Pilot-scale Supercritical Carbon Dioxide Research Articles

Antimicrobial treatments with chitosan microencapsulated angelica (Angelica archangelica) and marsh Labrador tea (Rhododendron tomentosum) supercritical CO2 extracts in linen-cotton jacquard woven textiles

In this study antimicrobial linen-cotton jacquard textiles were manufactured using green chemistry methods. The functionalization of the fabrics was executed by impregnating chitosan microencapsulated bio-based oils from angelica ( Angelica archangelica L.) (AAC) and marsh Labrador tea ( Rhododendron tomentosum Harmaja) (MLTC) obtained with pilot scale supercritical carbon dioxide extraction. The chemical compositions of the extracts of angelica and marsh Labrador tea were analyzed by a combination of gas chromatography and mass spectrometry. The antimicrobial activities of the extracts, AAC and MLTC microcapsules, and the microencapsulated textiles (AAC and MLTC textiles) were analyzed against gram-positive Staphylococcus aureus and gram-negative Escherichia coli bacteria, dimorphic yeast Candida albicans and filamentous mold Aspergillus brasiliensis. The AAC textile proved 40% inhibition against S. aureus, whereas the MLTC textile demonstrated 43.8% and 51.7% inhibition against both S. aureus and E. coli, respectively. Although the chitosan shell material itself indicated mild activity against both bacterial strains, the extracts increased the antibacterial activities in microencapsulated textiles. In addition, the antifungal impact of the MLTC textile was demonstrated against A. brasiliensis. According to the Fourier transform infrared spectroscopy with attenuated total reflection and field emission scanning electron microscopy analyses, covalent bonding between the microcapsules and textile fibers was established with citric acid as a cross-linker. The antimicrobial activity was also shown to persist in the MLTC textiles after six domestic washing cycles.

Optimization of an eco-friendly dyeing process in both laboratory scale and pilot scale supercritical carbon dioxide unit for polypropylene fabrics with special new disperse dyes

A new synthetic route was developed to create azo based dispersed dyes which are derived from 3-(3-Chloropheney)-2-((4-substituted) diazenyl)-3-oxopropanenitrile and 3-substituted 5-amino-4-arylazopyrazoles. The new dyestuff was used to dye unmodified polypropylene fabrics under both aqueous and supercritical carbon dioxide mediums. A pilot scale experiment was performed on the dyestuff 3a to prove the potentiality of the dyestuff toward polypropylene fabric. The new dyes were characterized by MS, IR and NMR spectral data and found to be in good agreement with the proposed structures. The colour uptake expressed as colour strength (K/S) was assessed and the values obtained showed that the dyed polypropylene fabrics using scCO2 method was significantly better than the aqueous one. The colour fastness properties of all the dyed fabrics were evaluated and exhibited excellent results. Moreover, it is also a green approach for using industrial emissions of CO2 instead of water in the textile dyeing process.

Effects of processing parameters on the caffeine extraction yield during decaffeination of black tea using pilot-scale supercritical carbon dioxide extraction technique.

In this pilot-scale study supercritical carbon dioxide (SCCO2) extraction technique was used for decaffeination of black tea. Pressure (250, 375, 500bar), extraction time (60, 180, 300min), temperature (55, 62.5, 70 °C), CO2 flow rate (1, 2, 3 L/min) and modifier quantity (0, 2.5, 5mol%) were selected as extraction parameters. Three-level and five-factor response surface methodology experimental design with a Box-Behnken type was employed to generate 46 different processing conditions.100% of caffeine from black tea was removed under two different extraction conditions; one of which was consist of 375bar pressure, 62.5 °C temperature, 300min extraction time, 2 L/min CO2 flow rate and 5mol% modifier concentration and the other was composed of same temperature, pressure and extraction time conditions with 3 L/min CO2 flow rate and 2.5mol% modifier concentration. Results showed that extraction time, pressure, CO2 flow rate and modifier quantity had great impact on decaffeination yield.

Microwave pretreatment of Moringa oleifera seed: Effect on oil obtained by pilot-scale supercritical carbon dioxide extraction and Soxhlet apparatus

The effect of microwave radiation (MW) at three levels of power (100, 200 and 400W) and for three radiation time (30, 60 and 90s) on Moringa oleifera seeds was studied as a pretreatment process prior to oil extraction by pilot-scale supercritical carbon dioxide (SC-CO2) extraction and Soxhlet apparatus. Extraction oil yield by Soxhlet increased with MW pretreatments at 100W for 30, 60 and 90s with respect to untreated seeds. Therefore, these MW conditions were selected for SC-CO2 extraction of oil, carried out at 40°C and 300bar. Combining MW pretreatment at 100W for 30s with SC-CO2 extraction, the maximum oil yield of 35.28% w/w was obtained. The chemical quality of oil extracted by SC-CO2 was higher than Soxhlet oil.

