Successful commercialization of microalgal bio-industry requires the design of an integrated microalgal biorefinery system that facilitates the co-production of biofuels, high-value products and industrial chemicals from the biomass. In this study, we investigated the use of sugar hydrolysate obtained from enzymatic saccharification of microalgal biomass (Chlorella sp. and T. suecica) as fermentation feedstock to produce industrially important chemicals, in particular acetic acid and butyric acid. By using hydrolysate with low sugar content as substrate for the anaerobic fermentation (1.5 - 2.4 g/L), we were able to prevent the bacterium C. saccharoperbutylacetonicum from activating its solventogenesis pathway. As a result, the fermentation process generated a product stream that was dominated by organic acids (acetic acid and butyric acid) rather than solvents (butanol, ethanol and acetone). Acetic acid constituted up to 92 wt% of Chlorella’s fermentation products and 80 wt% of T. suecica’s fermentation products. For T. suecica, the fermentation consumed almost all of the sugar available in the hydrolysate (up to 92% of initial sugar) and produced a reasonable yield of fermentation products (0.08 g fermentation products/g sugar). The Gompertz equation was successfully used to predict the formation kinetics of acetic acid and other fermentation products across both species. The results in the study demonstrate the production of industrially important chemicals, such as acetic acid and butyric acid, from the fermentation of microalgal sugar. The process described in the study can potentially be used as a value-adding step to generate biochemicals from cell debris in an integrated microalgal biorefinery system.
{"title":"Towards Biorefinery Production of Microalgal Biofuels and Bioproducts: Production of Acetic Acid from the Fermentation of Chlorella sp. and Tetraselmis suecica Hydrolysates","authors":"M. A. Kassim, M. Rashid, R. Halim","doi":"10.4236/GSC.2017.72012","DOIUrl":"https://doi.org/10.4236/GSC.2017.72012","url":null,"abstract":"Successful commercialization of microalgal bio-industry requires the design of an integrated microalgal biorefinery system that facilitates the co-production of biofuels, high-value products and industrial chemicals from the biomass. In this study, we investigated the use of sugar hydrolysate obtained from enzymatic saccharification of microalgal biomass (Chlorella sp. and T. suecica) as fermentation feedstock to produce industrially important chemicals, in particular acetic acid and butyric acid. By using hydrolysate with low sugar content as substrate for the anaerobic fermentation (1.5 - 2.4 g/L), we were able to prevent the bacterium C. saccharoperbutylacetonicum from activating its solventogenesis pathway. As a result, the fermentation process generated a product stream that was dominated by organic acids (acetic acid and butyric acid) rather than solvents (butanol, ethanol and acetone). Acetic acid constituted up to 92 wt% of Chlorella’s fermentation products and 80 wt% of T. suecica’s fermentation products. For T. suecica, the fermentation consumed almost all of the sugar available in the hydrolysate (up to 92% of initial sugar) and produced a reasonable yield of fermentation products (0.08 g fermentation products/g sugar). The Gompertz equation was successfully used to predict the formation kinetics of acetic acid and other fermentation products across both species. The results in the study demonstrate the production of industrially important chemicals, such as acetic acid and butyric acid, from the fermentation of microalgal sugar. The process described in the study can potentially be used as a value-adding step to generate biochemicals from cell debris in an integrated microalgal biorefinery system.","PeriodicalId":12770,"journal":{"name":"Green and Sustainable Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87271361","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}
I. G. Audu, I. Ziegler-Devin, Heiko Winter, M. Bremer, Anton Hoffmann, S. Fischer, M. Laborie, N. Brosse
This study aims at investigating the impact of ionic liquid extraction on lignin structure by studying the mechanism of lignin depolymerization in 1-ethyl-3-methylimidazolium acetate EMIM[OAc]) and comparing it with that of organosolv and milled wood methods. Ionic liquid mediated lignin (ILL) using EMIM[OAc]), ethanol organosolv lignin (EOL) and milled wood lignin (MWL) were isolated from Typha capensis (TC) and subjected to several analytical characterizations. Experimental data shows that ILL exhibited a relatively lower degree of condensation, lower aromatic C-C structures and a higher aliphatic OH with values of 0.42/Ar, 1.94/Ar and 1.33/Ar moieties compared with EOL values of 0.92/Ar, 2.22/Ar and 0.51/Ar moieties respectively. The ILL was depolymerized under mild conditions giving relatively higher β-aryl ether linkages content, higher molecular mass, and exhibited closer structures and reactivity to native lignin than EOL. These insights on TC lignin depolymerization in EMIM[OAc]) acetate may contribute to better value-addition of lignocellulosic biomass.
