Pub Date : 2017-01-01DOI: 10.1080/23312009.2017.1294470
O. Oluwasina, A. S. Olagboye, Ademola Boboye, F. Hassan
Abstract Enrichment of carboxymethyl chitosan with zinc provides alternative means of producing aqueous soluble chitosan-based material with antimicrobial and essential trace element properties. The change in FTIR spectra of bands at 3,266 and 3,106 cm−1 of the carboxymethyl chitosan from a strong to a weak band confirmed the formation of carboxymethyl chitosan zinc supplement. From the EDX result, elemental composition of carboxymethyl chitosan is 52.89% carbon, 39.34% oxygen, 0.38% sodium, 0.54% aluminum, 2.61% calcium, and 4.19% aluminum, while carboxymethyl chitosan zinc supplement recorded 49.55% carbon, 40.40% oxygen, 1.28% sodium, 2.37% nitrogen, and 6.40% zinc. The XRD spectrum of carboxymethyl chitosan showed a lower peak intensity as compared with that of its zinc supplement. The antibacterial activities showed that carboxymethyl chitosan zinc supplement was active against all tested bacterial having recorded 6.00, 5.00, 3.00, 7.00, and 6.00 zone of inhibition (mm), respectively, against Staphylococcus aureus, Bacillus cereus, Pseudomonas syringae, Pseudomonas aeruginosa, and Escherichia coli, while carboxymetyhl chitosan was active only against S. aureus (6.00 mm). Antifungal activities revealed that carboxymethyl chitosan zinc supplement had higher zone of inhibition (mm) 42.22, 40.00, 37.78, and 48.88 mm against Collectotrichum falcritum, Rhzoctonia solani, Colletotrihum lindematianum, and Trichhoderum rubrum, while carboxymethyl chitosan recorded 26.66, 18.88, 15.88, and 22.22 respectively. The combination of aqueous solubility and antimicrobial activities of the zinc-supplemented carboxymethyl chitosan prepared should make it a good replacement for carboxymethyl chitosan in various industrial applications like food, cosmetics, biomedical, and pharmaceutical.
{"title":"Carboxymethyl chitosan zinc supplement: Preparation, physicochemical, and preliminary antimicrobial analysis","authors":"O. Oluwasina, A. S. Olagboye, Ademola Boboye, F. Hassan","doi":"10.1080/23312009.2017.1294470","DOIUrl":"https://doi.org/10.1080/23312009.2017.1294470","url":null,"abstract":"Abstract Enrichment of carboxymethyl chitosan with zinc provides alternative means of producing aqueous soluble chitosan-based material with antimicrobial and essential trace element properties. The change in FTIR spectra of bands at 3,266 and 3,106 cm−1 of the carboxymethyl chitosan from a strong to a weak band confirmed the formation of carboxymethyl chitosan zinc supplement. From the EDX result, elemental composition of carboxymethyl chitosan is 52.89% carbon, 39.34% oxygen, 0.38% sodium, 0.54% aluminum, 2.61% calcium, and 4.19% aluminum, while carboxymethyl chitosan zinc supplement recorded 49.55% carbon, 40.40% oxygen, 1.28% sodium, 2.37% nitrogen, and 6.40% zinc. The XRD spectrum of carboxymethyl chitosan showed a lower peak intensity as compared with that of its zinc supplement. The antibacterial activities showed that carboxymethyl chitosan zinc supplement was active against all tested bacterial having recorded 6.00, 5.00, 3.00, 7.00, and 6.00 zone of inhibition (mm), respectively, against Staphylococcus aureus, Bacillus cereus, Pseudomonas syringae, Pseudomonas aeruginosa, and Escherichia coli, while carboxymetyhl chitosan was active only against S. aureus (6.00 mm). Antifungal activities revealed that carboxymethyl chitosan zinc supplement had higher zone of inhibition (mm) 42.22, 40.00, 37.78, and 48.88 mm against Collectotrichum falcritum, Rhzoctonia solani, Colletotrihum lindematianum, and Trichhoderum rubrum, while carboxymethyl chitosan recorded 26.66, 18.88, 15.88, and 22.22 respectively. The combination of aqueous solubility and antimicrobial activities of the zinc-supplemented carboxymethyl chitosan prepared should make it a good replacement for carboxymethyl chitosan in various industrial applications like food, cosmetics, biomedical, and pharmaceutical.","PeriodicalId":10640,"journal":{"name":"Cogent Chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23312009.2017.1294470","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43190674","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}
