The supercritical CO2 (scCO2) impregnation of nanodiamond (ND) in polymethylmethacrylate (PMMA) film was carried out over the pressure ranges of 12 MPa to 20 MPa and temperatures of 40 °C to 100 °C. The amount of ND impregnated in ND-PMMA composite film, and the refractive indices of the film were investigated. The refractive index increased linearly with the amount of ND accumulated in the film. The morphology on the surface and inside of the ND-PMMA composite film was characterized by SEM, TEM, AFM, and FT-IR analysis. The ND-PMMA film surface after scCO2 treatment was smoother than before scCO2 treatment, and the ND particles were embedded into the PMMA matrix and uniformly distributed near the interior of the film surface. The results of the retardation and birefringence of the ND-impregnated PMMA film after scCO2 treatment indicated that ND impregnation of PMMA film enhances the optical anisotropy of the original PMMA film.
{"title":"Supercritical CO2 impregnation of nanodiamonds into polymethylmethacrylate film and the film’s optical property","authors":"Jinhua Hu, Kunitoyo Osawa, Kaoru Tada, Kentaro Taki, Hirohisa Uchida, Kazuhiro Tamura","doi":"10.1016/j.supflu.2024.106506","DOIUrl":"10.1016/j.supflu.2024.106506","url":null,"abstract":"<div><div>The supercritical CO<sub>2</sub> (scCO<sub>2</sub>) impregnation of nanodiamond (ND) in polymethylmethacrylate (PMMA) film was carried out over the pressure ranges of 12 MPa to 20 MPa and temperatures of 40 °C to 100 °C. The amount of ND impregnated in ND-PMMA composite film, and the refractive indices of the film were investigated. The refractive index increased linearly with the amount of ND accumulated in the film. The morphology on the surface and inside of the ND-PMMA composite film was characterized by SEM, TEM, AFM, and FT-IR analysis. The ND-PMMA film surface after scCO<sub>2</sub> treatment was smoother than before scCO<sub>2</sub> treatment, and the ND particles were embedded into the PMMA matrix and uniformly distributed near the interior of the film surface. The results of the retardation and birefringence of the ND-impregnated PMMA film after scCO<sub>2</sub> treatment indicated that ND impregnation of PMMA film enhances the optical anisotropy of the original PMMA film.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"218 ","pages":"Article 106506"},"PeriodicalIF":3.4,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142929234","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 : 2024-12-26DOI: 10.1016/j.supflu.2024.106502
Ye-Seul Park , Vikash Chandra Roy , Jin-Seok Park , Wei Zhang , Byung-Soo Chun
The study aimed to identify the optimal subcritical water extraction (SWE) parameters for phlorotannin (marine polyphenols) from Ecklonia stolonifera using response surface methodology (RSM). The reaction temperature, time, and the solid-to-solvent ratio were optimized, and the best extraction conditions were 198.5°C, 36.21 min, and 12.23 g/mL, respectively. Under optimal conditions, the total phlorotannin content (TPC) was 50.01 ± 0.12 mg phloroglucinol/g dried seaweed powder. The results indicated that the E. stolonifera extract showed substantial ABTS+, DPPH radical scavenging, and FRAP activities (70.94 ± 0.15, 60.03 ± 0.35, and 29.45 ± 0.39 mg Trolox equivalent/g dried seaweed powder, respectively). The resulting extract exhibited potential antihypertensive (95.87 % ± 0.01 %), α-glucosidase inhibitory (69.29 % ± 1.83 %), and anti-inflammatory (68.55 % ± 0.98 %) activity compared with the positive control. In conclusion, this study underscores the immense potential of E. stolonifera as a valuable nutraceutical material when prepared by the SWE method.
