Pub Date : 2025-10-21DOI: 10.1016/j.supflu.2025.106823
Alex Eduardo Delhumeau, Amaël Obliger, Thierry Tassaing
We demonstrate the application of Bayesian inference for the analysis of concentration profile data obtained with infrared microspectroscopy (IRM) for the adsorption of supercritical CO2 in a semicrystalline polymer with simultaneous measurement of the adsorption-induced swelling. Low-density polyethylene (LDPE) is chosen as a model system in which Fick’s second law is expected to hold without any anomalous diffusion because the adsorption-induced swelling is negligible as confirmed by the present study. From fitting all of the spatiotemporal data of the adsorption process, the solubility and the Fickian diffusion coefficient of CO2 in LDPE are obtained. The Bayesian method provides the statistical uncertainty of the best-fit parameters in addition to rigorously quantifying how closely the proposed model with optimal parameters can explain the experimental data. The sorptive–diffusive process is confirmed to proceed with Fickian kinetics as has been frequently assumed though not formally demonstrated.
{"title":"Infrared microspectroscopy with Bayesian inference for revealing spatiotemporal evolution of supercritical CO2 sorption in low-density polyethylene","authors":"Alex Eduardo Delhumeau, Amaël Obliger, Thierry Tassaing","doi":"10.1016/j.supflu.2025.106823","DOIUrl":"10.1016/j.supflu.2025.106823","url":null,"abstract":"<div><div>We demonstrate the application of Bayesian inference for the analysis of concentration profile data obtained with infrared microspectroscopy (IRM) for the adsorption of supercritical CO<sub>2</sub> in a semicrystalline polymer with simultaneous measurement of the adsorption-induced swelling. Low-density polyethylene (LDPE) is chosen as a model system in which Fick’s second law is expected to hold without any anomalous diffusion because the adsorption-induced swelling is negligible as confirmed by the present study. From fitting all of the spatiotemporal data of the adsorption process, the solubility and the Fickian diffusion coefficient of CO<sub>2</sub> in LDPE are obtained. The Bayesian method provides the statistical uncertainty of the best-fit parameters in addition to rigorously quantifying how closely the proposed model with optimal parameters can explain the experimental data. The sorptive–diffusive process is confirmed to proceed with Fickian kinetics as has been frequently assumed though not formally demonstrated.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"229 ","pages":"Article 106823"},"PeriodicalIF":4.4,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145364351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-19DOI: 10.1016/j.supflu.2025.106824
Yuto Asai, Ikuo Ushiki
Mesoporous silica is a promising drug delivery carrier owing to its high surface area, tunable pores, and ability to stabilize amorphous drugs. In this study, supercritical fluid deposition (SCFD) using supercritical CO2 (15 MPa) was employed to load ibuprofen and ketoprofen into MCM-48 mesoporous silica. The effects of drug type, temperature (313 K to 333 K), and silica framework were evaluated systematically. Transmission electron microscopy (TEM) and nitrogen adsorption confirmed that the three-dimensional cubic mesostructure of MCM-48 remained intact after impregnation. Fourier-transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA) verified the successful incorporation, with distinct thermal events indicating external and pore-confined adsorption. Ibuprofen consistently achieved higher loading than ketoprofen, driven by its greater solubility in supercritical CO2, indicating that solubility is the dominant factor over surface affinity. Temperature had only a modest influence owing to the opposing effects of decreased CO2 density and reduced competitive CO2 adsorption at higher temperatures. Compared with SBA-15, MCM-48 exhibited superior uptake across all conditions, which was attributed to its larger surface area and interconnected pore network. These results demonstrate that SCFD enables the efficient, solvent-free incorporation of active compounds while preserving mesostructural integrity, offering guidance for the design of high-performance mesoporous carriers in pharmaceutical and related applications.
