共查询到20条相似文献,搜索用时 15 毫秒
1.
Hanjing Huang Shang-Tian Yang David E. Ramey 《Applied biochemistry and biotechnology》2004,114(1-3):671-688
An energy-efficient hollow-fiber membrane extraction process was successfully developed to separate and recover lactic acid
produced in fermentation. Although many fermentation processes have been developed for lactic acid production, and economical
method for lactic acid recovery from the fermentation broth is still needed. Continuous extraction of lactic acid from a simulated
aqueous stream was achieved by using Alamine 336 in 2-octanol contained in a hollow-fiber membrane extractor. In this process,
the extractant was simultaneously regenerated by stripping with NaOH in a second membrane extractor, and the final product
is a concentrated lactate salt solution. The extraction rate increased linearly with an increase in the Alamine 336 content
in the solvent (from 5 to 40%). Increasing the concentration of the undissociated lactic acid in the feed solution by either
increasing the lactate concentration (from 5 to 40 g/L) or decreasing the solution pH (from 5.0 to 4.0) also increased the
extraction rate. Based on these observations, a reactive extraction model with a first-order reaction mechanism for both lactic
acid and amine concentrations was proposed. The extraction rate also increased with an increase in the feed flow rate, but
not the flow rates of solvent and the stripping solution, suggesting that the process was not limited by diffusion in the
liquid films or membrane pores. A mathematical model considering both diffusion and chemical reaction in the extractor and
back extractor was developed to simulate the process. The model fits the experimental data well and can be used in scale up
design of the process. 相似文献
2.
María Ramos-Payán Rut Fernández-Torres Juan Luis Pérez-Bernal Manuel Callejón-Mochón Miguel Ángel Bello-López 《Analytica chimica acta》2014
A novel approach based on the use of nanometallic-decorated hollow fibers to assist electromembrane extraction is proposed. Microporous polypropylene hollow fibers, on which nanometallic silver was deposited, have been used for the first time as liquid membrane support in electromembrane extraction (EME). Different methods for the generation/deposition of silver nanoparticles (AgNPs) were studied. The best results were obtained with chemical reduction of silver nitrate using NaBH4 in aqueous solution followed by direct deposition on the hollow fibers. The extraction performance of the new supports was compared with a previously developed EME procedure used for the extraction of selected non-steroidal anti-inflammatory drugs (NSAIDs), resulting in an increase in the extraction ratio by a factor of 1.2–2 with a 30% reduction in the extraction time. The new nanometallic-decorated supports open new possibilities for EME due to the singular properties of nanometallic particles, including chemical fiber functionalization. 相似文献
3.
In this work,a novel hollow fiber membrane extractor was set up to extract inorganic anions from ethyl acetate using deionized water.Inorganic anions in slightly soluble organic solvents can be determined by the in-line hollow fiber membrane extractor coupled with ion chromatography at first time.Different aspects of the extraction procedure such as magnetic stirring speed, extraction flow rate and extraction time were optimized to achieve high extraction efficiency and good separation results. Satisfact... 相似文献
4.
5.
Removal of 2,4-dichlorophenol from wasterwater by vacuum membrane distillation using hydrophobic PPESK hollow hiber membrane 总被引:1,自引:0,他引:1
Zhao Jin Da Ling Yang Shou Hai Zhang Xi Gao Jian 《中国化学快报》2007,18(12):1543-1547
2,4-Dichlorophenol was removed from wasterwater using a new hydrophobic poly(phthalazinone ether sulfone ketone) (PPESK) hollow fiber membrane by vacuum membrane distillation(VMD). 相似文献
7.
Anna Poliwoda Małgorzata KrzyżakPiotr P. Wieczorek 《Journal of chromatography. A》2010,1217(22):3590-3597
In this work, the simple analytical method for the determination of four fluoroquinolone antibiotics: ciprofloxacin, enrofloxacin, norfloxacin and danofloxacin, in environmental surface water samples is described. Sample pretreatment step was performed by the application of a technique based on supported liquid membrane extraction with the configuration of single hollow fiber (HF-SLM). The HPLC system with diode array detection was used for final analysis of studied analytes. Various parameters affecting the extraction efficiency during HF-SLM enrichment, such as type of membrane diluent, pH of donor (sample) and acceptor phases, as well as an enrichment time and salt content of sample were studied. Using the presented hollow-fiber extraction high recovery (70–80%) was achieved. It gave enrichment factor above 100. The detection limits in surface water samples, for the four target antibiotics, were at range 0.01–0.02 μg/l, when 10 ml samples were processed. The obtained results demonstrate the applicability of presented method for the selective extraction of fluoroquinolones in environmental water samples at ultratrace level. Errors, expressed as relative standard deviation (RSD) were below 8%, for all tested concentration levels. 相似文献
8.
