Supercritical Fluid Extraction Process Research Articles

Thermodynamic properties estimation of (oil)-(moringa seeds)-(supercritical CO2) extractive system

Oils supercritical fluid extraction (SFE) with CO2 from biological sources has the potential to displace classical solid-liquid extraction with organic solvents by its lower energy consumption and environmental sustainability. Optimal design of oils SFE process requires thermodynamic properties estimation and modeling. Therefore, moringa seeds oil distribution constant and moringa seeds tortuosity factor were estimated by inverse method on a mechanistic SFE dynamic model. Experimental dynamics of SFE Moringa seeds oil were performed at different temperature and pressure as validation. Results were 0.0057 for tortuosity factor of moringa seeds and a thermodynamic model for distribution constant of (oil)-(moringa seeds)-(CO2) system. Estimated thermodynamic properties applied in model, reproduced the experimental extraction of SFE moringa seeds oil at 30 MPa and 353.15 K with less than 10% average error.

Life cycle assessment for identification of critical aspects in emerging technologies for the extraction of phenolic compounds from spruce bark

Polyphenolic compounds in bark are resources of great interest to produce renewable chemicals and several different technologies are available or under early development for the extraction of these types of compounds. Since critical environmental effects of a product are often set during the design phase, it is important to use life cycle assessment (LCA) to identify the steps resulting in the largest environmental burdens and the overall performance of the various technologies at an early stage during technology development. In addition, for a better understanding of the environmental impact of the future system, it is needed to consider an up-scaled process already in early process development. In the current study, LCAs of three different technologies; hot water extraction (HWE), ultrasound assisted extraction (UAE), and supercritical fluid extraction (SFE) for the extraction of phenolic compounds from spruce bark were compared in a large-scale production scenario. The study includes industrially relevant heat sources and heating technologies, downstream separations, solvent recovery, and heat recovery within the processes. The LCA shows that the simpler HWE process has a lower environmental impact per amount of phenolic compound extracted than UAE and SFE unless the extraction yields of the latter are more than about 5 times that of HWE. The reason for this result is mainly the environmental burden caused by the consumption of ethanol in the UAE and SFE processes, which accounts for more than 70% of the total environmental burden in most impact categories. Even if bioethanol produced with a particularly low carbon footprint would be used, the impact from ethanol use in the extractions would be considerable. UAE and SFE were also more dependent on the use of electricity. In the base case scenario, electricity produced with a low share of fossil resources was used, and electricity was in this case not one of the main contributors to the environmental impact of the processes. However, if the production of electricity is largely fossil-based, it comes out as a significant factor. Furthermore, the heat recovery in an up-scaled process is very important and accounts for a reduction of 35–60% net heat demand. As a complement to LCAs, future studies of promising polyphenolic compound production systems should also include economic aspects and performance.

Supercritical Fluid Extraction of Phenolic Compounds from Mango (Mangifera indica L.) Seed Kernels and Their Application as an Antioxidant in an Edible Oil.

Phenolic compounds from mango (M. indica) seed kernels (MSK) var. Sugar were obtained using supercritical CO2 and EtOH as an extraction solvent. For this purpose, a central composite design was carried out to evaluate the effect of extraction pressure (11–21 MPa), temperature (40–60 °C), and co-solvent contribution (5–15% w/w EtOH) on (i) extraction yield, (ii) oxidative stability (OS) of sunflower edible oil (SEO) with added extract using the Rancimat method, (iii) total phenolics content, (iv) total flavonoids content, and (v) DPPH radical assay. The most influential variable of the supercritical fluid extraction (SFE) process was the concentration of the co-solvent. The best OS of SEO was reached with the extract obtained at 21.0 MPa, 60 °C and 15% EtOH. Under these conditions, the extract increased the OS of SEO by up to 6.1 ± 0.2 h (OS of SEO without antioxidant, Control, was 3.5 h). The composition of the extract influenced the oxidative stability of the sunflower edible oil. By SFE it was possible to obtain extracts from mango seed kernels (MSK) var. Sugar that transfer OS to the SEO. These promissory extracts could be applied to foods and other products.

