首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 109 毫秒
1.
超声强化超临界流体萃取技术及其最新进展   总被引:1,自引:0,他引:1       下载免费PDF全文
谭伟  丘泰球 《声学技术》2007,26(1):70-74
文章较系统地介绍了超声强化超临界CO2萃取装置的设计,讨论了超声强化超临界CO2萃取技术的应用、萃取模型及其超声强化机理。超声强化与其他强化方法相比较,具有无污染、强化效率高等优点,超声波加入不仅降低了萃取系统的压力、萃取温度以及夹带剂用量和萃取时间,而且提高了萃取率,同时萃取对象的结构并没有发生变化。文章还提出了以后研究的重点。  相似文献   

2.
郑捷  胡爱军 《声学技术》2007,26(1):75-79
二十二碳六烯酸(DHA)和二十碳五烯酸(EPA)具有许多重要的生理活性和营养学功能。通过实验研究了提取温度、料液比、超声功率、频率以及提取时间对超声提取海藻DHA和EPA影响和超声提取的效果,结果表明,适当提高提取温度、溶剂量、超声功率或延长提取时间,DHA和EPA提取率随之提高。当超声功率为50W时,随着超声频率增加,DHA和EPA提取率反而降低。相同料液比时,55℃超声法提取1h比65℃溶剂法提取2h的DHA和EPA提取率提高25%~44%。不同料液比时,当料液比为1:4.5,超声法提取1h,DHA和EPA的提取率分别为79.48%、81.52%;而溶剂法料液比为1:5.5,提取2h时,DHA、EPA的提取率分别仅为63.57%、64.87%。超声提取不仅降低了提取温度、减少了提取时间和提取溶剂量,而且使DHA和EPA提取率明显提高。  相似文献   

3.
杨日福  丘泰球 《声学技术》2006,25(5):431-435
超临界CO2流体声速随压力和温度变化规律,对超声技术强化超临界流体萃取应用具有理论指导作用。为研究超临界CO2流体的超声速特性,设计了单探头脉冲回波法的声速测量探头,频率2.5MHz。采用汕头超声研究所生产的CTS-3600数字式超声探伤仪与声速测量探头连接。以温度每5℃和压力每1MPa为间隔,测量了温度为25℃~55℃,压力为7MPa~26MPa的CO2流体声速,根据不同温度下声速随压力变化的一组等温线,采用多项式拟合得到超临界CO2流体声速随压力和温度变化关系模型,在T=300K时计算模型计算值和文献参考值的相对误差。结果表明:超临界CO2流体声速随压力增加而增大,随温度升高而降低,在T=300K时模型计算值和文献参考值的相对误差在7%以内。  相似文献   

4.
多糖具有多种生物活性,是一种天然的功能性成分。由于它们独特的功能和低毒性,在保健食品和生物医药产品发展方面有广阔的应用前景。提取和纯化是制备多糖的关键步骤。多糖的提取方法有很多种,常采用溶剂提取法、超声波辅助提取法、微波法、酶提取法、超临界流体萃取法;本文就以上这几种方法进行了研究探讨。其中,溶剂提取法操作方便、适用面广,超声法提取具有高效、节能、省时的特点,微波法较大程度地提高多糖的萃取效率,酶法回收率高,超临界流体萃取提取率高。  相似文献   

5.
中国科学院半导体研究所于1992年7月7日在北京召开了SQ-3型超临界流体萃取设备鉴定会。代表们听取了设备研制报告,观看了设备录像,审查了技术文件,进行了认真讨论,提出了许多宝贵意见。最后,鉴定认为: SQ—3型超临界流体萃取设备的核心部分高压釜,在国内首次采用了快速开关型装置,对减轻科研和生产人员劳动强度、加快  相似文献   

6.
应用超临界流体技术制备超细粉体   总被引:3,自引:1,他引:2  
詹世平  黄慧  王景昌 《材料导报》2003,17(Z1):145-147,157
介绍了超临界流体技术的最新进展和应用情况,重点介绍了超临界流体萃取技术以及近年来发展起来的超临界流体制造超细粉体的两种新技术--超临界溶液快速膨胀和超临界流体反溶技术.  相似文献   

