Supercritical Carbon Dioxide Research Articles

Phase boundaries and copolymerization of acrylic acid + butyl methacrylate in supercritical carbon dioxide under high-pressure single-fluid initiation

Phase boundaries and copolymerization of acrylic acid + butyl methacrylate in supercritical carbon dioxide under high-pressure single-fluid initiation

Thermal optimization of ivermectin in supercritical carbon dioxide and ethanol to produce nano medicine

The solubility of ivermectin in high pressure carbon dioxide (CO2) at 338, 328, 318, and 308 K temperatures was investigated with and without an ethanol. Several methods were employed to model the data obtained from the experiments. ivermectin exhibited solubility values ranging from 0.130 × 10−5 to 1.760 × 10−4 in the binary system and 1.880 × 10−5 to 1.237 × 10−4 in the ternary system. The outcome indicated that the addition of ethanol significantly increased the mole fraction of ivermectin in CO2. The highest impact of ivermectin solubility was found in the ivermectin -Ethanol- CO2 system at 338 K and 12 MPa, which was about 14.35 times greater than binary system under the same conditions. The models proposed by Jouyban et al. and Sodeifian-Sajadian models showed the best correlation with average absolute relative deviation (AARD%) and Akaike information criterion (AICc) for binary and ternary approaches, respectively. The results confirmed that rapid expansion supercritical solution (RESS) and gas antisolvent (GAS) method can be apply for producing nanoparticles at the suitable ranges of the drug solubility.

Molecular dynamics simulation of solvation behavior and thickening properties of modified siloxanes in supercritical carbon dioxide under different pressure and temperature

Molecular dynamics simulation of solvation behavior and thickening properties of modified siloxanes in supercritical carbon dioxide under different pressure and temperature

Evaluating sacha inchi (Plukenetia volubilis) oil stability and physicochemical properties: A comparison between conventional extraction and supercritical fluids

This study aimed to compare the effects of two extraction techniques (conventional n-hexane and supercritical CO2) on the oil extraction yields, fatty acids profile, anti-hyaluronidase activity, oxidative stability, and in vitro bioactivities of oils from Sacha Inchi (Plukenetia volubilis). Higher oil extraction yield (99 %) was achieved using the SC-CO2, although similar fatty acids profiles were depicted between both treatments (p < 0.05). The SC-CO2 oil presented higher anti-hyaluronidase (31 %) activity, but lower oxidative stability (5.05 h) compared to the solvent extraction (10 %, and 5.3 h, respectively). In vitro assays further revealed that the best human normal colon cells (FHC) cell viability (100 %), anti-inflammatory (50 % lower NO production), and antioxidant (20 % ROS reduction) activities were consistently observed in both extraction treatments at concentrations of 50 μg/mL and higher. These findings highlight the potential of supercritical CO2 extraction in yielding Sacha Inchi oil with enhanced bioactive properties without the disadvantages of the use of organic solvents extraction.

Extraction of polyvinylidene fluoride binder materials for used secondary batteries using supercritical CO2 for an effective battery recycling process

In this study, a polyvinylidene fluoride (PVDF) binder material for secondary batteries was removed using a supercritical CO2 extraction process instead of conventional extraction processes such as leaching and pyrolysis. To determine the optimal process conditions, the phase behavior of the binder in CO2 was studied by measuring the pressure and temperature before the supercritical CO2 extraction. To design an effective extraction process, the extraction time, temperature, and pressure were studied under various experimental conditions using a supercritical extraction system. Various organic cosolvents were used in the experiment to improve the extraction efficiency. According to the experimental result, the optimal extraction conditions were determined to 353.2 K, 10 MPa, and 20 min with dimethylformamide (DMF) cosolvent. Under these process conditions, the removal rate of the binder was 98.8 %. However, there was a significant difference in cell performance such as initial discharge capacity and cycling stability depending on the extraction solvent. Specifically, cycling stability improved in the order of using DMF, NMP, DMSO, and DMAc. The extracted binder material was analyzed by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM) to compare the raw and processed materials and evaluate the reusability of the binder material.