Pub Date : 2017-01-01DOI: 10.1080/23312009.2017.1354800
Tibebu Alemu, Eyobel Mulugeta, Miresa Tadese
Abstract In this study, the mean levels of anion and metals in “Hora” natural mineral water and soil were determined. Accordingly, the levels of N–NH3, Cl−, N–NO3−, SO42−, Mg, and Ca in water were not exceeding the World Health Organization (WHO) drinking water guideline values for humans and the levels of N–NO3−, SO42−, and Ca were also far below the Canadian Ministers of Health (CMH) guideline values for livestock. The levels of Al, Mn, Zn, Cu, Ni, Pb, and Mo were above the WHO guideline values, while majority of the trace metals were not exceeding the maximum permissible value for livestock except for Ni and Co. Among the trace metals found in the soil, Mn and Pb were found to be higher compared to the recommended value (40 mg/kg) by the Ethiopian guideline. The drinking water quality index (DWQI) was calculated to be 67.6 based on 21 important quality parameters.
{"title":"Determination of physicochemical parameters of “Hora” natural mineral water and soil in Senkele Kebele, Oromia Region, Ethiopia","authors":"Tibebu Alemu, Eyobel Mulugeta, Miresa Tadese","doi":"10.1080/23312009.2017.1354800","DOIUrl":"https://doi.org/10.1080/23312009.2017.1354800","url":null,"abstract":"Abstract In this study, the mean levels of anion and metals in “Hora” natural mineral water and soil were determined. Accordingly, the levels of N–NH3, Cl−, N–NO3−, SO42−, Mg, and Ca in water were not exceeding the World Health Organization (WHO) drinking water guideline values for humans and the levels of N–NO3−, SO42−, and Ca were also far below the Canadian Ministers of Health (CMH) guideline values for livestock. The levels of Al, Mn, Zn, Cu, Ni, Pb, and Mo were above the WHO guideline values, while majority of the trace metals were not exceeding the maximum permissible value for livestock except for Ni and Co. Among the trace metals found in the soil, Mn and Pb were found to be higher compared to the recommended value (40 mg/kg) by the Ethiopian guideline. The drinking water quality index (DWQI) was calculated to be 67.6 based on 21 important quality parameters.","PeriodicalId":10640,"journal":{"name":"Cogent Chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23312009.2017.1354800","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42512957","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}
Pub Date : 2017-01-01DOI: 10.1080/23312009.2017.1357865
L. Nthunya, Monaheng L. Masheane, S. P. Malinga, E. Nxumalo, S. Mhlanga
Abstract Chitosan (CS)-based nanocomposite materials are highly prone to swelling when in contact with water. It is therefore essential to modify them to enhance their resistance to swelling, in order to be applicable in water treatment. In this study, the CS-based nanofibres were prepared using the electrospinning technique. The nanofibres were prepared from a polymer blend of CS, and other polymers (polyacrylamide (PAA) and polyethylene glycol (PEG)) added in small optimized quantities to enhance the ability to electrospun CS. Elastic polyisoprene (PIP) and functionalized multi-walled carbon nanotubes (f-MWCNTs) were incorporated in the electrospinnable solution blend of CS, PAA and PEG to reduce the swelling behaviour of the CS-based nanofibres and to improve their mechanical strength and thermal properties. PIP did not only improve the morphology of the resulting nanofibres but also reduced their swelling behaviour by twofold. The addition of f-MWCNTs was found to improve the tensile strength of the nanofibres by twofold, relative to nanofibres with no f-MWCNTs. The thermal degradation of the nanofibres was improved by a magnitude of 50°C. Antibacterial silver (Ag) and iron (Fe) nanoparticles (NPs) were embedded on the nanofibres for their possible use in disinfection processes. These NPs have demonstrated a potential to kill bacteria in water and, therefore, the prepared nanofibres can be used in disinfection water treatment processes with reduced swelling capacity.
