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This work aims to study the effect of pretreatment of wool fabrics with two imidazolium-based ionic liquids to impart durable antimicrobial properties. The used ionic liquids, cationic in nature, were ionically bonded to the anionic sites along the keratin macromolecules. These anionic sites have been enriched via treatment with the presynthesized anionic agent (AA) (sodium 4-(4,6-dichloro-1,3,5-triazinylamino)-benzenesulfonate). The effect of the treatment temperature of wool fabric with the AA, liquor ratio as well as the pH on the exhaustion percentage was studied. Antibacterial activity of the treated wool fabric towards Gram –ve bacteria (Escherichia coli), and fastness to washing were examined. The chemical structure of the synthesized AA was elucidated using liquid chromatography mass spectrometry. 相似文献
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Enantioselective esterification of (±)-menthol was studied using Candida rugosa lipase (CRL) in ionic liquids (1-butyl-3-methyl-imidazolium hexafluorophosphate ([BMIM][PF6]) and 1-butyl-3-methyl-imidazolium tetraflouroborate) and organic solvents of different hydrophobicities. Propionic anhydride was employed as an acylating agent. Because the enzyme showed comparable conversion yield and enantioselectivity in [BMIM][PF6] and hexane in a 24-h reaction, more work focused on these two reaction media. Comparison of the activity, stability and enantioselectivity of CRL was carried out by examining the effects of the mole ratio of substrates, temperature, incubation time and enzyme recycling. It was found that temperature control was more crucial in the ionic liquid than in hexane to reach high conversion and enantioselectivity. The ionic liquid system showed an advantage of using less acid anhydride to achieve higher (±)-menthol conversion yield and better enantioselectivity. Moreover, during an incubation of 4–60 days in the ionic liquid, CRL activity was 2.5 times higher than its initial value, while that in hexane decreased to less than 60% in 2 days. In addition, the enzyme showed potentiality of recycled use in the ionic liquid. These advantages of the ionic liquid suggest that it would be used as a green alternative to organic solvents for the enantioselective esterification of (±)-menthol. 相似文献
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为了解纤维素在咪唑类离子液体中的降解行为,用正交试验法分析了温度、转速、时间对纤维素降解程度的影响,并比较了纤维素在四种离子液体中的降解行为。结果表明,纤维素在1-乙基-3-甲基咪唑醋酸盐([EMIM]Ac)中的最佳溶解条件为,温度80℃,时间1h,转速230r/min。温度对纤维素降解程度影响最大,其次为时间和转速。同条件下,纤维素在[EMIM]Ac中的降解最轻,在1-烯丙基-3-甲基咪唑氯盐([AMIM]Cl)中降解最严重。没食子酸丙酯可显著缓解纤维素在离子液体中的降解程度。[EMIM]Ac、1-丁基-3-甲基咪唑醋酸盐([BMIM]Ac)遇没食子酸丙酯显紫红色,并在纤维素溶解后颜色消失。 相似文献
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Preliminary assessment of imidazolium-based room-temperature ionic liquids for extraction of organic contaminants from soils 总被引:2,自引:0,他引:2
Khodadoust AP Chandrasekaran S Dionysiou DD 《Environmental science & technology》2006,40(7):2339-2345
Alternative solvents known as room-temperature ionic liquids (RTILs) were considered for extraction of organic soil contaminants. A hydrophobic RTIL, 1-butyl-3-methyl imidazolium hexafluorophosphate ([bmim]PF6), and a hydrophilic RTIL, 1-butyl-3-methyl imidazolium chloride ([bmim]Cl), were selected as representative imidazolium-based RTILs to assess the extraction of several organic contaminants (OCs) from two model soils. The two soils were montmorillonite (clay minerals, high surface area, and no organic matter) and glacial till (organic matter). The soils were spiked separately with DDT, dieldrin, hexachlorobenzene, and pentachlorophenol. With the exception of DDT, extractions of OCs from montmorillonite using [bmim]PF6 (79-92%) were nearly as effective as extractions with acetone and ethanol (85-100%). The extraction of OCs from glacial till with RTILs (15-61%) was less effective than extraction with organic solvents (59-100%). The [bmim]Cl was as efficient as [bmim]PF6 for extraction of OCs from glacial till, while [bmim]PF6 was more efficient than [bmim]Cl for extraction of OCs from montmorillonite. The two RTILs were most effective for the extraction of dieldrin (the heaviest OC) from both soils. The extraction results for glacial till showed dependence of OC extraction on the viscosity and melting point of RTILs. 相似文献