Study on SFE‐CO2 and chemical composition of thuja essential oil

AbstractThuja (Thuja sutchuenensis Franch.) (family Cupressaceae) is a Chinese endemic plant once declared extinct in China. After being rediscovered in 1999, it attracted the attention of domestic scholars. This study aimed to investigate the extraction process and composition of the essential oil from thuja to provide a reference for further research. The main xylem of thuja collected from the Qinling‐Bashan mountains was used as the experimental material. The essential oil of thuja was extracted by the supercritical carbon dioxide fluid extraction (SFE‐CO2) process, and the composition of the essential oil was detected by gas chromatography‐mass spectrometry (GC‐MS). Extraction pressure, extraction temperature, and extraction dynamic time were the main factors influencing the extraction rate. The optimal conditions for the extraction include the following: maintaining the extraction pressure at 20 MPa, extracting for 60 min at 45 °C, and maintaining the CO2 flow rate at 1.5 L min–1 at 120 °C. Under the optimal extraction conditions, the oil extraction rates of three verification experiments were 18.87, 18.63, and 19.07%. The GC‐MS detected 136 components from the extracted thuja essential oil, and 75 components were identified. The main components of the essential oil were cis‐thujopsene (23.54%) and cedrol (13.08%). In this study, the optimal process for SFE‐CO2 of essential oil from the xylem of thuja was obtained. Under this optimized process, the average oil content was 18.86%.

Comparison of the Sub-Critical Fluid Extraction of the Essential Oil of Turmeric (Curcuma longa L.) with That of Hydrodistillation

Turmeric (Curcuma longa L.) is a spice plant grown in the tropics that contains both an essential oil and an oleoresin. The essential oil is important as a flavouring and has pharmaceutical properties, while the oleoresin is bright yellow in colour and has medicinal properties. The essential oil has traditionally been extracted by hydrodistillation/steam distillation with the total extract being extracted by solvent extraction and more recently by supercritical fluid extraction (SFE). The objective of the work described in this paper was to investigate the possibility of extracting the essential oil using sub-critical fluid extraction and to compare it with hydrodistillation. The experiments using hydrodistillation showed that unpeeled fresh turmeric was the preferred raw material, giving an oil yield of ≈6% dry weight basis, which is similar to that reported in the literature. The experimental programme on the extraction of the oil from dried unpeeled turmeric was carried out over a temperature range from 25 to 30 °C and pressures from 65 to 71 bar. Yields were generally higher than hydrodistillation (up to ≈9% dry weight basis) as were the compositions of the extracted oils. The preferred operating conditions were determined to be 25 °C temperature and 65 bar pressure. Curcumin, the major component of the oleoresin, was not found in the oil, thereby demonstrating that the sub-critical extract is a pure essential oil. It is suggested that consideration be given to evaluating an SFE process whereby the essential oil is initially fully extracted under sub-critical fluid extraction conditions, after which the oleoresin is extracted separately by raising the pressure to ≈250 bar.

Supercritical Fluid Extraction Kinetics of Cherry Seed Oil: Kinetics Modeling and ANN Optimization.

This study was primarily focused on the supercritical fluid extraction (SFE) of cherry seed oil and the optimization of the process using sequential extraction kinetics modeling and artificial neural networks (ANN). The SFE study was organized according to Box-Behnken design of experiment, with additional runs. Pressure, temperature and flow rate were chosen as independent variables. Five well known empirical kinetic models and three mass-transfer kinetics models based on the Sovová’s solution of SFE equations were successfully applied for kinetics modeling. The developed mass-transfer models exhibited better fit of experimental data, according to the calculated statistical tests (R2, SSE and AARD). The initial slope of the SFE curve was evaluated as an output variable in the ANN optimization. The obtained results suggested that it is advisable to lead SFE process at an increased pressure and CO2 flow rate with lower temperature and particle size values to reach a maximal initial slope.

Promising Green Technology in Obtaining Functional Plant Preparations: Combined Enzyme-Assisted Supercritical Fluid Extraction of Flavonoids Isolation from Medicago Sativa Leaves.