{"title":"Optimization of subcritical water extraction parameters of phlorotannins from brown alga (Ecklonia stolonifera): Bipotentialities and possible applications","authors":"Ye-Seul Park , Vikash Chandra Roy , Jin-Seok Park , Wei Zhang , Byung-Soo Chun","doi":"10.1016/j.supflu.2024.106502","DOIUrl":"10.1016/j.supflu.2024.106502","url":null,"abstract":"<div><div>The study aimed to identify the optimal subcritical water extraction (SWE) parameters for phlorotannin (marine polyphenols) from <em>Ecklonia stolonifera</em> using response surface methodology (RSM). The reaction temperature, time, and the solid-to-solvent ratio were optimized, and the best extraction conditions were 198.5°C, 36.21 min, and 12.23 g/mL, respectively. Under optimal conditions, the total phlorotannin content (TPC) was 50.01 ± 0.12 mg phloroglucinol/g dried seaweed powder. The results indicated that the <em>E. stolonifera</em> extract showed substantial ABTS<sup>+</sup>, DPPH radical scavenging, and FRAP activities (70.94 ± 0.15, 60.03 ± 0.35, and 29.45 ± 0.39 mg Trolox equivalent/g dried seaweed powder, respectively). The resulting extract exhibited potential antihypertensive (95.87 % ± 0.01 %), α-glucosidase inhibitory (69.29 % ± 1.83 %), and anti-inflammatory (68.55 % ± 0.98 %) activity compared with the positive control. In conclusion, this study underscores the immense potential of <em>E. stolonifera</em> as a valuable nutraceutical material when prepared by the SWE method.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"218 ","pages":"Article 106502"},"PeriodicalIF":3.4,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142929252","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 investigates the metallization of polyethylene terephthalate (PET) yarns with varying twist numbers using the supercritical CO2 (scCO2) catalyzation process. The research includes an analysis of the impact on surface morphology, crystallinity, and electrical resistance. The crystallinity of the PET yarns is affected by treatment in pure scCO2 and scCO2 containing palladium hexafluroacetylacetonate (Pd(hfa)2), which is the scCO2 catalyzation process and Pd(hfa)2 is used as the Pd catalyst source. Furthermore, this study uncovers the influence of the twist number on the fiber surfaces where the fibers come into contact in the twisted yarn. Specifically, the electrical resistance decreases with an increase in the twist number, attributed to an increase in conductive pathways and improved contact points between the fibers.
{"title":"Supercritical CO2 assisted metallization of polyethylene terephthalate yarns with various twist number","authors":"Hikaru Kondo , Tomoyuki Kurioka , Kazuhiro Shibata , Takumi Suda , Wan-Ting Chiu , Chun-Yi Chen , Yuko Mima , Roka Ueno , Arisa Jinno , Hiromichi Kurosu , Masato Sone , Tso-Fu Mark Chang","doi":"10.1016/j.supflu.2024.106501","DOIUrl":"10.1016/j.supflu.2024.106501","url":null,"abstract":"<div><div>This study investigates the metallization of polyethylene terephthalate (PET) yarns with varying twist numbers using the supercritical CO<sub>2</sub> (scCO<sub>2</sub>) catalyzation process. The research includes an analysis of the impact on surface morphology, crystallinity, and electrical resistance. The crystallinity of the PET yarns is affected by treatment in pure scCO<sub>2</sub> and scCO<sub>2</sub> containing palladium hexafluroacetylacetonate (Pd(hfa)<sub>2</sub>), which is the scCO<sub>2</sub> catalyzation process and Pd(hfa)<sub>2</sub> is used as the Pd catalyst source. Furthermore, this study uncovers the influence of the twist number on the fiber surfaces where the fibers come into contact in the twisted yarn. Specifically, the electrical resistance decreases with an increase in the twist number, attributed to an increase in conductive pathways and improved contact points between the fibers.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"218 ","pages":"Article 106501"},"PeriodicalIF":3.4,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142889234","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 : 2024-12-24DOI: 10.1016/j.supflu.2024.106491
Clément Sevestre, Julien Chabanon, Thomas Deleau, Christophe Coquelet
The development of new industrial applications in the pharmaceutical, food, and cosmetic fields uses supercritical carbon dioxide as a solvent or antisolvent in their processes for extracting non-polar molecules. Ethanol () is added in small quantities to isolate a polar molecule during a unit operation by solubilization or precipitation. Density measurements in pure carbon dioxide () and in binary - mixtures with mass compositions ( and ) were carried out using a vibrating tube densimeter. The isotherms were determined at temperatures of 303, 308, and 313 K, above the critical temperature, and for a pressure range from 5 to 10 MPa. Fine modeling around the critical point was performed using cubic equations of state with two or three parameters (Peng–Robinson and Coquelet–El Abbadi–Houriez EoS). The Huron-Vidal mixing rule coupled with the NRTL model was employed. To enhance the prediction around the critical point of pure carbon dioxide and binary - mixtures, White’s correction method was used. The results for pure supercritical carbon dioxide show modeling performance with a deviation of 5.8% around the critical point.