{"title":"Environmentally benign chitosan-based nanofibres for potential use in water treatment","authors":"L. Nthunya, Monaheng L. Masheane, S. P. Malinga, E. Nxumalo, S. Mhlanga","doi":"10.1080/23312009.2017.1357865","DOIUrl":"https://doi.org/10.1080/23312009.2017.1357865","url":null,"abstract":"Abstract Chitosan (CS)-based nanocomposite materials are highly prone to swelling when in contact with water. It is therefore essential to modify them to enhance their resistance to swelling, in order to be applicable in water treatment. In this study, the CS-based nanofibres were prepared using the electrospinning technique. The nanofibres were prepared from a polymer blend of CS, and other polymers (polyacrylamide (PAA) and polyethylene glycol (PEG)) added in small optimized quantities to enhance the ability to electrospun CS. Elastic polyisoprene (PIP) and functionalized multi-walled carbon nanotubes (f-MWCNTs) were incorporated in the electrospinnable solution blend of CS, PAA and PEG to reduce the swelling behaviour of the CS-based nanofibres and to improve their mechanical strength and thermal properties. PIP did not only improve the morphology of the resulting nanofibres but also reduced their swelling behaviour by twofold. The addition of f-MWCNTs was found to improve the tensile strength of the nanofibres by twofold, relative to nanofibres with no f-MWCNTs. The thermal degradation of the nanofibres was improved by a magnitude of 50°C. Antibacterial silver (Ag) and iron (Fe) nanoparticles (NPs) were embedded on the nanofibres for their possible use in disinfection processes. These NPs have demonstrated a potential to kill bacteria in water and, therefore, the prepared nanofibres can be used in disinfection water treatment processes with reduced swelling capacity.","PeriodicalId":10640,"journal":{"name":"Cogent Chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23312009.2017.1357865","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43998298","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}
Pub Date : 2017-01-01DOI: 10.1080/23312009.2017.1383707
M. Adegunwa, E. O. Adelekan, A. A. Adebowale, H. A. Bakare, E. Alamu
Abstract Some individuals are intolerant to gluten of wheat and other cereals like oats, rye and barley used for food formulations and this intolerance seriously impairs intestinal absorption. There is need to develop alternative gluten-free flours for baking and confectioneries. This research therefore aimed at determining the chemical and functional properties of plantain–tiger nut composite flour to be able to explore its potentials in food formulation. The flours made from matured plantains and tiger nuts were blended at the ratio of 100:0, 70:30, 60:40, 50:50, 40:60, 30:70 and 0:100 to make different plantain–tiger nuts flours and these were analysed using standard methods. The results revealed that protein ranged from 4.55 to 6.78/100 g, fat (2.25–32.75/100 g), crude fibre (3.50–6.13/100 g), bulk density (0.81–0.92 g/cm3), swelling power (38.38–2.37/g), Mg (30.65–49.08 mg/100 g), P (3.65–120.65 mg/100 g), K (71.62–212.08 mg/100 g), Vitamin C (3.18–5.30 mg/100 g) and Vitamin A (1.71–51.31 μg/100 g). There were significant differences (p < 0.05) in the pasting profile of the plantain–tiger nut flour blends and in functional properties of composite flour except for bulk density. Addition of tiger nut flour improved the proximate, mineral and vitamin composition of the composite flour and the study concluded that inclusion of tiger nut flour is a good protein, fat, mineral and vitamin supplement for plantain flour.