To elaborate a complete extraction protocol for the enhanced release of biologically active compounds from plant cells, this study aimed to optimize together the parameters of the supercritical fluid extraction (SFE) process (temperature, pressure, and percentage of cosolvent) and enzymatic treatment of plant material (pH, enzyme concentration, time, and temperature) by response surface methodology (RSM). Medicago sativa L. was selected as a plant material due to its richness in phenolics and flavonoids. HPLC-MS/MS analysis allowed evaluating the content of individual bioactive compounds in obtained extracts. The total content of polyphenolic compounds in the extract obtained after two-step optimization was much higher (546 ± 21 µg/g) than in the extract obtained from non-hydrolyzed material (275 ± 23 µg/g) and in the extract obtained by maceration (162 ± 20 µg/g). Furthermore, it was evidenced that extract with the highest content of polyphenolic compounds can support the cellular antioxidant system both as a free radical scavenger and by stimulating the antioxidant enzyme system.

Characterization of 14-Crown-4 Ethers for the Extraction of Lithium from Natural Brines: Synthesis, Solubility Measurements in Supercritical Carbon Dioxide, and Thermodynamic Modeling

Improving lithium mining methods is key to furthering lithium’s use as an energy metal. Current mining methods from brines are slow and inefficient and have significant environmental impacts, providing an avenue of research toward developing more effective and less environmentally damaging methods. Supercritical fluid extraction has been evaluated in earlier research for the extraction of metals such as uranium, mercury, and several alkali and earth alkaline metals from aqueous solutions but not for lithium. This study documents the synthesis and preliminary testing of two lithium extractants for possible application in a supercritical carbon dioxide fluid extraction process to recover lithium from natural brines. Based on their high solubility in supercritical carbon dioxide and their desirable structural properties, two 14-crown-4 ethers with different functional groups were selected. In this work, solubility measurements and thermodynamic modeling were carried out to characterize their solubility behavior in the range of P = 100–300 bar with T = 60 °C and T = 85 °C. The main conclusion from this work is the experimental observation of sufficiently high solubilities of the synthesized crown ethers in supercritical carbon dioxide. The highest measured solubility of M14C4, the nonfluorinated 14-crown-4 ether, was 0.30 mol/L at 60 °C and 205 bar, and the highest measured solubility of F14C4, the fluorinated 14-crown-4 ether, was 0.27 mol/L at 60 °C and 285 bar. Another major conclusion was the observed higher solubility of M14C4 than F14C4. We also showed that equation of state modeling provides insight into the factors affecting the crown ether solubility in supercritical carbon dioxide.

An Additional Condition of Efficiency of the Supercritical Fluid Extraction Process

An Additional Condition of Efficiency of the Supercritical Fluid Extraction Process

Experimental extraction of gallic acid from brown sumac seed (Rhus coriaria) using supercritical carbon dioxide and ethanol as co-solvent: Modeling and optimization

In this paper, the extraction of gallic acid (GA) from brown sumac seeds was evaluated using supercritical-CO2 (SC-CO2) fluid and ethanol as the co-solvent, as well as Soxhlet method. Response surface methodology (RSM) design and optimize the experiments with second order model with the adjusted coefficient of determination (adj. R2) of 95.7%. Then, the supercritical fluid extraction (SFE) process was modeled based on differential mass balances and the shrinking core model. To determine the equilibrium coefficient, four thermodynamic equations were used. Based on the results, the optimal temperature, pressure, CO2 flow rate and dynamic time were obtained as 35 °C, 30 MPa, 1.64 ml/min and 127.08 min, which resulted in 50.54% recovery (w/w), respectively. The mentioned mathematical model appropriately predicted the behavior of the process. Accordingly, the results obtained from thermodynamic equation of Peng–Robinson cubic plus association (PR-CPA) with adj. R2 of 93.12%, showed the highest accuracy.

Techno-economical optimization of uvaia (Eugenia pyriformis) extraction using supercritical fluid technology

This work presents an economic evaluation of supercritical fluid extraction (SFE) process from uvaia leaves. Extractions were performed at a previously optimized condition of pressure (200 bar) and temperature (60 °C) and were evaluated with the addition of 5% of two different co-solvents (ethyl acetate and ethanol). A scale-up study was performed by adopting constant values for the solvent to feed mass ratio (S/F) and the extraction time as criteria. Two different scales were assessed: 5-fold and 10-fold (vessel volume and mass due to the constant bed density). An economic evaluation using SuperPro Designer 8.5® to estimate the cost of manufacturing (COM) by testing 3 different scenarios was also performed. The addition of co-solvents resulted in lower estimated production costs, and the addition of 5% (w/w) of ethanol showed the best results among the conditions evaluated. The COM values are in a range from 622.9 to 1102.6 US$/kg extract.