介孔二氧化硅由于其高表面积、可调节的孔隙和稳定非晶药物的能力，是一种很有前途的药物递送载体。本研究采用超临界CO2（15 MPa）超临界流体沉积法（SCFD）将布洛芬和酮洛芬分别装载到MCM-48介孔二氧化硅中。系统评价了药物类型、温度（313 K ~ 333 K）和二氧化硅骨架的影响。透射电镜（TEM）和氮气吸附证实，浸渍后MCM-48的三维立方细观结构保持完整。傅里叶变换红外光谱（FT-IR）和热重分析（TGA）证实了成功的掺入，不同的热事件表明外部和孔隙限制吸附。布洛芬始终比酮洛芬获得更高的负载，这是因为它在超临界CO2中的溶解度更高，这表明溶解度是比表面亲和力更重要的因素。温度的影响不大，因为在较高温度下，二氧化碳密度降低和竞争性二氧化碳吸附减少会产生相反的影响。与SBA-15相比，MCM-48在所有条件下都表现出更好的吸收率，这归因于其更大的表面积和相互连接的孔隙网络。这些结果表明，SCFD能够在保持介孔结构完整性的同时高效、无溶剂地结合活性化合物，为制药和相关应用中高性能介孔载体的设计提供指导。
{"title":"Evaluation of drug loading onto MCM-48 via supercritical CO2 deposition: Effects of drug type, temperature, and silica structure","authors":"Yuto Asai, Ikuo Ushiki","doi":"10.1016/j.supflu.2025.106824","DOIUrl":"10.1016/j.supflu.2025.106824","url":null,"abstract":"<div><div>Mesoporous silica is a promising drug delivery carrier owing to its high surface area, tunable pores, and ability to stabilize amorphous drugs. In this study, supercritical fluid deposition (SCFD) using supercritical CO<sub>2</sub> (15 MPa) was employed to load ibuprofen and ketoprofen into MCM-48 mesoporous silica. The effects of drug type, temperature (313 K to 333 K), and silica framework were evaluated systematically. Transmission electron microscopy (TEM) and nitrogen adsorption confirmed that the three-dimensional cubic mesostructure of MCM-48 remained intact after impregnation. Fourier-transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA) verified the successful incorporation, with distinct thermal events indicating external and pore-confined adsorption. Ibuprofen consistently achieved higher loading than ketoprofen, driven by its greater solubility in supercritical CO<sub>2</sub>, indicating that solubility is the dominant factor over surface affinity. Temperature had only a modest influence owing to the opposing effects of decreased CO<sub>2</sub> density and reduced competitive CO<sub>2</sub> adsorption at higher temperatures. Compared with SBA-15, MCM-48 exhibited superior uptake across all conditions, which was attributed to its larger surface area and interconnected pore network. These results demonstrate that SCFD enables the efficient, solvent-free incorporation of active compounds while preserving mesostructural integrity, offering guidance for the design of high-performance mesoporous carriers in pharmaceutical and related applications.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"229 ","pages":"Article 106824"},"PeriodicalIF":4.4,"publicationDate":"2025-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145364356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-17DOI: 10.1016/j.supflu.2025.106822
Xiangyu Xu , Shaokui Liu , Liang He , Shaohua Hu , Xiaoping Ouyang , Qingzhi Zhou
Supercritical water oxidation (SCWO) is a highly efficient technology for treating radioactive organic waste. However, the deposition behavior of lanthanide salts in SCWO systems remains poorly understood. In this work, molecular dynamics simulations were performed to investigate the nucleation and growth mechanisms of LaCl3 in supercritical water (SCW) across a wide range of temperatures (673–1073 K) and densities (0.1–0.3 g/cm3). The nucleation and growth process can be divided into three stages: ion pairs, small ion clusters, and large ion clusters. The nucleation process was completed within 40 ps. The nucleation rate was of the order of 1030 cm−3·s−1, which increased with increasing temperature and density. Under high temperature and low density conditions, the LaCl3–H2O binding energy decreased, the electrostatic interaction weakened, the hydrogen bond network was significantly destroyed, and the ion diffusion coefficient increased, which promoted the collisions and cluster formation of La3+ and Cl- ions. The high charge and strong solvation effect of La3+ leads to the formation of a complex three-layer solvation shell structure, which is tightly associated with Cl- ions, and the LaCl3 clusters exhibit strong thermodynamic stability. This work provides a theoretical basis for solving the salt deposition problem in the treatment of radioactive organic wastewater and for the recovery of lanthanide metal elements.
