T. Usami, S. Salman, K. Kuroda, M. Gouda, A. Mahdy, M. Okido
Cobalt-nickel nanoparticles (Co-Ni-NPs) show promising electrochemical performance in oxygen and hydrogen evolution reactions (OER and HER) due to their physicochemical properties such as electronic configuration and great electrochemical stability. Therefore, developing new economically and environmentally friendly methods of synthesizing Co-Ni-NPs has become a practical requirement. Co-Ni-NPs were produced by employing the liquid-phase reduction method. Nickel and cobalt sulfate solutions in hydrazine monohydrate with various mixing ratios were used as raw materials. Nickel plays an important role in the nucleation process via increasing the reduction reaction rate throughout the formation of Co-Ni-NPs. Furthermore, the acceleration of the Co-Ni-NPs formation process may be attributed to the partial dissolution of Ni(OH)2 in the presence of N2H4 and/or citrate-anions and the formation of the Ni-N2H4 or Ni-Cit complexes in contrast to Co(OH)2.
{"title":"Synthesis of Cobalt-Nickel Nanoparticles via a Liquid-Phase Reduction Process","authors":"T. Usami, S. Salman, K. Kuroda, M. Gouda, A. Mahdy, M. Okido","doi":"10.1155/2021/9401024","DOIUrl":"https://doi.org/10.1155/2021/9401024","url":null,"abstract":"Cobalt-nickel nanoparticles (Co-Ni-NPs) show promising electrochemical performance in oxygen and hydrogen evolution reactions (OER and HER) due to their physicochemical properties such as electronic configuration and great electrochemical stability. Therefore, developing new economically and environmentally friendly methods of synthesizing Co-Ni-NPs has become a practical requirement. Co-Ni-NPs were produced by employing the liquid-phase reduction method. Nickel and cobalt sulfate solutions in hydrazine monohydrate with various mixing ratios were used as raw materials. Nickel plays an important role in the nucleation process via increasing the reduction reaction rate throughout the formation of Co-Ni-NPs. Furthermore, the acceleration of the Co-Ni-NPs formation process may be attributed to the partial dissolution of Ni(OH)2 in the presence of N2H4 and/or citrate-anions and the formation of the Ni-N2H4 or Ni-Cit complexes in contrast to Co(OH)2.","PeriodicalId":16378,"journal":{"name":"Journal of Nanotechnology","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2021-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88602748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Greissy Stefhany Encinas Estrada, Augusto Castillo Calderón
Lipases due to their ecological nature and catalytic versatility, are ideal for their application in the fish oil hydrolysis industry due to their selective property, which allows the preservation of polyunsaturated fatty acids (PUFAs) in the lipid structure. The objective of this research was to determine the activity and kinetic parameters of a commercial AY AMANO "30SD" lipase, as well as the temperature and time values to achieve an optimal degree of hydrolysis in semi-refined anchovy oil. The experiments were carried out in a jacketed minireactor with a working volume of 400 mL (oil-water-enzyme) with temperature control and pH 7.00, enzyme concentration 350 U/mL and stirring 160 rpm. A 3x3 factorial design and the response surface methodology were used. The results obtained from the study of the enzyme were: activity = 37 384.55 ± 395.07 U/g and kinetic parameters: Km = 7.98 g/L and Vmax. = 0.038887 g/Lxmin. Correspondingly, the following optimal parameters were obtained: Degree of hydrolysis 4.01%, temperature 46.86 °C and hydrolysis time 90 minutes, with a confidence level of 95% (p <0.05). Conclusions: The study allowed us to kinetically characterize the commercial lipase and determine the optimum degree of hydrolysis of the semi-refined anchovy oil.
