A new type of fire-retardant coating for wood based on epoxy-amine composites modified with copper(II) hexafluorosilicate has been developed. To optimize the composition of the fire-retardant coating, the values of ignition and self-ignition temperatures, the combustibility group indices and the smoke generation coefficient of the developed epoxy-amine composites were used. It was found that the values of the ignition and self-ignition temperatures of epoxy-amine composites containing a flame retardant are higher than those of composites without it, by 15–34 °C and 25–58 °C, respectively. Compared to unmodified epoxy-amine composites, CuSiF6-modified epoxy-amine composites have 204–327 °C lower values of the maximum temperature of combustion gases and 7.8–10.4% less mass loss during combustion. It is shown that modified epoxy-amine composites with an optimized composition are classified as hardly combustible materials with moderate smoke-forming ability. Based on the results of experimental studies, the technological mode of coating the wood was chosen. The developed epoxy-amine composite with reduced combustibility has been used as a fire-retardant coating for wooden structures. Testing for fire showed that developed coating belongs the first group of fire protection efficiency, which ensures reliable fire protection of wood. In contrast, the coatings based on epoxy-amine composites without a flame retardant do not provide fire protection of wood at all.
{"title":"Flame Protection Technologies for Wood: Developing and Testing for Fire of Timbers with a Flame-retardant Coating Based on the Epoxy-amine Composite Modified by Copper(II) Hexafluorosilicate","authors":"B. Mykhalichko, H. Lavrenyuk","doi":"10.3311/ppch.19050","DOIUrl":"https://doi.org/10.3311/ppch.19050","url":null,"abstract":"A new type of fire-retardant coating for wood based on epoxy-amine composites modified with copper(II) hexafluorosilicate has been developed. To optimize the composition of the fire-retardant coating, the values of ignition and self-ignition temperatures, the combustibility group indices and the smoke generation coefficient of the developed epoxy-amine composites were used. It was found that the values of the ignition and self-ignition temperatures of epoxy-amine composites containing a flame retardant are higher than those of composites without it, by 15–34 °C and 25–58 °C, respectively. Compared to unmodified epoxy-amine composites, CuSiF6-modified epoxy-amine composites have 204–327 °C lower values of the maximum temperature of combustion gases and 7.8–10.4% less mass loss during combustion. It is shown that modified epoxy-amine composites with an optimized composition are classified as hardly combustible materials with moderate smoke-forming ability. Based on the results of experimental studies, the technological mode of coating the wood was chosen. The developed epoxy-amine composite with reduced combustibility has been used as a fire-retardant coating for wooden structures. Testing for fire showed that developed coating belongs the first group of fire protection efficiency, which ensures reliable fire protection of wood. In contrast, the coatings based on epoxy-amine composites without a flame retardant do not provide fire protection of wood at all.","PeriodicalId":19922,"journal":{"name":"Periodica Polytechnica Chemical Engineering","volume":"52 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78138573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Application of nucleating agents is a common way to manipulate the structure and properties of crystalline polymers. Our goal was to synthesize N,N'-dicyclohexyl terephthalic dihydrazide (DCTDH) and study it from the viewpoint of applicability as a nucleating agent for isotactic polypropylene (iPP). We used differential scanning calorimetry to investigate the efficiency of DCTDH in samples containing the nucleating agent in a wide concentration range. We used polarized light microscopy to study the crystalline morphology developed in the presence of this nucleating agent. To characterize the mechanical properties of the nucleated samples, we performed tensile and impact tests on injection molded specimens. DCTDH proved to be a non-soluble α-nucleating agent in iPP, with a saturation concentration around 300 ppm. The nucleating agent has a significant effect on the crystalline structure of iPP, microspherulitic structure forms in its presence. Owing to the different structure, a considerable change in the mechanical properties is observable: with increasing nucleating agent content the tensile modulus increases, while impact resistance has a maximum value around 300 ppm nucleating agent content.
