Hydroxyapatite (HA) having chemical formula Ca10(PO<sub>4</sub>)<sub>6</sub>(OH)<sub>2</sub>, is the main chemical component of human bone tissue (70%). This is the reason why it ha...Hydroxyapatite (HA) having chemical formula Ca10(PO<sub>4</sub>)<sub>6</sub>(OH)<sub>2</sub>, is the main chemical component of human bone tissue (70%). This is the reason why it has been widely engaged in the dental and non-load bearing implantations, to cope up with the bone response as a bioactive material. In this study HA powder was synthesized by wet chemical method, using phosphoric acid (H3PO4) and eggshells. The synthesized HA powder was characterized by X-ray diffraction analysis, Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX) and Fourier transform (FT-IR) spectroscopy. The Thermos gravimetric analysis (TGA-DTA) was also carried out to evaluate the stability of the synthesized HA powder at higher temperatures. The results of the study indicate that sintered (at 900°C) HA powder resembles the feature of pure and single apatite phase having favourable Ca/P ratio ranging from 1.7 to 2.4.展开更多
Pyrolytic lignin, the water-insoluble fraction in bio-oil, often shows a high content and has strong intermolecular interactions with other compounds in bio-oil. In order to obtain pure pyrolytic lignin and facilitate...Pyrolytic lignin, the water-insoluble fraction in bio-oil, often shows a high content and has strong intermolecular interactions with other compounds in bio-oil. In order to obtain pure pyrolytic lignin and facilitate the utilization of aqueous phase obtained from water extraction of bio-oil, methanol–water extraction method was employed to further separate the bio-oil water-insoluble phase in this paper. Different technologies, including Fourier transform infrared spectroscopy, gel permeation chromatography, and nuclear magnetic resonance, were adopted to characterize the structures of pyrolytic lignins with different activities obtained through this method. Both the heating value and the polymerization degree of high-molecular-weight pyrolytic lignin were higher than those of low-molecular-weight pyrolytic lignin. The molecular weight distribution of high-molecular-weight pyrolytic lignin was relatively wider, among which the contents of dimers to pentamers all accounted for 12% –18%,while the low-molecular-weight pyrolytic lignin mainly consisted of trimers(75.38%). The pyrolytic lignins had similar basic structures, both of which contained syringyl and guaiacyl units, whereas the low-molecular-weight pyrolytic lignin had more abundant syringyl units, reactive carbonyl groups and hydroxyl groups. Meanwhile,thermogravimetric study revealed that the final char residue yield of low-molecular-weight pyrolytic lignin was lower than that of high-molecular-weight pyrolytic lignin.展开更多
Today, demand exists for cost-effective production of industrially important enzymes from entire scientific sectors. By keeping in mind the extensive industrial applications of cellulase, this study was performed to i...Today, demand exists for cost-effective production of industrially important enzymes from entire scientific sectors. By keeping in mind the extensive industrial applications of cellulase, this study was performed to immobilize the indigenous enzyme produced from Trichoderma viride under pre-optimized SSF of an agricultural waste material, wheat straw. To enhance the bio-catalytic and tolerance properties of the present enzyme gel matrix immobilization engineering was applied. Previously, 2.33~fold purified novel cellulase was immobilized in to a xerogel matrix of TMOS and PTMS. FTIR spectroscopy confirmed the successful immobilization of cellulase. The free and immobilized cellulase was characterized and stability profile showed that after 24 h incubation, immobilization enhanced the thermo-stability up to 75% against 80℃ as compare to the free enzyme. Xerogel matrix immobilization enhanced the catalytic efficiency of entrapped enzyme than that of the free cellulase. Among activators/inhibitors SDS, EDTA, and Hg2+ showed inhibitory effect while, gel matrix immobilization enhanced 80% tolerance capacity of the cellulase against inactivating agents.展开更多
Under the renewable energy context, sugarcane biomass pyrolysis has been growing as a convenient route to produce bio-oil, which can be set into the chemical industry and refineries as building blocks or combustion fu...Under the renewable energy context, sugarcane biomass pyrolysis has been growing as a convenient route to produce bio-oil, which can be set into the chemical industry and refineries as building blocks or combustion fuel. In this work sugarcane straw was submitted to direct pyrolysis in a fluidized bed pilot plant at 500°C, in presence of air. Sugarcane in natura was also pyrolysed as a model for comparison, in order to determine the viability of processing different sources of raw biomass. The physicochemical characterization of the biomass precursors as well as of the bio-oils was also carried out, which points both biomass feedstocks as suitable for bio-oil production in terms of viscosity, surface tension, density and acidity. The bio-oil obtained from sugarcane in natura presented higher carbon and hydrogen content as well as lower oxygen content. On the other hand, the metal content is higher in the bio-oil obtained from sugarcane straw, in special the iron and potassium contents were 807 ppm and 123 ppm against 27 ppm and 1 ppm in the bio-oil from sugarcane in natura. Aliphatic and aromatic compounds as well as carbohydrates scaffolds were identified as the main components of the bio-oil. GC-MS analyses showed aromatic products from lignine fragmentation and free sugars and sugar derivatives.展开更多
