Xingmao Jiang,Shuang Zhu,Jiajun Gao,Yaqian Yu,Chunyan Xiong,Chunxi Li,Weimin Yang
Polyethylene glycol [PEG, H(OCH 2 CH 2 ) n OH] like PEG-600, a green extractant for organic N-compounds in fuel oil, was very active for non-basic nitrogens but not effective for basic ones. Modification of PEG that replaced –OH group with –OCH 2 COOH group can produce HOOCCH 2 (OCH 2 CH 2 ) n OCH 2 COOH (dcPEG). For denitrogenation, dcPEG-600 was highly effective for both basic and non-basic nitrogens. N-distribution coefficient [ D N , (μg N ·g dcPEG −1 )/(μg N ·g oil −1 )] of dcPEG-600 to n -octane can reach as high as 200 for indole, 92.6 for pyrrole, 42.0 for quinoline, and 81.5 for pyridine, respectively. Besides, denitrogenation selectivity of dcPEG-600 to toluene ( D N / D toluene ) can amount to 462 for indole, 230 for pyrrole, 146 for quinoline, and 366 for pyridine, respectively. The high performance was ascribed to contribution of active O atom on ether group and active H atom on –COOH group. The active O atom (Lewis basic site) formed H-bond with the non-basic nitrogen (Brønsted acid). The active H atom (Brønsted acidic site) not only interacted with the basic one (Lewis base) but also brought in the good selectivity. Moreover, dcPEG-600 was still effective for real oil and could be recycled for several times without the denitrogenation performance significantly decreasing.
Yanrong Cheng,Xia Guo,Delan Ge,Wenlin Xu,Yaqiong Wang
Broadening the polarity range of polymer-based aqueous two-phase systems (ATPSs) is of practical significance. Recently, ionic liquids have been used as adjuvants to modify the polarity and properties of PEG-rich phases in PEG/salt ATPSs. However, thus far, only short alkyl (containing less than 8 carbon atoms)-chained ionic liquids have been able to promote the extraction performance of ATPSs; long alkyl-chained ionic liquids have decreased the extraction performance significantly due to their distribution in the bottom phase. In the present study, we found that by complexing with Triton X-100 (TX-100), long alkyl-chained imidazolium ionic liquids [C n mim]Br (n = 10 and 12) as adjuvants were enriched in the top phase of PEG/salt ATPSs, and hence, the polarity difference of the two phases were increased. By extracting two model substances (S-mandelic acid (MA) and l -tryptophan (Trp)), it was concluded that, although the long alkyl-chained [C n mim]Br adjuvant decreased the extraction performance of the ATPS substantially, the long alkyl-chained [C n mim]Br/TX-100 complex as the adjuvant enhanced the extraction performance of the ATPS significantly. Compared with the case without an adjuvant, when the [C 12 mim]Br/TX-100 complex and the [C 10 mim]Br/TX-100 complex were used as the adjuvants, the partition coefficients of MA and Trp in the PEG 600/(NH 4 ) 2 SO 4 ATPS were increased up to 3 ∼ 4 times, much better than those with short alkyl-chained ionic liquid as the adjuvant. Moreover, the [C 12 mim]Br/TX-100 complex is more conductive to the transfer of MA into the PEG-rich phase, and the [C 10 mim]Br/TX-100 complex is more conductive to the transfer of Trp into the PEG-rich phase.
Inorganic antimicrobial materials have the advantages of high safety, strong durability, stable antimicrobial performance, and good heat resistance compared with organic antimicrobial materials. In this study, Fe-doped small zinc oxide nanoparticles (FZO-NPs) with different iron contents were synthesized and then modified with 3-aminopropyltriethoxysilane (APTES) and poly(ethylene glycol)−600 (PEG-600) to afford FZO-APs. FZO-APs which were fully characterized can disperse in water with good dispersity and improved stability. In antimicrobial tests, FZO-AP4 displayed excellent antimicrobial effects under 10 min of 365 nm UV light against Gram-negative bacteria Escherichia coli ( E. coli ) and Gram-positive bacteria Staphylococcus aureus ( S. aureus ) with a minimum inhibitory concentration (MIC) of 0.20 and 0.15 mg/mL, respectively. The antimicrobial mechanism studies revealed that the consumption of glutathione (GSH) and ascorbic acid (ASA), and the generation of reactive oxygen species (ROS) could trigger lipid peroxidation (LPO) and ultimately induce ferroptosis in bacterial cells. The cause of the cell wall/membrane damage and the released Zn/Fe ions from the nanoparticles inside the bacterial cells further promote the antimicrobial effects. In addition, FZO-AP4 showed high inhibitory effects on bacterial biofilm formation and significantly disrupted the formed biofilm. Interestingly, higher bacterial biofilm residuals and bacterial survival were found in E. coli than in S. aureus after FZO-AP4 treatment, suggesting a potential link between the quorum sensing (QS) system of the bacteria and their different susceptibility towards FZO-AP4. This study proved the antibacterial effects of small water-soluble FZO-APs which is meaningful for the design and development of new inorganic nano-material for antimicrobial applications.
危险品化学品经营许可证（带存储）