{"title":"Kinetic study of a commercial lipase for hydrolysis of semi-refined oil of anchovy (Engraulis ringens) [Estudio cinético de una lipasa comercial para la hidrólisis de aceite semirrefinado de anchoa (Engraulis ringens)]","authors":"Greissy Stefhany Encinas Estrada, Augusto Castillo Calderón","doi":"10.32829/nanoj.v5i1.146","DOIUrl":"https://doi.org/10.32829/nanoj.v5i1.146","url":null,"abstract":"Lipases due to their ecological nature and catalytic versatility, are ideal for their application in the fish oil hydrolysis industry due to their selective property, which allows the preservation of polyunsaturated fatty acids (PUFAs) in the lipid structure. The objective of this research was to determine the activity and kinetic parameters of a commercial AY AMANO \"30SD\" lipase, as well as the temperature and time values to achieve an optimal degree of hydrolysis in semi-refined anchovy oil. The experiments were carried out in a jacketed minireactor with a working volume of 400 mL (oil-water-enzyme) with temperature control and pH 7.00, enzyme concentration 350 U/mL and stirring 160 rpm. A 3x3 factorial design and the response surface methodology were used. The results obtained from the study of the enzyme were: activity = 37 384.55 ± 395.07 U/g and kinetic parameters: Km = 7.98 g/L and Vmax. = 0.038887 g/Lxmin. Correspondingly, the following optimal parameters were obtained: Degree of hydrolysis 4.01%, temperature 46.86 °C and hydrolysis time 90 minutes, with a confidence level of 95% (p <0.05). Conclusions: The study allowed us to kinetically characterize the commercial lipase and determine the optimum degree of hydrolysis of the semi-refined anchovy oil.","PeriodicalId":16378,"journal":{"name":"Journal of Nanotechnology","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2021-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89937147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rumesh Samarawickrama, U.G.S. Wijayapala, N.D. Wanasekara, C. Fernando
Natural dyes can make less environmental problems associated with manufactured colouring agents and textile dyeing. But, the natural dyes fixing process was used chemicals called mordant. The most of times mordants were used metallic salts and metal salts mordants were not environmentally friendly. Therefore, remove the disadvantage associated with natural colorants and the use of nanoparticles. In this research, cotton fabric was treated with the nanoparticle of cellulose nanocrystals (CNCs) as mordant. The cellulose nanocrystals extraction process was done by using Whatman filter paper. The cellulose nanocrystals obtained will be further analyzed and characterized by using selected tools such as Particle size analysis and Fourier-transform infrared (FTIR) spectroscopy. The cotton fabrics mordanting processes were done by two types of pre-mordanting and post-mordanting methods. The three natural ingredients of Mangifera indica (Mango) leaves, Tectona grandis (Teak) leaves and Lannea coromandelica (Indian ash tree) leaves were used to extract the natural dyes using with aqueous extraction method. The extracts from dyeing processes were carried out after and before mordanting processes. The dyed sample from colour fastness to light, washing, and crocking were assessed according to standard methods. The cellulose nanocrystals gave very good colour fastness to light, wash, and rubbing when dyed with all three dye extractions. In the present study, innovative mordant of cellulose nanocrystals and natural dyeing with three natural dye extractions have been shown to give good dyeing results with cotton fabric.