{"title":"Molecular dynamics simulation of lanthanum(III) chloride nucleation and growth mechanisms in supercritical water","authors":"Xiangyu Xu , Shaokui Liu , Liang He , Shaohua Hu , Xiaoping Ouyang , Qingzhi Zhou","doi":"10.1016/j.supflu.2025.106822","DOIUrl":"10.1016/j.supflu.2025.106822","url":null,"abstract":"<div><div>Supercritical water oxidation (SCWO) is a highly efficient technology for treating radioactive organic waste. However, the deposition behavior of lanthanide salts in SCWO systems remains poorly understood. In this work, molecular dynamics simulations were performed to investigate the nucleation and growth mechanisms of LaCl<sub>3</sub> in supercritical water (SCW) across a wide range of temperatures (673–1073 K) and densities (0.1–0.3 g/cm<sup>3</sup>). The nucleation and growth process can be divided into three stages: ion pairs, small ion clusters, and large ion clusters. The nucleation process was completed within 40 ps. The nucleation rate was of the order of 10<sup>30</sup> cm<sup>−3</sup>·s<sup>−1</sup>, which increased with increasing temperature and density. Under high temperature and low density conditions, the LaCl<sub>3</sub>–H<sub>2</sub>O binding energy decreased, the electrostatic interaction weakened, the hydrogen bond network was significantly destroyed, and the ion diffusion coefficient increased, which promoted the collisions and cluster formation of La<sup>3+</sup> and Cl<sup>-</sup> ions. The high charge and strong solvation effect of La<sup>3+</sup> leads to the formation of a complex three-layer solvation shell structure, which is tightly associated with Cl<sup>-</sup> ions, and the LaCl<sub>3</sub> clusters exhibit strong thermodynamic stability. This work provides a theoretical basis for solving the salt deposition problem in the treatment of radioactive organic wastewater and for the recovery of lanthanide metal elements.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"229 ","pages":"Article 106822"},"PeriodicalIF":4.4,"publicationDate":"2025-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145418276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cultural heritage conservation is a complex and challenging field, involving a wide variety of materials with distinct properties, degradation behaviours and specific requirements, often demanding non-standardised methodologies. Conventional treatments frequently rely on hazardous products, raising concerns about user safety and environmental impact. In response, green chemistry principles have gained prominence, advocating for safer and more sustainable practices by replacing toxic products with less harmful alternatives, thereby mitigating risks to conservators, the environment, and heritage assets. Carbon dioxide (CO2), owing to its tuneable and non-toxic properties, has emerged as a green solvent alternative to traditional solvent-based methods in the conservation field. Therefore, this research reviews the application of dense CO2 technologies (liquid and supercritical) in conservation processes including cleaning, decontamination, degreasing, hydration, stabilisation, and consolidation, across a wide array of materials like textiles, wood, leather, metal, glass, paper and plastics. Drawing on experimental trials and case studies, key achievements, challenges, and emerging trends are highlighted, encouraging further research into these promising and sustainable CO2-based technologies.
{"title":"Dense carbon dioxide technologies applied to the conservation of cultural heritage: A review","authors":"Inês Soares , Angelica Bartoletti , Carolina Viana , Isabel Pombo Cardoso , Teresa Casimiro , Joana Lia Ferreira","doi":"10.1016/j.supflu.2025.106821","DOIUrl":"10.1016/j.supflu.2025.106821","url":null,"abstract":"<div><div>Cultural heritage conservation is a complex and challenging field, involving a wide variety of materials with distinct properties, degradation behaviours and specific requirements, often demanding non-standardised methodologies. Conventional treatments frequently rely on hazardous products, raising concerns about user safety and environmental impact. In response, green chemistry principles have gained prominence, advocating for safer and more sustainable practices by replacing toxic products with less harmful alternatives, thereby mitigating risks to conservators, the environment, and heritage assets. Carbon dioxide (CO<sub>2</sub>), owing to its tuneable and non-toxic properties, has emerged as a green solvent alternative to traditional solvent-based methods in the conservation field. Therefore, this research reviews the application of dense CO<sub>2</sub> technologies (liquid and supercritical) in conservation processes including cleaning, decontamination, degreasing, hydration, stabilisation, and consolidation, across a wide array of materials like textiles, wood, leather, metal, glass, paper and plastics. Drawing on experimental trials and case studies, key achievements, challenges, and emerging trends are highlighted, encouraging further research into these promising and sustainable CO<sub>2</sub>-based technologies.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"229 ","pages":"Article 106821"},"PeriodicalIF":4.4,"publicationDate":"2025-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145364357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-16DOI: 10.1016/j.supflu.2025.106817
Mustajab Safarov, Vishnu Jayaprakash, Changxu Wu, Huazhou Li
Compositional simulations are important for understanding, analyzing, and optimizing multiphase flows, especially in the petrochemical industry. These simulations are dependent on an accurate Equation of State (EOS) to model the relationships between phases under changing conditions. While cubic EOS (CEOS) models are widely used in the industry due to their simplicity and efficiency, the Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) EOS offers a more physically accurate representation of molecular interactions. Despite the potential of PC-SAFT EOS, the application to predict mixture critical points remains underexplored. These challenges primarily arise from computational complexities and spurious stationary points that have long limited the practical use of PC-SAFT EOS for mixture criticality.