{"title":"Effect of ethanol on supercritical CO2 solvent densities","authors":"Clément Sevestre, Julien Chabanon, Thomas Deleau, Christophe Coquelet","doi":"10.1016/j.supflu.2024.106491","DOIUrl":"10.1016/j.supflu.2024.106491","url":null,"abstract":"<div><div>The development of new industrial applications in the pharmaceutical, food, and cosmetic fields uses supercritical carbon dioxide as a solvent or antisolvent in their processes for extracting non-polar molecules. Ethanol (<span><math><mtext>EtOH</mtext></math></span>) is added in small quantities to isolate a polar molecule during a unit operation by solubilization or precipitation. Density measurements in pure carbon dioxide (<span><math><msub><mrow><mtext>CO</mtext></mrow><mrow><mn>2</mn></mrow></msub></math></span>) and in binary <span><math><msub><mrow><mtext>CO</mtext></mrow><mrow><mn>2</mn></mrow></msub></math></span>-<span><math><mtext>EtOH</mtext></math></span> mixtures with mass compositions (<span><math><mrow><msub><mrow><mi>w</mi></mrow><mrow><msub><mrow><mtext>CO</mtext></mrow><mrow><mn>2</mn></mrow></msub></mrow></msub><mo>=</mo><mn>0</mn><mo>.</mo><mn>99</mn></mrow></math></span> and <span><math><mrow><msub><mrow><mi>w</mi></mrow><mrow><msub><mrow><mtext>CO</mtext></mrow><mrow><mn>2</mn></mrow></msub></mrow></msub><mo>=</mo><mn>0</mn><mo>.</mo><mn>98</mn></mrow></math></span>) were carried out using a vibrating tube densimeter. The isotherms were determined at temperatures of 303, 308, and 313 K, above the critical temperature, and for a pressure range from 5 to 10 MPa. Fine modeling around the critical point was performed using cubic equations of state with two or three parameters (Peng–Robinson and Coquelet–El Abbadi–Houriez EoS). The Huron-Vidal mixing rule coupled with the NRTL model was employed. To enhance the prediction around the critical point of pure carbon dioxide and binary <span><math><msub><mrow><mtext>CO</mtext></mrow><mrow><mn>2</mn></mrow></msub></math></span>-<span><math><mtext>EtOH</mtext></math></span> mixtures, White’s correction method was used. The results for pure supercritical carbon dioxide show modeling performance with a deviation of 5.8% around the critical point.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"218 ","pages":"Article 106491"},"PeriodicalIF":3.4,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142990559","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}
A metal nanoparticle (NP)-carbon composite derived from metal-organic frameworks (MOFs) has garnered significant attention for its high catalytic activity. This study develops a simple method for preparing Pd/Ni NP-embedded carbon from MOFs. Palladium(Ⅱ) acetate (Pd(OAc)2) is used as the precursor for Pd NPs and is loaded into the pores of Ni-MOF-74 using supercritical carbon dioxide (scCO₂) assisted immobilization. Pd/Ni NPs are prepared by reduction and pyrosis of Pd(OAc)2-loaded Ni-MOF-74. Scanning transmission electron microscopy (STEM) clearly reveals that the Pd/Ni NPs are successfully immobilized in the carbon (Pd/Ni@C) and dispersed with sizes around 10 nm. Pd/Ni@C demonstrates high catalytic activity and high durability in Suzuki–Miyaura coupling reactions, despite having lower Pd content (4.7 wt%) than commercially available Pd@C (10 wt%). The active palladium species Pd(0) on Pd/Ni@C accelerated the Suzuki-Miyaura coupling reactions, because the Ni in Pd/Ni NPs played the sacrificial role to resist Pd-oxidation.
