Supercritical CO2 Fluid Research Articles

Short-term and High-performance Recycling of Cathode Material from Spent Lithium Ion Batteries

In the industrial practice of spent lithium-ion battery recycling, mechanical separation, pyrometallurgy and chemical dissolution technologies are often used to achieve the separation and recovery of cathode materials, but there are problems such as low material dissociation rate, low recovery rate, high energy consumption, serious lithium loss, and impurity ion embedding. In this paper, supercritical CO2 fluid was used to strengthen the separation of the cathode active material from the aluminum foil in the spent lithium-ion battery to achieve direct and efficient recovery of the active substance. The analysis of charge and discharge, AC impedance and differential capacitance curves show that the electrode of supercritical recovered material has higher ion diffusion coefficient and better redox reversibility, so it has higher charge and discharge capacity and better cycle stability than the traditional high-temperature calcined recovered material.

A method to improve dye-uptakes of less soluble disperse dyes for polyester fibers in supercritical CO2 fluid: A theoretical and experimental study

Two organic small molecules were used as assist-dissolving agents to increase the solubility of some dyes in ScCO2. Theoretical calculations showed that nicotinamide was better than benzoic acid. AIM and IGMH methods confirmed the hydrogen bonding and π-π stacking interactions between the agents and dyes. The mixtures of agents and dyes were made by the physical grinding and mixing method, and their solubilities and melting points were tested. The results indicated that the agents reduced the intermolecular forces in the dye crystals, thus enhancing the dye solubility in ScCO2. The dyeing experiment also proved the improvement of dyeing performance by the agents. The dye uptake increased from 20%∼30% to 60%∼70%, and the color intensity of the fibers improved. The best operating parameters were a temperature of 130 ℃ and a pressure of 28 MPa. The hue and color fastness of the dyed products were similar to those dyed with pure dyes.

Comparative analysis of volatile components of fresh and dried Tuber indicum truffles with different extraction methods

SummaryTuber indicum Cook&Massee (T. indicum) is mainly distributed in China, and it is also the truffle species with the largest yield China. Investigation and utilisation of its volatile components is still limited. By using headspace solid‐phase microextraction (HS‐SPME) and gas chromatography–mass spectrometry (GC–MS), the volatile components of fresh and dried T. indicum were compared in this study. It was found that after hot‐air drying of T. indicum, 73 components were retained in the truffles, and the remaining components changed during the drying process. The relative contents of alcohols and aldehydes in the dried truffles decreased by approximately 40% and 83%, respectively, while the relative contents of acids and esters increased by approximately 14 times and 5.5 times respectively. The drying process severely disrupts the flavour of the truffles. In advance, three extraction methods (steam distillation, Soxhlet extraction and supercritical CO2 fluid extraction [CO2‐SFE]) were performed on dried and fresh T. indicum, and their volatile components were compared. The results indicated that the alkanes extracted from fresh and dried truffles by steam distillation and Soxhlet extraction accounted for 30%–48%, while a richer variety of compounds were extracted from the two truffles by CO2‐SFE, with acids, esters and alcohols together amounting to approximately 70% in quantity, and they exceeded 95% in relative content. A richer variety of volatile compounds was extracted, and more fatty acids which yielded greasy, creamy, sweet and mushroomy aromas were enriched by CO2‐SFE compared to steam distillation and Soxhlet extraction. Therefore, CO2‐SFE extraction is a suitable method for extracting volatile components from T. indicum.