Bio-glycerol was synthesized from Cameroon palm kernel oil (PKO) through the transesterification procedure. Palm kernel oil extracted from palm kernel seeds using mechanical expression and solvent extraction was purif...Bio-glycerol was synthesized from Cameroon palm kernel oil (PKO) through the transesterification procedure. Palm kernel oil extracted from palm kernel seeds using mechanical expression and solvent extraction was purified and characterized by physico-chemical methods and used in the transesterification process to give biodiesel and bio-glycerol. The biodiesel was purified and characterized as reported in previous articles. Our focus in this article is on glycerol, an important by-product of the transesterification process which has potential pharmaceutical, cosmetic and engineering applications. The bio-glycerol was purified by acidification and the purified glycerol was subjected to physical and chemical characterization. The specific gravity of glycerol was obtained as 1.2 kg/L, viscosity at 40°C gave 1500 cSt and 500 cSt at 100°C;pH was 7.4;the flash point was 160°C, and the ASTM color was 2.0 before purification and zero after purification. The sulfur content was 0.016%w/v. This sulfur content is low thus posing no environment threat. The chemical composition of the synthesized bio-glycerol determined using IR spectroscopy and gas chromatography-mass spectrometry (GC-MS) confirmed the known chemical structure of glycerol. The purification and analysis of bio-glycerol is important as it can find applications in the pharmaceutical, cosmetic and food industries inter alia.展开更多
In this work, a modification of the sugarcane bagasse is performed, in order to obtain organic catalysts. The bagasse analysis is performed using X-ray diffraction (XRD) and Fourier Transformer Infrared Spectroscopy (...In this work, a modification of the sugarcane bagasse is performed, in order to obtain organic catalysts. The bagasse analysis is performed using X-ray diffraction (XRD) and Fourier Transformer Infrared Spectroscopy (FTIR), which indicated that characteristic peaks determined its chemical compounds. In addition, Scanning Electron Microscopy (SEM) is used to know the morphology. Finally, a discoloration test is conducted on an azo compound (methylene blue) in an aqueous medium, obtaining an efficiency of 98.6%.展开更多
文摘Hydroxyapatite (HA) having chemical formula Ca10(PO<sub>4</sub>)<sub>6</sub>(OH)<sub>2</sub>, is the main chemical component of human bone tissue (70%). This is the reason why it has been widely engaged in the dental and non-load bearing implantations, to cope up with the bone response as a bioactive material. In this study HA powder was synthesized by wet chemical method, using phosphoric acid (H3PO4) and eggshells. The synthesized HA powder was characterized by X-ray diffraction analysis, Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX) and Fourier transform (FT-IR) spectroscopy. The Thermos gravimetric analysis (TGA-DTA) was also carried out to evaluate the stability of the synthesized HA powder at higher temperatures. The results of the study indicate that sintered (at 900°C) HA powder resembles the feature of pure and single apatite phase having favourable Ca/P ratio ranging from 1.7 to 2.4.
基金Supported by the National Science and Technology Supporting Plan Through Contract(2015BAD15B06)the National Natural Science Foundation of China(51276166)+1 种基金the National Basic Research Program of China(2013CB228101)Guangdong Province Key Laboratory of Efficient and Clean Energy Utilization(2013A061401005)
文摘Pyrolytic lignin, the water-insoluble fraction in bio-oil, often shows a high content and has strong intermolecular interactions with other compounds in bio-oil. In order to obtain pure pyrolytic lignin and facilitate the utilization of aqueous phase obtained from water extraction of bio-oil, methanol–water extraction method was employed to further separate the bio-oil water-insoluble phase in this paper. Different technologies, including Fourier transform infrared spectroscopy, gel permeation chromatography, and nuclear magnetic resonance, were adopted to characterize the structures of pyrolytic lignins with different activities obtained through this method. Both the heating value and the polymerization degree of high-molecular-weight pyrolytic lignin were higher than those of low-molecular-weight pyrolytic lignin. The molecular weight distribution of high-molecular-weight pyrolytic lignin was relatively wider, among which the contents of dimers to pentamers all accounted for 12% –18%,while the low-molecular-weight pyrolytic lignin mainly consisted of trimers(75.38%). The pyrolytic lignins had similar basic structures, both of which contained syringyl and guaiacyl units, whereas the low-molecular-weight pyrolytic lignin had more abundant syringyl units, reactive carbonyl groups and hydroxyl groups. Meanwhile,thermogravimetric study revealed that the final char residue yield of low-molecular-weight pyrolytic lignin was lower than that of high-molecular-weight pyrolytic lignin.