7.
近年来,环境保护部门要求各地对全国农村土壤质量和场地土壤污染状况展开调查,选择合适的多环芳烃分析方法尤为重要。用于土壤中多环芳烃的提取方法目前主要有索氏提取法、超声提取法、超临界流体萃取、微波辅助萃取、加压流体萃取等方法。高污染的提取物通常需要使用多种净化方法。检测多环芳烃的方法主要有薄层层析荧光光度法、高效液相色谱法、气相色谱质谱法。其中高效液相色谱法可获得较低的检出限,气相色谱质谱法定性能力较好,可排除假阳性。在实际应用过程中,应根据土壤性质和限值要求选择合适的检测方法。  相似文献   

8.
《流程工业》2003,(10):30-31
超临界流体萃取技术是70年代末才兴起的一种新型生物分离精制技术,近年来发展迅速,超临界流体技术是因应人类对于能源危机的意识而崛起于80年代。更因为环保及其出众的萃取效果,而于90年代被大量运用于取代有机溶剂的萃取技术。  相似文献   

9.
4月13日,由华东理工大学和江苏省昆山市大地天然物技术开发有限公司合作的“超临界萃取新工艺及装置生产生姜和当归净油技术”,通过了国家化工行业生产力促进中心组织的评估。超临界萃取作为一项新的分离技术正在受到世界各国的重视。自1996年起,大地天然物技术开发有限公司与华东理工大学国家重点工程实验室合作,进行了超临界萃取生产装置工业化和新产品开发研制工作。目前超临界萃取工业示范装置已建成,并已经过3个多月的运行。通过试生产,各项指标均达到设计要求,现已制得生姜净油和当归净油两种产品。专家们一致认为,该…  相似文献   

10.
介绍了超临界二氧化碳萃取、低温粉碎及卫星推进系统注动衰退模拟研究等特种流体的新技术应用的研究进展。  相似文献   

11.
The use of supercritical argon is described for the extraction of petroleum hydrocarbons from soil samples. Argon is an attractive solvent because it is inexpensive and inert. Additionally, it has a clear spectral window in the infrared region which makes it useful for on-line (i.e., directly coupled) experiments. Spiking studies conducted with gasoline, no. 1 fuel oil, and no. 5 fuel oil on sand, loam, and clay show that component recovery rates for argon supercritical fluid extraction (SFE) generally increase with increasing pressure and/or temperature. The highest recovery rates (and recoveries) were obtained for Ar SFE at 500 atm and 150 °C. Under these conditions, the components of the gasoline and no. 1 fuel oil spikes could be recovered in as little as 12 min. However, the no. 5 fuel oil components could not be quantitatively removed from the loam and clay matrixes even for extraction times as long as 100 min. We also show in this work that Ar SFE performs similarly to CO(2) SFE for petroleum hydrocarbon contamination in real-world soil samples under moderate pressure and temperature conditions. Specifically, Ar SFE and CO(2) SFE have similar recoveries and reproducibilities, but Ar SFE requires a slightly longer extraction time.  相似文献   

12.
Ali MY  Cole RB 《Analytical chemistry》1998,70(15):3242-3248
Lipid material represents a potential interference for determination of nonpolar compounds (e.g., polycyclic aromatic hydrocarbons) in biological tissue samples. This study reports the development of a selective extraction method using supercritical CO2 that allows the GC/MS quantitation of PAHs in the presence of a substantial lipid background. Selective extraction of PAHs relies upon addition of C18 adsorbent beads to the initial sample slurry. The dried mixture, including C18 adsorbent, is placed in the supercritical fluid extraction (SFE) chamber. During the SFE process, lipids are preferentially retained on the C18 beads. This "SFE plus C18" procedure was developed by first optimizing SFE conditions (100 degrees C, 350 bar) for recovery of PAH standards. PAHs containing added model lipid compounds (stearic acid and cholesterol) were then subjected to SFE plus C18 treatment followed by GC/MS analysis. Using this approach, a recovery of 94-100% of PAHs was obtained while only 9-17% of the lipid material present was coextracted from the same test sample. The developed method is demonstrated to permit efficient recovery and detection of PAHs spiked into crab tissue, a matrix with a high lipid content.  相似文献   