{"title":"Effect of N,N'-Dicyclohexyl Terephthalic Dihydrazide on the Crystallization and Properties of Isotactic Polypropylene","authors":"F. Horváth, Levente Bihari, A. Menyhárd","doi":"10.3311/ppch.19074","DOIUrl":"https://doi.org/10.3311/ppch.19074","url":null,"abstract":"Application of nucleating agents is a common way to manipulate the structure and properties of crystalline polymers. Our goal was to synthesize N,N'-dicyclohexyl terephthalic dihydrazide (DCTDH) and study it from the viewpoint of applicability as a nucleating agent for isotactic polypropylene (iPP). We used differential scanning calorimetry to investigate the efficiency of DCTDH in samples containing the nucleating agent in a wide concentration range. We used polarized light microscopy to study the crystalline morphology developed in the presence of this nucleating agent. To characterize the mechanical properties of the nucleated samples, we performed tensile and impact tests on injection molded specimens. DCTDH proved to be a non-soluble α-nucleating agent in iPP, with a saturation concentration around 300 ppm. The nucleating agent has a significant effect on the crystalline structure of iPP, microspherulitic structure forms in its presence. Owing to the different structure, a considerable change in the mechanical properties is observable: with increasing nucleating agent content the tensile modulus increases, while impact resistance has a maximum value around 300 ppm nucleating agent content.","PeriodicalId":19922,"journal":{"name":"Periodica Polytechnica Chemical Engineering","volume":"39 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75190279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Andrea Fodor-Kardos, A. Ujhidy, G. Nagy, B. Gyetvai, J. Tóth
The aim of the study was to investigate the preparation of granular veterinary premix containing two different antibiotics by fluid bed granulation process. The particle size and density of the active ingredients were investigated for the proper selection of the filler material. The used antibiotics were tylosin tartarate and colistin sulfate, while isomalt sugar alcohol and cellulose materials were selected as filler and binder, respectively. The colistin sulfate was fed together with the binder solution because of its low density, fine particle size and relatively low (1.2%) concentration in the product. The type and concentration of the binder in its solution, the feeding rate and the total amount of added binder solution were optimized for obtaining dust free granules with desirable abrasion resistance and good flowability. The active ingredient content for both antibiotics was preserved even at the elevated temperature applied during the fluid granulation process.
{"title":"Preparation of Veterinary Premix with Dual Active Ingredients in Granular Form","authors":"Andrea Fodor-Kardos, A. Ujhidy, G. Nagy, B. Gyetvai, J. Tóth","doi":"10.3311/ppch.18703","DOIUrl":"https://doi.org/10.3311/ppch.18703","url":null,"abstract":"The aim of the study was to investigate the preparation of granular veterinary premix containing two different antibiotics by fluid bed granulation process. The particle size and density of the active ingredients were investigated for the proper selection of the filler material. The used antibiotics were tylosin tartarate and colistin sulfate, while isomalt sugar alcohol and cellulose materials were selected as filler and binder, respectively. The colistin sulfate was fed together with the binder solution because of its low density, fine particle size and relatively low (1.2%) concentration in the product. The type and concentration of the binder in its solution, the feeding rate and the total amount of added binder solution were optimized for obtaining dust free granules with desirable abrasion resistance and good flowability. The active ingredient content for both antibiotics was preserved even at the elevated temperature applied during the fluid granulation process.","PeriodicalId":19922,"journal":{"name":"Periodica Polytechnica Chemical Engineering","volume":"68 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85756909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mariana Menoncin, Miklós Murai, Péter Szombathy, D. Szieberth
Molnár János Cave (MJC) is the only underwater cave and the only active one in the Buda Thermal Karst system (BTK). At MJC, there is a large amount of water that can be considered as a possible source of drinking water. We evaluated the physical and chemical parameters of the cave water to understand natural and possible anthropogenic interference in water quality. Therefore, measurements of temperature and chemical compositions were performed for dripwaters and water from the cave conduits over a four-year period and compared to historical data. Statistical analysis of the produced data revealed yearly changes as well seasonal periodicity in the component ion concentrations. In the case of dripwaters, we observed a periodicity that revealed information about the origin of the dripwater. For the first time, we had identified seasonal variations in conduit waters. Previous studies only analyzed water at the entrance of the cave. Then, this research focuses on the water from the newly discovered inner passages.