Pilot-scale supercritical carbon dioxide extraction, physico-chemical properties and profile characterization of Moringa oleifera seed oil in comparison with conventional extraction methods

Moringa oleifera seed has gained importance over the years due to its great source of high quality oil that can be used in high value food, cosmetic, and pharmaceutical products. However, Moringa oil has never been successfully produced on the industrial basis due to the insufficient information available on the effective technique for oil extraction. It is generally extracted using organic solvent and screw pressing. Screw pressing generally produces low oil yield, on the other hand, the solvent extraction produces higher yield but its residue is the major health concern. This research proposed an alternative oil extraction from Moringa seeds using a pilot-scale supercritical fluid extraction (SFE) unit. SFE is considered as a green technology that is non-toxic and allows the elimination of polluting organic solvents. Carbon dioxide (CO2) was used as a solvent under near-critical and supercritical conditions in the pressure ranges from 15 to 35MPa and the temperature ranges from 25 to 35°C at the fixed flow rate of 20kg/h. The extractions made under higher pressure enhanced the oil yield. Extraction at highest pressure of 35MPa and moderate temperature of 30°C showed the most solvation power and extracted the maximum oil quantity of 75.27%. The oleic acid was the most abundant unsaturated fatty acid in Moringa oil amounted to 72.26–74.72%. At the lowest pressure (15MPa) CO2 was the most selective solvent for the extraction of oleic acid, tocopherols, and sterols. By comparison, the physico-chemical properties of oils extracted by supercritical CO2 were not substantially different from those of oils extracted by conventional methods. Overall, Moringa oil can be effectively extracted using a pilot-scale SFE at a relatively low temperature and pressure to give high quality oil.

Pilot-scale supercritical carbon dioxide extractions for the recovery of triacylglycerols from microalgae: a practical tool for algal biofuels research

We describe the preliminary extractions from a pilot-scale supercritical carbon dioxide (SC-CO2) extractor for the isolation of algal lipids suitable for small-scale conversion to liquid hydrocarbon fuels. Flowable oils were recovered from SC-CO2 extractions of lyophilized Nannochloropsis granulata. The extracted oils were determined to be composed primarily of triacylglycerols (TAG) by liquid chromatography–mass spectrometry analysis. Gravimetric lipid yield was increased significantly from 15.56 to 28.45 mg g−1 ash-free dry weight (AFDW) with an increase in temperature from 50°C to 70°C, at 35 MPa over 270 min. Varying pressure had no significant effect on lipid yield. Liquid chromatography–mass spectrometry analysis of the SC-SO2 extracts indicated that the TAG profile remained constant regardless of extraction pressure, and analysis of fatty acid methyl esters (FAME) revealed a uniform profile throughout all extraction conditions. Our optimized gravimetric lipid yields from N. granulata (28.45 mg g−1 AFDW) were approximately half of the yields obtained by Soxhlet extraction with hexane (57.53 mg g−1 AFDW); however, the FAME yields were similar regardless of extraction technique (18.23 mg FAME g−1 and 17.35 mg FAME g−1 AFDW from SC-CO2 extraction and hexane extraction, respectively). Further extractions with Botryococcus braunii indicated that fatty acid extraction by SC-CO2 was as efficient as hexane extraction. These results highlight the suitability of SC-CO2 for large-scale oil extraction of microalgae for biofuel or biojet analyses due to its selectivity for TAG extraction.

Bioactive Components of Commercial and Supercritical Carbon Dioxide Processed Wheat Germ Oil

AbstractWheat germ oil (WGO) is a specialty product with a very high nutritional value. The chemical composition of both commercial and pilot scale supercritical carbon dioxide (SC‐CO2) processed WGO was examined. This study showed that methods used for oil extraction and refining did not have a significant effect on the fatty acid composition of the oil. SC‐CO2 extracted oil had a higher tocopherol content than that of commercially hexane extracted oil. The phospholipid content of the SC‐CO2 extracted oil was very low indicating that the SC‐CO2 extraction method could eliminate the degumming step from edible oil refining processes. Although the conventional chemical oil refining technique reduced the tocopherol content of the WGO, it was possible to concentrate tocopherols in WGO by using physical refining methods such as molecular distillation.

Enrichment of hyperforin from St. John's wort (Hypericum perforatum) by pilot-scale supercritical carbon dioxide extraction.

St. John's Wort (Hypericum perforatum L.) was extracted with supercritical carbon dioxide using a pilot batch extraction plant. The effects of pressure, temperature, flow rate and extraction time were examined with respect to extraction yield and hyperforin content. Supercritical carbon dioxide showed a high selectivity for phloroglucinols. Extracts were analyzed using an isocratic HPLC method with a mixture of hyperforin/adhyperforin as an external standard. Within the studied range of extraction pressure (90-150 bar) and extraction time (1-5 h), extraction at 90 bar for 3 h and 120 bar for 1 h provided higher hyperforin content (up to 35%) in the resulting extracts. An increase in extraction temperature showed a negative effect, leading to increased degradation of hyperforin into orthoforin. When the total mass of carbon dioxide passing the extraction vessel was kept constant, changes in mass flow rate did not affect the extraction result.

Short Communication: Concentration of Conjugated Linoleic Acid from Milk Fat with a Continuous Supercritical Fluid Processing System

A continuous pilot-scale supercritical carbon dioxide system was utilized for the concentration of conjugated linoleic acids (cis-9, trans-11 C18:2) from anhydrous milk fat, which was separated into five fractions (S1 to S5) in the pressure and temperature range of 2.4 to 24.1MPa (350 to 3500psi) and 40 to 60°C, respectively. The highest concentration of CLA attained showed an increase of about 89% and occurred in the raffinate fraction (S1) when the solvent to feed ratio was 65. This was followed by a gradual decrease in the concentration of this fatty acid from S2 to S5. This study shows the feasibility of selectively enhancing the CLA concentration in one of the fractions of milk fat with a benign solvent in a one-step process. Other unique attributes of the CLA-rich fraction are also listed.