13.
To provide a green method to remove chromated copper arsenate (CCA) in the wood before its dumping, incineration, reuse or disposal, extraction of CCA from wood wastes using supercritical carbon dioxide (ScCO(2)) containing an organophosphorus reagent, Cyanex 302, was investigated. The majority of copper metal was removed using Cyanex 302 in supercritical fluid extraction (SFE). The order of extraction efficiency was found to be Cu>As>Cr. Factors that affected SFE efficiencies, such as matrices, oxidation state of metal species [Cr(III), Cr(VI), As(III), and As(V)], and SFE pressure, were studied. Using this in situ chelation/SFE technique to remove leachable metals from the CCA-treated wood was found to significantly reduce the risk of leaching metals into the environment during storage, or waste disposal.  相似文献   

14.
The construction of a supercritical fluid extraction (SFE) plant inside or in close proximity to a sugarcane biorefinery producing first and second generation ethanol demonstrated to be very promising, increasing the economic potential of the SFE process in up to 57 %, since the SFE plant could use directly the ethanol, CO2, heat, and electricity already available, with lower prices. In this study, Brazilian ginseng roots were used as model bioactive compounds source and first the statistical influence of the extraction conditions including pressure (10–20 MPa), temperature (323–363 K), and CO2/ethanol proportion ratio (90:10, 50:50, and 0:100 %, w/w) on the β-ecdysone content in the extracts was experimentally evaluated and compared with literature results. SFE process evaluated experimentally at the present study showed higher selective extraction for β-ecdysone from Brazilian ginseng roots, providing an extract with up to 2.16 times higher β-ecdysone than the results obtained in previous studies. Thermal integration of the SFE process diminished energy requirements of the process, resulting in a reduction of cold utility requirement of 87 % and a final electricity demand of 7.5 kWh/g of β-ecdysone in the extract. In a situation in which the Brazilian ginseng roots price was increased to 4.71 USD/g, only the SFE integrated with the biorefinery solution would be economically feasible. Finally, the selling of the ginseng roots leftover could be an interesting answer to increase the economical attractiveness of the integrated SFE process to the biorefinery.  相似文献   

15.
A new method, employing supercritical fluid extraction (SFE) connected on-line with high-performance liquid chromatography, was developed for the determination of pyrethrins and piperonyl butoxide in aqueous solutions. The principle of the laboratory-made device for SFE is based on the low mutual solubility of water and supercritical (liquid) CO2. This device works in continuous mode that offers extraction of unlimited sample volumes. Different extraction temperatures and pressures were tested to find optimum extraction conditions. The addition of organic modifier and inorganic salt to the water sample to increase extraction recovery was investigated. The method was evaluated, and it was applied for the extraction of aqueous samples spiked with commercial insecticides. The working concentration range of the method was from the limit of quantification (0.1 microg L(-1)) to the solubility of the analytes in water.  相似文献   

16.
The possibility of using supercritical fluid extraction (SFE) of radionuclides for spent nuclear fuel reprocessing and for decontamination of various environmental objects is considered. Subcritical and supercritical media (CO2 and Freons) containing various organic ligands can be used for extractive recovery of actinides and other radionuclides from diverse matrices, including oxides of these elements. SFE is also suitable for recovery of actinides and their separation from fission products, and also for decontamination of various surfaces. In the process, the volume of secondary radioactive aqueous and toxic organic wastes, which are formed in large amounts in the existing processes and give rise to long-term environmental problems, is reduced to a minimum.  相似文献   