{"title":"Assessment of Water Quality in the Molnár János Cave – Budapest, Hungary","authors":"Mariana Menoncin, Miklós Murai, Péter Szombathy, D. Szieberth","doi":"10.3311/ppch.18969","DOIUrl":"https://doi.org/10.3311/ppch.18969","url":null,"abstract":"Molnár János Cave (MJC) is the only underwater cave and the only active one in the Buda Thermal Karst system (BTK). At MJC, there is a large amount of water that can be considered as a possible source of drinking water. We evaluated the physical and chemical parameters of the cave water to understand natural and possible anthropogenic interference in water quality. Therefore, measurements of temperature and chemical compositions were performed for dripwaters and water from the cave conduits over a four-year period and compared to historical data. Statistical analysis of the produced data revealed yearly changes as well seasonal periodicity in the component ion concentrations. In the case of dripwaters, we observed a periodicity that revealed information about the origin of the dripwater. For the first time, we had identified seasonal variations in conduit waters. Previous studies only analyzed water at the entrance of the cave. Then, this research focuses on the water from the newly discovered inner passages.","PeriodicalId":19922,"journal":{"name":"Periodica Polytechnica Chemical Engineering","volume":"16 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89256817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nanoparticles biosynthesis has been extensively studied for its biomedical applications. In this study, the in-vitro antibacterial and antifungal activity of greenly fabricated silver nanoparticles (NPs) from Senna alata leaf extract (SaAgNPs) and silver nanoparticle cream blend (SaAgNPs-cream blend) were investigated. The SaAgNPs were characterized using UV-visible spectrophotometry, FTIR, SEM, TGA, DLS, EDX, and XRD. The presence of surface plasmon band around 500 nm indicates AgNPs formation and functional groups such as alkenes, carboxylic acids, and alkyl aryl ether responsible for capping and stabilization of the nanoparticles. The SaAgNPs were spherical and 1.00 µm in size; TGA shows the formation of stable SaAgNPs, DLS shows 1.8 % intensity with 1905 nm average diameter and a polydispersity index of 0.595. EDX analysis confirmed the formation of pure silver nanoparticles. SaAgNPs supported the production of cosmetically acceptable SaAgNPs-cream blend with appropriate pH and viscosity. SaAgNPs and the SaAgNPs cream-blends had antibacterial activity against all and some of the test bacterial and fungal isolates. SaAgNPs had the highest activity against Pseudomonas aeruginosa 27853, Rhizopus sp. and Candida tropicalis with a zone of 16 mm and 30 mm. The cream-blends had activity against 68.75 % and 75 % of the test bacteria and fungi with the highest activity against Streptococcus epidermidis B (7.0 mm) and Candida albicans B (8.0 mm). In conclusion, the crude Senna alata leaf extracts, the bio-fabrication SaAgNPs and SaAgNPs-cream blend have antibacterial antifungal potentials which can be effectively utilized for the control of pathogenic bacteria and fungi.
{"title":"In–Vitro Antibacterial and Antifungal Efficacy of Greenly Fabricated Senna alata Leaf Extract Silver Nanoparticles and Silver Nanoparticle-Cream Blend","authors":"B. Adebayo-Tayo, S. Borode, S. Alao","doi":"10.3311/ppch.18271","DOIUrl":"https://doi.org/10.3311/ppch.18271","url":null,"abstract":"Nanoparticles biosynthesis has been extensively studied for its biomedical applications. In this study, the in-vitro antibacterial and antifungal activity of greenly fabricated silver nanoparticles (NPs) from Senna alata leaf extract (SaAgNPs) and silver nanoparticle cream blend (SaAgNPs-cream blend) were investigated. The SaAgNPs were characterized using UV-visible spectrophotometry, FTIR, SEM, TGA, DLS, EDX, and XRD. The presence of surface plasmon band around 500 nm indicates AgNPs formation and functional groups such as alkenes, carboxylic acids, and alkyl aryl ether responsible for capping and stabilization of the nanoparticles. The SaAgNPs were spherical and 1.00 µm in size; TGA shows the formation of stable SaAgNPs, DLS shows 1.8 % intensity with 1905 nm average diameter and a polydispersity index of 0.595. EDX analysis confirmed the formation of pure silver nanoparticles. SaAgNPs supported the production of cosmetically acceptable SaAgNPs-cream blend with appropriate pH and viscosity. SaAgNPs and the SaAgNPs cream-blends had antibacterial activity against all and some of the test bacterial and fungal isolates. SaAgNPs had the highest activity against Pseudomonas aeruginosa 27853, Rhizopus sp. and Candida tropicalis with a zone of 16 mm and 30 mm. The cream-blends had activity against 68.75 % and 75 % of the test bacteria and fungi with the highest activity against Streptococcus epidermidis B (7.0 mm) and Candida albicans B (8.0 mm). In conclusion, the crude Senna alata leaf extracts, the bio-fabrication SaAgNPs and