9.
Monika Michel Luke Chimuka Ewa Cukrowska Bogus?aw Buszewski 《Analytica chimica acta》2009,632(1):86-171
The influence of temperature in a single hollow fibre supported liquid membrane extraction of triazole fungicides with a stagnant acceptor phase was investigated. The mass transfer parameters such as diffusion coefficient, flux and apparent viscosity were determined at temperature ranging from 278 K to 313 K. Increase in temperature led to an increase in diffusion coefficient and flux. The apparent viscosity also decreased with an increase in temperature. The degree of trapping in the acceptor phase influenced the mass transfer at higher temperature. At lower temperature, the transport of analytes from the donor solution through the donor-membrane interface and through the membrane mainly affected the transport of triazole fungicides. The effect of temperature in a single hollow fibre SLM extraction technique is therefore more pronounced where transport is donor controlled and/or membrane controlled. The partition coefficient of analytes from the acceptor solution to the membrane, KA was found to be much higher than that of from the donor solution to the membrane KD, thus least trapped triazole fungicides preferred to remain in the membrane even with an increased extraction temperature. 相似文献
10.
采用中空纤维液相微萃取与高效液相色谱联用技术测定了尿液样品中的痕量己烯雌酚;考察了样品相酸度、中间相种类、接收相浓度、搅拌速度、萃取时间等对液-液-液三相微萃取效率的影响,进而确定了最佳萃取条件.结果表明,当样品相pH为2.5,中间相为甲苯,接收相为3μL 0.25mol/L氢氧化钠溶液,搅拌速度为800r/min,萃取时间为50min时,萃取效率最佳.在最佳萃取条件下,样品的回收率为76.4%,相对标准偏差为3.8%. 相似文献
11.
S.K. Gupta N.S. Rathore J.V. Sonawane A.K. Pabby P. Janardan R.D. Changrani P.K. Dey 《Journal of membrane science》2007,300(1-2):131-136
The applicability of dispersion-free solvent extraction (DFSX), through microporous hydrophobic membrane has been studied. The hollow fiber membrane contactor, with surface area of 381 cm2 was employed to extract U(VI) in macro concentration (35 g dm−3) from aqueous acidic solutions. Prior to deployment of this technique for recovery of U(VI) from oxalate supernatant waste, chemical parameters such as extractant concentration, feed acidity, concentration of U(VI) in feed were studied. The study revealed that 30% tri-n-butyl phosphate (TBP) in n-dodecane as an extractant and feed in 3 M HNO3 gave an optimum extraction of U(VI) and it was possible to strip back utilizing 0.05 M HNO3. It was established to recover more than 90% of U(VI) from oxalate supernatant waste, which was often generated from nuclear chemical facilities. 相似文献
12.
Jia Liu Qianyi Song Wenqing Zheng Wenhui Jia Haijiao Jia Yaqin Nan Fangfang Ren James Jianmin Bao Youxin Li 《Journal of separation science》2022,45(13):2415-2428
A novel boronic acid and carboxyl-modified glucose molecularly imprinted polymer were prepared through suspension polymerization, which is based on 1.0 mmol glucose as a template, 1.2 mmol methacrylamidophenylboronic acid, and 6.8 mmol methacrylic acids as monomers, 19 mmol ethyleneglycol dimethacrylate, and 1 mmol methylene-bis-acrylamide as crosslinkers. The prepared glucose-molecularly imprinted polymer had a particle size of 25–70 μm, and was thermally stable below 215°C, with a specific surface area of 174.82 m2/g and average pore size of 9.48 nm. The best selectivity between glucose and fructose was 2.71 and the maximum adsorption capacity of glucose- molecularly imprinted polymer was up to 236.32 mg/g which was consistent with the Langmuir adsorption model. The similar adsorption abilities in six successive runs and the good desorption rate (99.4%) verified glucose-molecularly imprinted polymer could be reused. It was successfully used for extracting glucose from cellulose hydrolysis. The adsorption amount of glucose was 2.61 mg/mL and selectivity between glucose and xylose reached 4.12. A newly established chromatography (glucose-molecularly imprinted polymer) mediated hollow fiber membrane method in time separated pure glucose from cellulose hydrolysates on a large scale, and purified glucose solution with a concentration of 3.84 mg/mL was obtained, which offered a feasible way for the industrial production of glucose from cellulose hydrolysates. 相似文献
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14.