{"title":"Supercritical CO2-assisted preparation of catalytically-active Pd/Ni nanoparticle-embedded carbon from a metal-organic framework","authors":"Kiyoshi Matsuyama , Masashi Eiro , Ayano Shoji , Takafumi Kato","doi":"10.1016/j.supflu.2024.106500","DOIUrl":"10.1016/j.supflu.2024.106500","url":null,"abstract":"<div><div>A metal nanoparticle (NP)-carbon composite derived from metal-organic frameworks (MOFs) has garnered significant attention for its high catalytic activity. This study develops a simple method for preparing Pd/Ni NP-embedded carbon from MOFs. Palladium(Ⅱ) acetate (Pd(OAc)<sub>2</sub>) is used as the precursor for Pd NPs and is loaded into the pores of Ni-MOF-74 using supercritical carbon dioxide (scCO₂) assisted immobilization. Pd/Ni NPs are prepared by reduction and pyrosis of Pd(OAc)<sub>2</sub>-loaded Ni-MOF-74. Scanning transmission electron microscopy (STEM) clearly reveals that the Pd/Ni NPs are successfully immobilized in the carbon (Pd/Ni@C) and dispersed with sizes around 10 nm. Pd/Ni@C demonstrates high catalytic activity and high durability in Suzuki–Miyaura coupling reactions, despite having lower Pd content (4.7 wt%) than commercially available Pd@C (10 wt%). The active palladium species Pd(0) on Pd/Ni@C accelerated the Suzuki-Miyaura coupling reactions, because the Ni in Pd/Ni NPs played the sacrificial role to resist Pd-oxidation.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"218 ","pages":"Article 106500"},"PeriodicalIF":3.4,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874110","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 : 2024-12-16DOI: 10.1016/j.supflu.2024.106499
Jelena Vladić , Igor Jerković , Valentina Pavić , Dragoljub Cvetković , Stela Jokić , Krunoslav Aladić , Kristian Pastor , Ana Rita C. Duarte
This study evaluated the potential of deep eutectic systems (DESs) to enhance the chemical and microbiological stability, as well as the antibacterial activity of dill (Anethum graveolens L.) supercritical extracts, rich in carvone and limonene, over six months of storage. Various betaine-based DESs were tested for their ability to preserve the chemical integrity and enhance the antibacterial properties of dill extracts. Significant alterations in the headspace profile of extracts during storage indicated degradation reactions. The dill-Bet/LA extract system (dill extract in Bet/LA) proved most effective, significantly slowing degradation and enhancing antibacterial activity compared to the dill-control extract. Specifically, this system exhibited 20–40-fold greater efficacy against Gram-negative bacteria and 5–8-fold stronger activity against Gram-positive bacteria than the dill-control. Furthermore, the dill-Bet/LA system was also the most effective in preserving antimicrobial potency during storage, demonstrating its potential as a sustainable solution for extending the shelf life and bioactivity of dill supercritical extracts.
