Supercritical fluid extraction of jojoba oil

Supercritical fluid extraction of jojoba oil from Simmondsia chinensis seeds using CO₂ as the solvent is presented in this study. The effects of process parameters such as pressure and temperature of extraction, particle size of jojoba seeds, flow rate of CO₂, and concentration of entrainer (hexane) on the extraction yield were examined. Increases in the supercritical CO₂ flow rate, temperature, and pressure generally improved the performance. The extraction yield increased as the particle size decreased, indicating the importance of decreasing intraparticle diffusional resistance. The maximum extraction yield obtained was 50.6 wt% with a 0.23-mm particle size and a 2 mL/min CO₂ flow rate at 90°C and 600 bar. Use of an entrainer at a concentration of 5 vol% improved the yield to 52.2 wt% for the same particle size and also enabled the use of relatively lower pressure and temperature, i.e., 300 bar and 70°C.     

Pilot-Scale Multi-Stage Countercurrent Extraction of Scutellarein from Erigeron breviscapus (Vant.) Hand-Mazz

Abstract

A low-temperature, timesaving, lower solvent consumption, and energy cost and multi-stage countercurrent extraction (MCCE) technique was developed for pilot-scale production of scutellarein from Erigeron breviscapus (Vant.) Hand-Mazz. The optimum conditions of MCCE process were obtained using the orthogonal array design method, i.e., 70% (v/v) of ethanol water solution, 16 L/kg of solvent to herbal sample ratio, 45°C of extraction temperature and 30 min of extraction time. A comparison between the MCCE technique and single pot extraction (SPE) under respective optimized operation conditions was made and time courses of scutellarein of MCCE and SPE processes were plotted, indicating that the MCCE technique can lower the extraction temperature and decrease five-sixth of the extraction time and two-thirds of the solvent consumption at the equivalent extraction yield of scutellarein.     

Extraction of Total Phenolics of Sour Cherry Pomace by High Pressure Solvent and Subcritical Fluid and Determination of the Antioxidant Activities of the Extracts

Abstract

High pressure liquid extraction (HPE) and subcritical fluid (CO₂+ethanol) extraction (SCE) were used for the extraction of total phenolic compounds (TPC) from sour cherry pomace. Antiradical efficiency (AE) of the extracts was also determined. Ethanol was the solvent for HPE and co‐solvent for SCE. Combinations of pressure (50, 125, 200 MPa), temperature (20, 40, 60°C), solid/solvent ratio (0.05, 0.15, 0.25 g/ml) and extraction time (10, 25, 40 min) were variables for HPE according to the Box‐Behnken experimental design. The variables used for SCE were pressure (20, 40, 60 MPa), temperature (40, 50, 60°C), ethanol concentration (14, 17, 20 wt%) and extraction time (10, 25, 40 min). For HPE, TPC, and AE at the optimum conditions (176–193 MPa, 60°C, 0.06–0.07 g solid/ml solvent, 25 min) were found as 3.80 mg gae/g sample and 22 mg DPPH^?/g sample, respectively. TPC and AE at the optimum conditions (54.8–59 MPa, 50.6–54.4°C, 20 wt% ethanol, 40 min) for SCE were determined as 0.60 mg gae/g sample and 2.30 mg DPPH^?/g sample for sour cherry pomace, respectively.     

Response Surface Methodology to Supercritical Carbon Dioxide Extraction of Essential Oil from Amormum krevanh Pierre

Abstract

Response surface methodology was employed to investigate the effects of operating conditions and predict the optimal conditions for supercritical carbon dioxide extraction of essential oil from Amomum krevanh Pierre. The factors investigated were operating temperature (33–67°C), the operating pressure (91–259 bar), and the extraction time (20–70 min). The main effect of the operating pressure and the interaction effect between the operating temperature and the extraction time were found to be significant factors. From the response surface model, an optimal condition for essential oil content within the range of experimental study was found to be at 33°C, 175 bar, and 70 min, which gave the oil yield of 17.3 mg/g dry wt. The essential oil yield obtained at all conditions were higher than that obtained by organic solvent extraction (9.74 mg/g dry wt.) while the composition of the extract was similar, which were 1,8-cineole (70.87%), β-pinene (8.89%), and limonene (4.81%).     