Advances in E-Waste Recycling: Physical and Chemical Treatment Methods

The unprecedented rise in production and consumption of electronic devices has resulted in staggering amounts of electronic waste (e-waste). Improper recycling and disposal of e-waste can cause severe environmental and public health repercussions due to the presence of toxic substances like lead, mercury, and flame retardants. This article introduced advanced e-waste recycling technologies, focusing on physical and chemical treatment methods. Physical treatments such as gravity separation, electrostatic separation, and inverse flotation enable efficient and cost-effective recovery of precious metals like gold, silver, platinum, and rare earth metals from e-waste components. These physical processes are often environmentally friendly, scalable, and can handle diverse e-waste streams. Chemical treatments, including the dimethylformamide technique, supercritical fluid technique, and pyrolysis, allow for separating hazardous substances and recovering valuable materials not amenable to physical processes. Supercritical CO2 fluid destroys toxic organic compounds while enabling metal recovery. Pyrolysis converts plastics into liquid oil and gas products. By enhancing the separation and purification of valued materials, these physical and chemical e-waste recycling techniques provide more profitable, efficient, and sustainable solutions to ever-growing e-waste volumes.

Progress and Prospects for Research and Technology Development of Supercritical CO2 Thermal Conversion Systems for Power, Energy Storage, and Waste Heat Recovery

CO2 is an environmentally friendly heat transfer fluid and has many advantages in thermal energy and power systems due to its peculiar thermal transport and physical properties. Supercritical CO2 (S-CO2) thermal energy conversion systems are promising for innovative technology in domestic and industrial applications including heat pump, air-conditioning, power generation, renewable energy systems, energy storage, thermal management, waste heat recovery and others. Both S-CO2 and transcritical CO2 thermodynamic cycles have been extensively investigated in order to improve the efficiencies of thermal and power systems and achieve net zero carbon emissions. This paper focuses on the progress and prospects for current research and technology development of S-CO2 thermal energy conversion systems and their applications including power generation, energy storage and waste heat recovery. First, the CO2 thermal transport and physical properties and benefits using CO2 as a heat transfer fluid in thermal energy and power systems are discussed. Then, classification of CO2 thermodynamic systems is presented. Next, S-CO2 for power generation, energy storage and waste heat recovery systems are presented. Finally, research needs of subcritical and supercritical CO2 heat transfer, fluid flow and heat exchangers for the development of various thermal energy and power systems are discussed.

One-dimensional sepiolite confined ionic liquids structure to improve the electrochemical performance of polyethylene-oxide based composite polymer electrolyte

Polyethylene-oxide (PEO) based composite polymer electrolytes (CPEs) with one-dimensional sepiolite confined ionic liquids (ILs) structure is constructed to further improve Li+ conductivity and reduce cost. Silicon nanorods (SNRs) is obtained by microwave-assisted acid activation of sepiolite and then ILs is confined into SNRs by supercritical CO2 fluid. The specific surface area of SNRs reduces from 170.88 m2 g-1 to 2.19 m2 g-1 after ILs confining, and the morphology and component of ILs in SNRs channel are clearly detected, indicating that the SNRs confined ILs structure (ILs@SNRs) is successfully obtained. The Li+ conductivity of CPEs increases from 1.40 × 10-6 S cm-1 to 0.922 × 10-4 S cm-1, which indicates that ILs confined in SNRs provide a fast channel for Li+ transmission. Besides, the reduction of PEO crystallinity is also favorable to Li+ transmission. The corresponding lithium symmetrical battery and LiFePO4 battery has excellent electrochemical performances. The good rate performance is attributed to the high Li+ migration number of 0.261 compare to 0.122 of PEO. Compared with the simple mixing of polymer and ILs, the confined ILs in SNRs channel will not be lost, which maintains the stability of Li+ transmission and reduces the consumption amount of ILs thus greatly reducing the cost of CPEs.

Comparative study on different extraction methods of oil extract from Mentha asiatica Boriss. and optimization of the extraction process by response surface methodology

