Supercritical Extraction Conditions Research Articles

Optimization of supercritical CO2 fluid extraction process, component analysis, and antioxidant spectral activity correlation of Huoluo Xiaoling Dan

ABSTRACT This study elucidated the optimization conditions, GC-MS analysis conditions, total antioxidant activity, and components closely related to antioxidant activity for supercritical extraction of active ingredients in Huoluo Xiaoling Dan (HLXLD). The yield, octyl acetate content, and total antioxidant activity of HLXLD under different conditions were obtained through orthogonal experiments, and the optimal supercritical extraction conditions were determined to be 45°C, 25 MPa, and 4 h. The supercritical extract was subjected to GC-MS analysis and matched with the WILEY and NIST databases, resulting in the qualitative identification of 37 chemical components with a matching degree above 60. The similarity evaluation system of traditional Chinese medicine fingerprint was used to evaluate all orthogonal experimental samples, with a similarity ranging from 0.522 to 0.989. Thirteen common characteristic peaks were selected, and the quantification of these peaks was performed using peak area normalization method. The combination of the content of common characteristic peaks in different samples and their total antioxidant activity was analyzed using multivariate statistical methods such as principal component analysis and multiple regression equation. It was found that five components, F3, F2, F5, F7 and F12, among the common characteristic peaks were closely related to antioxidant activity.

Bioactive Fractions Isolated from By-Products of the Guava (Psidium guajava) and Mango (Mangifera indica L.) Agri-Food Industry

Valorizing agri-food industrial waste is essential for a circular economy, yielding high-value products, waste reduction, technological solutions, employment opportunities, and enhanced food security. This work shows the valorization of seeds generated as residues from the agri-food industries of guava pera (Psidium guajava) and Tommy Atkins mango (Mangifera indica L.), through extraction with supercritical carbon dioxide (scCO2). After the optimization of the initial solid condition of the raw material (i.e., particle size and moisture content), scCO2 pressure and temperature were established through the response surface methodology (RSM) to obtain an oily extract with the highest content in bioactive compounds of commercial relevance, as well as with a high antioxidant capacity. The total amount of oily extract in guava and mango seeds was 14% and 9%, respectively, while the maximum recovery of supercritical extract was 95% from guava seeds at 38 MPa and 50 °C, and 88% from mango seeds at 37 MPa and 63 °C. Bioactive fractions rich in squalene, γ-tocopherol, α-tocopherol, campesterol, β-sitosterol, and stigmasterol were obtained. The best supercritical extraction conditions, in terms of the bioactive fractions richest in minor compounds, were at 17 MPa and 50 °C for guava seeds and at 23 MPa and 63 °C for mango seeds. At these conditions, the highest antioxidant capacities were also found for the extracts. Thus, these bioactive fractions could be used in a variety of products in the cosmetic, food, pharmaceutical, and medical activities due to the beneficial properties of the identified compounds in health as antioxidants, anti-inflammatories, and cholesterol reducers.

Supercritical fluid extraction of cannabinoids (THC and CBD) from four different strains of cannabis grown in different regions

The aim of this study is to investigate the cannabinoid content of different types of cannabis plants grown in different climatic regions under different supercritical extraction conditions. Extractions were carried out at different pressures of 15 and 33 MPa and 40 and 60 °C temperatures. All conditions were tested both in the presence and absence of co-solvent ethanol. Extraction yield was highly dependent on pressure, co-solvent, climatic conditions and strain. The cannabinoid composition of the extracts was determined with HPLC analyses. The highest CBD and THC yields were obtained from Papatya strain (90.82% THC, 3.71% CBD) and Elnur strain (58.22% THC, 3.29% CBD). Narlı strain yielded the highest CBD (7.70%) result. This work demonstrates the effectiveness of the climatic conditions on the strains with supercritical extraction of cannabinoids. It is the first study to show the different climatic conditions effect on the yield of CBD and THC in different strains.

Ag removal from e-waste using supercritical fluid: improving efficiency and selectivity

ABSTRACT E-waste, including toxic and precious metals, requires an effective and environment-friendly disposal method. Extraction by supercritical CO2 is attractive, being inexpensive, available, and environment-friendly. This paper reports an investigation of Ag extraction from waste printed circuit boards [WPCBs] using supercritical CO2. Effects of temperature, pressure, dynamic time, various co-solvents, modifiers, and complex formers on the efficiency of the process are studied. The optimum reaction parameters are calculated through Response Surface Methodology (RSM). In addition, both calculated and experimental results are analysed using Design Expert software program, and the mathematical equations are presented for different parameters and experimental conditions. The optimum conditions for supercritical extraction are 217 bar, 51 ᵒC, and 40 mins, and the most appropriate ligand and co-solvent are found to be Cyanex 302 and acetone. Finally, a 98.75 Ag extraction from waste printed circuit boards was achieved using the proposed method.