{"title":"Impact of Ionic Liquid 1-Ethyl-3-Methylimidazolium Acetate Mediated Extraction on Lignin Features","authors":"I. G. Audu, I. Ziegler-Devin, Heiko Winter, M. Bremer, Anton Hoffmann, S. Fischer, M. Laborie, N. Brosse","doi":"10.4236/GSC.2017.72010","DOIUrl":"https://doi.org/10.4236/GSC.2017.72010","url":null,"abstract":"This study aims at investigating the impact of ionic liquid extraction on lignin structure by studying the mechanism of lignin depolymerization in 1-ethyl-3-methylimidazolium acetate EMIM[OAc]) and comparing it with that of organosolv and milled wood methods. Ionic liquid mediated lignin (ILL) using EMIM[OAc]), ethanol organosolv lignin (EOL) and milled wood lignin (MWL) were isolated from Typha capensis (TC) and subjected to several analytical characterizations. Experimental data shows that ILL exhibited a relatively lower degree of condensation, lower aromatic C-C structures and a higher aliphatic OH with values of 0.42/Ar, 1.94/Ar and 1.33/Ar moieties compared with EOL values of 0.92/Ar, 2.22/Ar and 0.51/Ar moieties respectively. The ILL was depolymerized under mild conditions giving relatively higher β-aryl ether linkages content, higher molecular mass, and exhibited closer structures and reactivity to native lignin than EOL. These insights on TC lignin depolymerization in EMIM[OAc]) acetate may contribute to better value-addition of lignocellulosic biomass.","PeriodicalId":12770,"journal":{"name":"Green and Sustainable Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85036164","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 ligand exchange reaction is a typical reaction of ferrocenes. This reaction proceeds via the abstraction of a cyclopentadienyl ring by a Lewis acid followed by coordination of an aromatic compound to the resulting species. This reaction with conventional heating requires a long reaction time. Furthermore, the reactions with heterocycles are lower than those with the corresponding hydrocarbons, and do not produce any products in some cases. In this paper, the ligand exchange reaction of ferrocene and a heterocyclic aromatic compound during microwave irradiation and its effect are discussed. As a result, for some heterocycles, the decrease in the reaction time was confirmed. Furthermore, under the microwave irradiation conditions, the tendency in which the difference in their reactivities became low was confirmed.
{"title":"Microwave Irradiation Effect on the Ligand Exchange Reaction between Ferrocene and Heterocycles","authors":"Y. Okada, Atsushi Niou, S. Nakano","doi":"10.4236/GSC.2017.72008","DOIUrl":"https://doi.org/10.4236/GSC.2017.72008","url":null,"abstract":"The ligand exchange reaction is a typical reaction \u0000of ferrocenes. This reaction proceeds via the abstraction of a cyclopentadienyl \u0000ring by a Lewis acid followed by coordination of an aromatic compound to the \u0000resulting species. This reaction with conventional heating requires a long \u0000reaction time. Furthermore, the reactions with heterocycles are lower than \u0000those with the corresponding hydrocarbons, and do not produce any products in \u0000some cases. In this paper, the ligand exchange reaction of ferrocene and a \u0000heterocyclic aromatic compound during microwave irradiation and its effect are \u0000discussed. As a result, for some heterocycles, the decrease in the reaction \u0000time was confirmed. Furthermore, under the microwave irradiation conditions, \u0000the tendency in which the difference in their reactivities became low was \u0000confirmed.","PeriodicalId":12770,"journal":{"name":"Green and Sustainable Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76293530","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}
Sruthi Vasamsetty, Sunitha Medidi, Satheesh Ampolu, Ravi Kumar Majji, Mastan Rao Kotupalli, Chikurumilli China Satyanarayana, Annapurna Nowduri, P. Sanasi
An efficient greener one pot synthesis of dimethyl-dihydro-7H-chromeno[3, 2-h]quinolin-8(9H)-one derivatives has been synthesized through cyclization of aromatic aldehyde, dimidone and 8-hydroxy-quinoline through one-pot condensation method is described. The synthesized compounds are screened for further biological activities against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis, Bacillus using cut plate method and disc diffusion method.