{"title":"Improving Dyeing Properties of Cotton Fabrics to Natural Dyes with Cellulose Nanocrystals (CNCs) [Mejora de las propiedades de teñido de telas de algodón a tintes naturales con nanocristales de celulosa (CNC)]","authors":"Rumesh Samarawickrama, U.G.S. Wijayapala, N.D. Wanasekara, C. Fernando","doi":"10.32829/nanoj.v5i1.141","DOIUrl":"https://doi.org/10.32829/nanoj.v5i1.141","url":null,"abstract":"Natural dyes can make less environmental problems associated with manufactured colouring agents and textile dyeing. But, the natural dyes fixing process was used chemicals called mordant. The most of times mordants were used metallic salts and metal salts mordants were not environmentally friendly. Therefore, remove the disadvantage associated with natural colorants and the use of nanoparticles. In this research, cotton fabric was treated with the nanoparticle of cellulose nanocrystals (CNCs) as mordant. The cellulose nanocrystals extraction process was done by using Whatman filter paper. The cellulose nanocrystals obtained will be further analyzed and characterized by using selected tools such as Particle size analysis and Fourier-transform infrared (FTIR) spectroscopy. The cotton fabrics mordanting processes were done by two types of pre-mordanting and post-mordanting methods. The three natural ingredients of Mangifera indica (Mango) leaves, Tectona grandis (Teak) leaves and Lannea coromandelica (Indian ash tree) leaves were used to extract the natural dyes using with aqueous extraction method. The extracts from dyeing processes were carried out after and before mordanting processes. The dyed sample from colour fastness to light, washing, and crocking were assessed according to standard methods. The cellulose nanocrystals gave very good colour fastness to light, wash, and rubbing when dyed with all three dye extractions. In the present study, innovative mordant of cellulose nanocrystals and natural dyeing with three natural dye extractions have been shown to give good dyeing results with cotton fabric.","PeriodicalId":16378,"journal":{"name":"Journal of Nanotechnology","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2021-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91219361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bernard Otieno Sadia, J. Cherutoi, Cleophas Mecha Achisa
The economic burden and high mortality associated with multidrug-resistant bacteria is a major public health concern. Biosynthesized copper nanoparticles (CuNPs) could be a potential alternative to combat bacterial resistance to conventional medicine. This study for the first time aimed at optimizing the synthesis conditions (concentration of copper ions, temperature, and pH) to obtain the smallest size of CuNPs, characterizing and testing the antibacterial efficacy of CuNPs prepared from Senna didymobotrya (S. didymobotrya) roots. Extraction was done by the Soxhlet method using methanol as the solvent. Gas chromatography-mass spectrometry (GC-MS) analysis was performed to identify compounds in S. didymobotrya root extracts. Box–Behnken design was used to obtain optimal synthesis conditions as determined using a particle analyzer. Characterization was done using ultraviolet-visible (UV-Vis), particle size analyzer, X-ray diffraction, zeta potentiometer, and Fourier transform infrared (FT-IR). Bioassay was conducted using the Kirby–Bauer disk diffusion susceptibility test. The major compounds identified by GC-MS in reference to the NIST library were benzoic acid, thymol, N-benzyl-2-phenethylamine, benzaldehyde, vanillin, phenylacetic acid, and benzothiazole. UV-Vis spectrum showed a characteristic peak at 570 nm indicating the formation of CuNPs. The optimum synthesis conditions were temperature of 80°C, pH 3.0, and copper ion concentration of 0.0125 M. The FT-IR spectrum showed absorptions in the range 3500–3400 cm−1 (N-H stretch), 3400–2400 cm−1 (O-H stretch), and 988–830 cm−1 (C-H bend) and peak at 1612 cm−1 (C=C stretch), and 1271 cm−1 (C-O bend). Cu nanoparticle sizes were 5.55–63.60 nm. The zeta potential value was −69.4 mV indicating that they were stable. The biosynthesized nanoparticles exhibited significant antimicrobial activity on Escherichia coli and Staphylococcus aureus with the zone of inhibition diameters of 26.00 ± 0.58 mm and 30.00 ± 0.58 mm compared to amoxicillin clavulanate (standard) with inhibition diameters of 20 ± 0.58 mm and 28.00 ± 0.58 mm, respectively.