SaAgNPs-cream blend have antibacterial antifungal potentials which can be effectively utilized for the control of pathogenic bacteria and fungi.","PeriodicalId":19922,"journal":{"name":"Periodica Polytechnica Chemical Engineering","volume":"350 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82589282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pharmaceutical stability studies are conducted to estimate the shelf life, i.e. the period during which the drug product maintains its identity and stability. In the evaluation of process, regression curve is fitted on the data obtained during the study and the shelf life is determined using the fitted curve. The evaluation process suggested by ICH considers only the case of the true relationship between the measured attribute and time being linear. However, no method is suggested for the practitioner to decide if the linear model is appropriate for their dataset. This is a major problem, as a falsely selected model may distort the estimated shelf life to a great extent, resulting in unreliable quality control. The difficulty of model misspecification detection in stability studies is that very few observations are available. The conventional methods applied for model verification might not be appropriate or efficient due to the small sample size. In this paper, this problem is addressed and some developed methods are proposed to detect model misspecification. The methods can be applied for any process where the regression estimation is performed on independent small samples. Besides stability studies, frequently performed construction of single calibration curves for an analytical measurement is another case where the methods may be applied. It is shown that our methods are statistically appropriate and some of them have high efficiency in the detection of model misspecification when applied in simulated situations which resemble pre-approval and post-approval stability studies.
{"title":"Testing the Fit of Regression Models Estimated with Extremely Small Samples: Application in Pharmaceutical Stability Studies","authors":"Máté Mihalovits, S. Kemény","doi":"10.3311/ppch.18793","DOIUrl":"https://doi.org/10.3311/ppch.18793","url":null,"abstract":"Pharmaceutical stability studies are conducted to estimate the shelf life, i.e. the period during which the drug product maintains its identity and stability. In the evaluation of process, regression curve is fitted on the data obtained during the study and the shelf life is determined using the fitted curve. The evaluation process suggested by ICH considers only the case of the true relationship between the measured attribute and time being linear. However, no method is suggested for the practitioner to decide if the linear model is appropriate for their dataset. This is a major problem, as a falsely selected model may distort the estimated shelf life to a great extent, resulting in unreliable quality control. The difficulty of model misspecification detection in stability studies is that very few observations are available. The conventional methods applied for model verification might not be appropriate or efficient due to the small sample size. In this paper, this problem is addressed and some developed methods are proposed to detect model misspecification. The methods can be applied for any process where the regression estimation is performed on independent small samples. Besides stability studies, frequently performed construction of single calibration curves for an analytical measurement is another case where the methods may be applied. It is shown that our methods are statistically appropriate and some of them have high efficiency in the detection of model misspecification when applied in simulated situations which resemble pre-approval and post-approval stability studies.","PeriodicalId":19922,"journal":{"name":"Periodica Polytechnica Chemical Engineering","volume":"243 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76574982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
According to our best knowledge, this is the first report applying Artificial neural networks (ANN) for simulation of batch propionic acid (PA) fermentation. Therefore, the main focus of this research was to investigate the applicability of ANN on PA fermentations. To demonstrate this, we used the results of 40 Propionibacterium acidipropionici fermentations (ca 2,000 data points) to build up the ANN, and additional two independent fermentations to demonstrate the prediction capability of the observed ANN. Analyzing the predicted output parameters we observed, that ratio of propionic acid to acetic acid (PA/AA) variables can only be used for ANN after normalization. Finally, the fit of the ANN model to the measured data was fine (average correlation coefficients over 0.9). A special feature was also tested: fermentation time was also used as an input parameter, thus making the ANN suitable to predict time course of PA fermentations as well which was also satisfying.