This study performs a systematic evaluation of two critical point computational methods using PC-SAFT EOS. The critical point calculation methods are applied to compute mixture critical temperatures and pressures, vapor–liquid equilibrium phase envelopes, and to trace full critical loci. Furthermore, the evaluation covers many distinct multicomponent mixtures ranging from two to eleven components. By directly comparing our results against experimental data and the results yielded by CEOS, we provide an evaluation of the performance of PC-SAFT EOS in predicting the critical points of pure compounds and mixtures.
For pure compounds in the tested mixtures, the results show that Global Optimization (GO) method demonstrates slightly better performance than the Newton–Raphson (NR) method for critical temperature () predictions with Average Absolute Relative Deviations (AARD%) of 1.538%, while both show nearly identical performance for critical pressure () predictions. For mixtures, PC-SAFT-based NR demonstrates superior performance in predicting critical points with AARD% of 1.687% for predictions and 4.623% for predictions. In contrast, GO demonstrates higher deviations, particularly for some heavier mixtures. When calculating critical loci of mixtures, both methods produce root mean square error values with typical errors below 10 K for predictions and 0.5 MPa for predictions.
{"title":"Numerically stable determination of mixture critical points and loci with PC-SAFT Equation of State","authors":"Mustajab Safarov, Vishnu Jayaprakash, Changxu Wu, Huazhou Li","doi":"10.1016/j.supflu.2025.106817","DOIUrl":"10.1016/j.supflu.2025.106817","url":null,"abstract":"<div><div>Compositional simulations are important for understanding, analyzing, and optimizing multiphase flows, especially in the petrochemical industry. These simulations are dependent on an accurate Equation of State (EOS) to model the relationships between phases under changing conditions. While cubic EOS (CEOS) models are widely used in the industry due to their simplicity and efficiency, the Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) EOS offers a more physically accurate representation of molecular interactions. Despite the potential of PC-SAFT EOS, the application to predict mixture critical points remains underexplored. These challenges primarily arise from computational complexities and spurious stationary points that have long limited the practical use of PC-SAFT EOS for mixture criticality.</div><div>This study performs a systematic evaluation of two critical point computational methods using PC-SAFT EOS. The critical point calculation methods are applied to compute mixture critical temperatures and pressures, vapor–liquid equilibrium phase envelopes, and to trace full critical loci. Furthermore, the evaluation covers many distinct multicomponent mixtures ranging from two to eleven components. By directly comparing our results against experimental data and the results yielded by CEOS, we provide an evaluation of the performance of PC-SAFT EOS in predicting the critical points of pure compounds and mixtures.</div><div>For pure compounds in the tested mixtures, the results show that Global Optimization (GO) method demonstrates slightly better performance than the Newton–Raphson (NR) method for critical temperature (<span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span>) predictions with Average Absolute Relative Deviations (AARD%) of 1.538%, while both show nearly identical performance for critical pressure (<span><math><msub><mrow><mi>P</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span>) predictions. For mixtures, PC-SAFT-based NR demonstrates superior performance in predicting critical points with AARD% of 1.687% for <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span> predictions and 4.623% for <span><math><msub><mrow><mi>P</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span> predictions. In contrast, GO demonstrates higher deviations, particularly for some heavier mixtures. When calculating critical loci of mixtures, both methods produce root mean square error values with typical errors below 10 K for <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span> predictions and 0.5 MPa for <span><math><msub><mrow><mi>P</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span> predictions.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"229 ","pages":"Article 106817"},"PeriodicalIF":4.4,"publicationDate":"2025-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145364352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study aimed to enhance the dissolution rate of Teriflunomide, a medication for multiple sclerosis that exhibits low water solubility despite its high permeability. To tackle this issue, the Gas Antisolvent technique was utilized to decrease the particle size of Teriflunomide. Three critical parameters were examined: pressure (10, 13, and 16 MPa), temperature (308, 318, and 328 K), and the ratio of Teriflunomide to Hydroxypropyl methylcellulose (1, 5, and 9 w/w). The optimization of these variables was carried out using the Box-Behnken Design method. The coprecipitation of Teriflunomide with Hydroxypropyl methylcellulose was investigated under optimal conditions (16 MPa, 315 K, and a 1 w/w ratio). DSC, XRD, FTIR, SEM, and DLS were employed to examine and characterize the thermal stability, crystallinity, and to assess the shape and position of the absorption peaks, as well as the morphology and particle size. The resulting TEF-HPMC nanoparticles were measured at 561 ± 25 nm, which was found to be significantly smaller than the original sample (125 ± 28 μm).