Optimization of Supercritical Extraction Conditions of Senna Alata and Evaluation of Biological Activity

Supercritical fluid extraction (SFE) offer faster extraction process, decreased solvent usage and more selectivity on desired compounds. In this present study, the influence of pressure (100, 200 and 300 bar) and temperature (40, 50 and 60˚C) on the Senna alata crude yield were investigated with fixed supercritical carbon dioxide (SC-CO2) at the flow rate of 35 g/min. The parameters were optimised and modelled using response surface methodology (RSM) and central composite design (CCD). The analysis of variance (ANOVA) experimental design consists of 13 experimental runs with 5 replicates at the central points. Well-fitting quadratic model were successfully established for crude extract through backward elimination. The optimum crude extract yield pointed out by RSM was at the pressure of 300 bar and temperature 40˚C respectively. Extraction yields based on SC-CO2 varied in the range of 0.28 to 3.62%. The highest hyaluronidase inhibition activity and total flavonoids content obtained by S.alata crude extracts were 41.19% and 52.53% w/w, respectively. SC-CO2 proves to have great potential for extraction of yield, hyaluronidase inhibition activity and total flavonoids content for S.alata.

СРАВНИТЕЛЬНЫЙ АНАЛИЗ СОСТАВА НИЗКОМОЛЕКУЛЯРНЫХ ПРОДУКТОВ СВЕРХКРИТИЧЕСКОЙ ЭКСТРАКЦИИ СОЛОМЫ ПШЕНИЦЫ ЭТАНОЛОМ И ДИМЕТИЛКАРБОНАТОМ

Supercritical extraction is a promising method for the preparation of lignocellulosic raw material for subse-quent biochemical processing. This paper presents a comparative analysis of low-molecular-weight prod-ucts extracted from wheat straw in a batch-type autoclave at a temperature of 285С for 10 min. Ethanol and dimethyl carbonate were used as solvents, since these compounds are known to be similar in terms of their dissolution ability but different in terms of their alkylating properties. It is found that wheat straw ex-traction using dimethyl carbonate demonstrates a high level of efficiency. Compared to ethanolysis, a greater extract yield characterized by a high content of hexanol-soluble compounds was obtained. These compounds predominantly included methyl esters of carboxylic acids. On the other hand, lignin fragmentation products were dominated by veratrous-type compounds. A mechanism is proposed for obtaining low-molecular lignin fragmentation products under the conditions of supercritical extraction, which is based on the processes of a radical cleavage of alkyl aryl ester bonds and C-C bonds in the side radical, as well as on the reactions of dehydration, esterification and re-esterification. When this mechanism is applied under the conditions of supercritical ethanolysis, it additionally involves the reactions of hydrogenation and keto-enol rearrangement with the formation of ketones.

Optimization on Supercritical CO<sub>2</sub> Extraction Process to Improve the Quality of Patchouli Oil by Response Surface Methodology Approach

Until now, the patchouli oil is the largest commodity export of essential oil for Indonesia. But the price of patchouli oil is often unstable due to the quality of oil which fluctuates depending on the components. To improve the performance and quality of patchouli oil had been carried out the purification process using supercritical CO2 fluid extraction method. Optimization conditions of the extraction process using the approach of Response Surface Methodology (RSM) and the influence of independent variables include temperature (35–45 °C), pressure (80–150 atm) and the time of extraction (60–300 min), and then evaluated using a Box-Behnken Design (BBD). Analysis of the components in the extract was carried out by using GC-MS and GC-FID to detect the changes of compositions of the components containing the oil before and after the extraction process. The optimum condition of supercritical extraction within experimental range of the studied variables was at 38 °C, 146.35 atm and 74 min for predicted oil yield of 6.41% and at 41.45 °C, 135.17 atm and 252.62 min and the predicted patchouli alcohol content was 25.34%. The extracted oil is enriched with the main components such as patchouli alcohol compared to the original patchouli oil. The results of RSM evaluation showed consistency between the variables contained in the experiment and the prediction.