Dandan Han Minglei Tian 《International journal of environmental analytical chemistry》2013,93(9):1036-1045
A new hollow fibre liquid phase microextraction technology with an ionic liquid as the carrier was developed to determine the fluoroquinolone antibiotics in milk. In this technology, a porous polypropylene hollow fibre was filled with aqueous ionic liquid and the extraction efficiency of different factors, such as the type of hollow fibre membrane carrier, the pH and ionic strength of the donor solution, the pH of the acceptor solution, the stirring rate and the extraction time, were investigated. The optimised extraction condition was: [OMim][BF4] impregnated in the pores of the hollow fibre; 0.1?mol?L?1 of Na2HPO4 (pH 11.0) as the acceptor solution was injected into the lumen of the hollow fibre; 0.1?mol?L?1 H3PO4 (pH 5.0) was used as the donor solution; 600?rpm was selected as the stirring rate; 120?min was the optimum extraction time. The proposed method provided very high factors with 130-fold, 156-fold and 116-fold enrichment of ofloxacin, ciprofloxacin and enrofloxacin, respectively. 相似文献
15.
The separation of potassium and sodium ions from their mixture was performed by electrodialyzing a mixed solution of potassium
chloride and sodium chloride in the presence of 18-crown-6 using a commercial cation-exchange membrane. After 18-crown-6 had
been impregnated in the membrane, the mixed solution containing 18-crown-6 was electrodialyzed as the desalting-side solution.
The permeation of potassium ions through the membrane decreased remarkably and the electrical resistance of the membrane increased
during electrodialysis with increasing concentration of 18-crown-6 in the solution. Because potassium ions form a more stable
complex with 18-crown-6 than sodium ions and because the complex permeated through the membrane with difficulty, sodium ions
are thought to selectively permeate through the membrane. The current efficiency in electrodialysis was greater than 97.0%.
Received: 1 June 1999/Accepted in revised form: 13 August 1999 相似文献
16.
Yuqing Luo Yongxi Wang Fang Hu Shan Zhu Shuaifei Zhang 《Journal of Dispersion Science and Technology》2019,40(6):819-827
Phase separation behavior is a critical character in determining the usefulness of a solvent extraction system in hydrometallurgy. A survey of the synergistic mixture containing dinonylnaphthalene sulfonic acid (HDNNS) and 2-ethylhexly 4-pyridinecarboxylate ester (4PC) for the extraction of copper or nickel from acidic single metal sulfate solution has been carried out to suggest how the physicochemical properties (density, viscosity and interfacial tension) and the morphology of the reverse micelles in the loaded organic phase affect the phase separation behavior in this paper. The specific settling rates (SSR), physicochemical properties, metal concentration and the excess water uptake (the content of water solubilized into the water pool of the reverse micelles) in the loaded organic phase during the extraction of Cu(II)/Ni(II) have been measured. The results show that the most effective parameters affecting the phase separation behavior are the viscosity and the excess water uptake of the loaded organic phase. We assume that the deceleration of the SSR is mainly due to the apparent increase of these two parameters or in a microscopic view, the apparent change of the morphology of the reverse micelles in the loaded organic phase. The small angle X-ray scattering (SAXS) results provide a direct evidence of such microstructural changes and well supports our assumption. 相似文献
17.
A simple and efficient hollow fiber liquid‐phase microextraction (HF‐LPME) technique in conjunction with high‐performance liquid chromatography is presented for extraction and quantitative determination of aristolochic acid I in human urine samples. Several parameters influencing the efficiency of HF‐LPME were investigated and optimized, including extraction solvent, stirring rate, extraction time, pH of donor phase and acceptor phase. Excellent sample clean‐up was observed and good linearity with coefficient of 0.9999 was obtained in the range of 15.4–960 µg/L. This method provided a 230‐fold enrichment factor and good repeatability with relative standard deviations (RSD) lower than 6.0%. The limit of detection value for the analyte in urine sample was 0.01 µg/L at a signal‐to‐noise ratio of 3. The extraction recovery from urine samples was 61.8% with an RSD of 9.71%. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
18.