{"title":"Production of teriflunomide-hydroxypropyl methyl cellulose composites utilizing the Gas Antisolvent (GAS) process and Box-Behnken Design","authors":"Mahshid Askarizadeh , Nadia Esfandiari , Bizhan Honarvar , Seyed Ali Sajadian , Amin Azdarpour","doi":"10.1016/j.supflu.2025.106820","DOIUrl":"10.1016/j.supflu.2025.106820","url":null,"abstract":"<div><div>This study aimed to enhance the dissolution rate of Teriflunomide, a medication for multiple sclerosis that exhibits low water solubility despite its high permeability. To tackle this issue, the Gas Antisolvent technique was utilized to decrease the particle size of Teriflunomide. Three critical parameters were examined: pressure (10, 13, and 16 MPa), temperature (308, 318, and 328 K), and the ratio of Teriflunomide to Hydroxypropyl methylcellulose (1, 5, and 9 w/w). The optimization of these variables was carried out using the Box-Behnken Design method. The coprecipitation of Teriflunomide with Hydroxypropyl methylcellulose was investigated under optimal conditions (16 MPa, 315 K, and a 1 w/w ratio). DSC, XRD, FTIR, SEM, and DLS were employed to examine and characterize the thermal stability, crystallinity, and to assess the shape and position of the absorption peaks, as well as the morphology and particle size. The resulting TEF-HPMC nanoparticles were measured at 561 ± 25 nm, which was found to be significantly smaller than the original sample (125 ± 28 μm).</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"229 ","pages":"Article 106820"},"PeriodicalIF":4.4,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145323371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-15DOI: 10.1016/j.supflu.2025.106819
Kelly Roberta Pinheiro Pantoja , Giselle Cristine Melo Aires , Sophia Aimy Oppata , João Pedro Ferraz de Carvalho , Renato Macedo Cordeiro , Raul Nunes de Carvalho Junior
This study investigates the extraction of avocado oil from the Margarida variety using supercritical CO₂, with the aim of obtaining a product of superior quality compared to commercial avocado oil from the Hass variety, obtained by cold pressing. The quality of the oils was evaluated in terms of their physicochemical properties, composition of bioactive compounds (fatty acids, lutein, phenolic compounds, and α-tocopherol), and nutritional quality indices. Additionally, the study assessed the reproducibility of Ultra-Performance Convergence Chromatography (UPC²) compared to Gas Chromatography coupled with Mass Spectrometry (GC/MS) for the analysis of fatty acid profiles. The supercritical extraction yielded a high yield (44.90 %) and produced an oil with low levels of free fatty acids (1.04 %) and peroxides (7.03 meq/kg). The oil is rich in natural antioxidants, such as lutein (113.32 µg/g), phenolic compounds (137.75 µg GAE/g), and α-tocopherol (51.90 µg/g), and has a high concentration of beneficial fatty acids, with 44.41 % oleic acid and 28.37 % linoleic acid. With an excellent nutritional profile, evidenced by low atherogenic and thrombogenic indices. Statistical tests indicated no significant differences between the chromatographic techniques. Margarida oil demonstrates nutritional and functional properties superior to commercial Hass oil.