Advances and challenges in the fractionation of edible oils and fats through supercritical fluid processing.

Petrochemical solvents are widely used for the extraction and fractionation of biomolecules from edible oils and fats at an industrial scale. However, owing to its safety concerns, toxicity, price fluctuations, and sustainability, alternative solvents and technologies have been actively explored in recent years. Technologies, such as ultrasound and microwave-assisted extraction, supercritical carbon dioxide extraction, supercritical fluid fractionation, and sub-critical water extraction, and solvents, like ionic liquids and deep eutectic solvents, are reported for extraction and fractionation of biomolecules. Among them, supercritical carbon dioxide extraction and fractionation are some of the most promising green technologies with the potential to replace petrochemical-based conventional techniques. The addition of cosolvents, such as water, ethanol, and acetone, improves the extraction of amphiphilic and polar compounds from edible oils and fats. Supercritical fluid processing has diverse applications, including concentration of solutes, selective separation of desired molecules, and separation of undesirable compounds from the feed material. Temperature, pressure, particle size, porosity, flow rate, solvent-to-feed ratio, density, viscosity, diffusivity, solubility, partition coefficient, and separation factor are the fundamental factors governing the extraction and fractionation of desired biomolecules from lipids. Supercritical fluids stand alone compared to conventional fluids, because of their tunable solvent properties. Overall, it is to be noted that supercritical fluid-based methods have lots of scope to replace conventional solvent-based methods and progress toward the creation of sustainable food-processing techniques. This review critically evaluates the parameters responsible for the extraction and fractionation of biomolecules from edible oils and fats under supercritical conditions.

Physicochemical Properties, Heavy Metal and Pesticide Contaminations, and Microbial Limit Tests of Cannabis Oral Drops

Cannabis, a medicinal herb renowned for its therapeutic potential, is utilized in the treatment of various ailments, including the stimulation of appetite in cancer patients. In Thailand, the predominant dosage form is oral drops; however, the absence of robust quality control measures for these products poses significant health risks to patients. The primary objectives of this study were to formulate and evaluate cannabis oral drops, with a comprehensive evaluation encompassing physicochemical properties such as appearance, pH, Δ9-tetrahydrocannabinol, and cannabidiol contents. Furthermore, heavy metals (specifically arsenic, cadmium, and lead), pesticides (including pyrethroids, organochlorines, organophosphates, and carbamates), and microbial contaminations (Staphylococcus aureus, Clostridium spp., and Salmonella spp.) were evaluated. The results revealed that the optimal formulation, comprising cannabis extract derived from supercritical carbon dioxide fluid, vitamin E acetate, and medium-chain triglyceride oil, exhibited a pH of approximately 4.0, a Δ9-tetrahydrocannabinol content of approximately 27 mg/mL, and a cannabidiol content of approximately 9 mg/mL. Furthermore, there were no heavy metals or pesticides detected. Microbial limit tests demonstrated the absence of Staphylococcus aureus, Clostridium spp., and Salmonella spp. In conclusion, this endeavor successfully achieved the development of high-quality cannabis oral drops, showcasing the potential for safe and therapeutic use.

Response surface optimization for supercritical carbon dioxide extraction of Korarima (Aframomum corrorima) seed oil and its antibacterial activity evaluation

