Shuang Meng,Yan Zhuang,Xue Yang,Dongxuan Guo,Jinlong Li
Volatile organic compounds (VOCs) emitted from industrial activities and transportation pose significant health risks to humans and contribute to environmental issues. As a result, there has been growing interest in developing effective technologies for VOC removal. This study investigates the removal of low-concentration VOCs from air using a membrane catalytic process that combines a supported ionic liquid membrane (SILM) with a novel visible light-driven photocatalyst. The system, consisting of a 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6) SILM and N-doped La–TiO2 photocatalysts, achieves a mineralization rate of 40%–60% and a removal efficiency of approximately 75% for VOCs under visible light exposure for 10 hours. The synergistic effects of membrane separation and photocatalytic degradation significantly enhance the overall VOC removal efficiency compared to using either method alone. The membrane catalytic system demonstrates particular applicability and stability for various organic compounds, including toluene, acetone, chloroform, benzene, and xylene. Overall, this work presents a promising approach for the removal and mineralization of VOCs.
Ionic liquids (ILs) which belong to the molten salt of a high ionic environment exhibit a number of unique properties, including the formation of various heterogeneities in their microemulsion. We found that auto-generated radicals within a [Bmim][PF 6 ]/[C 16 mim][PF 6 ]/PBS reverse micelles (IL-RMs) and then the radicals were quantified in this study. For the radical confirmation, EPR spectroscopy with 5,5-dimethyl-1-pyrroline N-oxide (DMPO) free radical scavenger was carried out. A spectroscopic chemical probe of 1,1-diphenyl-2-picrylhydrazine (DPPHH) was employed to quantify the radicals in the IL-RM systems. The mechanism of the radical generation was also proposed. The DPPHH probe method is simple, rapid, and sensitive to quantify free radicals in the IL-RM systems. Finally, IL-RMs were successfully applied to degrade Rhodamine B (Rho-B) dye with low degradation cost, simple operation, short time consumption, and remarkable degradation effect. The results show a near 100% degradation rate for 10 μmol·L −1 Rho-B in the IL-RMs system with pH 7.4 PBS containing 1 mmol·L −1 chloroacetic acid as an aqueous phase. Graphical abstract
It was the first report that the concentrated hydrolyzates from the enzymatic hydrolysis of dilute NaOH (3 wt%)-soaking rice straw at 30 °C was used to form [Bmim]PF 6 -hydrolyzate (50:50, v/v) media for bioconverting ethyl 4-chloro-3-oxobutanoate (COBE) into ethyl ( R )-4-chloro-3-hydroxybutanoate [( R )-CHBE] (>99% e.e. ) with recombinant E. coli CCZU-A13. Compared with pure glucose, the hydrolyzates could promote both initial reaction rate and the intracellular NADH content. Furthermore, emulsifier OP-10 (20 mM) was employed to improve the reductase activity. Moreover, Hp-β-cyclodextrin (0.01 mol Hp-β-cyclodextrin/mol COBE) was also added into this bioreaction system for enhancing the biosynthesis of ( R )-CHBE from COBE by E. coli CCZU-A13 whole-cells. The yield of ( R )-CHBE (>99% e.e. ) from 800 mM COBE was obtained at 100% in the [Bmim]PF 6 -hydrolyzate (50:50, v/v) media by supplementation of OP-10 (20 mM) and Hp-β-CD (8 mM). In conclusion, an effective strategy for the biosynthesis of ( R )-CHBE was successfully demonstrated.
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