{"title":"Optimization, Characterization, and Antibacterial Activity of Copper Nanoparticles Synthesized Using Senna didymobotrya Root Extract","authors":"Bernard Otieno Sadia, J. Cherutoi, Cleophas Mecha Achisa","doi":"10.1155/2021/5611434","DOIUrl":"https://doi.org/10.1155/2021/5611434","url":null,"abstract":"The economic burden and high mortality associated with multidrug-resistant bacteria is a major public health concern. Biosynthesized copper nanoparticles (CuNPs) could be a potential alternative to combat bacterial resistance to conventional medicine. This study for the first time aimed at optimizing the synthesis conditions (concentration of copper ions, temperature, and pH) to obtain the smallest size of CuNPs, characterizing and testing the antibacterial efficacy of CuNPs prepared from Senna didymobotrya (S. didymobotrya) roots. Extraction was done by the Soxhlet method using methanol as the solvent. Gas chromatography-mass spectrometry (GC-MS) analysis was performed to identify compounds in S. didymobotrya root extracts. Box–Behnken design was used to obtain optimal synthesis conditions as determined using a particle analyzer. Characterization was done using ultraviolet-visible (UV-Vis), particle size analyzer, X-ray diffraction, zeta potentiometer, and Fourier transform infrared (FT-IR). Bioassay was conducted using the Kirby–Bauer disk diffusion susceptibility test. The major compounds identified by GC-MS in reference to the NIST library were benzoic acid, thymol, N-benzyl-2-phenethylamine, benzaldehyde, vanillin, phenylacetic acid, and benzothiazole. UV-Vis spectrum showed a characteristic peak at 570 nm indicating the formation of CuNPs. The optimum synthesis conditions were temperature of 80°C, pH 3.0, and copper ion concentration of 0.0125 M. The FT-IR spectrum showed absorptions in the range 3500–3400 cm−1 (N-H stretch), 3400–2400 cm−1 (O-H stretch), and 988–830 cm−1 (C-H bend) and peak at 1612 cm−1 (C=C stretch), and 1271 cm−1 (C-O bend). Cu nanoparticle sizes were 5.55–63.60 nm. The zeta potential value was −69.4 mV indicating that they were stable. The biosynthesized nanoparticles exhibited significant antimicrobial activity on Escherichia coli and Staphylococcus aureus with the zone of inhibition diameters of 26.00 ± 0.58 mm and 30.00 ± 0.58 mm compared to amoxicillin clavulanate (standard) with inhibition diameters of 20 ± 0.58 mm and 28.00 ± 0.58 mm, respectively.","PeriodicalId":16378,"journal":{"name":"Journal of Nanotechnology","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2021-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72645930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Toga Khalid Mohamed, Marivt Osman Widdatallah, Maida Musa Ali, Afraa Mubarak Alhaj, DhiaEldin AbdElmagied Elhag
An extremely worrying and alarming increase in the level of multiple drug resistance is reported in Sudan, in which bacterial strains are becoming resistant to many commonly available antibiotics. Eventually, it is becoming extremely difficult to treat debilitating infections. In search of promising solutions to this arising crisis, Camellia sinensis silver nanoparticles were synthesized using the green synthesis method. The synthesis of the Camellia sinensis silver nanoparticles is confirmed using analytical methods as ultraviolet-visible spectroscopy, X-ray diffractometer, and scanning electron microscopy. Using the ultraviolet-visible spectroscopy, an absorption band of 412 nm was observed. Furthermore, scanning electron microscopy revealed the presence of silver nanoparticles which fell within the range of 1–100 nm, and X-ray diffractometer analysis showed three intense peaks with a maximum intense peak at 24.3 theta. Nanoparticles distribution between 12 nm and 64 nm was observed with an average diameter of 18.115 nm. It also revealed orthorhombic-shaped nanoparticles. The synthesized nanoparticles showed antimicrobial activity against Staphylococcus aureus with a zone of inhibition of 7 mm, but none was detected against Escherichia coli. The obtained physicochemical properties were correlated with the antibacterial activity of the silver nanoparticles.