AbstractIn the current study, the lipophilic solvent (n‐hexane) extraction, steam distillation (SD) and supercritical CO2 fluid extraction (SC–CO2) methods were used to extract the volatile components of Mentha asiatica Boriss. Comparisons were made between the extraction yield, chemical component and biological activity. Gas chromatography quadrupole‐time‐of‐flight mass spectrometry (GC–QTOF–MS) and semi‐quantitative analysis of chemical contents by flame ionization detector (GC–FID) were used to study the chemical ingredients in Mentha asiatica Boriss. aromatic extract. The oil extract obtained from lipophilic solvent (n‐hexane) extraction (1.27 ± 0.03%, w/W) showed the highest yield, followed by supercritical CO2 fluid extraction (1.15 ± 0.04%, w/W), the extraction rate of SD was (0.37 ± 0.01%，w/W). The oil extract of Mentha asiatica Boriss. contained a total of 70 components that were identified. In the following, the primary volatile compounds of the essential oil produced using the three extraction techniques: α‐thujene, camphene, sabinene, β‐pinene, β‐cymene, limonene, β‐terpinene, camphol, α‐terpinene, carvenone, carvone, piperitone oxide, thymol, myrtenyl acetate, dihydrojasmone, caryophyllene, germacrene D and caryophyllene oxide. Findings from this study indicate that the three methods of essential oil extraction produced oils with varying antioxidant capacities against DPPH and ABTS free radicals. Against Staphylococcus aureus, Candida albicans, Bacillus subtilis and Escherichia coli, all of the essential oils simultaneously showed clear inhibitory actions. Response surface methodology (RSM) and the Box–Benhnken design with three factors and three levels were both utilized to optimize the distillation process of essential oils. The appropriate extraction parameters were a 3 h extraction period, a solid–liquid ratio of 1:10 and a 3 h soaking time. The highest yield of essential oil was 0.38%. The impact of extraction parameters on essential oil yield was examined using the SD method. The findings indicated that the main factors affecting the yield of volatile oil extracted by SD were soaking time > ratio of solid to liquid > extraction time.

Inspection of Capparis spinosa essential oils for quality assurance of fish burgers during refrigerated storage.

Fish products are highly perishable as a result of easy spoilage by microorganism populations. The aim of this study is to evaluate the effects of Capparis spinosa essential oils (CSEOs) on physicochemical, sensory, oxidative, and microbiological attributes for fish burgers during refrigerated storage (8 days). For this purpose, CSEOs were prepared by water distillation (CS-WD), CO2 supercritical fluid (CS-SCF), subcritical water (CS-SW) to determine bioactive substances. Total phenol and flavonoid contents and also antioxidant activity were measured inCSEOs extracted by these procedures and phytochemical identification was performed through gas chromatography and mass spectroscopy. These essential oils (EOs) were used at 0.2% in fish burgers, and controls (without additives) and those containing sodium erythorbate were also prepared. Physicochemical, oxidative, microbiological, and sensory functions were examined every 2 days. Phytochemicals were found in CSEOs, and the highest was related to isopropyl isothiocyanate. Addition of CSEOs led to dark, yellow and red colors for fish burgers compared with control. The manufacture of primary and secondary products in oxidation and different microorganisms in samples were significantly decreased by CSEOs compared with controls (p < .05). The antioxidant feature of the burger with CS-SCF was higher than that of the sample treated with CS-WD, but these EOs indicated almost the same antimicrobial attributes, and the lowest antioxidant and microbial activities were found for CS-SW in the fish burger. The sensory results demonstrated that CSEOs did not reduce scores, which maintained the acceptance quality of burgers during refrigerated storage. As a conclusion, CSEOs can be used as effective antioxidants and preservatives in burgers, and sensory acceptance was preserved during storage.

Active Ingredients of Schisandra chinensis Fruit Oil and their Effect on Propionibacterium acnes-Induced Inflammation in HaCaT Cells.