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Ionic liquids are being developed as a replacement for volatile organic solvents in a range of industrial applications. These liquids have a vanishingly small vapor pressure, making them an attractive alternative to the volatile organic solvents. However, a thorough assessment of the environmental impact of the use of ionic liquids requires a more complete understanding of their fate and transport in environmental systems. Toward this end, we measured the adsorption of the ionic liquid 1-butyl, 3-methylimidazolium chloride (Bmim CI) onto a range of surfaces meant to represent those commonly found in the near-surface environment. We measured adsorption onto the Gram-positive soil bacterial species Bacillus subtilis, onto gibbsite, onto quartz, and onto Na-montmorillonite. We conducted experiments as a function of pH, solid:solute ratio, time, and ionic strength. The experimental results reveal that Bmim CI is unstable in water below pH 6 and above pH 10 and that it exhibits pH independent and ionic strength dependent adsorption onto Na-montmorillonite with 0.4, 0.8, 1.0, 1.2, and 2.0 g/L of clay. We observed no adsorption of the Bmim CI onto B. subtilis (3.95 or 7.91 g (dry weight) bacteria/L) at pH 5.5-8.5 or onto gibbsite (500 or 1285 g/L) or quartz (1000 and 2000 g/L) over the pH range 6-10. Calculated distribution coefficient (KD) values for Bmim CI onto the Na-montmorillonite change as a function of ionic strength; the 10(-4) M ionic strength KD value is 1735 +/- 269 L/Kg, and the 10(-1) M ionic strength KD is 1133 +/- 291 L/Kg. Our results suggest that the geologic retardation of this class of ionic liquid, if present as a dissolved contaminant in the subsurface, would be significant when a significant fraction of interlayer clays are present. However, adsorption onto other common geologic and biological surfaces is likely to be minimal, and the ionic liquids may travel unimpeded in groundwater systems in which these types of surfaces dominate. 相似文献
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离子液体的合成及在萃取分离中的应用 总被引:2,自引:0,他引:2
离子液体作为一类新型的环境友好的“绿色溶剂”,具有很多独特的性质,在很多领域有着诱人的应用前景。本文综述了离子液体的合成、检测、对高分子材料的溶解及降解性能及在萃取分离中的应用。 相似文献
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The use of petroleum-derived solvents, particularly volatile organic compounds (VOCs), in the chemical industry has increased the contamination and residual effects of these solvents. Ionic liquids (ILs) can potentially replace VOCs, thereby reducing the risks of environmental contamination and toxicity. In this context, the objectives of this study were as follows: 1 — to obtain an ionic liquid for use in extracting carotenoids from tomatoes with ultrasound assistance; and 2 — to determine the stability and antioxidant activity of tomato carotenoid extracts. Ultrasound can also efficiently extract carotenoid compounds with ionic liquids in comparison with conventional VOC solvents (obtained from an all-trans-lycopene 7.5–8.0 μg·g− 1 tomato sample by IL and 6.2–7.7 μg·g− 1 by acetone). Similarly, the activation energies (Ea) in aqueous medium were obtained for the IL carotenoid extract (10.8 kJ·mol− 1) and acetone carotenoid extract (9.4 kJ·mol− 1). The antioxidant activities of the tomato carotenoid extract were 7.4 and 12.4 relative to α-tocopherol for the ionic liquid extract and acetone extract, respectively. The combination of chromatographic analysis and degradation kinetics provided data for positive assessment similarity of thermal and light stabilities of tomato carotenoids extracted by IL and extracted by acetone. 相似文献
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酱油发酵酱醅中筛选到一株戊糖片球菌,对该菌的生长温度、生长pH值、食盐耐受度等生长特性进行研究。采用离子交换色谱法对该菌株产有机酸的情况进行测定;将该菌株添加到低盐固态酱油后酵过程中,以不添加乳酸菌的实验组作对照,对酱油样品理化指标、经济指标进行分析,并采用顶空固相微萃取-气相色谱-质谱法(HS-SPME-GC-MS)对酱油挥发性香气成分进行对比分析。结果表明,该乳酸菌的生长条件与酱油酱醅发酵环境相适应,其发酵产酸以乳酸和乙酸为主,与酱油中有机酸主成分相一致,将该菌株用于低盐固态酱油发酵,对酱油香气和其他指标均有不同程度的促进作用。 相似文献
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R Briandet V Leriche B Carpentier M N Bellon-Fontaine 《Journal of food protection》1999,62(9):994-998