{"title":"Catalyst Free One-Pot Synthesis of Chromeno Quinolines and Their Antibacterial Activity","authors":"Sruthi Vasamsetty, Sunitha Medidi, Satheesh Ampolu, Ravi Kumar Majji, Mastan Rao Kotupalli, Chikurumilli China Satyanarayana, Annapurna Nowduri, P. Sanasi","doi":"10.4236/GSC.2017.72011","DOIUrl":"https://doi.org/10.4236/GSC.2017.72011","url":null,"abstract":"An efficient greener one pot synthesis of dimethyl-dihydro-7H-chromeno[3, 2-h]quinolin-8(9H)-one derivatives has been synthesized through cyclization of aromatic aldehyde, dimidone and 8-hydroxy-quinoline through one-pot condensation method is described. The synthesized compounds are screened for further biological activities against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis, Bacillus using cut plate method and disc diffusion method.","PeriodicalId":12770,"journal":{"name":"Green and Sustainable Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82544198","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}
M. R. Tappin, Felipe M. Knopp, Igor C. Cardoso, Roberta T. Santos, B. Drummond, A. Siani, E. P. Bon, M. A. Ferrara
The bioconversion of the hydrophobic and volatile limonene to perillic acid, a potential anticancer agent, by the yeast Yarrowia lipolytica was studied in two steps. Firstly, experimental design was used for process optimization using high-purity limonene as substrate and secondly orange essential oil containing 89.1% limonene was used as substrate under the previously optimized conditions. Limonene concentration and pH were identified by fractional factorial design as significant factors and were optimized by central composite design. Under optimized process conditions (0.16% (v/v) limonene; pH 6.9), the 24 h biotransformation process resulted in the accumulation of 0.368 g·L-1 of perillic acid corresponding to a molar yield of 23.1%. A subsequent substrate addition under the same reaction conditions doubled perillic acid concentration to 0.793 g·L-1 and a molar yield of 24.2%. The use of orange essential oil under the optimized reaction conditions increased both perillic acid accumulation and yield to 0.872 g·L-1 and 29.7%, respectively. The robustness of Y. lipolytica allowed the efficient biotransformation of a crude by-product of the citrus industry into a valuable fine chemical.
{"title":"Synthesis of the Prospective Anticancer Molecule Perillic Acid from Orange Essential Oil by the Yeast Yarrowia lipolytica","authors":"M. R. Tappin, Felipe M. Knopp, Igor C. Cardoso, Roberta T. Santos, B. Drummond, A. Siani, E. P. Bon, M. A. Ferrara","doi":"10.4236/GSC.2017.72013","DOIUrl":"https://doi.org/10.4236/GSC.2017.72013","url":null,"abstract":"The bioconversion of the hydrophobic and volatile limonene to perillic acid, a potential anticancer agent, by the yeast Yarrowia lipolytica was studied in two steps. Firstly, experimental design was used for process optimization using high-purity limonene as substrate and secondly orange essential oil containing 89.1% limonene was used as substrate under the previously optimized conditions. Limonene concentration and pH were identified by fractional factorial design as significant factors and were optimized by central composite design. Under optimized process conditions (0.16% (v/v) limonene; pH 6.9), the 24 h biotransformation process resulted in the accumulation of 0.368 g·L-1 of perillic acid corresponding to a molar yield of 23.1%. A subsequent substrate addition under the same reaction conditions doubled perillic acid concentration to 0.793 g·L-1 and a molar yield of 24.2%. The use of orange essential oil under the optimized reaction conditions increased both perillic acid accumulation and yield to 0.872 g·L-1 and 29.7%, respectively. The robustness of Y. lipolytica allowed the efficient biotransformation of a crude by-product of the citrus industry into a valuable fine chemical.","PeriodicalId":12770,"journal":{"name":"Green and Sustainable Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75409183","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}