Application of Green Solvents for Rare Earth Element Recovery from Aluminate Phosphors

Two processes applying green solvents for recovering rare earth elements (REEs) from different types of aluminate phosphors are demonstrated in this report. For magnesium aluminate-type phosphors, a pretreatment with peroxide calcination was implemented first, and then followed by a supercritical fluid extraction (SFE) process. Supercritical carbon dioxide (sc-CO2) provides an effective and green medium for extracting REEs from dry materials. With the addition of a complex agent, tri-n-butyl phosphate-nitric acid complex, highly efficient and selective extraction of REEs using supercritical carbon dioxide can be achieved. The highest extraction efficiency was 92% for europium from the europium doped barium magnesium aluminate phosphor (BAM), whereas the highest extraction selectivity was more than 99% for the REEs combined from the trichromatic phosphor. On the other hand, for strontium aluminate type phosphors, a direct acid leaching process is suggested. It was found out that acetic acid, which is considerably green, could have high recovery rate for dysprosium (>99%) and europium (~83%) from this strontium aluminate phosphor materials. Nevertheless, both green processes showed promising results and could have high potential for industrial applications.

Experimental Optimization and Modeling of Supercritical Fluid Extraction of Oil from Pinus gerardiana

AbstractThe influence of different temperatures, pressures, and flow rates on the supercritical fluid extraction (SFE) of oil from Pinus gerardiana was investigated. Extraction was designed using the Box‐Behnken design and artificial neural network. Furthermore, a mathematical model of broken and intact cells was applied to consider mass transfer kinetics of extracted natural materials. The experimental oil extraction was performed by Soxhlet and supercritical carbon dioxide methods and the yield and composition of the obtained oils was compared. Although the yield of the SFE process was lower than that of the Soxhlet extraction, the SFE presented the advantage of shorter extraction time and lower temperatures. Also, the chemical compositions of the obtained oils from Soxhlet and SFE processes were the same.

Utilization of supercritical CO2 in bioactive principles isolation from Helichrysum italicum and their adsorption on selected fabrics

Helichrysum italicum (Roth) G. Don fil., Asteraceae, possesses numerous secondary plant metabolites with a wide range of biological activities. Yet, data on the potential of supercritical fluid extraction (SFE) in their isolation are scarce. This study provides analyses of the chemical profiles of extracts obtained by SFE with or without ethanol as a cosolvent using GC-FID, GC-MS, HPLC, and UHPLC-MS techniques. Among the compounds with proven biological activity identified, the presence of arzanol was confirmed. In the next step, the integrated process of supercritical fluid extraction and impregnation was applied to deliver active compounds to cotton gauze and polypropylene fabric for possible topical applications. The analytical procedures results showed a considerable affinity of both textile materials for incorporating active components present in the H. italicum. The study indicated the high-pressure techniques applied as very efficient in the isolation of bioactive components from H. italicum and their adsorption on selected carriers.

Prospective principles of catalyst utilization using supercritical fluid media

An overview of prospective principles of catalyst utilization using supercritical fluid media is presented. The processes in which these working media act as solvents and extractants, reagents and reaction media are considered. At the same time, we are talking about both heterogeneous catalysts and catalytic complexes dissolved in the water runoff of industrial enterprises. Using the LD-145 catalyst as an example, we studied the possibility of extending its service life instead of recycling, due to a change in the physical and chemical principles of its regeneration. We are talking about replacing the high-temperature process of vapor-air oxidation of catalyst-deactivating compounds with a supercritical fluid extraction process. At the same time, the extractant used is not widespread carbon dioxide, but propane/butane mixture, the use of which makes the process significantly more efficient. This is because a number of binary systems “deactivating compound – extractant” change the type of phase behavior from V-VI to I-II when changing carbon dioxide to propane/butane mixture. Thus, these systems, for example, involving naphthalene, phenol and some other substances in the supercritical fluid state fall outside the binodal of the binary system into the region of unlimited miscibility of components, which significantly increases the kinetics of the catalyst regeneration.