{"title":"Applicability of Neural Networks for the Fermentation of Propionic Acid by Propionibacterium acidipropionici","authors":"Aladár Vidra, Á. Németh","doi":"10.3311/ppch.18283","DOIUrl":"https://doi.org/10.3311/ppch.18283","url":null,"abstract":"According to our best knowledge, this is the first report applying Artificial neural networks (ANN) for simulation of batch propionic acid (PA) fermentation. Therefore, the main focus of this research was to investigate the applicability of ANN on PA fermentations. To demonstrate this, we used the results of 40 Propionibacterium acidipropionici fermentations (ca 2,000 data points) to build up the ANN, and additional two independent fermentations to demonstrate the prediction capability of the observed ANN. Analyzing the predicted output parameters we observed, that ratio of propionic acid to acetic acid (PA/AA) variables can only be used for ANN after normalization. Finally, the fit of the ANN model to the measured data was fine (average correlation coefficients over 0.9). A special feature was also tested: fermentation time was also used as an input parameter, thus making the ANN suitable to predict time course of PA fermentations as well which was also satisfying.","PeriodicalId":19922,"journal":{"name":"Periodica Polytechnica Chemical Engineering","volume":"27 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84347920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Microbial fuel cells (MFCs) are capable of converting the chemical energy of biodegradable organic matter directly into electricity, thus they can be applied in various fields: waste elimination, biosensor industry and production of renewable energy. In this study, the efficiency of noble metal free carbon aerogel based cathode catalysts was investigated and compared to plain glassy carbon cloth without catalyst (CC ) and platinum containing carbon powder catalyst ( PtC ) in H-type MFCs. Surface extension by carbon aerogel (CA ) enhanced the maximum power density by 34 % compared to CC, to 14.1 W m−3. With nitrogen doped carbon aerogel (NCA) the performance was further increased to 15.7 W m−3. Co-doping the resorcinol-melamine-formaldehyde based aerogel with graphene oxide (GNCA) resulted in an additional power increase of 70 %, indicating that the electrocatalytic activity of NCAs can be considerably improved by co-doping with graphene oxide. Although the performance of GNCA remained below that of PtC (50.2 W m−3) in our investigations, it can be concluded that GNCA based coatings may provide a noble metal free, and therefore competitive and sustainable alternatives for cathode catalysis in MFC based technologies.
微生物燃料电池(MFCs)能够将可生物降解有机物的化学能直接转化为电能，因此可以应用于废物消除，生物传感器工业和可再生能源生产等各个领域。本研究考察了贵金属游离碳气凝胶阴极催化剂在h型mfc中的效率，并与无催化剂的普通玻碳布(CC)和含铂碳粉催化剂(PtC)进行了比较。与CC相比，碳气凝胶(CA)的表面延伸使最大功率密度提高了34%，达到14.1 W m−3。氮掺杂碳气凝胶(NCA)的性能进一步提高到15.7 W m−3。间苯二酚-三聚氰胺-甲醛基气凝胶与氧化石墨烯(GNCA)共掺杂导致功率增加70%，表明氧化石墨烯共掺杂可以显著提高NCAs的电催化活性。虽然在我们的研究中，GNCA的性能仍然低于PtC (50.2 W m−3)，但可以得出结论，GNCA基涂层可能为MFC阴极催化技术提供了一种无贵金属的、具有竞争力和可持续性的替代品。
{"title":"Improving the Performance of Microbial Fuel Cells with Modified Carbon Aerogel Based Cathode Catalysts","authors":"B. Lóránt, K. László, G. Tardy","doi":"10.3311/ppch.18854","DOIUrl":"https://doi.org/10.3311/ppch.18854","url":null,"abstract":"Microbial fuel cells (MFCs) are capable of converting the chemical energy of biodegradable organic matter directly into electricity, thus they can be applied in various fields: waste elimination, biosensor industry and production of renewable energy. In this study, the efficiency of noble metal free carbon aerogel based cathode catalysts was investigated and compared to plain glassy carbon cloth without catalyst (CC ) and platinum containing carbon powder catalyst ( PtC ) in H-type MFCs. Surface extension by carbon aerogel (CA ) enhanced the maximum power density by 34 % compared to CC, to 14.1 W m−3. With nitrogen doped carbon aerogel (NCA) the performance was further increased to 15.7 W m−3. Co-doping the resorcinol-melamine-formaldehyde based aerogel with graphene oxide (GNCA) resulted in an additional power increase of 70 %, indicating that the electrocatalytic activity of NCAs can be considerably improved by co-doping with graphene oxide. Although the performance of GNCA remained below that of PtC (50.2 W m−3) in our investigations, it can be concluded that GNCA based coatings may provide a noble metal free, and therefore competitive and sustainable alternatives for cathode catalysis in MFC based technologies.","PeriodicalId":19922,"journal":{"name":"Periodica Polytechnica Chemical Engineering","volume":"263 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79041115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Béri, Sara Nagy, Ádám Kolay Kovács, E. Vági, E. Székely
The first semi-continuous Pressurized Liquid Extraction (PLE) of hemp threshing residue with ethanol was carried out according to a 32 full factorial experimental design with pressure and temperature as independent variables at 8-10-12 MPa and 323-333-343 K, respectively. The total- and cannabidiol (CBD) yield curves were fitted to the modified two-parameter Brunner equation. Best results, concerning CBD, can be achieved at 12 MPa and 343 K. Solvent mass-consumption and operation time were considerably decreased compared to a previous supercritical fluid extraction study on the same material. Furthermore, the concentration profiles were evaluated to study the mass transfer. The winterized dry extracts were further studied in a methanol-hexane-water ternary system concerning CBD distribution ratio, showing high methanol dependency.