Propionibacterium acnes causes upregulation of inflammatory factors, such as cycloxygenase-2, prostaglandin E2, interleukin-1β, and tumor necrosis factor-alpha, increased levels of reactive oxygen species (ROS) and inward flow of calcium ions. This causes increased levels of the antimicrobial peptide LL-37 and inflammation of the skin, leading to redness, swelling, itching and other symptoms. Schisandra chinensis fruit oil (SCO) is rich in lignan active ingredients with various antioxidant and anti-inflammatory properties. In this study, SCO is obtained by supercritical CO2 fluid extraction. SCO's anti-inflammatory actions were investigated using P. acnes-induced inflammation HaCaT cells model. A method based on reversed-phase high-pressure liquid chromatography with a diode array detector was developed and validated for the simultaneous detection of five lignan components. Levels of inflammatory factors and LL-37 were measured by ELISA kit and western blot respectively. Ca2+ and ROS levels detected by flow cytometry. The experimental results show that the contents of schisanol A, schisanol B, schisanin A, schisanin B, and schisanin C were 33.89 ± 0.24, 14.89 ± 0.45, 8.92 ± 0.02, 29.14 ± 0.67, and 4.74 ± 0.09 mg/g, respectively. Studies have demonstrated that SCO can alleviate skin inflammation by inhibiting the COX-2/PGE2 and NF-κB signalling pathway. In addition, SCO can inhibit ROS production, significantly block inward Ca2+ flow, alleviate cell damage, and modulate the content of the antimicrobial peptide LL-37. In summary, our study elucidated the anti-inflammatory activity of SCO in a cell model and provided a scientific basis for its application as a raw material in skin care.

Mechanism for the Formation of Nanoscale Oxides in a Medium of Supercritical CO2 Fluid

A possible mechanism is considered for the formation of nanoscale oxides based on titanium and aluminum isopropoxides in a medium of supercritical CO2 fluid. It is shown that because of intermolecular interactions and high pressure in the system, the supercritical fluid acquires the properties of a condensed medium, the main role of which is to restrain processes of hydrolysis. At the first stage of the hydrolysis of titanium isopropoxide, the water molecule is coordinated in the outer sphere of the central atom due to the formation of intermolecular hydrogen bonds. It is then coordinated into the inner sphere with the formation of a five-coordinate transition state and its destruction, creating a product substituted for the hydroxo group. The next steps proceed in a similar way. The described mechanism agrees with experimental findings and produces nanosized X-ray amorphous titanium oxide. (With aluminum isopropoxide, only the hydrolyzed hydroxo form can be produced.) Results suggest the production of nanosized oxides from isopropoxides in a medium of supercritical CO2 fluid is possible for transitional d-elements.

Mechanism for the Formation of Nanoscale Oxides in a Medium of Supercritical CO2 Fluid

Mechanism for the Formation of Nanoscale Oxides in a Medium of Supercritical CO2 Fluid

Optimization of Supercritical Fluid CO2 Extraction from Yellow Horn Seed and Its Anti-Fatigue and Antioxidant Activity.

A supercritical fluid carbon dioxide (SF-CO2) extraction method was used to obtain the optimum process for extracting yellow horn seed oil. The anti-fatigue and antioxidant properties of the extracted oil were investigated through animal experiments. The optimum process conditions for SF-CO2 extraction of the yellow horn oil were 40 MPa, 50 °C and 120 min, with an extraction yield of 31.61%. The high-dose group of yellow horn oil could significantly increase the weight-bearing swimming time, the hepatic glycogen (HG) content and decrease the lactic acid (LA) content and blood urea nitrogen (BUN) content (p < 0.05) in mice. Moreover, it improved the antioxidant ability by reducing the malondialdehyde (MDA) content (p < 0.01) and raising the glutathione reductase (GR) content and superoxide dismutase (SOD) content (p < 0.05) in mice. Yellow horn oil has the effects of being an anti-fatigue and antioxidant substance, which provides a basis for its further utilization and development.

Long-term supercritical CO2 exposure dependence of physicochemical properties and CH4 adsorbability of moisture-equilibrated coal matrices