{"title":"Green Synthesis, Characterization, and Evaluation of the Antimicrobial Activity of Camellia sinensis Silver Nanoparticles","authors":"Toga Khalid Mohamed, Marivt Osman Widdatallah, Maida Musa Ali, Afraa Mubarak Alhaj, DhiaEldin AbdElmagied Elhag","doi":"10.1155/2021/2867404","DOIUrl":"https://doi.org/10.1155/2021/2867404","url":null,"abstract":"An extremely worrying and alarming increase in the level of multiple drug resistance is reported in Sudan, in which bacterial strains are becoming resistant to many commonly available antibiotics. Eventually, it is becoming extremely difficult to treat debilitating infections. In search of promising solutions to this arising crisis, Camellia sinensis silver nanoparticles were synthesized using the green synthesis method. The synthesis of the Camellia sinensis silver nanoparticles is confirmed using analytical methods as ultraviolet-visible spectroscopy, X-ray diffractometer, and scanning electron microscopy. Using the ultraviolet-visible spectroscopy, an absorption band of 412 nm was observed. Furthermore, scanning electron microscopy revealed the presence of silver nanoparticles which fell within the range of 1–100 nm, and X-ray diffractometer analysis showed three intense peaks with a maximum intense peak at 24.3 theta. Nanoparticles distribution between 12 nm and 64 nm was observed with an average diameter of 18.115 nm. It also revealed orthorhombic-shaped nanoparticles. The synthesized nanoparticles showed antimicrobial activity against Staphylococcus aureus with a zone of inhibition of 7 mm, but none was detected against Escherichia coli. The obtained physicochemical properties were correlated with the antibacterial activity of the silver nanoparticles.","PeriodicalId":16378,"journal":{"name":"Journal of Nanotechnology","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2021-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87570693","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ZnO/Si heterojunctions have been fabricated by spinning ZnO nanoflakes on the p-type single crystal silicon by using the spin coating technique. Photoluminescence spectra of as-grown and annealed ZnO/Si heterojunctions have been recorded under the excitation of 336 nm. Multipeaks between ∼360 nm and ∼430 nm from annealed ZnO/Si heterojunctions have been analyzed, the origins of which have been ascribed to the effects of one or multiple LO phonons. The rectifying effects can be observed from the prototypical devices based on ZnO/Si heterojunctions. Although the parameters obtained by analyzing the current density-voltage characteristics are away from those from the ideal device, it is believed that ZnO/Si heterojunctions in the present work will be a potential candidate in the optoelectronic field through modulating and optimizing the fabrication conditions.
{"title":"Multipeak Emissions and Electrical Properties of ZnO/Si Heterojunctions Based on ZnO Nanoflakes by Spin Coating Technique","authors":"Yalan Ma, P. Ji, Yong Li, Yueli Song","doi":"10.1155/2021/9267962","DOIUrl":"https://doi.org/10.1155/2021/9267962","url":null,"abstract":"ZnO/Si heterojunctions have been fabricated by spinning ZnO nanoflakes on the p-type single crystal silicon by using the spin coating technique. Photoluminescence spectra of as-grown and annealed ZnO/Si heterojunctions have been recorded under the excitation of 336 nm. Multipeaks between ∼360 nm and ∼430 nm from annealed ZnO/Si heterojunctions have been analyzed, the origins of which have been ascribed to the effects of one or multiple LO phonons. The rectifying effects can be observed from the prototypical devices based on ZnO/Si heterojunctions. Although the parameters obtained by analyzing the current density-voltage characteristics are away from those from the ideal device, it is believed that ZnO/Si heterojunctions in the present work will be a potential candidate in the optoelectronic field through modulating and optimizing the fabrication conditions.","PeriodicalId":16378,"journal":{"name":"Journal of Nanotechnology","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2021-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84124659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Pisitsak, Kwandee Chamchoy, Varanrada Chinprateep, Wiphawan Khobthong, Pisutsaran Chitichotpanya, S. Ummartyotin
Gold nanoparticles (AuNPs) were synthesized under ambient conditions from chloroauric acid in aqueous solution at pH 4. Tannin-rich extract from Xylocarpus granatum bark was used as both reducing and capping agent, rapidly converting Au (I) salt to AuNPs. Transmission electron microscopy showed the as-prepared AuNPs to be predominantly spherical, with an average diameter of 17 nm. The AuNPs were tested for catalytic reduction of Congo red (CR), a carcinogenic azo dye, in aqueous sodium borohydride solution. Cotton samples were coated with the AuNPs, taking on a reddish-purple color. The samples showed significantly reduced tearing strength after coating, though tensile strength was unaffected. UV-visible spectroscopy was used to determine the dye concentration in the water. CR degradation was observed only when AuNPs were present, and the efficiency of degradation was strongly linked to the AuNP loading. The AuNP-coated fabrics left only a 4.7% CR concentration in the solution after 24 h and therefore promise as a heterogeneous catalyst for degradation of CR in aqueous solution.