文摘Today, demand exists for cost-effective production of industrially important enzymes from entire scientific sectors. By keeping in mind the extensive industrial applications of cellulase, this study was performed to immobilize the indigenous enzyme produced from Trichoderma viride under pre-optimized SSF of an agricultural waste material, wheat straw. To enhance the bio-catalytic and tolerance properties of the present enzyme gel matrix immobilization engineering was applied. Previously, 2.33~fold purified novel cellulase was immobilized in to a xerogel matrix of TMOS and PTMS. FTIR spectroscopy confirmed the successful immobilization of cellulase. The free and immobilized cellulase was characterized and stability profile showed that after 24 h incubation, immobilization enhanced the thermo-stability up to 75% against 80℃ as compare to the free enzyme. Xerogel matrix immobilization enhanced the catalytic efficiency of entrapped enzyme than that of the free cellulase. Among activators/inhibitors SDS, EDTA, and Hg2+ showed inhibitory effect while, gel matrix immobilization enhanced 80% tolerance capacity of the cellulase against inactivating agents.
文摘Under the renewable energy context, sugarcane biomass pyrolysis has been growing as a convenient route to produce bio-oil, which can be set into the chemical industry and refineries as building blocks or combustion fuel. In this work sugarcane straw was submitted to direct pyrolysis in a fluidized bed pilot plant at 500°C, in presence of air. Sugarcane in natura was also pyrolysed as a model for comparison, in order to determine the viability of processing different sources of raw biomass. The physicochemical characterization of the biomass precursors as well as of the bio-oils was also carried out, which points both biomass feedstocks as suitable for bio-oil production in terms of viscosity, surface tension, density and acidity. The bio-oil obtained from sugarcane in natura presented higher carbon and hydrogen content as well as lower oxygen content. On the other hand, the metal content is higher in the bio-oil obtained from sugarcane straw, in special the iron and potassium contents were 807 ppm and 123 ppm against 27 ppm and 1 ppm in the bio-oil from sugarcane in natura. Aliphatic and aromatic compounds as well as carbohydrates scaffolds were identified as the main components of the bio-oil. GC-MS analyses showed aromatic products from lignine fragmentation and free sugars and sugar derivatives.
文摘Bio-glycerol was synthesized from Cameroon palm kernel oil (PKO) through the transesterification procedure. Palm kernel oil extracted from palm kernel seeds using mechanical expression and solvent extraction was purified and characterized by physico-chemical methods and used in the transesterification process to give biodiesel and bio-glycerol. The biodiesel was purified and characterized as reported in previous articles. Our focus in this article is on glycerol, an important by-product of the transesterification process which has potential pharmaceutical, cosmetic and engineering applications. The bio-glycerol was purified by acidification and the purified glycerol was subjected to physical and chemical characterization. The specific gravity of glycerol was obtained as 1.2 kg/L, viscosity at 40°C gave 1500 cSt and 500 cSt at 100°C;pH was 7.4;the flash point was 160°C, and the ASTM color was 2.0 before purification and zero after purification. The sulfur content was 0.016%w/v. This sulfur content is low thus posing no environment threat. The chemical composition of the synthesized bio-glycerol determined using IR spectroscopy and gas chromatography-mass spectrometry (GC-MS) confirmed the known chemical structure of glycerol. The purification and analysis of bio-glycerol is important as it can find applications in the pharmaceutical, cosmetic and food industries inter alia.
文摘In this work, a modification of the sugarcane bagasse is performed, in order to obtain organic catalysts. The bagasse analysis is performed using X-ray diffraction (XRD) and Fourier Transformer Infrared Spectroscopy (FTIR), which indicated that characteristic peaks determined its chemical compounds. In addition, Scanning Electron Microscopy (SEM) is used to know the morphology. Finally, a discoloration test is conducted on an azo compound (methylene blue) in an aqueous medium, obtaining an efficiency of 98.6%.