S. Al‐Zuhair, H. Taher, Salama M. Al Dhaheri, Shereen Wajeeh, M. Nour, E. Elnajjar
Biodiesel production had received a considerable attention as a green, non-toxic and renewable alternative to petroleum diesel. To avoid using vegetable oils, which are expensive and compete with food, as feedstock, waste oils have been proposed. However, these waste materials contain a large amount of free fatty acids that complicates the production process. In this work, biodiesel production using an alternative feedstock; namely oils from date-pits, has been investigated. These oils have the same favorable features of straight oils, and at the same time are considered waste, since they are extracted from a waste material. The yield of oils extracted using n-hexane in a Soxhlet apparatus was compared to that of oils extracted using methanol-chloroform solvent mixture. The extracted oils were then converted to biodiesel via transesterification with methanol in presence of Novozym𪥣 or Eversa®Transform. The highest oils extraction yield of 11.7%, per dry weight sample, was obtained using Soxhlet extraction apparatus compared to 8.9% using methanol-chloroform mixture. The highest biodiesel production yield was 30% of the oil used, achieved after 6 hours using Novozym𪥣 at 40°C, 5:1 methanol to oil molar ratio and 10wt% enzyme loading. By using a chemical alkaline catalyst, NaOH, at the same conditions, the yield was 27%.
{"title":"Biodiesel Production from Oils Extracted from Date Pits","authors":"S. Al‐Zuhair, H. Taher, Salama M. Al Dhaheri, Shereen Wajeeh, M. Nour, E. Elnajjar","doi":"10.4236/GSC.2017.71004","DOIUrl":"https://doi.org/10.4236/GSC.2017.71004","url":null,"abstract":"Biodiesel production had received a considerable attention as a green, non-toxic and renewable alternative to petroleum diesel. To avoid using vegetable oils, which are expensive and compete with food, as feedstock, waste oils have been proposed. However, these waste materials contain a large amount of free fatty acids that complicates the production process. In this work, biodiesel production using an alternative feedstock; namely oils from date-pits, has been investigated. These oils have the same favorable features of straight oils, and at the same time are considered waste, since they are extracted from a waste material. The yield of oils extracted using n-hexane in a Soxhlet apparatus was compared to that of oils extracted using methanol-chloroform solvent mixture. The extracted oils were then converted to biodiesel via transesterification with methanol in presence of Novozym𪥣 or Eversa®Transform. The highest oils extraction yield of 11.7%, per dry weight sample, was obtained using Soxhlet extraction apparatus compared to 8.9% using methanol-chloroform mixture. The highest biodiesel production yield was 30% of the oil used, achieved after 6 hours using Novozym𪥣 at 40°C, 5:1 methanol to oil molar ratio and 10wt% enzyme loading. By using a chemical alkaline catalyst, NaOH, at the same conditions, the yield was 27%.","PeriodicalId":12770,"journal":{"name":"Green and Sustainable Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82771213","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}
Recent results for synthesis of conjugated polymers, poly(arylene vinylene)s exemplified as poly(fluorene vinylene)s and poly(phenylene vinylene)s, by acyclic diene metathesis (ADMET) polymerization have been introduced. The methods using molybdenum and ruthenium catalysts afforded defect-free, high molecular weight polymers with all trans olefinic double bonds, and significant reduction of by-products (halogen, sulfur etc.) in addition of decrease of structurally defects have been attained. The methods also demonstrated precise synthesis of end-functionalized polymers that showed unique optical properties combined with the end groups. Catalytic one-pot syntheses of end-functionalized poly(9,9-dialkylfluorene-2,7-vinylene)s have been attained by both ruthenium (by chain-transfer) and molybdenum catalysts and the method should provide more green route for synthesis of conjugated materials with better device performance.