{"title":"Synthesis of Gold Nanoparticles Using Tannin-Rich Extract and Coating onto Cotton Textiles for Catalytic Degradation of Congo Red","authors":"P. Pisitsak, Kwandee Chamchoy, Varanrada Chinprateep, Wiphawan Khobthong, Pisutsaran Chitichotpanya, S. Ummartyotin","doi":"10.1155/2021/6380283","DOIUrl":"https://doi.org/10.1155/2021/6380283","url":null,"abstract":"Gold nanoparticles (AuNPs) were synthesized under ambient conditions from chloroauric acid in aqueous solution at pH 4. Tannin-rich extract from Xylocarpus granatum bark was used as both reducing and capping agent, rapidly converting Au (I) salt to AuNPs. Transmission electron microscopy showed the as-prepared AuNPs to be predominantly spherical, with an average diameter of 17 nm. The AuNPs were tested for catalytic reduction of Congo red (CR), a carcinogenic azo dye, in aqueous sodium borohydride solution. Cotton samples were coated with the AuNPs, taking on a reddish-purple color. The samples showed significantly reduced tearing strength after coating, though tensile strength was unaffected. UV-visible spectroscopy was used to determine the dye concentration in the water. CR degradation was observed only when AuNPs were present, and the efficiency of degradation was strongly linked to the AuNP loading. The AuNP-coated fabrics left only a 4.7% CR concentration in the solution after 24 h and therefore promise as a heterogeneous catalyst for degradation of CR in aqueous solution.","PeriodicalId":16378,"journal":{"name":"Journal of Nanotechnology","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2021-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86781476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Chotirat, S. Niyomwas, Witthawat Wongpisan, S. Supothina
The vanadium dioxide (VO2) thin films were synthesized by sol-gel dipping on a glass slide substrate at low temperature of 500°C in a vacuum tube furnace at a pressure of 2 × 10−3 mbar by 2-step calcination without an intermediate gas purging. Synthesis conditions, including temperature, vacuum pressure, and calcination steps in the vacuum tube furnace, were investigated to find the optimum condition that promoted the formation of VO2 phase. It was found that the 2nd calcination step was very important in realizing the monoclinic vanadium dioxide (VO2 (M)). The results of the valence electron analysis revealed the outstanding phase of VO2 and a small amount of V2O5 and V2O3 phases. The small crystallites of the VO2 were homogeneously distributed on the surface, and the grain was of an irregular shape of ∼220−380 nm in size. The film’s thickness was in a range of 69−74 nm. The film exhibited a metal-to-insulator transformation temperature of ∼68oC and good thermochromic property. Visible optical transmittance remained at ∼40−50% when the sample’s temperature changed from 25 to 80°C for a near infrared (NIR) region.