ABSTRACT Further understanding into the impacts of supercritical CO2 fluid exposure toward CO2 storage and coalbed methane (CH4) recovery is significant to evaluate validity, stability, and safety of CO2-ECBM. For purpose of addressing the potential impacts, the long-term static interactions between supercritical CO2 fluid and moisture-equilibrated coal matrices with various degrees of coalification were conducted at 318.15 K and 12.00 MPa for 240 days in this study. Furthermore, the changes of the physicochemical properties dominating adsorbability of moisture-equilibrated coals due to the exposure were revealed. Ultimately, the impacts of the exposure toward CH4 adsorbability of moisture-equilibrated coals were addressed. Results indicate that the long-term supercritical CO2 exposure induces complex effects typically including organic matter extraction, mineral dissolution and formation, and matrix swelling to the coals, thereby further reducing the micropores within pore diameter ranges of 0.38–0.71 nm and 0.74–0.90 nm of the low-rank moisture-equilibrated coals, and slightly increasing those of 0.40–0.70 nm and 0.75–0.90 nm of the high-rank moisture-equilibrated coal. Additionally, the complex effects reduce the mesopores with pore diameter less than 8.00 nm for all the coal samples. Moreover, the exposure alters the surface chemistry of the coals. Particularly, the exposure increases the oxygen-containing functional groups typically comprising C-O, C=O, and -COOH of the low-rank moisture-equilibrated coals by 25.32–27.16%, and weakens the graphitization of the high-rank coal by 34.00%. Moreover, the induced synergistic effects decrease the number of pores with diameter less than approximately 8.00 nm of all the moisture-equilibrated coals. Furthermore, the CO2 exposure significantly reduces CH4 adsorption capacity of the moisture-equilibrated coal matrices indicated by the decreasing amplitude in absolute adsorption amount of 6.20–18.00%. Overall, the long-term supercritical CO2 exposure could favor CH4 production during CO2-ECBM. Future study should focus on in-situ characterization and accurate quantitative analysis on extraction, mineral dissolution and formation, and matrix swelling due to CO2 exposure, and distinguishment in the contribution of these effects to pores and functional groups of coals.

Chemical composition, antioxidant, and antimicrobial activities of P. roxburghii oleoresin essential oils extracted by steam distillation, superheated steam, and supercritical fluid CO2 extraction.

Pinus roxburghii is a rich source of high-quality oleoresin that is composed of resin acids and essential oil (EO). The present research work was planned to study and compare the yield, biological activities, and chemical profiling of P. roxburghii oleoresin EOs extracted through various green extraction methods. Steam distillation (SD), supercritical fluid extraction, and superheated SD (SHSD) at different temperatures (120, 140, and 160°C) were employed to extract EOs from P. roxburghii oleoresin. Antioxidant potential of EOs was determined by total antioxidant content/ferric-reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH)-free radical scavenging activity (DPPH-FRSA), hydrogen peroxide scavenging assays, and percentage inhibition in linoleic acid. Antimicrobial activity of EOs was determined by resazurin microtiter-plate, disc diffusion, and micro-dilution broth susceptibility assays. Gas chromatography-mass spectrometry was used to determine the chemical composition of EOs. It was observed that extraction methods significantly affected the yield, biological activities, and chemical composition of EOs. The maximum yield (19.92%) was found in EO extracted by SHSD at 160°C. EO extracted by SHSD at 120°C showed the highest DPPH-FRSA (63.33%±0.47%), linoleic acid oxidation inhibition (96.55%±1.71%), hydrogen peroxide scavenging activity (59.42%±0.32%), and total antioxidant contents/FRAP (134.49%±1.34mg/L of gallic acid equivalent). The antimicrobial activity results showed that superheated steam-extracted EO of 120°C revealed the highest antifungal and antibacterial activity. It is concluded that SHSD is an alternative and effective technique for the extraction of oleoresins EO that improves the EO yield and biological activities. Further research on optimization and experimental parameters for the extraction of P. roxburghii oleoresin EO by SHSD is required.