{"title":"Evaluation of nutritional and functional properties of plantain (Musa paradisiaca L.) and tigernut (Cyperus esculentus L.) flour blends for food formulations","authors":"M. Adegunwa, E. O. Adelekan, A. A. Adebowale, H. A. Bakare, E. Alamu","doi":"10.1080/23312009.2017.1383707","DOIUrl":"https://doi.org/10.1080/23312009.2017.1383707","url":null,"abstract":"Abstract Some individuals are intolerant to gluten of wheat and other cereals like oats, rye and barley used for food formulations and this intolerance seriously impairs intestinal absorption. There is need to develop alternative gluten-free flours for baking and confectioneries. This research therefore aimed at determining the chemical and functional properties of plantain–tiger nut composite flour to be able to explore its potentials in food formulation. The flours made from matured plantains and tiger nuts were blended at the ratio of 100:0, 70:30, 60:40, 50:50, 40:60, 30:70 and 0:100 to make different plantain–tiger nuts flours and these were analysed using standard methods. The results revealed that protein ranged from 4.55 to 6.78/100 g, fat (2.25–32.75/100 g), crude fibre (3.50–6.13/100 g), bulk density (0.81–0.92 g/cm3), swelling power (38.38–2.37/g), Mg (30.65–49.08 mg/100 g), P (3.65–120.65 mg/100 g), K (71.62–212.08 mg/100 g), Vitamin C (3.18–5.30 mg/100 g) and Vitamin A (1.71–51.31 μg/100 g). There were significant differences (p < 0.05) in the pasting profile of the plantain–tiger nut flour blends and in functional properties of composite flour except for bulk density. Addition of tiger nut flour improved the proximate, mineral and vitamin composition of the composite flour and the study concluded that inclusion of tiger nut flour is a good protein, fat, mineral and vitamin supplement for plantain flour.","PeriodicalId":10640,"journal":{"name":"Cogent Chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23312009.2017.1383707","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46810454","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}
Pub Date : 2017-01-01DOI: 10.1080/23312009.2017.1379164
Y. Akimoto, K. Okajima
Abstract Non-uniform current distributions of proton-exchange membrane fuel cells (PEMFCs) result in unequal utilization of reactants and catalysts in solution. To prevent the degradation of PEMFC, an in situ approach for characterizing PEMFC stacks is needed. In this study, the current distribution of two-cell PEMFC stacks is replicated from measured magnetic flux densities and operating conditions produced by three-dimensional finite element modeling that included electromagnetic field modeling and electrochemical reactions. I–V curves under normal conditions were replicated from electrochemistry and compared to the measured curves, and magnetic flux density distributions were investigated to determine the operating state. From these results, we discuss the potential use of the proposed approach in in situ applications.
{"title":"In situ approach for characterizing PEMFC using a combination of magnetic sensor probes and 3DFEM simulation","authors":"Y. Akimoto, K. Okajima","doi":"10.1080/23312009.2017.1379164","DOIUrl":"https://doi.org/10.1080/23312009.2017.1379164","url":null,"abstract":"Abstract Non-uniform current distributions of proton-exchange membrane fuel cells (PEMFCs) result in unequal utilization of reactants and catalysts in solution. To prevent the degradation of PEMFC, an in situ approach for characterizing PEMFC stacks is needed. In this study, the current distribution of two-cell PEMFC stacks is replicated from measured magnetic flux densities and operating conditions produced by three-dimensional finite element modeling that included electromagnetic field modeling and electrochemical reactions. I–V curves under normal conditions were replicated from electrochemistry and compared to the measured curves, and magnetic flux density distributions were investigated to determine the operating state. From these results, we discuss the potential use of the proposed approach in in situ applications.","PeriodicalId":10640,"journal":{"name":"Cogent Chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23312009.2017.1379164","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45902164","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}
Pub Date : 2017-01-01DOI: 10.1080/23312009.2017.1296748
M. Arslan
Abstract Lathyrus sativus L., (grass pea) is an annual plant widely grown as a pulse crop and its dried seeds are harvested and consumed as human food since ancient times. This plant is also commonly grown for animal feed and forage. Grass pea seeds may represent a potential source of several important nutrients for human and animal nutrition. Fatty acid compositions of 173 different grass pea accessions have been studied. Present results indicate that total saturated fatty acids, total monounsaturated fatty acids, total polyunsaturated fatty acids, and total fatty acids ranged from 295.72 to 436.94, 113.19 to 170.78, 127.39 to 179.39, 538.04 to 778.98 mg 100 g−1, respectively. In addition, unsaturated fatty acids, oleic acid, linoleic acid, γ-linolenic acid, and α-linolenic acid that are the main components of fatty acids ranged from 109.22 to 163.95,59.57 to 82.98, 16.18 to 30.38, and 45.56 to 71.59 mg 100 g−1, respectively.