A sequential separation of linderane and norisoboldine using supercritical fluid and ionic liquid-based ultrasonic-assisted extraction from Lindera aggregate

ABSTRACT

Linderane (LDR) and norisoboldine (NOR) are two typical active compounds in Lindera aggregate (Sims.) Kosterm. In this study, a new method of sequential extraction of LDR and NOR from L. aggregate was developed by supercritical fluid extraction (SFE) and ionic liquid-based ultrasonic-assisted extraction (IL-UAE) for the first time. The suitable SFE with CO₂ conditions for LDR were 60 min dynamic extraction time, 40°C temperature and 30 MPa pressure. And the optimal IL-UAE factors for NOR were 2.06 mol/L 1-butyl-3-methylimidazolium bromide ([Bmim] Br) aqueous solution, 44 mL/g liquid–solid ratio, and 67 min ultrasonic time. Compared with the traditional extraction process, the sequential methods not only can obtain higher extraction efficiency, but also can realize the selective extraction for two different kinds of constituents with less consumption of traditional organic solvent. In addition, this environmentally friendly method could be used in a large-scale industry.     

Extraction of Hydrocarbons from Crude Oil Tank Bottom Sludges using Supercritical Ethane

Abstract

A custom‐built, solvent recirculating, supercritical fluid extraction (SFE) apparatus was used to study the extraction of hydrocarbons from a crude oil tank bottom sludge (COTBS) with supercritical ethane. The SFE experiments were carried out varying the pressure (10 MPa and 17.20 MPa) and temperature (35°C and 65°C). The yield of the extracted hydrocarbon fraction increased with increase in extraction pressure at constant temperature, and decreased with increase in extraction temperature at constant pressure. The maximum extraction yield was obtained at the pressure and temperature conditions that lead to the highest solvent density. The extracted hydrocarbon fraction was a significantly upgraded liquid relative to the original untreated COTBS.     

Supercritical CO2 extraction of pigment components with pharmaceutical importance from Chlorella vulgaris

BACKGROUND: Chlorella vulgaris is a green microalgae that contains various pigment components of carotenoids and chlorophylls. Supercritical CO₂ is widely used for extraction of pharmaceutical compounds because it is non‐oxic and easily separated from extracted material by simply depressurizing. In this work, pharmaceutical compounds from Chlorella vulgaris have been extracted using supercritical CO₂ with or without entrainer at various extraction conditions. RESULTS: Based on high performance liquid chromatography (HPLC) analysis, the extracts contained pigment components, such as lutein, β‐carotene, chlorophyll a and b. Higher extraction pressure and temperature promoted higher lutein extraction by supercritical CO₂. The optimum pressure and temperature for extraction were obtained as 50 MPa and 80 °C. Ethanol as an entrainer was more effective than acetone for the extraction of pigment components. Pigment components in the extract obtained by supercritical CO₂ with and without entrainer were compared with the extract obtained by a conventional extraction method. CONCLUSION: Supercritical CO₂ has been successfully applied for the extraction of pigment components from Chlorella vulgaris. Supercritical CO₂ enabled high selectivity for lutein extraction; however, the lutein yield was lower than that obtained by extraction using supercritical CO₂ with ethanol and soxhlet. Copyright © 2008 Society of Chemical Industry     

Optimum Extraction of Osthole and Imperatorin from the Fruits of Cnidium monnieri (L.) Cusson by Supercritical Fluid