Supercritical CO2 extraction of ucuúba (Virola surinamensis) seed oil: global yield, kinetic data, fatty acid profile, and antimicrobial activities

Virola surinamensis is an abundant floodplain tree, popularly known as ucuúba, that grows in the Amazon. In this study, ucuúba seed oil was obtained by supercritical fluid extraction under different operating conditions, as well as Soxhlet extraction. The operating conditions for supercritical extraction were an extraction temperature of 40, 60, or 80 °C, a pressure of 350 bar, and a CO2 mass flow of 7.9 × 10−5 kg/s. The supercritical extraction curves were fitted to mass transfer models, and the fatty acid profiles of the extracts were determined by gas chromatography. The antimicrobial activity was assessed against Candida albicans, Staphylococcus aureus, and Escherichia coli. The highest yield obtained using supercritical CO2 was 64.39% and the lowest was 59.21%. The phytochemical analysis showed the presence of steroids, terpenes, coumarins, and phenolic compounds. All ucuúba oil samples showed antioxidant activity. Regarding the antimicrobial activity, ucuúba oil only showed activity against S. aureus.

Supercritical Fluids for Higher Extraction Yields of Lipids from Archeological Ceramics.

The extraction and study of organic residues from ceramics has been a subject of interest for the last 50 years in archeology and archeological science. Lipids are among the best-preserved organic substances in archeological contexts and can provide information about the diets of ancient populations as well as past environments. Here, we present a method which demonstrates significantly improved extraction of lipids from archeological pots by replacing liquid organic solvents with supercritical fluids. Optimization of the procedure using response surface methodology (RSM) approach showed that, on our system, optimal conditions for supercritical extraction of lipids from synthetic fired clay ceramics could be achieved using carbon dioxide with 16 vol % of cosolvent EtOH-H2O (95:5 v/v) in 90 min at a flow rate of 2.3 mL/min, for a pressure of 30 MPa and a temperature of 50 °C. For all reference and archeological samples included in this study, lipid yields obtained by supercritical fluid extraction under these optimal conditions were systematically higher than by conventional solvent extraction. This study also highlighted a variability of the ratio of unsaturated versus saturated fatty acids depending on the extraction method. This can have important implications in the identification of the residue(s). The increased extraction efficiency provided by supercritical fluids, as well as their minimally destructive nature, enable new and refined approaches to residue analysis and dating of archeological ceramics.

Supercritical CO2 extraction of hemp (Cannabis sativa L.) seed oil

In this work, hemp (Cannabis sativa L.) seed oil was produced by extraction with supercritical CO2 under different extraction conditions (temperature, pressure and time). The objective was to evaluate the influence of extraction conditions on concentration of tocopherols, fatty acids and pigments in hemp seed oil. The composition of hemp seed oil obtained with supercritical CO2 was compared with the hemp oil extracted by n-hexane using Soxhlet method and with oil obtained by pressing using screw expeller. Using supercritical CO2 extraction the extracts higher in concentration of tocopherol were produced. The amount of α- tocopherol in supercritical extracts ranged from 37.09 to 110.61mgL−1, depending on the applied process conditions, while γ-tocopherol content was significantly higher (2–3 times). The content of pigments in the hemp oil obtained by supercritical CO2 had been changed significantly during the extraction time from 9.79 to 178.76mgkg−1 for total chlorophyll content and 8.15 to 57.66mgkg−1 for total carotene content. By selecting the relevant process conditions of supercritical extraction it is possible to obtain hemp seed oil with physical or nutritional properties of interest to the food industry.

Supercritical fluid extraction of volatile oil from Lippia alba (Mill.) cultivated in Aragón (Spain)

The objective of this study is the supercritical extraction of the volatile oil from Lippia alba (Mill.) cultivated in Aragón. The influence of extraction pressure and temperature and cosolvent percentage on overall yield and volatile oil composition was studied. The supercritical extraction conditions were optimized using the 2007 crop; operating at 35.0MPa, 40°C and 5% of ethanol as cosolvent, 2009 and 2011 crops were also tested. Supercritical fluid extract compositions and overall yields were compared with the extracts obtained by conventional extraction techniques such as hydrodistillation (HD) and organic solvent extraction (OSE). Four terpenoids (linalool, 1,8-cineole, β-caryophyllene and β-caryophyllene oxide) were selected as target compounds and their content in the different extracts was monitored by gas chromatography. Linalool was selected as indicator of the plant adaptation to the commercial purposes. HD is the technique that provides the highest percentage of linalool in all the extracts, but showed always the lowest overall yields; whereas, SFE extracts provides a good balance between the overall yield and presence of the four target compounds.