{"title":"Fatty acid characteristics of grass pea (Lathyrus sativus) in an East Mediterranean environment","authors":"M. Arslan","doi":"10.1080/23312009.2017.1296748","DOIUrl":"https://doi.org/10.1080/23312009.2017.1296748","url":null,"abstract":"Abstract Lathyrus sativus L., (grass pea) is an annual plant widely grown as a pulse crop and its dried seeds are harvested and consumed as human food since ancient times. This plant is also commonly grown for animal feed and forage. Grass pea seeds may represent a potential source of several important nutrients for human and animal nutrition. Fatty acid compositions of 173 different grass pea accessions have been studied. Present results indicate that total saturated fatty acids, total monounsaturated fatty acids, total polyunsaturated fatty acids, and total fatty acids ranged from 295.72 to 436.94, 113.19 to 170.78, 127.39 to 179.39, 538.04 to 778.98 mg 100 g−1, respectively. In addition, unsaturated fatty acids, oleic acid, linoleic acid, γ-linolenic acid, and α-linolenic acid that are the main components of fatty acids ranged from 109.22 to 163.95,59.57 to 82.98, 16.18 to 30.38, and 45.56 to 71.59 mg 100 g−1, respectively.","PeriodicalId":10640,"journal":{"name":"Cogent Chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23312009.2017.1296748","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42399094","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}
Pub Date : 2017-01-01DOI: 10.1080/23312009.2017.1417672
A. M. Alosaimi, M. A. Hussein, M. Abdelaal, M. Elfaky, T. R. Sobahi, A. Abdel-Daiem
Abstract The current work is focused on the preparation and characterization of a new group of polysulfone-based organoclay nanocomposite as a promising breast anticancer agent. Polysulfone/organoclay nanocomposites which had abbreviations of PSFH1–3 and PSFB1–3 were prepared using a solution casting technique at room temperature using chloroform as a solvent. PSFH1–3 and PSFB1–3 referred to polysulfone-based halloysite and bentonite in their unmodified and modified forms. Chemical modification of both types was carried out using tetraethylammonium chloride and hexadecyltributylphosphonium bromide, respectively. The final products were produced with different compositions based on the variable loading of modified organoclay. The impacts of the modified fillers on the morphological, thermal, and mechanical properties of the nanocomposites were investigated. A pure polysulfone (PSF) membrane was prepared as a reference. The prepared PSF/organoclay nanocomposite membranes (PSFH1–3, PSFB1–3) were characterized with the aid of FT-IR spectroscopy, SEM, X-ray diffraction, and TGA techniques. The results demonstrated that the impact of the organoclay on the main features of the polysulfone was remarkable and that the incorporation of organic cations alters the thermal stability of polysulfone. X-ray diffraction patterns revealed the formation of intercalated clay mineral layers in the PSF matrix but PSFH3 and PSFB2 have an exfoliated structure. A good dispersion of the organoclay mineral particles was detected by SEM images. The chemical structure of the surfactant affected the thermal behavior of organoclays. Moreover, in the tensile tests, the addition of clay caused a decrease in both the tensile strain at the break and the modulus of elasticity in tension for the nanocomposite membranes. The biological screening showed positive effects for PSFB1 and PSFB2, but PSFH3 and PSFB3 have more promising anticancer effects.