This work describes an optimized supercritical fluid extraction (SFE) process of osthole and imperatorin from the fruits of Cnidium monnieri (L.) Cusson. Response surface methodology (RSM) was employed to evaluate the effects of independent variables on the yields of osthole and imperatorin. The independent variables were extraction pressure (100 to 300 bar), temperature (50 to 70°C), and ethanol flow rate (0 to 0.4 mL/min). Results indicated that the data could be well fitted to two second-order polynomial models in the selected experimental domain. The effects of independent variables of pressure, temperature, ethanol rate flow, as well as the interactions between pressure and ethanol flow rate, and between temperature and ethanol flow rate on the extraction yield were significant for osthole or imperatorin extraction (p < 0.05). The models predicted that the optimized conditions were 243 bar, 64°C, ethanol flow rate of 0.28 mL/min, giving maximum yields of 1.29% and 0.53% for osthole and imperatorin, respectively, that were in good agreement with the experimental values. The extraction yields obtained with the optimized SFE and Soxhlet extraction were compared.     

Comparative study of solvent extraction and supported liquid membrane for the extraction of gallium (III) from chloride solution using organophosphorus acids as extractants

ABSTRACT

The transport of Ga(III) from chloride solution by supported liquid membrane (SLM) using organophosphorus acids as carriers was studied and compared with solvent extraction results. The diffusion coefficient, permeability coefficient and mass transfer resistance for both processes were analyzed by investigating various parameters, such as flow pattern, flow rate, pH, Ga(III)/extractant concentration and temperature. Under optimized conditions, the extraction percentage of 97.0% and permeability coefficient of 9.22 × 10^?6 m/s was achieved for SLM process. Kinetic modeling was proposed to determine the mass diffusion coefficient of Ga(III) complex across the membrane and stability of this SLM system was also examined.     

Removal of Cr(VI) From Aqueous Solution by Turkish Vermiculite: Equilibrium,Thermodynamic and Kinetic Studies

Abstract

The adsorption of Cr(VI) from aqueous solution by Turkish vermiculite were investigated in terms of equilibrium, kinetics, and thermodynamics. Experimental parameters affecting the removal process such as pH of solution, adsorbent dosage, contact time, and temperature were studied. Equilibrium adsorption data were evaluated by Langmuir, Freundlich and Dubinin–Radushkevich (D–R) isotherm models. Langmuir model fitted the equilibrium data better than the Freundlich model. The monolayer adsorption capacity of Turkish vermiculite for Cr(VI) was found to be 87.7 mg/g at pH 1.5, 10 g/L adsorbent dosage and 20°C. The mean free energy of adsorption (5.9 kJ/mol) obtained from the D–R isotherm indicated that the type of sorption was essentially physical. The calculated thermodynamic parameters (ΔG ^o , ΔH ^o and ΔS ^o ) showed that the removal of Cr(VI) ions from aqueous solution by the vermiculite was feasible, spontaneous and exothermic at 20–50°C. Equilibrium data were also tested using the adsorption kinetic models and the results showed that the adsorption processes of Cr(VI) onto Turkish vermiculite followed well pseudo-second order kinetics.     

Sulfur containing poly(N‐isopropylacrylamide) copolymer hydrogels for thermosensitive extraction of gold(III) ions

Poly[N‐isopropylacrylamide‐co‐[2‐(methylthio)ethyl methacrylate]], poly(NIPA‐co‐MTEMA) gels were prepared by free radical polymerization in aqueous solution. The homogeneous and heterogeneous gels were prepared by using 10 mM MTEMA in 5.0%(v/v) ethanol at 10°C and 30 mM MTEMA in 20%(v/v) ethanol at 50°C, in 1.0 and 1.5M NIPA solution, respectively. Homogeneous and heterogeneous gels had swelling ratios at 540 ± 28% and 551 ± 37%, respectively. The extraction of Au(III) ion was studied in batch method. The optimum pHs for the extraction of Au(III) by homogeneous and heterogeneous gels were 1–3 and 1–5, respectively. The suitable extraction time was 3 h at 50°C when using a rod‐shaped copolymer (0.7 cm diameter and 1 cm length). The adsorption behavior obeyed the Langmuir and Freundlich isotherms. The maximum sorption capacities of Au(III) onto homogeneous and heterogeneous gels were 62.8 and 322 μmol/g, respectively. The desorption equilibrium was reached within 2–3 h at 10°C by 0.1M thiourea in 5%(v/v) HCl. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Methanol-Water Extraction of Saponins From Seeds of Saponaria Vaccaria L. — Calibration Equation,Extraction Condition Analysis,and Modeling