{"title":"High-quality margarida avocado oil obtained by Sc-CO2 compared to commercial hass avocado oil from cold pressing and comparative lipid profile analysis by UPC² and GC/MS","authors":"Kelly Roberta Pinheiro Pantoja , Giselle Cristine Melo Aires , Sophia Aimy Oppata , João Pedro Ferraz de Carvalho , Renato Macedo Cordeiro , Raul Nunes de Carvalho Junior","doi":"10.1016/j.supflu.2025.106819","DOIUrl":"10.1016/j.supflu.2025.106819","url":null,"abstract":"<div><div>This study investigates the extraction of avocado oil from the Margarida variety using supercritical CO₂, with the aim of obtaining a product of superior quality compared to commercial avocado oil from the Hass variety, obtained by cold pressing. The quality of the oils was evaluated in terms of their physicochemical properties, composition of bioactive compounds (fatty acids, lutein, phenolic compounds, and α-tocopherol), and nutritional quality indices. Additionally, the study assessed the reproducibility of Ultra-Performance Convergence Chromatography (UPC²) compared to Gas Chromatography coupled with Mass Spectrometry (GC/MS) for the analysis of fatty acid profiles. The supercritical extraction yielded a high yield (44.90 %) and produced an oil with low levels of free fatty acids (1.04 %) and peroxides (7.03 meq/kg). The oil is rich in natural antioxidants, such as lutein (113.32 µg/g), phenolic compounds (137.75 µg GAE/g), and α-tocopherol (51.90 µg/g), and has a high concentration of beneficial fatty acids, with 44.41 % oleic acid and 28.37 % linoleic acid. With an excellent nutritional profile, evidenced by low atherogenic and thrombogenic indices. Statistical tests indicated no significant differences between the chromatographic techniques. Margarida oil demonstrates nutritional and functional properties superior to commercial Hass oil.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"229 ","pages":"Article 106819"},"PeriodicalIF":4.4,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145364354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The integrated preparation strategy of multi-layer foam materials is expected to meet the demand for frequency-selective electromagnetic shielding properties. In this study, a synergistic regulation strategy of magnetic field and supercritical CO2 foaming technology was employed to achieve the parallel alternate arrangement of conductive layers and porous layers. The impact of the layered cell structure in liquid silicone rubber/ ferrosoferric oxide modified graphene/ carbon nanotube (LSR/Fe3O4@G/CNT) on the electromagnetic shielding performance in the X-band (8.4 GHz–12.4 GHz) was systematically investigated. The results demonstrate that the electromagnetic shielding effectiveness (SET) of the unfoamed material remained stable at 11.4 dB. In contrast, the layered foam material exhibited frequency-selective electromagnetic shielding characteristics and the maximum SET reaching 33.4 dB after foaming. By adjusting the foaming parameters, the position of the shielding peak can be effectively regulated, enabling the multi-layered silicone rubber foam to achieve high shielding efficiency within specific frequency bands.
{"title":"Multilayer integrated design for frequency-tunable silicone rubber-based electromagnetic shielding foams","authors":"Zuoze Fan, Xiaohan Wang, Bo Wang, Yishen Zhao, Ruyun Xu, Guangxian Li, Xia Liao","doi":"10.1016/j.supflu.2025.106818","DOIUrl":"10.1016/j.supflu.2025.106818","url":null,"abstract":"<div><div>The integrated preparation strategy of multi-layer foam materials is expected to meet the demand for frequency-selective electromagnetic shielding properties. In this study, a synergistic regulation strategy of magnetic field and supercritical CO<sub>2</sub> foaming technology was employed to achieve the parallel alternate arrangement of conductive layers and porous layers. The impact of the layered cell structure in liquid silicone rubber/ ferrosoferric oxide modified graphene/ carbon nanotube (LSR/Fe<sub>3</sub>O<sub>4</sub>@G/CNT) on the electromagnetic shielding performance in the X-band (8.4 GHz–12.4 GHz) was systematically investigated. The results demonstrate that the electromagnetic shielding effectiveness (<em>SE</em><sub>T</sub>) of the unfoamed material remained stable at 11.4 dB. In contrast, the layered foam material exhibited frequency-selective electromagnetic shielding characteristics and the maximum <em>SE</em><sub>T</sub> reaching 33.4 dB after foaming. By adjusting the foaming parameters, the position of the shielding peak can be effectively regulated, enabling the multi-layered silicone rubber foam to achieve high shielding efficiency within specific frequency bands.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"229 ","pages":"Article 106818"},"PeriodicalIF":4.4,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145364355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-11DOI: 10.1016/j.supflu.2025.106814
A. Pizzano , S.B. Rodriguez Reartes , P.E. Hegel