{"title":"Polysulfone-based modified organoclay nanocomposites as a promising breast anticancer agent","authors":"A. M. Alosaimi, M. A. Hussein, M. Abdelaal, M. Elfaky, T. R. Sobahi, A. Abdel-Daiem","doi":"10.1080/23312009.2017.1417672","DOIUrl":"https://doi.org/10.1080/23312009.2017.1417672","url":null,"abstract":"Abstract The current work is focused on the preparation and characterization of a new group of polysulfone-based organoclay nanocomposite as a promising breast anticancer agent. Polysulfone/organoclay nanocomposites which had abbreviations of PSFH1–3 and PSFB1–3 were prepared using a solution casting technique at room temperature using chloroform as a solvent. PSFH1–3 and PSFB1–3 referred to polysulfone-based halloysite and bentonite in their unmodified and modified forms. Chemical modification of both types was carried out using tetraethylammonium chloride and hexadecyltributylphosphonium bromide, respectively. The final products were produced with different compositions based on the variable loading of modified organoclay. The impacts of the modified fillers on the morphological, thermal, and mechanical properties of the nanocomposites were investigated. A pure polysulfone (PSF) membrane was prepared as a reference. The prepared PSF/organoclay nanocomposite membranes (PSFH1–3, PSFB1–3) were characterized with the aid of FT-IR spectroscopy, SEM, X-ray diffraction, and TGA techniques. The results demonstrated that the impact of the organoclay on the main features of the polysulfone was remarkable and that the incorporation of organic cations alters the thermal stability of polysulfone. X-ray diffraction patterns revealed the formation of intercalated clay mineral layers in the PSF matrix but PSFH3 and PSFB2 have an exfoliated structure. A good dispersion of the organoclay mineral particles was detected by SEM images. The chemical structure of the surfactant affected the thermal behavior of organoclays. Moreover, in the tensile tests, the addition of clay caused a decrease in both the tensile strain at the break and the modulus of elasticity in tension for the nanocomposite membranes. The biological screening showed positive effects for PSFB1 and PSFB2, but PSFH3 and PSFB3 have more promising anticancer effects.","PeriodicalId":10640,"journal":{"name":"Cogent Chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23312009.2017.1417672","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48130174","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}
Pub Date : 2017-01-01DOI: 10.1080/23312009.2017.1298980
Qaiser Ali Khan, Ahmed Shaur, T. Khan, Y. Joya, M. S. Awan
Abstract Large-scale fabrication of graphene and reduced graphene oxide (rGO) is important for industrial and research applications of this material. Chemical solution methods offer a low-cost alternate to produce rGO with high yield. This research is to explore the effect of chemical and thermal reduction on the quality of chemically synthesized graphene and its derivatives. A top-down process involved the chemical oxidation of the precursor graphite powder (size ~10 μm) using a concentrated mixture of sulphuric acid and nitric acid. Oxidized graphite powder was thermally exfoliated at 1,050°C for 30 s to produce graphene oxide (GO). Chemical reduction in GO sheets with sodium borohydride led to the formation of rGO. Characterization by Raman spectroscopy revealed an intensity ratio of 2D/G bands of rGO as approximately 0.5 indicating a multi-layered structure. X-ray diffraction, field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) results indicated a multi-layered rGO with a lateral size up to 5 μm.