{"title":"Low-Temperature Synthesis of Vanadium Dioxide Thin Films by Sol-Gel Dip Coating Method","authors":"L. Chotirat, S. Niyomwas, Witthawat Wongpisan, S. Supothina","doi":"10.1155/2021/4868152","DOIUrl":"https://doi.org/10.1155/2021/4868152","url":null,"abstract":"The vanadium dioxide (VO2) thin films were synthesized by sol-gel dipping on a glass slide substrate at low temperature of 500°C in a vacuum tube furnace at a pressure of 2 × 10−3 mbar by 2-step calcination without an intermediate gas purging. Synthesis conditions, including temperature, vacuum pressure, and calcination steps in the vacuum tube furnace, were investigated to find the optimum condition that promoted the formation of VO2 phase. It was found that the 2nd calcination step was very important in realizing the monoclinic vanadium dioxide (VO2 (M)). The results of the valence electron analysis revealed the outstanding phase of VO2 and a small amount of V2O5 and V2O3 phases. The small crystallites of the VO2 were homogeneously distributed on the surface, and the grain was of an irregular shape of ∼220−380 nm in size. The film’s thickness was in a range of 69−74 nm. The film exhibited a metal-to-insulator transformation temperature of ∼68oC and good thermochromic property. Visible optical transmittance remained at ∼40−50% when the sample’s temperature changed from 25 to 80°C for a near infrared (NIR) region.","PeriodicalId":16378,"journal":{"name":"Journal of Nanotechnology","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2021-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83660427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The present study describes the antioxidant, antimicrobial, and photocatalytic activity of silver nanoparticles (AGNPs) synthesized using six varieties of Catharanthus roseus flower extracts for the first time. Initially, the synthesized AgNPs were visually confirmed by color change. Further, the formation, size, and shape of the synthesized AgNPs were characterized by UV-Vis spectroscopy and scanning electron microscopy (SEM). The SEM image of purple flower AgNPs and the calculated bandgap energies of the synthesized AgNPs showed that the synthesized AgNPs were in the range of 0–30 nm. Qualitative phytochemical analysis revealed the presence of the phytocompounds that were responsible for the capping, formation, bioreduction, and stabilization of AgNPs. The antioxidant ability of the AgNPs and their respective flower extracts were analyzed using TFC, TPC, TAC, DPPH, FRAP, and IC50 assays. The results of the antioxidant assays indicated that the AgNPs showed higher antioxidant activity compared to their respective flower extracts. The synthesized AgNPs showed significant antimicrobial activity against Gram-negative Escherichia coli compared to Gram-positive Staphylococcus aureus assayed using the agar well diffusion method. Furthermore, the photocatalytic activity of the synthesized purple flower AgNPs at two different concentrations 5000 ppm and 333 ppm was analyzed by the removal of methyl orange dye from an aqueous solution under sunlight irradiation in the presence of NaBH4 catalyst. Results indicated that 333 ppm purple flower AgNPs exhibited an efficient photocatalytic activity in the degradation of methyl orange compared to 5000 ppm purple flower AgNPs in 20 minutes. Thus, the results obtained indicated that Catharanthus roseus is an ecofriendly source for the green synthesis of AgNPs which can be used as a novel antioxidant, antimicrobial, and photocatalytic agent; thereby, it can be used in a variety of applications to improve the quality of human life.
{"title":"Green Synthesis of Silver Nanoparticles Using Catharanthus roseus Flower Extracts and the Determination of Their Antioxidant, Antimicrobial, and Photocatalytic Activity","authors":"M. Kandiah, Kavishadhi N. Chandrasekaran","doi":"10.1155/2021/5512786","DOIUrl":"https://doi.org/10.1155/2021/5512786","url":null,"abstract":"The present study describes the antioxidant, antimicrobial, and photocatalytic activity of silver nanoparticles (AGNPs) synthesized using six varieties of Catharanthus roseus flower extracts for the first time. Initially, the synthesized AgNPs were visually confirmed by color change. Further, the formation, size, and shape of the synthesized AgNPs were characterized by UV-Vis spectroscopy and scanning electron microscopy (SEM). The SEM image of purple flower AgNPs and the calculated bandgap energies of the synthesized AgNPs showed that the synthesized AgNPs were in the range of 0–30 nm. Qualitative phytochemical analysis revealed the presence of the phytocompounds that were responsible for the capping, formation, bioreduction, and stabilization of AgNPs. The antioxidant ability of the AgNPs and their respective flower extracts were analyzed using TFC, TPC, TAC, DPPH, FRAP, and IC50 assays. The results of the antioxidant assays indicated that the AgNPs showed higher antioxidant activity compared to their respective flower extracts. The