本研究评估了深度共晶系统（DESs）在提高莳萝（Anethum graveolens L.）超临界提取物的化学和微生物稳定性以及抗菌活性方面的潜力，这些提取物富含香芹酮和柠檬烯，超过6个月的储存。以甜菜素为基础，测试了各种脱脂油对莳萝提取物的化学完整性和抗菌性能的影响。在储存过程中提取物顶空剖面的显著变化表明了降解反应。与对照提取物相比，莳萝-Bet/LA提取物体系（Bet/LA中的莳萝提取物）被证明是最有效的，显著减缓了降解并增强了抗菌活性。具体来说，该体系对革兰氏阴性菌的抑制效果是对照的20 - 40倍，对革兰氏阳性菌的抑制效果是对照的5 - 8倍。此外，莳萝- bet /LA体系在储存过程中也最有效地保持了抗菌效力，表明其作为延长莳萝超临界提取物的保质期和生物活性的可持续解决方案的潜力。
{"title":"Exploring the potential of deep eutectic systems for the preservation of the chemical profile and antibacterial potential of dill (Anethum graveolens L.) supercritical CO₂ extracts","authors":"Jelena Vladić , Igor Jerković , Valentina Pavić , Dragoljub Cvetković , Stela Jokić , Krunoslav Aladić , Kristian Pastor , Ana Rita C. Duarte","doi":"10.1016/j.supflu.2024.106499","DOIUrl":"10.1016/j.supflu.2024.106499","url":null,"abstract":"<div><div>This study evaluated the potential of deep eutectic systems (DESs) to enhance the chemical and microbiological stability, as well as the antibacterial activity of dill (<em>Anethum graveolens</em> L.) supercritical extracts, rich in carvone and limonene, over six months of storage. Various betaine-based DESs were tested for their ability to preserve the chemical integrity and enhance the antibacterial properties of dill extracts. Significant alterations in the headspace profile of extracts during storage indicated degradation reactions. The dill-Bet/LA extract system (dill extract in Bet/LA) proved most effective, significantly slowing degradation and enhancing antibacterial activity compared to the dill-control extract. Specifically, this system exhibited 20–40-fold greater efficacy against Gram-negative bacteria and 5–8-fold stronger activity against Gram-positive bacteria than the dill-control. Furthermore, the dill-Bet/LA system was also the most effective in preserving antimicrobial potency during storage, demonstrating its potential as a sustainable solution for extending the shelf life and bioactivity of dill supercritical extracts.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"218 ","pages":"Article 106499"},"PeriodicalIF":3.4,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-16DOI: 10.1016/j.supflu.2024.106498
Isadora de Souza Lopes , Rafael Augusto Juliato , Cristiane Conte Paim de Andrade , Ana Clara Troya Raineri Fiocco , Renata Galhardo Borguini , Manuela Cristina Pessanha de Araújo Santiago , Luiz Henrique Fasolin , Carolina Siqueira Franco Picone
Uvaia (Eugenia pyriformis Cambess) is a Brazilian native fruit with a high concentration of phenolic compounds. In this study, we optimized the extraction of flavonoids and other phenolic compounds from uvaia pulp (UP) and seed (US) by Pressurized Liquid Extraction (PLE) using an ethanolic solution as solvent. Both temperature and ethanol concentration enhanced the extraction of the phenolics from UP and US. The increase in ethanol concentration decreased the yield of flavonoid extraction from UP. In the case of the US, higher temperatures and lower ethanol percentage improved the yield of flavonoid extraction. All extracts showed high antioxidant activity under optimized conditions, especially the US extracts (507.40 µM Trolox.g−1 of dry US). The present findings highlight the effectiveness of PLE in obtaining antioxidant extracts from UP and US, and also contribute to the valorization of uvaia fruit and its residues.