Supercritical CO2 extracts and essential oil of ginger (Zingiber officinale R.): Chemical composition and antibacterial activity

This paper reports the assessment of chemical profile and antibacterial activity of ginger (Zingiber officinale Roscoe) roots extracts using supercritical CO2 as solvent. The effects of the supercritical extraction conditions on the chemical composition and antibacterial activity of the extracts obtained were evaluated and compared with essential oil of ginger obtained from hydrodistillation technique. The extractions using CO2 were performed in a laboratory scale unit at pressures of 10.0MPa, 17.5MPa and 25.0MPa and at 293.15K, 313.15K and 333.15K. The operating conditions tested achieved a maximum yield of 2.62wt% for the CO2 extraction and 1.79wt% for the hydrodistillation. When CO2 was used as the solvent, the pressure and temperature had a significant effect on the extraction yield. The chemical profiles determined by gas chromatography were found to be similar for the two methods; however, the quantities of the compounds extracted were different. The main compounds present in the extracts obtained using CO2 were α-zingiberene, β-sesquiphellandrene, α-farnesene, geranial, β-bisabolene and β-eudesmol. For the oil obtained by hydrodistillation, α-curcumene, geranial and camphene were the most abundant compounds. Antibacterial activity assays were performed on the ginger extracts and essential oil using the agar well method. The extracts obtained using supercritical CO2 presented antibacterial effects against Gram-positive bacteria. The oil obtained by hydrodistillation differed from the other samples tested and had a lower capacity for inhibition of Pseudomonas aeroginosa bacteria than the supercritical extract. For the Gram-negative bacterias Salmonella typhimurium and Shigella flexneri the oil showed slight inhibition.

Chemometric analysis of tocopherols content in soybean oil obtained by supercritical CO2

The objective of this work was to evaluate the concentration of tocopherol isomers in different fractions of soybean oil obtained at different extraction process conditions. GC–MS analysis shown that the total content of tocopherols in the collected fractions were in the range from 31.74 to 1410.55mg total tocopherols/kg of extract, depending on investigated extraction conditions. By selecting the relevant process conditions of supercritical extraction, as well as by fractionation, it is possible to obtain soybean oil with different mass concentrations of tocopherols.Chemometric analysis was applied on different tocopherols isomers to model the relationships between the contents of different tocopherols isomers in soybean oil. The linear regression method was used to derive the significant models for predicting the tocopherols contents. To confirm the predictive power of the models, predicted contents of total tocopherols were calculated by using derived models and compared with the experimental values. High agreement between experimental and predicted values, obtained in the validation procedure, indicated the good quality of the models.

Effect of ethanol content on supercritical carbon dioxide extraction of caffeine from tea stalk and fiber wastes

This study presents the effect of ethanol content on supercritical carbon dioxide extraction of caffeine from tea plant wastes. Tea stalk and fiber wastes of Turkish tea plants that have no economical value were evaluated as raw material throughout the caffeine extraction experiments. These wastes were supplied from tea factory marked “Çaykur” in the east blacksea region. They were separately ground, sieved and dried at 105 °C temperature in an oven. Parameters affecting caffeine leaching from tea wastes were determined to be, ethanol flow rate, extraction time, extraction temperature, carbon dioxide flow rate, process pressure and particle size. The maximum yield of caffeine from tea stalk wastes and fiber wastes were 14.95 mg/g tea stalk and 18.92 mg/g tea fiber, respectively. When the supercritical extraction conditions used of ethanol as cosolvent have been compared with the conditions of used only carbon dioxide, approximately the same yield has been reached at 2 h extraction period instead of 7 h. Beside of saving of the time and the amount of carbon dioxide, the supercritical extraction yield with cosolvent increase had been recorded as 62.5% and 63.1%, respectively, in comparison with the chloroform extraction as conventional method of tea stalk and fiber wastes.

Pressure Distribution and Defect Formation in Green Ceramic Bodies During Supercritical Extraction of Binder

Supercritical extraction (SCE) with carbon dioxide at 10–40 MPa and 55°–90°C has been used to remove binder from multilayer green ceramic bodies. Defects such as cracking and delamination were occasionally observed in the green bodies following the extraction process, and these defects were attributed to pressure gradients that arise during isothermal depressurization from conditions of SCE. A model based on flow in porous media was developed to describe the temporal and spatial distribution of pressure within the green body during depressurization. The model incorporates both nonideal pressure–volume–temperature behavior and nonconstant viscosity of the supercritical fluid. The effects of the body size and gas‐phase permeability on the pressure within the green body were examined.