{"title":"Pressurized Liquid Extraction of Hemp Residue and Purification of the Extract with Liquid-Liquid Extraction","authors":"J. Béri, Sara Nagy, Ádám Kolay Kovács, E. Vági, E. Székely","doi":"10.3311/ppch.18456","DOIUrl":"https://doi.org/10.3311/ppch.18456","url":null,"abstract":"The first semi-continuous Pressurized Liquid Extraction (PLE) of hemp threshing residue with ethanol was carried out according to a 32 full factorial experimental design with pressure and temperature as independent variables at 8-10-12 MPa and 323-333-343 K, respectively. The total- and cannabidiol (CBD) yield curves were fitted to the modified two-parameter Brunner equation. Best results, concerning CBD, can be achieved at 12 MPa and 343 K. Solvent mass-consumption and operation time were considerably decreased compared to a previous supercritical fluid extraction study on the same material. Furthermore, the concentration profiles were evaluated to study the mass transfer. The winterized dry extracts were further studied in a methanol-hexane-water ternary system concerning CBD distribution ratio, showing high methanol dependency.","PeriodicalId":19922,"journal":{"name":"Periodica Polytechnica Chemical Engineering","volume":"31 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75621464","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sabariah Rozali, Nurul Hannan Mohd Safari, Abdul Rahman Hassan, M. Ahmad, R. Yunus
In this study, the effect of poly(vinyl pyrrolidone) (PVP) additive on the fabrication of asymmetric nanofiltration (NF) membranes was investigated in terms of performance, structural details and key properties. On addition of PVP ranging from 2 to 10 wt% into the dope solution, the fabricated NF membranes exhibited significantly different in properties and improved performance. In particular, the membranes made from 2 wt% PVP had the highest water flux and salt rejection of about 3.61 × 10–6 m3/m2s and 44.49 %, respectively. Modeling results revealed that small amount of PVP (2–4 wt%) produced finer structural properties. Moreover, the key properties (rp, ∆x/Ak and ζ) of the fabricated NF membranes were found to be within the range of that of commercial NF membranes.
{"title":"Assessment on Performance-properties of Asymmetric Nanofiltration Membranes from Polyethersulfone/n-Methyl-2-pyrrolidone/water Blends with Poly(vinyl pyrrolidone) as Additive","authors":"Sabariah Rozali, Nurul Hannan Mohd Safari, Abdul Rahman Hassan, M. Ahmad, R. Yunus","doi":"10.3311/ppch.18357","DOIUrl":"https://doi.org/10.3311/ppch.18357","url":null,"abstract":"In this study, the effect of poly(vinyl pyrrolidone) (PVP) additive on the fabrication of asymmetric nanofiltration (NF) membranes was investigated in terms of performance, structural details and key properties. On addition of PVP ranging from 2 to 10 wt% into the dope solution, the fabricated NF membranes exhibited significantly different in properties and improved performance. In particular, the membranes made from 2 wt% PVP had the highest water flux and salt rejection of about 3.61 × 10–6 m3/m2s and 44.49 %, respectively. Modeling results revealed that small amount of PVP (2–4 wt%) produced finer structural properties. Moreover, the key properties (rp, ∆x/Ak and ζ) of the fabricated NF membranes were found to be within the range of that of commercial NF membranes.","PeriodicalId":19922,"journal":{"name":"Periodica Polytechnica Chemical Engineering","volume":"59 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76664762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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