{"title":"Uvaia (Eugenia pyriformis Cambess) fruit: Exploring its antioxidant potential through pressurized liquid extraction","authors":"Isadora de Souza Lopes , Rafael Augusto Juliato , Cristiane Conte Paim de Andrade , Ana Clara Troya Raineri Fiocco , Renata Galhardo Borguini , Manuela Cristina Pessanha de Araújo Santiago , Luiz Henrique Fasolin , Carolina Siqueira Franco Picone","doi":"10.1016/j.supflu.2024.106498","DOIUrl":"10.1016/j.supflu.2024.106498","url":null,"abstract":"<div><div>Uvaia (<em>Eugenia pyriformis</em> Cambess) is a Brazilian native fruit with a high concentration of phenolic compounds. In this study, we optimized the extraction of flavonoids and other phenolic compounds from uvaia pulp (U<sub>P</sub>) and seed (U<sub>S</sub>) by Pressurized Liquid Extraction (PLE) using an ethanolic solution as solvent. Both temperature and ethanol concentration enhanced the extraction of the phenolics from U<sub>P</sub> and U<sub>S</sub>. The increase in ethanol concentration decreased the yield of flavonoid extraction from U<sub>P</sub>. In the case of the U<sub>S</sub>, higher temperatures and lower ethanol percentage improved the yield of flavonoid extraction. All extracts showed high antioxidant activity under optimized conditions, especially the U<sub>S</sub> extracts (507.40 µM Trolox.g<sup>−1</sup> of dry U<sub>S</sub>). The present findings highlight the effectiveness of PLE in obtaining antioxidant extracts from U<sub>P</sub> and U<sub>S</sub>, and also contribute to the valorization of uvaia fruit and its residues.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"218 ","pages":"Article 106498"},"PeriodicalIF":3.4,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142889233","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 : 2024-12-16DOI: 10.1016/j.supflu.2024.106496
Govind Dubey, Prabu Vairakannu, Pankaj Tiwari
The present research aimed at the direct coal liquefaction (DCL) of three Indian coals with toluene and Fe2O3 catalyst within a temperature range of 400 ℃- 450 °C. The maximum overall conversion of 41.87 wt% and oil yield of 16.25 wt% was observed for lignite coal, at 60 min residence time and 450 ℃ for catalytic, with an increase of 6 % and 4.72 %, respectively, compared to that of thermal liquefaction. The activation energies were in the 40 kJ/mol to 370 kJ/mol range. The CO2 levels peaked at 15.45 vol% for catalytic and 11.18 vol% for thermal DCL in the case of lignite coal. The hydrogen sulfide and carbonyl sulfide gases with maximum concentrations of 563 ppm and 230 ppm, respectively, were also detected. The oil possesses carbon chains ranging from C8 to C25, whereas both asphaltene and preasphaltene fractions extend to a broader range of C8-C30.
{"title":"Study of mechanism, kinetics, and product characterization of thermal and catalytic liquefaction of Northeastern Indian coals using supercritical toluene","authors":"Govind Dubey, Prabu Vairakannu, Pankaj Tiwari","doi":"10.1016/j.supflu.2024.106496","DOIUrl":"10.1016/j.supflu.2024.106496","url":null,"abstract":"<div><div>The present research aimed at the direct coal liquefaction (DCL) of three Indian coals with toluene and Fe<sub>2</sub>O<sub>3</sub> catalyst within a temperature range of 400 ℃- 450 °C. The maximum overall conversion of 41.87 wt% and oil yield of 16.25 wt% was observed for lignite coal, at 60 min residence time and 450 ℃ for catalytic, with an increase of 6 % and 4.72 %, respectively, compared to that of thermal liquefaction. The activation energies were in the 40 kJ/mol to 370 kJ/mol range. The CO<sub>2</sub> levels peaked at 15.45 vol% for catalytic and 11.18 vol% for thermal DCL in the case of lignite coal. The hydrogen sulfide and carbonyl sulfide gases with maximum concentrations of 563 ppm and 230 ppm, respectively, were also detected. The oil possesses carbon chains ranging from C<sub>8</sub> to C<sub>25</sub>, whereas both asphaltene and preasphaltene fractions extend to a broader range of C<sub>8</sub>-C<sub>30</sub>.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"218 ","pages":"Article 106496"},"PeriodicalIF":3.4,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874112","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 : 2024-12-15DOI: 10.1016/j.supflu.2024.106497
Yu Su , Qingxin Zheng , Yoshiki Suga , Masaru Watanabe
Here, the solubility of terephthalic acid (TPA) in water was measured under hydrothermal conditions at temperatures from 423.15 K to 623.15 K by a semi-dynamic gravimetric system. The whole process, using water as the only solvent, was considered safe and environmentally friendly. The results indicated that the TPA solubility in water increased exponentially with the temperature. Particularly, at 573.15 K (10 MPa) and 623.15 K (20 MPa), the water solubility of TPA was measured to be 108.1 and 347.4 g kg−1, respectively. It was the first time to measure the TPA solubility in water at over 523.15 K experimentally. Fitted curves for the TPA solubility in water as functions of temperature and water density were plotted, and the thermodynamic properties for the dissolution of TPA into water were obtained and plotted. The TPA solubility results obtained would be helpful to improve the production or recycling of TPA under hydrothermal conditions.
