly weaken the combination ability of [Bmim]+ and [FeCl4]-, and NHD may form a stronger interaction with [Bmim]+. The FT-IR spectra and DFT calculations demonstrated that both polyether alcohol and amide could interact with C2-H on [Bmim]+. The CV curves and the MK charges show that the addition of aprotic polar solvents could effectively improve the activity of Fe3+ under the action of a hydrogen bond, and the effect of amide solvents on the activation of Fe3+ is stronger than that of polyether alcohol solvents. In conclusion, it is found that the composites with stronger ferric activity have much better catalytic oxidation ability for the conversion performance of hydrogen sulfide, and the the interactions induced by the molecular weight and the polarity of the solvent have a significant effect on the configuration of the Fe-IL ion pairs.
RESUMO
Ferroptosis is a kind of regulated cell death, supporting the pathological process of lung inflammation, including asthma. Quercetin (QCT), a kind of natural dietary flavonoid, exerts anti-inflammatory and anti-ferroptosis effects in various diseases. However, the role of QCT in ferroptosis-associated airway inflammation of neutrophilic asthma remains to be described. Our study aimed to investigate the therapeutic effects of QCT on neutrophilic airway inflammation of asthma. Ferrostatin-1 (Fer-1), as a kind of ferroptosis inhibitor, was used to demonstrate whether neutrophilic airway inflammation of asthma relied on ferroptosis. In our study, the alleviation effect of QCT on neutrophilic airway inflammation was similar to Fer-1. Moreover, the significantly decreased levels of ferroptosis anti-oxidant protein (GPX4 and SLC7A11), increased malondialdehyde (MDA) levels, upregulated levels of 4-hydroxynonenal (4-HNE) expression by immunohistochemistry, and distorted mitochondria morphological changes in the lung tissues suggested lung ferroptosis in neutrophilic airway inflammation, which could be reversed by QCT treatment. In vitro experiments showed that QCT reduced LPS-induced ferroptosis through upregulating cell viability and levels of ferroptosis anti-oxidant protein (SLC7A11 and GPX4), reducing inflammatory cytokines, and decreasing the levels of MDA. Furthermore, ferroptosis was accompanied by enhancing M1 phenotype in neutrophilic airway inflammation, and QCT suppressed ferroptosis by inhibiting the pro-inflammatory M1 profile in vitro and in vivo, just as Fer-1 did. In conclusion, our study found that QCT ameliorated ferroptosis-associated neutrophilic airway inflammation accompanied by inhibiting M1 macrophage polarization. QCT may be a promising ferroptosis inhibitor for neutrophilic airway inflammation.