Jin-feng Peng Rui LiuJing-fu Liu Bin HeXia-lin Hu Gui-bin Jiang 《Spectrochimica Acta Part B: Atomic Spectroscopy》2007
A new procedure, based on hollow fiber supported liquid membrane preconcentration coupled with graphite furnace atomic absorption spectrometry (GFAAS) detection, was developed for the determination of trace Cd in seawater samples. With 1-octanol that contained a mixture of dithizone (carrier) and oleic acid immobilized in the pores of the polypropylene hollow fiber as a liquid membrane, Cd was selectively extracted from water samples into 0.05 M HNO3 that filled the lumen of the hollow fiber as a stripping solution. The main extraction related parameters were optimized, and the effects of salinity and some coexisting interferants were also evaluated. Under the optimum extraction conditions, an enrichment factor of 387 was obtained for a 100-mL sample solution. In combination with graphite furnace atomic absorption spectrometry, a very low detection limit (0.8 ng L− 1) and a relative standard deviation (2.5% at 50 ng L− 1 level) were achieved. Five seawater samples were analyzed by the proposed method without dilution, with detected Cd concentration in the range of 56.4–264.8 ng L− 1 and the relative spiked recoveries over 89%. For comparison, these samples were also analyzed by the Inductively Coupled Plasma Mass Spectrometry (ICP-MS) method after a 10-fold dilution for matrix effect elimination. Statistical analysis with a one-way ANOVA shows no significant differences (at 0.05 level) between the results obtained by the proposed and ICP-MS methods. Additionally, analysis of certified reference materials (GBW (E) 080040) shows good agreement with the certified value. These results indicate that this present method is very sensitive and reliable, and can effectively eliminate complex matrix interferences in seawater samples. 相似文献
19.
Lars Erik Eng Eibak Astrid Gjelstad Knut Einar Rasmussen Stig Pedersen-Bjergaard 《Journal of chromatography. A》2010,1217(31):5050-5056
Amitriptyline, citalopram, fluoxetine, and fluvoxamine were isolated by electro membrane extraction (EME) from 70 μl of untreated plasma (pH 7.4), through a supported liquid membrane (SLM) of 1-ethyl-2-nitrobenzene immobilized in the pores of a porous polypropylene hollow fiber, and into 30 μl of 10 mM HCOOH as acceptor solution inside the lumen of the hollow fiber. The driving force of the extraction was a 9 V potential sustained over the SLM with a common battery, with the positive electrode placed in the plasma sample and the negative electrode placed in the acceptor solution. Extractions were performed under totally stagnant conditions with a very simple device for 1 min (kinetic regime), and subsequently the acceptor solution was analyzed directly by liquid chromatography–mass spectrometry (LC–MS). Recoveries were 12, 13, 22, and 17% for fluoxetine, amitriptyline, citalopram, and fluvoxamine, respectively. Sample clean-up was comparable to reversed-phase solid-phase extraction (SPE), but EME required substantially less time than SPE. The time advantage of EME was further improved by parallel extraction of three samples (for 1 min) with the same 9 V battery. EME from plasma combined with LC–MS provided limits of quantification (S/N = 10) in the range 0.4–2.3 ng/ml, linearity in the range 1–1000 ng/ml with r2-values of 0.998–0.999, and repeatability in the range 3.2–8.9% RSD in the mid-therapeutic window (100 ng/ml). 相似文献
20.
David L. Grzenia Daniel J. Schell S. Ranil Wickramasinghe 《Journal of membrane science》2008,322(1):189-195
Production of bioethanol from lignocellulosic biomass requires pretreatment of the biomass in order to improve the susceptibility of the cellulose to enzymatic hydrolysis to glucose. When dilute acid is used to perform this process, the hemicellulose is also hydrolyzed to its component sugars while simultaneously releasing acetyl groups attached to the hemicellulose backbone. Other compounds from the lignin and sugar degradation products are also produced that inhibit subsequent bioconversion of the solubilized sugars to the desired products. In this work we focused on removal of acetic acid from a dilute sulphuric acid pretreated corn stover hydrolysate.Acetic acid has been extracted into an organic phase at pH values below its pKa. The organic phase diluent consisted of octanol. Alamine 336, a tertiary amine and Aliquat 336 a quaternary amine were used as the aliphatic amine extractants. Our results indicate more than 60% removal of acetic acid using Alamine 336. Extraction rates were much slower for Aliquat 336 probably due to the higher viscosity of the Aliquat 336/octanol phase.The presence of sulphate anions, as a result of dilute sulphuric acid pretreatment, results in the co-extraction of bisulphate anion. Bisulphate anion is preferentially extracted at pH values below its pKa. Consequently the pH of the hydrolysate increases from between 1 and 2 to above 4.0 during extraction. In addition, extraction of low molecular weight lignins and phenolics is also observed. Thus the membrane extraction process developed here may be used not only for removal of acetic acid but also to adjust the pH of the hydrolysate to values that are more compatible for fermentation and to remove other inhibitory compounds. 相似文献