{"title":"Measurement of solubility of terephthalic acid in water under hydrothermal conditions","authors":"Yu Su , Qingxin Zheng , Yoshiki Suga , Masaru Watanabe","doi":"10.1016/j.supflu.2024.106497","DOIUrl":"10.1016/j.supflu.2024.106497","url":null,"abstract":"<div><div>Here, the solubility of terephthalic acid (TPA) in water was measured under hydrothermal conditions at temperatures from 423.15 K to 623.15 K by a semi-dynamic gravimetric system. The whole process, using water as the only solvent, was considered safe and environmentally friendly. The results indicated that the TPA solubility in water increased exponentially with the temperature. Particularly, at 573.15 K (10 MPa) and 623.15 K (20 MPa), the water solubility of TPA was measured to be 108.1 and 347.4 g kg<sup>−1</sup>, respectively. It was the first time to measure the TPA solubility in water at over 523.15 K experimentally. Fitted curves for the TPA solubility in water as functions of temperature and water density were plotted, and the thermodynamic properties for the dissolution of TPA into water were obtained and plotted. The TPA solubility results obtained would be helpful to improve the production or recycling of TPA under hydrothermal conditions.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"218 ","pages":"Article 106497"},"PeriodicalIF":3.4,"publicationDate":"2024-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-12DOI: 10.1016/j.supflu.2024.106495
Jiquan Chen , Zitao Lin , Xingying Tang , Ke Li , Riguang Zhu , Jianqiao Yang
This paper presents a comparative study of the corrosion behavior of Inconel 625 in supercritical water with different oxygen contents and phosphate phases. The results showed that the dissolved phosphate phase could compete with oxygen and that the addition of oxygen converted Cr2O3 to Cr6 +, resulting in a reduction in the thickness of the oxide film. The oxide film formed consisted of three distinct layers. The outer layer consists of NiO, Fe2O3, and NiFe2O4, which were formed by the diffusion of metal cations outward. The middle layer was a metal phosphate passivation layer which could prevent the diffusion of Fe, Ni, etc. and retard corrosion. The inner layer was formed by inward oxidation of oxygen ions with Cr to form Cr2O3. Phosphate molten salt were highly corrosive and can directly dissolve Cr2O3 into soluble Cr3+, a process accelerated by oxygen, increasing the Cr3+ content from 59.63 % to 77.54 %.
{"title":"Comparative study of the corrosion behavior of Inconel 625 in supercritical water containing dissolved and molten phosphates","authors":"Jiquan Chen , Zitao Lin , Xingying Tang , Ke Li , Riguang Zhu , Jianqiao Yang","doi":"10.1016/j.supflu.2024.106495","DOIUrl":"10.1016/j.supflu.2024.106495","url":null,"abstract":"<div><div>This paper presents a comparative study of the corrosion behavior of Inconel 625 in supercritical water with different oxygen contents and phosphate phases. The results showed that the dissolved phosphate phase could compete with oxygen and that the addition of oxygen converted Cr<sub>2</sub>O<sub>3</sub> to Cr<sup>6 +</sup>, resulting in a reduction in the thickness of the oxide film. The oxide film formed consisted of three distinct layers. The outer layer consists of NiO, Fe<sub>2</sub>O<sub>3</sub>, and NiFe<sub>2</sub>O<sub>4</sub>, which were formed by the diffusion of metal cations outward. The middle layer was a metal phosphate passivation layer which could prevent the diffusion of Fe, Ni, etc. and retard corrosion. The inner layer was formed by inward oxidation of oxygen ions with Cr to form Cr<sub>2</sub>O<sub>3</sub>. Phosphate molten salt were highly corrosive and can directly dissolve Cr<sub>2</sub>O<sub>3</sub> into soluble Cr<sup>3+</sup>, a process accelerated by oxygen, increasing the Cr<sup>3+</sup> content from 59.63 % to 77.54 %.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"218 ","pages":"Article 106495"},"PeriodicalIF":3.4,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874113","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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