Bisdesmosides, monodesmosides, and other bisdesmosidic saponins were observed in the particles of Saponaria vaccaria L seeds (15.35% dry basis) with diameter of 0.044 to 1.19 mm and an average thickness of 124 µm as investigated with liquid chromatography-mass spectroscopy at methanol concentration of 30%, 50%, 70%, and 90% (vol., aq.), temperature of 30°C, 45°C, and 60°C, and eight extraction time intervals between 1 and 180 min. The saponins yield increased significantly with temperature (45°C to 60°C) and methanol concentration (50% to 70%) with negligible effect of moisture content. The maximum yield was obtained at 60°C for 70% methanol concentration and 30 min of extraction time. The mass transfer properties of the test material may have potentials for modeling, simulation and optimization of similar products and processes. A diffusional mathematical model simulated extraction kinetics, and estimated partition coefficient, and effective diffusivity of saponins very well.     

Carrier Facilitated Transport of Europium(III) Across Supported Liquid Membranes Containing N,N,N′,N′-tetra-2-ethylhexyl-3-oxapentane-diamide (T2EHDGA) as the Extractant

Studies on the solvent extraction and pertraction behavior of europium(III) was carried out from acidic feed solutions using N,N,N′,N′-tetra-2-ethylhexyl-3-oxapentane-diamide (T2EHDGA) in n-dodecane as the solvent. The nature of the extracted species from the solvent extraction studies conformed to Eu(NO₃)₃ · 3T2EHDGA which is in variance with the analogous Eu(III) – TODGA (linear homolog of T2EHDGA) extraction system. The transport behavior of Eu(III) was investigated from a feed containing 3.0 M HNO₃ into a receiver phase containing 0.01 M HNO₃ across a PTFE flat sheet supported liquid membrane (SLM) containing 0.2 M T2EHDGA in n-dodecane as the carrier solvent and 30% iso-decanol as the phase modifier. Effects of feed acidity, carrier extractant concentration, membrane pore size, and Eu concentration in the feed on the transport rates of Eu(III) were also investigated. Membrane diffusion coefficient (D _o) for the pertracted species was calculated using the Wilke-Chang equation as 4.25 × 10^?6 cm² · s^?1. The influence of Eu concentration on the flux was also investigated. The role of temperature on the transport rates was investigated and the thermodynamic parameters were calculated.     

Separation and Purification of Three High-Purity Isoflavonoids from Belamcanda chinensis (L.) DC. by Supercritical Fluid Extraction and High-Speed Counter-Current Chromatography

Supercritical fluid extraction (SFE) was used to extract three isoflavonoids including irigenin, irisfloretin and dichtomitin from Belamcanda chinensis (L.) DC. The parameters including pressure, temperature, sample particle size, and flow rate of CO₂ were optimized with an orthogonal test. Under the optimized conditions of 15 MPa, 55°C, a sample particle size of 20–40 mesh and CO₂ flow rate of 40 L h^?1. The process was then scaled up by 10 times using a preparative SFE system. The yield of the crude extract from SFE was 4.1%, which contained irigenin, irisfloretin, and dichtomitin 0.71%, 0.49%, and 0.05%, respectively. To compare the extraction methods, Soxhlet Extraction (SE) was performed. The results indicated that SFE was better than SE. Irigenin, irisfloretin, and dichtomitin in the SFE extract were then separated and purified by high-speed counter-current chromatography (HSCCC) with a two-phase solvent system composed of petroleum ether–ethyl acetate–methanol–water (2:4:3:3, v/v). From 5.0 g of dry crude extract, 27.8 mg irigenin, 16.4 mg irisfloretin, and 2.1 mg dichtomitin were obtained at purities of 97.1%, 96.4%, and 98.0%, respectively, as determined by HPLC-PDA. These results well indicate that SFE and HSCCC are very powerful techniques for the extraction and purification of irigenin, irisfloretin, and dichtomitin from B. chinensis.     