synthesized AgNPs showed significant antimicrobial activity against Gram-negative Escherichia coli compared to Gram-positive Staphylococcus aureus assayed using the agar well diffusion method. Furthermore, the photocatalytic activity of the synthesized purple flower AgNPs at two different concentrations 5000 ppm and 333 ppm was analyzed by the removal of methyl orange dye from an aqueous solution under sunlight irradiation in the presence of NaBH4 catalyst. Results indicated that 333 ppm purple flower AgNPs exhibited an efficient photocatalytic activity in the degradation of methyl orange compared to 5000 ppm purple flower AgNPs in 20 minutes. Thus, the results obtained indicated that Catharanthus roseus is an ecofriendly source for the green synthesis of AgNPs which can be used as a novel antioxidant, antimicrobial, and photocatalytic agent; thereby, it can be used in a variety of applications to improve the quality of human life.","PeriodicalId":16378,"journal":{"name":"Journal of Nanotechnology","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2021-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83621502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. N. X. Que, T. T. Khôi, N. Thuy, T. T. Dung, Dao Thi Thanh Binh, N. Huy
The treatment of wastewater from the textile industry containing organic dyes faces many challenges since these compounds resist the biodegradation process in conventional treatment units. Among the physicochemical processes, photocatalysis is considered a facile, cheap, and environmental-friendly technology for treating persistent organic pollutants in waters at low concentrations. This study investigated several physicochemical factors determining the photocatalytic activity of titanate nanotubes (TNTs) to remove Procion MX 032 (PMX), an azo dye, in waters. Degradation of PMX by photocatalytic oxidation process at room temperature (30°C) was set up with the UV irradiation in the presence of different types of photocatalyst such as ST-01 (100% anatase), industrial TiO2, TNTs calcined at 120°C and 500°C. Effect of reaction time, catalyst amount, pH, light wavelength and intensity, and oxidants was investigated. Consequently, TNTs calcined at 500°C provided the highest removal efficiency. The photocatalytic oxidation of PMX by TNT calcined at 500°C was affected by pH variation, getting the highest removal at pH of 8, and inhibited with the presence of H2O2 and O2. Particularly, the PMX degradation using titanate nanotubes was optimized under the UV-A intensity of 100 W/m2. The dye was degraded by more than 95% at the TNTs concentration of 75 mg/L and pH 8.0 after 90 min. The results suggest that photocatalysis using TNTs can be a simple but efficient treatment method to remove PMX and potentially be applied for the treatment of wastewaters containing dyes.
{"title":"Factors Determining the Removal Efficiency of Procion MX in Waters Using Titanate Nanotubes Catalyzed by UV Irradiation","authors":"V. N. X. Que, T. T. Khôi, N. Thuy, T. T. Dung, Dao Thi Thanh Binh, N. Huy","doi":"10.1155/2021/8870453","DOIUrl":"https://doi.org/10.1155/2021/8870453","url":null,"abstract":"The treatment of wastewater from the textile industry containing organic dyes faces many challenges since these compounds resist the biodegradation process in conventional treatment units. Among the physicochemical processes, photocatalysis is considered a facile, cheap, and environmental-friendly technology for treating persistent organic pollutants in waters at low concentrations. This study investigated several physicochemical factors determining the photocatalytic activity of titanate nanotubes (TNTs) to remove Procion MX 032 (PMX), an azo dye, in waters. Degradation of PMX by photocatalytic oxidation process at room temperature (30°C) was set up with the UV irradiation in the presence of different types of photocatalyst such as ST-01 (100% anatase), industrial TiO2, TNTs calcined at 120°C and 500°C. Effect of reaction time, catalyst amount, pH, light wavelength and intensity, and oxidants was investigated. Consequently, TNTs calcined at 500°C provided the highest removal efficiency. The photocatalytic oxidation of PMX by TNT calcined at 500°C was affected by pH variation, getting the highest removal at pH of 8, and inhibited with the presence of H2O2 and O2. Particularly, the PMX degradation using titanate nanotubes was optimized under the UV-A intensity of 100 W/m2. The dye was degraded by more than 95% at the TNTs concentration of 75 mg/L and pH 8.0 after 90 min. The results suggest that photocatalysis using TNTs can be a simple but efficient treatment method to remove PMX and potentially be applied for the treatment of wastewaters containing dyes.","PeriodicalId":16378,"journal":{"name":"Journal of Nanotechnology","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2021-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75983962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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