{"title":"ADMET Polymerization: Greener Method for Synthesis of End-Functionalized Poly(Arylene Vinylene)s","authors":"Tahmina Haque, K. Nomura","doi":"10.4236/GSC.2017.71001","DOIUrl":"https://doi.org/10.4236/GSC.2017.71001","url":null,"abstract":"Recent results for synthesis of conjugated polymers, \u0000poly(arylene vinylene)s exemplified as poly(fluorene vinylene)s and \u0000poly(phenylene vinylene)s, by acyclic diene metathesis (ADMET) polymerization \u0000have been introduced. The methods using molybdenum and ruthenium catalysts \u0000afforded defect-free, high molecular weight polymers with all trans olefinic double bonds, and \u0000significant reduction of by-products (halogen, sulfur etc.) in addition of \u0000decrease of structurally defects have been attained. The methods also \u0000demonstrated precise synthesis of end-functionalized polymers that showed \u0000unique optical properties combined with the end groups. Catalytic one-pot \u0000syntheses of end-functionalized poly(9,9-dialkylfluorene-2,7-vinylene)s have \u0000been attained by both ruthenium (by chain-transfer) and molybdenum catalysts \u0000and the method should provide more green route for synthesis of conjugated \u0000materials with better device performance.","PeriodicalId":12770,"journal":{"name":"Green and Sustainable Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85666520","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. Nikoleishvili, G. Gorelishvili, V. Kveselava, G. Tsurtsumia, N. Nioradze, R. Kurtanidze, D. Dzanashvili
Cobalt-Boron oxides containing catalyst CoO·B2O3 (CoB2O4) are synthesized for hydrogen generation by catalytic reforming of basic solution of sodium hypophosphite (NaH2PO2) and identified by chemical and X-ray analysis. Reforming is performed in temperature range of 30°C - 80°C. Reaction rate constants at each value of temperature (k30°C = 8.53 × 10?4 s?1; k40°C = 1.62 × 10?4 s??; k50°C = 3.06 × 10?3 s?1; k60°C = 5.06 × 10?3 s?1; k80°C = 1.39 × 10?2 s?1), temperature coefficient of rate of chemical reaction (γ = 0.917) and activation energy (EA = 49.59 kJ·mol?1) are calculated.
{"title":"Hydrogen Generation by Reforming of Sodium Hypophosphite on Cobalt-Boron Oxides Containing Catalyst","authors":"P. Nikoleishvili, G. Gorelishvili, V. Kveselava, G. Tsurtsumia, N. Nioradze, R. Kurtanidze, D. Dzanashvili","doi":"10.4236/GSC.2017.71007","DOIUrl":"https://doi.org/10.4236/GSC.2017.71007","url":null,"abstract":"Cobalt-Boron oxides containing catalyst CoO·B2O3 (CoB2O4) are synthesized for hydrogen generation by catalytic reforming of basic \u0000solution of sodium hypophosphite (NaH2PO2) and identified \u0000by chemical and X-ray analysis. Reforming is performed in temperature range of \u000030°C - 80°C. Reaction rate constants at each value of temperature \u0000(k30°C = 8.53 × 10?4 s?1; k40°C = 1.62 × 10?4 s??; k50°C = 3.06 × 10?3 s?1; k60°C = 5.06 × 10?3 s?1; k80°C = 1.39 × 10?2 s?1), temperature \u0000coefficient of rate of chemical reaction (γ = 0.917) and activation energy (EA = 49.59 kJ·mol?1) are calculated.","PeriodicalId":12770,"journal":{"name":"Green and Sustainable Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91410170","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}
Indians have been considered as forerunners in the art of natural dyeing. Although indigenous knowledge system has been practiced over the years in the past, the use of natural dyes has diminished over generations due to lack of documentation and precise knowledge of the extracting and dyeing techniques. As a result, natural dyes are not commercially successful. Presently, all environmentally unfriendly synthetic compounds are used for dyeing textile materials. They are non-biodegradable, carcinogenic and generate water pollution as well as waste disposal problems. Natural dyes provide a reasonable solution to these problems. Thus, it is imperative to develop technology for extraction of natural dyes and for their application on textile materials. In this study, attempt has been made to extract natural dyes from a variety of plants sources (such as rhizomes of turmeric, Curcuma longa; fruits of harda, Terminalia chebula; petals of safflower, Carthamus tinctorius; roots of barberry, Berberis lycium etc.) using specific techniques. These dyes were tested for their dyeing potential on different textile materials (cotton, silk and wool). Dyeing was done using three different dyeing techniques (pre-, simultaneous- and post-mordanting) wherein different mordants such as alum, copper sulphate and ferrous sulphate etc., were used to fix dye on to the textile material. A rainbow of natural dyes was obtained with varied shades of each colour. Shade cards were prepared for each dye and the colour obtained varied depending on the type of the mordant applied and the mordanting technique used.