In the last years, there has been an increasing use of eco-friendly lubricant options produced from renewable raw materials, which are less toxic to humans and ecosystems. As the demand for sustainable products rises, lubricants derived from vegetable oils and animal fats are gaining attraction. In this study, we evaluate the purification of a biolubricant synthesized via classical alkali-catalyst esterification of fatty acid methyl esters (FAME) with trimethylolpropane (TMP) using CO2 as solvent media. Unlike conventional purification solvents, using CO2 minimizes environmental impact and aligns with green chemistry principles. We investigate the purification and upgrading of the filtrated biolubricant (28 wt% FAME) using CO2 -both in its liquid and supercritical states- as a green solvent for designing a more sustainable separation process. The study examines phase equilibria of the multicomponent mixture (liquid-liquid-vapor to liquid-vapor phase transition), solubility of biolubricant in CO2 (8.0–22.4 mg/g biolubricant/CO2 according to operating conditions) and the purification process. The final bio-based base oils are analyzed to determine their FAME content, viscosity, and viscosity index. Results show that purified bio-based base oils contain as little as 2.9 wt% FAME, with a viscosity of 0.051 Pa.s at 313.2 K and a viscosity index of 196, comparable to those of the trimethylolpropane triolein standard. These findings suggest that the bio-based base oils produced and purified are suitable for lubrication applications, matching or exceeding the quality of conventional lubricants.
{"title":"Upgrading and purification of biolubricants by extraction of fatty acid methyl esters with dense CO2","authors":"A. Pizzano , S.B. Rodriguez Reartes , P.E. Hegel","doi":"10.1016/j.supflu.2025.106814","DOIUrl":"10.1016/j.supflu.2025.106814","url":null,"abstract":"<div><div>In the last years, there has been an increasing use of eco-friendly lubricant options produced from renewable raw materials, which are less toxic to humans and ecosystems. As the demand for sustainable products rises, lubricants derived from vegetable oils and animal fats are gaining attraction. In this study, we evaluate the purification of a biolubricant synthesized via classical alkali-catalyst esterification of fatty acid methyl esters (FAME) with trimethylolpropane (TMP) using CO<sub>2</sub> as solvent media. Unlike conventional purification solvents, using CO<sub>2</sub> minimizes environmental impact and aligns with green chemistry principles. We investigate the purification and upgrading of the filtrated biolubricant (28 wt% FAME) using CO<sub>2</sub> -both in its liquid and supercritical states- as a green solvent for designing a more sustainable separation process. The study examines phase equilibria of the multicomponent mixture (liquid-liquid-vapor to liquid-vapor phase transition), solubility of biolubricant in CO<sub>2</sub> (8.0–22.4 mg/g biolubricant/CO<sub>2</sub> according to operating conditions) and the purification process. The final bio-based base oils are analyzed to determine their FAME content, viscosity, and viscosity index. Results show that purified bio-based base oils contain as little as 2.9 wt% FAME, with a viscosity of 0.051 Pa.s at 313.2 K and a viscosity index of 196, comparable to those of the trimethylolpropane triolein standard. These findings suggest that the bio-based base oils produced and purified are suitable for lubrication applications, matching or exceeding the quality of conventional lubricants.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"229 ","pages":"Article 106814"},"PeriodicalIF":4.4,"publicationDate":"2025-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145322498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-11DOI: 10.1016/j.supflu.2025.106804
Jiawei Zhao , Lifeng Yang , Feiyu Chen , Wendeng Jiang , Mian Hu , Zhongting Hu , Zhiyan Pan , Junliang Wang
316 L stainless steel (316 L SS) is an important candidate material for super/subcritical water oxidation facilities; however, corrosion negatively affects its service life, especially in the presence of halogen ions such as chlorine. In this work, Ti-6Al-4V (TC4) coatings were deposited on 316 L SS substrates by cold spraying (CS) and subsequently remelted by laser remelting (LR). The corrosion resistance of the coatings was evaluated in subcritical (260 °C, 15.7 MPa) and supercritical (380 °C, 22.3 MPa) water containing 3.5 wt% NaCl and 3.0 wt% H2O2 for up to 300 h. Scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS) analysis revealed that LR effectively densified the coating surface and enhanced its structural integrity. Corrosion assessments based on weight change, SEM, EDS, and X-ray computed tomography (CT) indicated that the TC4 coating significantly improved the corrosion resistance of 316 L SS by inhibiting the outward diffusion of metallic elements and the inward diffusion of oxygen. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses showed that the oxide film formed on the TC4 coating consisted mainly of Ti, Al, Fe, and Cr oxides, and the inhibition effect of the coating on the matrix elements varied after different treatment processes. In particular, the 0.6 mm laser-enhanced coating has a lower corrosion weight change, a more uniform and dense corrosion surface, and a better inhibition. The combination of CS and LR is demonstrated to be an effective approach for enhancing the corrosion resistance of 316 L SS, showing great potential for application in super/subcritical water oxidation reactors.