Solubility enhancement of pantoprazole sodium sesquihydrate through supercritical solvent: Machine learning based study

Theoretical/experimental measurement and optimization of solubility is considered as an active field of research in different scientific areas such as pharmaceutics. Novel orally administered therapeutic medicines have recently suffered from low solubility and bioavailability. Therefore, finding better methods to improve the drug solubility and bioavailability are of prime importance. Application of CO2 supercritical fluid (CO2SCF) as a well-known procedure has attracted numerous attentions in pharmaceutical industry to increase the drug solubility and bioavailability due to its low flammability, reasonable cost, and negligible detrimental impacts for ecosystem. Pantoprazole sodium sesquihydrate is an extensively-used drug, which is indicated for the alleviation of the undesirable signs ofesophagitiscaused by stomach acid due togastroesophageal reflux disease(GERD). The purpose of this research is to analyze and optimize the solubility of Pantoprazole sodium sesquihydrate using four different tree-based models where we have temperature and pressure as input features. These models include the regression tree, the boosting model based on it (gradient boosting), the bagging model based on it (random forest), and finally a more recently developed boosting model (extreme gradient boosting). All of these models, after optimization with their hyper-parameters, show an R2-score of more than 0.9. Finally, extreme gradient boosting was selected as the main model of this work, which has a 1.07 × 10-2 maximum error and an RMSE error rate of 5.85 × 10-3.

Overcrowded Additive in Electrolyte and Crystalline Li2CO3 Artificial Solid Electrolyte Interphase on TiNb2O7 Anode Enable Long Lifespan Aqueous Lithium-Ion Batteries

Aqueous lithium-ion batteries (ALIBs) are attracting intense attention because of the intrinsic nonflammable nature of the aqueous electrolytes. However, its own narrow electrochemical window has led to numerous problems such as dissolution of electrode materials, hydrogen evolution at the anode, and poor cycling stability. Here, we report an “overcrowded electrolyte” using 1,4-dioxane as an additive, which has lone pairs of electrons on the oxygen atom to disrupt the original water-hydrogen bonding network by forming intermolecular hydrogen bonds, thereby inhibiting the hydrogen evolution reaction (HER) and decreasing the water activity. Furthermore, a layer of crystalline Li2CO3 is coated onto the surface of the TiNb2O7 anode material by supercritical fluid CO2 technology. The dense hydrophobic Li2CO3 coating layer can serve as a physical protection, which effectively blocks the direct contact between electrolyte and electrode. Under the synergistic effect of those two aspects, HER is greatly suppressed and the interface stability is enhanced. As a result, LiMn2O4/TiNb2O7 full cells exhibit a high initial coulomb efficiency of 95% with a capacity retention rate of 92% over 500 cycles under 1 C rate. This work provides a fundamental understanding of the interfacial chemistry of ALIBs and makes an important step forward in the development of high-performance and low-cost ALIBs for practical applications.

Leakage reduction mechanism of supercritical CO2 scallop damper seal: Vortex structure and turbulence dissipation

The scallop damper seal (SDS) is a new sealing solution utilized in supercritical CO2(S-CO2) turbomachinery, and its sealing performance is of great interest. Analyzing the energy dissipation of fluid in the seal is critical for understanding the leakage characteristics of SDS. In this paper, we develop a high-order compressible flow solver with real gas thermophysical modeling. The vortex structure and turbulence dissipation of leakage flow are investigated to uncover the leakage reduction mechanism of SDS. By comparing the flow fields within a labyrinth seal (LABY) and a full-partition pocket damper seal (FPDS), we demonstrate that SDS has better leakage reduction performance for S-CO2. The results indicate that S-CO2 fluid flows into the SDS cavity and expands significantly. The formed vortex dissipates sufficiently more energy, reducing the leakage flow rate (LFR). The increase in the Mach number of the fluid flowing through the SDS gap is limited. Still, the gas permeability phenomenon caused by the throttling effect is observed in the clearance of LABY and FPDS, resulting in an increased LFR. At the differential pressure of 5 MPa, the LFR of SDS is 36.6% and 54.4% lower than that of LABY and FPDS, respectively. Although the rotor rotation leads to an asymmetric distribution of vortex in the SDS cavity, the vortex develops rapidly and occupies the entire space. For the seal design of S-CO2 turbomachinery, enhancing the turbulence dissipation of fluid in the cavity and reducing the gas permeability of fluid in clearance should be the focus of attention.

Supercritical Fluid Nanospray Mass Spectrometry: II. Effects on Ionization.