{"title":"Rainbow of Natural Dyes on Textiles Using Plants Extracts: Sustainable and Eco-Friendly Processes","authors":"J. Arora, P. Agarwal, Gunjan Gupta","doi":"10.4236/GSC.2017.71003","DOIUrl":"https://doi.org/10.4236/GSC.2017.71003","url":null,"abstract":"Indians have been considered as forerunners in the art of natural dyeing. Although indigenous knowledge system has been practiced over the years in the past, the use of natural dyes has diminished over generations due to lack of documentation and precise knowledge of the extracting and dyeing techniques. As a result, natural dyes are not commercially successful. Presently, all environmentally unfriendly synthetic compounds are used for dyeing textile materials. They are non-biodegradable, carcinogenic and generate water pollution as well as waste disposal problems. Natural dyes provide a reasonable solution to these problems. Thus, it is imperative to develop technology for extraction of natural dyes and for their application on textile materials. In this study, attempt has been made to extract natural dyes from a variety of plants sources (such as rhizomes of turmeric, Curcuma longa; fruits of harda, Terminalia chebula; petals of safflower, Carthamus tinctorius; roots of barberry, Berberis lycium etc.) using specific techniques. These dyes were tested for their dyeing potential on different textile materials (cotton, silk and wool). Dyeing was done using three different dyeing techniques (pre-, simultaneous- and post-mordanting) wherein different mordants such as alum, copper sulphate and ferrous sulphate etc., were used to fix dye on to the textile material. A rainbow of natural dyes was obtained with varied shades of each colour. Shade cards were prepared for each dye and the colour obtained varied depending on the type of the mordant applied and the mordanting technique used.","PeriodicalId":12770,"journal":{"name":"Green and Sustainable Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75835583","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}
Ørnulf Nordseth, Raj Kumar, K. Bergum, L. Fara, S. Foss, H. Haug, Florin Drăgan, D. Craciunescu, P. Sterian, I. Chilibon, C. Vasiliu, L. Baschir, D. Savastru, E. Monakhov, B. Svensson
Research on silicon-based tandem heterojunction solar cells (STHSC) incorporating metal oxides is one of the main directions for development of high-efficiency solar cells. In this work, the optical characteristics of a STHSC consisting of a ZnO/Cu2O subcell on top of a silicon-based subcell were studied by optical modelling. Cu2O is a direct-gap p-type semiconductor which is attractive for application in solar cells due to its high absorptance of ultra-violet and visible light, nontoxicity, and low-cost producibility. Highly Al-doped ZnO and undoped Cu2O thin films were prepared on quartz substrates by magnetron sputter deposition. Thermal annealing of the Cu2O layer at 900°C enhances the electrical properties and reduces optical absorption, presumably as a result of increased grain size. Hall effect measurements show that the majority carrier (hole) mobility increases from 10 to 50 cm2/V×s and the resistivity decreases from 560 to 200 Ω×cm after annealing. A Cu2O absorber layer of 2 μm thickness will generate about 10 mA/cm2 of photocurrent under AM1.5G illumination. The optical analysis of the STHSC involved calculating the spectral curves for absorptance, transmittance, and reflectance for different thicknesses of the thin film layers constituting the ZnO/Cu2O subcell. The complex refractive indices of the thin films were derived from spectroscopic ellipsometry measurements and implemented in the simulation model. The lowest reflectance and highest transmittance for the ZnO/Cu2O subcell are obtained for a thickness of approximately 80 nm for both the top and bottom AZO layers. The SiNx anti-reflection coating for the c-Si bottom subcell must be optimized to accommodate the shift of the photon spectrum towards longer wavelengths. By increasing the thickness of the SiNx layer from 80 nm to 120 nm, the total reflectance for the STHSC device is reduced from 12.7% to 9.7%.
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