β-Carotene Isomer Composition of Sub- and Supercritical Carbon Dioxide Extracts. Antioxidant Activity Measurement

In the present work sub- and supercritical extraction conditions using carbon dioxide were studied in order to obtain extracts with different compositions from the green microalgae Dunaliella salina. Different compositions of beta-carotene isomers were identified in the extracts by using HPLC-DAD. Also, antioxidant activity of the extracts was measured using a TEAC assay. An experimental design was applied considering two factors, extraction pressure and temperature, in a wide range of values, trying to maximize the extraction yield. Higher yields were obtained at high pressures and low temperatures, that is, at higher CO2 densities. Attempts were made to correlate the antioxidant activity of the extracts with their chemical composition by means of principal component analysis. A certain relationship was found between their antioxidant activity and the isomeric composition of beta-carotenes. As a result, an original equation is proposed to predict the antioxidant activity of extracts from D. salina in terms of the ratio 9-cis-beta-carotene/all-trans-beta-carotene, the concentration of alpha-carotene, and, especially, the concentration of 9-cis-beta-carotene.

Removal of plutonium and americium from waste matrices by supercritical carbon dioxide extraction

The extraction of plutonium from tissue paper matrix was carried out using supercritical carbon dioxide (Sc-CO2). The removal of plutonium was also studied from other matrices such as teflon, glass and stainless steel. Initial experiments were carried out under subcritical conditions. Supercritical extraction conditions were also employed in some experiments for the recovery of plutonium from tissue paper matrix. Complete extraction of Pu(III) as well as Pu(IV) in their nitrate form from tissue paper was achieved for the first time using supercritical carbon dioxide modified with n-octyl(phenyl)-N,N-diisobutyl carbamoylmethyl phosphine oxide (φCMPO) in methanol. Pu(IV) was also completely removed from other matrices such as teflon, stainless steel and glass. Studies on the extraction of Am(III) using supercritical carbon dioxide modified with CMPO in methanol resulted in its complete recovery from tissue paper.

Effect of Pre-Swelling on Extractability and Solvent Swelling of Ermenek Lignite (Turkey)

Swelling of Ermenek lignite (Turkey) by dimethyl sulfoxide (DMSO), dimethylformamide (DMF), pyridine, tetrahydrofuran (THF), aceton, ethylenediamine (ETDA), 1–2 dimetoxiethan, dioxane, toluene was carried out. Influence of pre-swelling, acid washing (1 N HCl) and supercritical extraction conditions (temperature) on extraction yields was also investigated. It was concluded that DMSO and DMF are the most suitable solvents for swelling of Ermenek lignite and Ermenek lignite can directly liquefy without swelling and any prewashing treatment.

Supercritical extraction of scrap tire with different solvents and the effect of tire oil on the supercritical extraction of coal

Scrap tires are a growing environmental problem because they are not biodegradable. In this investigation, supercritical extraction of scrap tire and co-processing of coal with tire oil were studied. In the first stage, tires were extracted at 400 °C with a number of different solvents. The effects of the hydrocarbon and polar solvents used under the supercritical extraction conditions on the conversion and oil product of tire were determined, and it was observed that all volatile organic material of the scrap tire was converted to the liquid or gas product. In the second stage, coal and supercritical extracted tire oil (SCETO) samples were extracted with different solvents using various tire oil/coal ratios. In general, the use of tire oil generated an improvement for coal conversion. Further, the oil yield was higher than those of coal alone runs. The SCETOs were characterized using spectroscopic (FTIR) and chromatographic analytical techniques (GC–MS). GC–MS, and FTIR results showed that the oils are mainly comprised of alkyl aromatic species. A significant amount of alkyl-substituted phenol compounds was also found to be present in the oils.

Predicting solubility in supercritical solvents using estimated virial coefficients and fluctuation theory

A theoretical method based on combining the virial expansion and fluctuation theory for calculating the chemical potential of a solute in a supercritical fluid is presented. The method is compared to literature results from Monte Carlo simulations based the Widom method for evaluating the chemical potential. For one-center and two-center Lennard Jones (2CLJ) potential models, the average difference from simulated results for the chemical potential is about 5% at densities up to twice the critical density. The method requires virial coefficients up to C( T) (the third) to achieve this level of accuracy. Correlations based on corresponding states principles for the prediction of B( T) [AIChE J. 20 (1974) 263; AIChE J. 21 (1975) 827; AIChE J. 24 (1978) 1978] and C( T) [AIChE J. 29 (1983) 107] are used to estimate these virial coefficients. A comparison with experimentally determined values for naphthalene in carbon dioxide shows the estimates to be accurate at typical supercritical extraction conditions. These correlations are then used to determine virial coefficients and chemical potentials for naphthalene, benzoic acid and phenanthrene in carbon dioxide at several different state conditions for which solubility data exist. The theoretical results are compared to chemical potentials obtained from experimental solubility data. The method is found to be accurate, tractable and systematically improvable through the inclusion of higher order terms in the virial expansion.