316 L不锈钢（316 L SS）是超/亚临界水氧化设施的重要候选材料；然而，腐蚀会对其使用寿命产生负面影响，特别是在氯等卤素离子存在的情况下。采用冷喷涂（CS）技术在316 L SS基板上沉积Ti-6Al-4V （TC4）涂层，然后采用激光重熔（LR）技术进行重熔。在含3.5 wt% NaCl和3.0 wt% H2O2的亚临界水（260°C, 15.7 MPa）和超临界水（380°C, 22.3 MPa）中对涂层的耐蚀性进行了测试，测试时间为300 h。扫描电镜/能谱分析（SEM/EDS）表明，LR有效致密化了涂层表面，增强了涂层的结构完整性。基于重量变化、SEM、EDS和x射线计算机断层扫描（CT）的腐蚀评估表明，TC4涂层通过抑制金属元素的向外扩散和氧的向内扩散，显著提高了316 L SS的耐蚀性。x射线衍射（XRD）和x射线光电子能谱（XPS）分析表明，TC4涂层上形成的氧化膜主要由Ti、Al、Fe和Cr氧化物组成，不同处理工艺对基体元素的抑制效果不同。特别是0.6 mm激光增强涂层的腐蚀重量变化更小，腐蚀表面更均匀致密，缓蚀性更好。CS和LR的结合是提高316 L SS耐腐蚀性能的有效途径，在超/亚临界水氧化反应器中具有很大的应用潜力。
{"title":"Microstructure and corrosion of cold-sprayed/laser-remelted TC4 coatings on 316 L SS in oxygenated NaCl-containing super/subcritical water","authors":"Jiawei Zhao , Lifeng Yang , Feiyu Chen , Wendeng Jiang , Mian Hu , Zhongting Hu , Zhiyan Pan , Junliang Wang","doi":"10.1016/j.supflu.2025.106804","DOIUrl":"10.1016/j.supflu.2025.106804","url":null,"abstract":"<div><div>316 L stainless steel (316 L SS) is an important candidate material for super/subcritical water oxidation facilities; however, corrosion negatively affects its service life, especially in the presence of halogen ions such as chlorine. In this work, Ti-6Al-4V (TC4) coatings were deposited on 316 L SS substrates by cold spraying (CS) and subsequently remelted by laser remelting (LR). The corrosion resistance of the coatings was evaluated in subcritical (260 °C, 15.7 MPa) and supercritical (380 °C, 22.3 MPa) water containing 3.5 wt% NaCl and 3.0 wt% H<sub>2</sub>O<sub>2</sub> for up to 300 h. Scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS) analysis revealed that LR effectively densified the coating surface and enhanced its structural integrity. Corrosion assessments based on weight change, SEM, EDS, and X-ray computed tomography (CT) indicated that the TC4 coating significantly improved the corrosion resistance of 316 L SS by inhibiting the outward diffusion of metallic elements and the inward diffusion of oxygen. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses showed that the oxide film formed on the TC4 coating consisted mainly of Ti, Al, Fe, and Cr oxides, and the inhibition effect of the coating on the matrix elements varied after different treatment processes. In particular, the 0.6 mm laser-enhanced coating has a lower corrosion weight change, a more uniform and dense corrosion surface, and a better inhibition. The combination of CS and LR is demonstrated to be an effective approach for enhancing the corrosion resistance of 316 L SS, showing great potential for application in super/subcritical water oxidation reactors.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"229 ","pages":"Article 106804"},"PeriodicalIF":4.4,"publicationDate":"2025-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145322496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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