Oils extracted from natural plants are valuable resources because of their diverse biocidal activity against microorganisms. This paper reports, for the first time, supercritical CO2 extraction of oil from Korarima (Aframomum corrorima) seeds and its antibacterial activity evaluation. The influences of pressure, temperature, and extraction time on the yield of supercritical CO2-extracted oil (scCO2-extracted oil) were optimized using the Response Surface Methodology. Under the optimal extraction conditions of 46 °C, 15.5MPa, and 147min, the extraction yield reached 1.60±0.04%, consistent with the theoretical value of 1.58%. The compositions of the scCO2-extracted oil were identified by GC-MS, primarily consisting of nerolidol (33.97-41.20%), geraniol (23.08-24.50%), and α-terpinene (8.90-9.06%). The oil exhibited significant antibacterial activity against Staphylococcus. aureus with a minimum inhibitory concentration of 1mg·mL-1. This study highlights the potential applications of supercritical CO2 extraction technology for extracting Korarima seed oil and its use as an antibacterial ingredient in cosmetics and pharmaceuticals.

Comprehensive analysis and thermo-economic optimization of the dry cooling system for supercritical CO2 power cycle

Comprehensive analysis and thermo-economic optimization of the dry cooling system for supercritical CO2 power cycle

Effect of supercritical CO2 drying variables and gel composition on the textural properties of cellulose aerogels

Effect of supercritical CO2 drying variables and gel composition on the textural properties of cellulose aerogels

Novel biphasic high-entropy ceramic aerogels and their fiber composites with low thermal conductivity, high thermal stability and significant thermal insulation property

A novel biphasic high-entropy (Y0.2Ho0.2Tm0.2Yb0.2Lu0.2)2SiO5/(Y0.2Ho0.2Tm0.2Yb0.2Lu0.2)2Zr2O7 ceramic aerogel (BP-HEZSA) was prepared using formamide/sol-gel, supercritical CO2 drying and combined with a heat treatment process. The results indicate that BP-HEZSA exhibits a biphasic high-entropy structure at 1200 °C, and it maintained its stability at 1400 °C while demonstrating a homogeneous distribution of elements. BP-HEZSA exhibited nanoscale fine grains (with a size range of 18.82nm to 27.62nm), high BET specific surface area (16.24 m2·g-1), and good pore structure, all of which were controlled by the thermal treatment temperature. BP-HEZSA had low room temperature thermal conductivity and high structural and phase thermal stability at high temperatures. Furthermore, the applicability of the aerogel was improved by compounding with aluminosilicate fibers. The composites exhibited low density and low thermal conductivities (0.04-0.14W·m-1K-1). Butane blowtorch testing confirmed superior thermal insulation in composites, meeting demands for high-temperature resistance in advanced nanostructured materials.

Low-carbon Treatment and Remediation of Oil Sludge in Mid-to-high Latitude Regions: A Coupled Approach of Freeze-Thaw and Supercritical CO2 Extraction

Low-carbon Treatment and Remediation of Oil Sludge in Mid-to-high Latitude Regions: A Coupled Approach of Freeze-Thaw and Supercritical CO2 Extraction

Accuracy assessment of the turbomachinery performance maps correction models used in dynamic characteristics of supercritical CO2 Brayton power cycle

The supercritical CO2 Brayton cycle (SCO2BC) has emerged as a promising next-generation power generation technology due to its potential for high thermal efficiency and compact components design. Dynamic modeling of SCO2BC is crucial for understanding and analyzing its performance under design and off-design conditions. Turbomachines are critical components in SCO2BC dynamic models. While turbomachinery components are often modeled using their design-point turbomachinery performance maps (TPM), these maps become less accurate during off-design operations. Despite the existence of various TPM correction methods that ensure model validity, the implementation of the accurate ones within dynamic SCO2BC models remains scarce in the literature. This is crucial as it potentially compromises the accuracy of the obtained results. Therefore, there is a need to investigate the errors in the existing literature TPM correction models (in dynamic SCO2BC simulation) by comparing them against dynamic SCO2BC models employing a highly accurate correction method. Thus, in the current work, the common TPM correction methods from the literature are implemented in SCO2BC dynamic models and compared against a baseline mode, which uses the highly-accurate Pham method (at both the component and cycle levels). To the authors’ knowledge, this is the first work to address this research gap for the SCO2BC dynamic simulations and on both component and cycle levels. Additionally, another novelty is the usage of Simcenter Amesim software to dynamically model the SCO2BC aided with Pham model. Multible dynamic models for both the turbomachines of SCO2BC and the whole cycle are constructed and equipped with the different TPM correction methods found in literature to compare their dynamic behaviour that of Pham model. The Ideal Gas Compressibility factor (IGZ) method demonstrates a better performance than the other tested methods, as it exhibits the lowest discrepancy compared to the Pham model. Many of the other tested methods show significant errors. Furthermore, a popular hybrid correction combining IGZ and Pham (IGZ-Ph) is also investigated. Surprisingly, while seemingly beneficial, this hybrid approach negatively impacts accuracy, even resulting in predictions as if no correction was applied.