17.
The methods of accelerated solvent extraction (ASE) and supercritical fluid extraction (SFE) of polycyclic aromatic hydrocarbons (PAHs), aliphatic hydrocarbons, and chlorinated hydrocarbons from marine samples were investigated. The results of extractions of a certified sediment and four samples of suspended particulate matter (SPM) were compared to classical Soxhlet (SOX), ultrasonication (USE), and methanolic saponification extraction (MSE) methods. The recovery data, including precision and systematic deviations of each method, were evaluated statistically. It was found that recoveries and precision of ASE and SFE compared well with the other methods investigated. Using SFE, the average recoveries of PAHs in three different samples ranged from 96 to 105%, for ASE the recoveries were in the range of 97-108% compared to the reference methods. Compared to the certified values of sediment HS-6, the average recoveries of SFE and ASE were 87 and 88%, most compounds being within the limits of confidence. Also, for alkanes the average recoveries by SFE and ASE were equal to the results obtained by SOX, USE, and MSE. In the case of SFE, the recoveries were in the range 93-115%, and ASE achieved recoveries of 94-107% as compared to the other methods. For ASE and SFE, the influence of water on the extraction efficiency was examined. While the natural water content of the SPM sample (56 wt %) led to insufficient recoveries in ASE and SFE, quantitative extractions were achieved in SFE after addition of anhydrous sodium sulfate to the sample. Finally, ASE was applied to SPM-loaded filter candles whereby a mixture of n-hexane/acetone as extraction solvent allowed the simultaneous determination of PAHs, alkanes, and chlorinated hydrocarbons.  相似文献   

18.
Off-line supercritical fluid extraction (SFE) followed by gamma-radiolysis as an alternative treatment technique for PCB-contaminated soil was investigated in this study using BZ #54 (2, 2',6,6'-tetrachlorobiphenyl) as the model compound. The preliminary results indicate that removal of BZ #54 from spiked sand and soil using SFE at 150 degrees C and 20 MPa is 98% and 93%, respectively. The reduction efficiency of 864 mg/l BZ #54 in isooctane by gamma-radiolysis is 99.8% at an absorbed dose of 500 kGy.  相似文献   

19.
Accelerated solvent extraction (ASE) has been applied to the quantitative extraction of a selected list of semi-volatiles, which include polycyclic aromatic hydrocarbons (PAHs), phenols, polychlorinated biphenyls (PCBs) and total petroleum hydrocarbons. Two conventional supercritical fluid extraction (SFE) systems, the Suprex Prep Master and SFE/50 systems have been modified to function as ASE systems. Using solvent instead of supercritical fluid, extraction in an enclosed system proceeded under high pressure and temperature. Parameters such as extraction temperature and effect of modifiers were investigated. Although limited by a 150 degrees C maximum oven temperature, effective extraction could be carried out in less than 25 min for all the compounds studied. The technique was applied to a variety of real matrices contaminated with hydrocarbons, PAHs and phenols. Validations of the technique were performed using standard reference materials. Recoveries for these matrices were good (>75%) and precision (R.S.D.) was generally less than 10%. Primarily a rapid field extraction technique, comparison with other rapid extraction such as sonication and microwave assisted extraction (MAP) were made. Recoveries were found to be comparable to MAP and superior to sonication. On the present ASE system, only sequential extraction can be carried out but given the rapid nature of the process, about 15 samples can be carried out in a working day.  相似文献   

20.
The efficiencies of three extraction techniques for removal of nonpesticidal organophosphates from soil were determined. Traditional Soxhlet extraction was compared to supercritical fluid extraction (SFE) and a low solvent volume flow through technique referred to here as high-pressure solvent extraction (HPSE). SFE, optimized by varying parameters of temperature, pressure, and methanol polarity modifier, showed at least 90% efficiency in the extraction of OPs from both spiked and native soils. HPSE experiments showed efficient and consistent recoveries over a range of temperatures up to 200 °C and pressures up to 170 atm. Recovery of TCP from spiked soils with HPSE depends on the system variables of temperature and pressure, which dictate density and flow rate. HPSE provided extraction efficiencies comparable to those obtained with Soxhlet extraction and SFE but with substantial savings of time and cost.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号