{"title":"Characterization of reduced graphene oxide produced through a modified Hoffman method","authors":"Qaiser Ali Khan, Ahmed Shaur, T. Khan, Y. Joya, M. S. Awan","doi":"10.1080/23312009.2017.1298980","DOIUrl":"https://doi.org/10.1080/23312009.2017.1298980","url":null,"abstract":"Abstract Large-scale fabrication of graphene and reduced graphene oxide (rGO) is important for industrial and research applications of this material. Chemical solution methods offer a low-cost alternate to produce rGO with high yield. This research is to explore the effect of chemical and thermal reduction on the quality of chemically synthesized graphene and its derivatives. A top-down process involved the chemical oxidation of the precursor graphite powder (size ~10 μm) using a concentrated mixture of sulphuric acid and nitric acid. Oxidized graphite powder was thermally exfoliated at 1,050°C for 30 s to produce graphene oxide (GO). Chemical reduction in GO sheets with sodium borohydride led to the formation of rGO. Characterization by Raman spectroscopy revealed an intensity ratio of 2D/G bands of rGO as approximately 0.5 indicating a multi-layered structure. X-ray diffraction, field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) results indicated a multi-layered rGO with a lateral size up to 5 μm.","PeriodicalId":10640,"journal":{"name":"Cogent Chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23312009.2017.1298980","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42022099","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}
Pub Date : 2017-01-01DOI: 10.1080/23312009.2017.1317582
Atefeh Ghasemi, A. Davoodnia, M. Pordel, N. Tavakoli-Hoseini
Abstract Under mild conditions and without any additional organic solvent, synthesis of carbamatoalkyl naphthols by the one-pot three-component reaction of β-naphthol with a wide range of aromatic aldehydes and methyl carbamate could be carried out in the presence of P2O5 supported on SiO2 (P2O5/SiO2). The results showed that the catalyst has high activity and the desired products were obtained in high yields in short reaction times. Other beneficial features of this protocol include inexpensive and easily obtained catalyst, simple work-up, and the recyclability and reusability of the catalyst for up to five consecutive runs.
{"title":"P2O5 supported on SiO2 as an efficient and reusable catalyst for rapid one-pot synthesis of carbamatoalkyl naphthols under solvent-free conditions","authors":"Atefeh Ghasemi, A. Davoodnia, M. Pordel, N. Tavakoli-Hoseini","doi":"10.1080/23312009.2017.1317582","DOIUrl":"https://doi.org/10.1080/23312009.2017.1317582","url":null,"abstract":"Abstract Under mild conditions and without any additional organic solvent, synthesis of carbamatoalkyl naphthols by the one-pot three-component reaction of β-naphthol with a wide range of aromatic aldehydes and methyl carbamate could be carried out in the presence of P2O5 supported on SiO2 (P2O5/SiO2). The results showed that the catalyst has high activity and the desired products were obtained in high yields in short reaction times. Other beneficial features of this protocol include inexpensive and easily obtained catalyst, simple work-up, and the recyclability and reusability of the catalyst for up to five consecutive runs.","PeriodicalId":10640,"journal":{"name":"Cogent Chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23312009.2017.1317582","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44880551","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}
Pub Date : 2017-01-01DOI: 10.1080/23312009.2017.1284296
T. Çiftçi
Abstract A novel adsorbent Fe3O4/Ni/NixB-nanocomposite coated nutshell was synthesized and used for the identification of the adsorption characteristics for both As(III) and As(V). The point of zero charge of pH of the adsorbent was determined as 8.0. The adsorption of arsenic on the adsorbent was optimum at pH 7.5. The Langmuir isotherm well fitted to the equilibrium data with a maximum adsorption capacity of 3.6 and 2.6 mg/g for As(III) and As(V), respectively. The separation factor, RL, calculated from the Langmuir isotherm and the parameter, n, calculated from the Freundlich isotherm showed that the adsorption of both As(III) and As(V) on Fe3O4/Ni/NixB nanocomposite coated nutshell was favorable. The D–R isotherm showed that the adsorption was chemical in nature. The kinetic data followed the pseudo-second-order model which supported that the adsorption mechanism was chemical. The adsorption method was applied to real samples with a column. The removal efficiencies were about 100%. The adsorbent effectively reduced the concentration of arsenic species in water sample from 100 μg/L to the level below 10 μg/L (the recommended limit of arsenic in drinking water). The regeneration of the spent adsorbent was successfully done with 3% NaCl + 2% NaOH solution. The adsorption and the regeneration cycle were repeated for three times without loss efficiency.
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