Direct coupling of pressurized gas receiver to a Brayton supercritical CO2 power cycle in solar thermal power plants

Direct coupling of pressurized gas receiver to a Brayton supercritical CO2 power cycle in solar thermal power plants

Enhancing polymeric bone scaffolds mechanical characteristics using supercritical CO2 foaming and reinforcing agents

BackgroundAs an alternative to conventional medicine, scaffolds have emerged to mimic and/or replace damaged tissue. 3D porous matrix scaffolds made of biodegradable and biocompatible polymers, including PLGA, have proven to be of particular interest for use as bone substitutes in Tissue Engineering. MethodsThe study used high-pressure CO2 foaming to produce PLGA-based foams. Previously, melt-extrusion was used to introduce reinforcement agents, Mg(OH)2, Hydroxyapatite (HAp) and Mg, to achieve foams with improved properties. Foam morphology was analysed using SEM, EDS, and 3D scanner techniques, and foam strength was measured using compression tests. A statistical analysis was carried out to study the effect of pressure and temperature on foams pore size and hardness. Significant findingsThe foams produced were rigid, non-sticky and time-stable, and showed high porosity. The pressure was found to be the only significant variable to tune both porosity and cell densities of scaffolds. Setting a pore size at 500 μm, compressive stresses of 1.85 MPa, 3.81 MPa were achieved for Mg(OH)2 and HAp, respectively. Those results were comparable to literature´s trabecular bovine bone compression resistance of 4.2 MPa. This finding indicated the possibility of getting, at the same time, convenient results for porosity and mechanical resistance for their use as bone replacement agents. Finally, a 20 % w/w ratio of reinforcing agent was found to produce the best pore size-stress ratio.

A New Methodology Based on Experimental Design and Sovová’s Broken and Intact Cells Model for the Prediction of Supercritical CO2 Extraction Kinetics

Nowadays, supercritical CO2 extraction is highly regarded in industry, and several studies dealing with scale-up calculations aim to facilitate the transition from small scale to large scale. To complete this transition, it would be interesting to be able to predict supercritical CO2 extraction kinetics, which is the aim of this work. A new methodology based on the association of Sovová’s broken and intact cell model and response surface methodology was developed to predict SC-CO2 extraction kinetics from different biomass (Argan kernels, evening primrose, Punica granatum, Camellia sinensis, and dry paprika) at different operating conditions (200–700 bar, 40–60 °C, 0.14–10 kg/h) inside an operating domain. The absolute average relative deviations between the experimental and predicted data ranged from 1.86 to 29.03%, showing satisfactory reliability of this new methodology.