Nanospraying supercritical fluids coupled to a mass spectrometer (nSF-MS) using a 90% supercritical fluid CO2 carrier (sCO2) has shown an enhanced desolvation compared to traditional liquid eluents. Capillaries of 25, 50, and 75 μm internal diameter (i.d.) with pulled emitter tips provided high MS detection sensitivity. Presented here is an evaluation of the effect of proton affinity, hydrophobicity, and nanoemitter tip size on the nSF-MS signal. This was done using a set of primary, secondary, tertiary, and quaternary amines with butyl, hexyl, octyl, and decyl chains as analytes. Each amine class was analyzed individually to evaluate hydrophobicity and proton affinity effects on signal intensity. The system has shown a mass sensitive detection on a linear dynamic range of 0.1-100 μM. Results indicate that hydrophobicity has a larger effect on the signal response than proton affinity. Nanospraying a mixture of all amine classes using the 75 μm emitter has shown a quaternary amine signal not suppressed by competing analytes. Competing ionization was observed for primary, secondary, and tertiary amines. The 75 and 50 μm emitters demonstrated increased signal with increasing hydrophobicity. Surprisingly, the 25 μm i.d. emitter yielded a signal decrease as the alkyl chain length increased, contrary to conventional understanding. Nanospraying the evaporative fluid in a sub-500 nm emitter likely resulted in differences in the ionization mechanism. Results suggest that 90% sCO2 with 9.99% methanol and 0.01% formic acid yielded fast desolvation, high ionization efficiency, and low matrix effect, which could benefit complex biological matrix analysis.

Release Kinetics Model Fitting of Drugs with Different Structures from Viscose Fabric.

(1) Background: It is simpler and more environmentally friendly to use supercritical CO2 fluid technology to process skincare viscose fabrics. Therefore, it is significant to study the release properties of drug-loaded viscose fabrics to choose suitable skincare drugs. In this work, the release kinetics model fittings were investigated in order to clarify the release mechanism and provide a theoretical basis for processing skincare viscose fabrics with supercritical CO2 fluid. (2) Methods: Nine kinds of drugs with different substituent groups, different molecular weights, and different substitution positions were loaded onto viscose fabrics using supercritical CO2 fluid. Then, the drug-loaded viscose fabrics were placed in an ethanol medium, and the release curves were drawn. Finally, the release kinetics were fitted using zero-order release kinetics, the first-order kinetics model, the Higuchi model, and the Korsmeyer-Peppas model. (3) Results: The Korsmeyer-Peppas model was the best-fitting model for all the drugs. Drugs with different substituent groups were released via a non-Fickian diffusion mechanism. On the contrary, other drugs were released via a Fickian diffusion mechanism. (4) Conclusions: In view of the release kinetics, it was found that the viscose fabric can swell when a drug with a higher solubility parameter is loaded onto it using supercritical CO2 fluid, and the release rate is also slower.

Moisturizing and Antioxidant Effects of Artemisia argyi Essence Liquid in HaCaT Keratinocytes

Artemisia argyi essence liquid (AL) is an aqueous solution extracted from A. argyi using CO2 supercritical fluid extraction. There have been few investigations on the aqueous solution of A. argyi extracted via CO2 supercritical fluid extraction. This study aimed to explore the moisturizing and antioxidant effects of AL and to clarify the potential mechanism underlying those effects. Expression levels of skin moisture-related components and the H2O2-induced oxidative stress responses in human keratinocyte cells were measured via quantitative RT-qPCR, Western blot, and immunofluorescence. Our results showed that AL enhanced the expression of AQP3 and HAS2 by activating the EGFR-mediated STAT3 and MAPK signaling pathways. In addition, AL can play an antioxidant role by inhibiting the NF-κB signaling pathway and activating the Nrf2/HO-1 signaling pathway, consequently increasing the expression of antioxidant enzymes (GPX1, SOD2) and decreasing the production of reactive oxygen species (ROS). This study revealed that AL could be used as a potential moisturizing and antioxidant cosmetic ingredient.