Identification of a Supercritical Fluid Extraction Process for Modelling the Energy Consumption

Identification of a Supercritical Fluid Extraction Process for Modelling the Energy Consumption

Physicochemical and multi-scale structural alterations of pea starch induced by supercritical carbon dioxide + ethanol extraction

The objective of this study was to establish the impacts of supercritical fluid extraction (SFE) processing on the physicochemical properties of pea flour and the structure of isolated pea starch. A significant (p < 0.05) increase in protein content and reduction in several pasting and thermal parameters as measured by rapid visco-analyzer and differential scanning calorimeter were observed after SFE. Additionally, SFE increased starch digestibility as determined by an in vitro starch digestion assay. An increased amylopectin content and crystallinity along with the loss of double helix content was supported by size exclusion chromatography and FT-IR data, respectively. X-ray diffraction and scanning electron microscopy showed minimal alterations of starch, by SFE, in long-range crystalline and morphological structure of starch granules, respectively. The data demonstrated SFE influenced the physicochemical and structural characteristics of pea starch. These outcomes illustrated that SFE might be a green and novel technology for starch modification.

Effect of Drying Methods on Lutein Content and Recovery by Supercritical Extraction from the Microalga Muriellopsis sp. (MCH35) Cultivated in the Arid North of Chile.

In this study, we determined the effect of drying on extraction kinetics, yield, and lutein content and recovery of the microalga Muriellopsis sp. (MCH35) using the supercritical fluid extraction (SFE) process. The strain was cultivated in an open-raceways reactor in the presence of seawater culture media and arid outdoor conditions in the north of Chile. Spray-drying (SD) and freeze-drying (FD) techniques were used for dehydrating the microalgal biomass. Extraction experiments were performed by using Box-Behnken designs, and the parameters were studied: pressure (30–50 MPa), temperature (40–70 °C), and co-solvent (0–30% ethanol), with a CO2 flow rate of 3.62 g/min for 60 min. Spline linear model was applied in the central point of the experimental design to obtain an overall extraction curve and to reveal extraction kinetics involved in the SFE process. A significant increase in all variables was observed when the level of ethanol (15–30% v/v) was increased. However, temperature and pressure were non-significant parameters in the SFE process. The FD method showed an increase in lutein content and recovery by 0.3–2.5-fold more than the SD method. Overall, Muriellopsis sp. (MCH35) is a potential candidate for cost-effective lutein production, especially in desert areas and for different biotechnological applications.

Utilization of Wood Railway Sleepers Using a Supercritical Fluid Extraction Process

In this work, we propose an alternative method for the utilization of sleepers, based on the use of a supercritical fluid extraction process. The preference for the implementation of a supercritical fluid extraction process for “extractable-extractant” systems exhibiting I–II types of phase behavior is given. On the example of supercritical fluid extraction of the impregnation material of spent wood railway sleepers, the efficiency of replacing the carbon dioxide participating as an extractant with a propane/butane mixture, which provide the desired change in the type of phase behavior in relation to such components of the impregnation material as phenol, anthracene and naphthalene is shown. The phase equilibria of thermodynamic systems involving carbon dioxide and a propane/butane mixture on the one hand and coal oil components such as phenol, anthracene, and naphthalene on the other are studied. The proposed method of processing spent railway sleepers allows you to select from it up to 97 % of the mass impregnation source material.

Optimizing the supercritical fluid extraction process of bioactive compounds from processed tomato skin by-products

Abstract A supercritical fluid extraction (SC-CO2) was used to extract high-quality oil from tomato skin by-products. The effects of pressure and extraction time on oil yield was investigated in the study. Lycopene and β-carotene content as well as p-coumaric acid, ferulic acid, caffeic acid, chlorogenic acid, vanillic acid, epicatechin, naringenin, catechin, quercetin and luteolin were estimated. The highest oil yield of 79.00% was obtained after 80 min with a pressure of 550 bar. The resulting oleoresin in carotenoids with lycopene and β-carotene content respectively of 0.86 and 1.5 mg/100 g, this oleoresin was found to be the richest. Naringenin was the most abundant flavonoid identified with a maximum content in oleoresin extracted at 550 bar (84.04 mg/kg DW) followed by caffeic acid (26.60 mg/kg DW). A moderate radical scavenging potential was further observed. Overall, results highlight that pressure is a key parameter for the extraction bioactive oleoresin from tomato skin by-products.