6,6′‐Bis(5,5,8,8‐tetramethyl‐5,6,7,8‐tetrahydro‐benzo[1,2,4]triazin‐3‐yl) [2,2′]bipyridine,an Effective Extracting Agent for the Separation of Americium(III) and Curium(III) from the Lanthanides

Abstract

The extraction of americium(III), curium(III), and the lanthanides(III) from nitric acid by 6,6′‐bis(5,5,8,8‐tetramethyl‐5,6,7,8‐tetrahydro‐benzo[1,2,4]triazin‐3‐yl)‐[2,2′]bipyridine (CyMe₄‐BTBP) has been studied. Since the extraction kinetics were slow, N,N′‐dimethyl‐N,N′‐dioctyl‐2‐(2‐hexyloxy‐ethyl)malonamide (DMDOHEMA) was added as a phase transfer reagent. With a mixture of 0.01 M CyMe₄‐BTBP+0.25 M DMDOHEMA in n‐octanol, extraction equilibrium was reached within 5 min of mixing. At a nitric acid concentration of 1 M, an americium(III) distribution ratio of approx. 10 was achieved. Americium(III)/lanthanide(III) separation factors between 50 (dysprosium) and 1500 (lanthanum) were obtained. Whereas americium(III) and curium(III) were extracted as disolvates, the stoichiometries of the lanthanide(III) complexes were not identified unambiguously, owing to the presence of DMDOHEMA. In the absence of DMDOHEMA, both americium(III) and europium(III) were extracted as disolvates. Back‐extraction with 0.1 M nitric acid was thermodynamically possible but rather slow. Using a buffered glycolate solution of pH=4, an americium(III) distribution ratio of 0.01 was obtained within 5 min of mixing. There was no evidence of degradation of the extractant, for example, the extraction performance of CyMe₄‐BTBP during hydrolylsis with 1 M nitric acid did not change over a two month contact.     

High-temperature electro-ceramics and their application to SiC power modules

This paper presents the research achievement in Japan to develop highly-refractive electro-ceramics for application to silicon carbide (SiC) power modules such as heat-resistive passive components (snubber capacitors and resistors), metalised substrates, ceramic circuit boards, and high-temperature packaging technologies. To enable the operation of SiC devices at high temperatures, the ability to withstand 250 °C and temperature cycle between ?40 and 250 °C must be ensured for all the ceramic components and packaging technologies. For the passive components, the following properties were achieved, which would enable the operation of SiC devices at high switching speeds and high temperatures: low-resistance resistors which exhibit a resistance variation of less than 2% over a temperature range of ?40 to 250 ℃ and with almost no variation at frequencies of less than 10 MHz; multi-layered ceramic capacitors (MLCCs) with a capacitance variation of less than ± 10% within the above-mentioned temperature range and with high self-resonant frequencies of about 10 MHz. In addition, Cu-metalised ceramic substrates using high thermal conductive Si₃N₄ (180 W /(m·K)) and ceramic circuit boards produced using a co-firing process were developed. It was shown that prototype SiC power modules (2-in-1 structure) fabricated using the developed ceramic components could be operated at 225 °C, while exhibiting a high switching speed, 10–20 times faster than that of conventional Si IGBT (150 °C operation).     

Effect of shade and thermo-mechanical viscosity stimulation methods on the rheological properties of nanohybrid resin composite