The aim of this study was to examine the physicochemical surface properties and the ability to adhere to stainless steel of three strains of Listeria monocytogenes after different cultivation procedures. To this end, bacteria were cultivated at 37 degrees C after storage at two frequently used temperatures (4 degrees C or -80 degrees C) and were then transferred into the liquid medium (trypticase soy broth supplemented with 6 g liter(-1) of yeast extract, pH 7.3) between one and four times. In addition, the influence of supplementing the growth medium with lactic acid was explored, this organic acid being representative of both the dairy and cured meat industries. The hydrophobic/hydrophilic and electron-acceptor/electron-donor characteristics of the strains were evaluated by the microbial adhesion to solvents method. Using this technique, we recorded an increase in the hydrophobic properties of one strain stored at 4 degrees C, with an increasing number of transfers in the media (P < 0.05). Another plant-isolated strain appeared more hydrophobic and stuck better to stainless steel when cells were stored at 4 degrees C rather than at -80 degrees C. Preculturing L. monocytogenes in a lactic acid-supplemented medium increased the affinity of microbial cells to solvents and the bacterial attachment to stainless steel (P < 0.05). 相似文献
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Abstract: In this research, a microextraction technique based on ionic liquids (ILs) termed in situ solvent formation microextraction (ISFME) was used for determination of nickel in solutions. 1‐(2‐pyridylazo)‐2‐naphtol (PAN) was chosen as a complexing agent. After preconcentration, the settled IL‐phase was dissolved in 50 μL of ethanol and aspirated into the flame atomic absorption spectrometer (FAAS) using a home‐made microsample introduction system. Injection of 50 μL volumes of analyte into an air–acetylene flame provided very sensitive spike‐like and reproducible signals. ISFME is based on phase separation phenomenon of ionic liquids in aqueous solutions. This method is simple and rapid for extraction and preconcentration of metal ions from food samples and can be applied for the sample solutions containing very high concentrations of salt. Furthermore, this technique is much safer in comparison with the organic solvent extraction because of using ionic liquid. The effective parameters such as amount of IL, salt effect, concentration of the chelating agent and ion pairing agent were inspected by a full factorial design to identify important parameters and their interactions. Next, a central composite design was applied to obtain optimum point of the important parameters. Under the optimum conditions, the calibration graph was linear over the range of 2 to 80 ng/mL. The limit of detection and relative standard deviation (n= 6) were 0.6 ng/mL and 2%, respectively. 相似文献
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为了更好的研究工业乳酸发酵中的分解代谢物阻遏效应,在实验室规模反应器对凝结芽孢杆菌混合碳源乳酸发酵进行不同通气量、p H、中和剂等条件的发酵特性研究,并研究了不同金属离子、渗透压等条件对饥饿状态下凝结芽孢杆菌自溶的影响。结果表明:凝结芽孢杆菌葡萄糖+海藻糖混合碳源乳酸发酵呈现明显的分解代谢物阻遏效应,且发酵可分为葡萄糖消耗阶段、有机酸消耗阶段和海藻糖消耗阶段。不同发酵条件在葡萄糖消耗阶段对菌体生长和乳酸生成影响较小,但对发酵后期海藻糖利用阶段菌体生长和乳酸合成有明显影响。在海藻糖消耗阶段,通气量为7.2 L/h时有较高的底物消耗速率和产酸速率;用NaOH作为中和剂在p H6.5时海藻糖消耗速率和乳酸生成速率均高于pH6.0,而p H5.5时不利用海藻糖且不生产乳酸;与NaOH作为中和剂相比,在p H6.5条件下Ca(OH)2作为中和剂使海藻糖消耗速率和乳酸生成速率分别提高21.0%和28.3%。发现Ca2+、Mg2+等二价离子确实对菌体自溶有一定的缓解作用,且Na+能在饥饿状态下维持菌体的活性,为研... 相似文献
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Stimulatory or protective effects of organic acids at low concentrations, e.g. acetic and lactic acid, on microorganisms have previously been reported. Especially in case of Zygosaccharomyces bailii, a peculiar growth stimulation by these two acids has recently been noticed. In order to elucidate this interesting phenomenon, growth and fermentative metabolism of Z. bailii was investigated in media with low pH (pH 4.0), high sugar (15% (w/v)) and different acetic and lactic acid concentrations. At both experimental temperatures (7 and 30 °C), a growth stimulation in the presence of 2.5% (v/v) lactic acid was observed. Furthermore at 7 °C, the yeast exhibited another unusual behaviour as it grew much faster in media containing 1.25% (v/v) acetic acid than in the control (without any acid). Production of fermentative metabolites was also increased together with the enhanced growth at both temperatures. These possible stimulatory effects of acetic and lactic acid should be taken into consideration when the acids are used at low doses for food preservative purpose. Presence of the acids may stimulate Z. bailii growth and fermentative metabolism, particularly at refrigeration temperature, consequently resulting in an earlier spoilage. 相似文献
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以新鲜红皮萝卜为原料,分别接种分离自自然发酵泡菜中的乳明串株菌、乳酸乳球菌、食窦魏斯氏、发酵乳杆菌、植物乳杆菌进行纯种乳酸菌发酵制作泡菜。通过测定泡菜的乳酸菌菌相、总酸度、感官评价、挥发性成分及有机酸,对分离自自然发酵泡菜中不同乳酸菌纯种发酵泡萝卜的风味进行研究。结果表明,发酵达到终点时,接种不同乳酸菌发酵的泡菜中大部分乳酸菌的活菌数相差不大,都在7.0lg CFU/m L左右,泡菜液中的乳酸菌几乎全为植物乳杆菌;大部分乳酸菌纯种发酵泡菜中总酸含量>4g/kg;不同乳酸菌发酵的泡菜挥发性成分及有机酸的种类差异不显著。 相似文献