Supercritical carbon dioxide extracts of Schinus terebinthifolia fruits and their utilization against microbial illness, lipase, and butyrylcholinesterase activities in vitro

Supercritical carbon dioxide extracts of Schinus terebinthifolia fruits and their utilization against microbial illness, lipase, and butyrylcholinesterase activities in vitro

Performance and optimization evaluation for integration of sCO2 power system into the aircraft propulsion system

The aviation industry accounts for part of the CO2 emissions contributing to climate change. The industry has established a target to reduce 2050 net aviation carbon emissions by 50 % relative to 2005 levels. With this in mind, waste heat recovery is a key pathway to achieve reduced emissions and improve system efficiency. The waste heat may potentially be converted to electric power using a supercritical CO2 Brayton power cycle. The sCO2 power system offers the advantage of compactness owing to the high working fluid density, which is an important consideration for aircraft performance. The present work focuses on the integration of the sCO2 power system into the aircraft propulsion system and evaluation of its performance. Detailed optimization of the sCO2 waste heat system will be evaluated with a focus on cycle efficiency and net power under different operating conditions, including ground, takeoff, climb, cruise, and landing operations. The study is divided into two parts with two different turbofan engines, one with a nominal thrust of 30 kN and the other with a nominal thrust of 9 kN. The first part shows the effect and operation of the waste heat recovery unit under the different operating conditions. The second part is focused on cycle optimization and performance evaluation. The results demonstrate the potential of waste heat recovery during a range of operational conditions. The sCO2 cycle efficiency can reach between 25 and 39 % (depending on aircraft engine) with net power output in the range of 100 to 260 kW.

Green extraction of marine phospholipids from Conger eel by-product using SC-CO2: Lipidomic profiles and biological activities

This paper presents an eco-friendly approach to recovering phospholipids (PLs) from the Conger myriaster head (CMH) via supercritical carbon dioxide (SC–CO2) extraction using ethanol as a cosolvent. The lipidomic profile and biological activities of the extracted PLs were investigated. Purity assessments, PL composition analysis, and fatty acid profiling were performed to characterize the PLs. Biological activity was determined through antioxidant, antimicrobial, antihypertensive, anti-inflammatory, and anticancer evaluations. The results showed that the yields of the SC–CO2 extracted CMH PLs (SCHP) and organic solvent extracted CMH PLs (OCHP) were 3.26% ± 0.20 % (76.18% ± 0.09% purity) and 9.02% ± 0.21% (purity = 18.29% ± 0.04%), respectively. The 31P NMR analysis revealed a diverse PL composition in both extracts, with the SCHP showing higher PC content and selective extraction characteristics. The SCHP exhibited significantly superior antioxidant, antimicrobial, antihypertensive, and anti-dementia activities compared to the OCHP. Both extracts inhibited nitric oxide production in RAW 264.7 cells, suggesting anti-inflammatory activity. Selective anticancer activity was observed, with high toxicity in SK-N-SH cells but no cytotoxicity in RAW 264.7 and HaCaT cells. The findings highlight the potential of SC-CO2 extraction using ethanol to obtain bioactive PLs from marine by-products, with promising applications in the pharmaceutical, cosmetic, and food industries.

Analytical advances in the determinations of dietary sphingolipids in milk, dairy products, and infant formula and impacts on human health

SummarySphingolipids (SL) are bioactive compounds in milk, dairy products, and infant formula. SL has been found to have different health benefits, such as anti‐inflammatory, antimicrobial, anticancer, and cholesterol‐lowering characteristics. SL requires careful extraction, separation, and identification due to their unique characteristics. This review discusses the importance of extracting, purifying, and analysing SL from milk and dairy products. OE (Organic extraction), SPE (solid‐phase extraction), and SFE (supercritical CO2) techniques, as well as dispersive OE and SPE, are the most common methods. In addition, this review discussed various analytical techniques that can be used to determine and quantify SL classes, including TLC (thin‐layer chromatography), HPLC (high‐performance liquid chromatography), nuclear magnetic resonance spectroscopy, and mass spectrometry. These techniques are crucial for understanding the amounts of SL dairy products and infant formula. The paper also focuses on the different types of SL present in milk, dairy products, and infant formula and their concentrations. SL has the potential to be applied to the development of functional foods, and further research in this area is needed. This article sheds light on the extract, purification, and analysis of SL dairy products and infant formula, as well as their potential health benefits.