The aim of the present study is to measure the rheological properties of nanohybrid resin composite of three shades in pre-polymerized phase using different thermomechanical stimulations. Nanohybrid composite (Kerr Herculite XRV Ultra) in enamel, dentin, and incisal shades was included. Rheological measurements were made with a rotational rheometer in dynamic oscillation mode using three methods: (a) Strain Sweep test explored a range of deformation γ₀ from 0.025 to 3% with a frequency ω = 1 Hz (temperature set at 25 and 65?°C), (b) Frequency Sweep test explored frequencies between 1 and 100 rad/s applying a deformation γ₀ = 0.5% (temperature set at 25; 45; 65?°C), and (c) Ramp Temperature test explored a heating phase from 25 to 75?°C then a cooling phase back to 25?°C applying a γ₀ = 0.5% and a ω = 10 rad/s. Data were analyzed using a three-way ANOVA and Tukey’s test (α = 0.05). Viscosity measurement (p < 0.05) and shade of the composites (p < 0.05) significantly affected the results. Viscosity turned out to be subordinate to strain amplitude, frequency, temperature, and axial force applied during each test. Enamel shade was the most viscous whereas dentin shade was 8% less viscous (p < 0.05). The incisal shade was significantly less viscous (70%) than enamel (p < 0.05). Pre-heating decreased viscosity of incisal shade (30%) above 50?°C but this value was 90 and 98%, respectively, for strain and frequency sweep test. Preheating had a side effect as in the cooling phase, viscosity increased from 66 to 450% exceeding the value recorded at the beginning of the test. Preheating was not effective to reduce viscosity, and may reveal some side effects. The composite tested might not be pre-heated above 45?°C.     

Selective Competitive Biosorption of Au(III) and Cu(II) in Binary Systems by Magnetospirillum gryphiswaldense

The biosorption of Au(III) and Cu(II) ions in both single and binary systems by Magnetospirillum gryphiswaldense (MSR-1) was investigated. For comparison with the selective reinforced competitive biosorption process in a binary system, the experimental research first explored the biosorption of Au(III) and Cu(II) in a single system under various conditions. The biomass exhibited the highest single Au(III) and Cu(II) ion adsorption yields at room temperature (25°C), pH values of 2.5 and 5.0, respectively, and a biomass concentration of 10 g · L^?1 (3.83 g · L^?1, dry basis). The experimental data from the single component system for the two metallic ions fitted well to a Langmuir isotherm and a pseudo second-order kinetic models. In the Au(III)-Cu(II) binary system, the coexistence of Cu(II) cations promoted the adsorption of Au(III) within a certain range of ratios. A new sigmoidal Cu(II) biosorption isotherm was determined specifically to reveal the Cu(II) adsorption behavior in this case.     

Drying Kinetics and Color Retention of Dehydrated Rosehips

Abstract

Freshly harvested rosehips (Rosa canina L.) were dehydrated in a parallel flow type air dryer at six air temperatures (30, 40, 50, 60, and 70°C) at air velocities of 0.5, 1.0, and 1.5 m/s. Drying air temperature and velocity significantly influenced drying time and energy requirement. Minimum and maximum energy requirement for drying of rosehips were determined as 6.69 kWh/kg for 70°C at 0.5 m/s, and 42.46 kWh/kg for 50°C, 1.5 m/s. In order to reduce drying energy consumption, it is recommended that the drying air velocity must not be more than 0.5 m/s and drying air temperature should be 70°C. In addition, the influence of drying air temperature and air velocity on the color of dried rosehip has been studied. Hunter L, a, b values were used to evaluate changes in the total color difference (ΔE) on dried rosehips. 70°C drying air temperature and 1 m/s air velocity were found to yield better quality product.     

Reactive separation of p-nitro phenol (PNP) from aqueous solution using tri-n-butyl phosphate: equilibrium and COSMO-RS studies

ABSTRACT

The present study is aimed to optimized diluent type, tri-n-butyl phosphate (TBP) composition and temperature for the reactive extraction of p-nitro phenol (PNP) in two different PNP concentration ranges [(0.00036–0.00646) kmol·m^?3 and (0.00646–0.01437) kmol·m^?3] as found in industrial effluents. 1-Octanol is investigated as the best diluent with TBP based on COSMO-RS theory. Equilibrium study based on mass action law is performed to find the insights of extraction mechanisms, equilibrium constant (K = 295.12 k·mol^?1) and stoichiometry (m:n = 1:1) as also confirmed by FTIR. Thermodynamic parameters, enthalpy (ΔH°), and entropy (ΔS°) are determined 27.51 K J mol^?1 and ?50.21 J mol^?1 K^?1, respectively.