Catalytic hydrodeoxygenation(HDO)is one of the most promising strategies to transform oxygen-rich biomass derivatives into high value-added chemicals and fuels,but highly challenging due to the lack of highly efficien...Catalytic hydrodeoxygenation(HDO)is one of the most promising strategies to transform oxygen-rich biomass derivatives into high value-added chemicals and fuels,but highly challenging due to the lack of highly efficient nonprecious metal catalysts.Herein,we report for the first time of a facile synthetic approach to controllably fabricate well-defined Ni-Co alloy NPs confined on the tip of N-CNTs as HDO catalyst.The resultant Ni-Co alloy catalyst possesses outstanding HDO performance towards biomass-derived vanillin into 2-methoxy-4-methylphenol in water with 100%conversion efficiency and selectivity under mild reaction conditions,surpassing the reported high performance nonprecious HDO catalysts.Impressively,our experimental results also unveil that the Ni-Co alloy catalyst can be generically applied to catalyze HDO of vanillin derivatives and other aromatic aldehydes in water with 100%conversion efficiency and over 90%selectivity.Importantly,our DFT calculations and experimental results confirm that the achieved outstanding HDO catalytic performance is due to the greatly promoted selective adsorption and activation of C=O,and desorption of the activated hydrogen species by the synergism of the alloyed Ni-Co NPs.The findings of this work affords a new strategy to design and develop efficient transition metal-based catalysts for HDO reactions in water.展开更多
The solvent extraction of copper and zinc from the bioleaching solutions of low-grade sulfide ores with LIX984 and D2EHPA was investigated. The influences of extractant content, aqueous pH value, phase ratio and (equi...The solvent extraction of copper and zinc from the bioleaching solutions of low-grade sulfide ores with LIX984 and D2EHPA was investigated. The influences of extractant content, aqueous pH value, phase ratio and (equilibration) time on metals extraction were studied. The results show that LIX984 has a higher selectivity for copper than for iron, zinc and other metals, and has the copper extraction rate above 97%, while the zinc and iron extraction rate is less than 1.6% respectively. Zinc extraction is carried out following the copper extraction from the raffinate. The zinc extraction with di(2-ethylhexyl) phosphoric acid(D2EHPA) is low due to its poor cation exchange. A sodium salt of D2EHPA is used and the zinc extraction rate is enhanced to above 98%. Though iron (Ⅲ) is strongly extracted before the extraction of zinc by D2EHPA, it is difficult to strip iron from the organic phase by sulfuric acid. The zinc stripping rate is above 99% with 100g/L sulfuric acid, while that of iron is 0.16%. Hence, the separation of zinc from iron can be achieved by the selective stripping.展开更多
[Objective] This study aimed to compare the contents of total alkaloids in different solvent extracts from climbing groundsel herb produced in Guizhou Province and their antibacterial activity. [Method] The content of...[Objective] This study aimed to compare the contents of total alkaloids in different solvent extracts from climbing groundsel herb produced in Guizhou Province and their antibacterial activity. [Method] The content of total alkaloids was measured by UV spectrophotometry, and Oxford cups were used to investigate the antibacterial activity of each solvent extract. [Result] There was a good linear correlation between the absorbance measured by the UV spectrophotometer and the content of total al- kaloids within the concentration of 0.011 0-0.054 8 mg/ml at 207 nm, and the re- gression equation was Y=23.654X＋0.021, R=0. 999 7 and the average recovery rate was 99.2%. The contents of total alkaloids in 60% ethanol extract, 95% ethanol and water ethanol were 38.71, 52.25 and 60.50 mg/g, respectively. The 60% ethanol ex- tract had strong antibacterial activity against Streptococcus pneumoniae, Staphylo- coccus aureus and Escherichia coil; the water extractive had stronger antibacterial activity against Escherichia colr, 95% ethanol extract had weak antibacterial activity, with no inhibition of Pseudomonas aeruginosa. [Conclusion] This method is accurate, simple, with good repeatability, which can be used for the determination of alkaloids content of the climbing groundsel herb; there is no positive correlation between the content of total alkaloids in different solvent extracts of climbing groundsel herb and their antibacterial activity.展开更多
文摘Catalytic hydrodeoxygenation(HDO)is one of the most promising strategies to transform oxygen-rich biomass derivatives into high value-added chemicals and fuels,but highly challenging due to the lack of highly efficient nonprecious metal catalysts.Herein,we report for the first time of a facile synthetic approach to controllably fabricate well-defined Ni-Co alloy NPs confined on the tip of N-CNTs as HDO catalyst.The resultant Ni-Co alloy catalyst possesses outstanding HDO performance towards biomass-derived vanillin into 2-methoxy-4-methylphenol in water with 100%conversion efficiency and selectivity under mild reaction conditions,surpassing the reported high performance nonprecious HDO catalysts.Impressively,our experimental results also unveil that the Ni-Co alloy catalyst can be generically applied to catalyze HDO of vanillin derivatives and other aromatic aldehydes in water with 100%conversion efficiency and over 90%selectivity.Importantly,our DFT calculations and experimental results confirm that the achieved outstanding HDO catalytic performance is due to the greatly promoted selective adsorption and activation of C=O,and desorption of the activated hydrogen species by the synergism of the alloyed Ni-Co NPs.The findings of this work affords a new strategy to design and develop efficient transition metal-based catalysts for HDO reactions in water.
基金Project(50321402) supported by the National Natural Science Foundation of China
文摘The solvent extraction of copper and zinc from the bioleaching solutions of low-grade sulfide ores with LIX984 and D2EHPA was investigated. The influences of extractant content, aqueous pH value, phase ratio and (equilibration) time on metals extraction were studied. The results show that LIX984 has a higher selectivity for copper than for iron, zinc and other metals, and has the copper extraction rate above 97%, while the zinc and iron extraction rate is less than 1.6% respectively. Zinc extraction is carried out following the copper extraction from the raffinate. The zinc extraction with di(2-ethylhexyl) phosphoric acid(D2EHPA) is low due to its poor cation exchange. A sodium salt of D2EHPA is used and the zinc extraction rate is enhanced to above 98%. Though iron (Ⅲ) is strongly extracted before the extraction of zinc by D2EHPA, it is difficult to strip iron from the organic phase by sulfuric acid. The zinc stripping rate is above 99% with 100g/L sulfuric acid, while that of iron is 0.16%. Hence, the separation of zinc from iron can be achieved by the selective stripping.
基金Supported by the Clinical Scientific Research Capacity Construction Program for Country-level Hospitals of Department of Health,Guizhou Province(gzwxky2011-1-022)~~
文摘[Objective] This study aimed to compare the contents of total alkaloids in different solvent extracts from climbing groundsel herb produced in Guizhou Province and their antibacterial activity. [Method] The content of total alkaloids was measured by UV spectrophotometry, and Oxford cups were used to investigate the antibacterial activity of each solvent extract. [Result] There was a good linear correlation between the absorbance measured by the UV spectrophotometer and the content of total al- kaloids within the concentration of 0.011 0-0.054 8 mg/ml at 207 nm, and the re- gression equation was Y=23.654X＋0.021, R=0. 999 7 and the average recovery rate was 99.2%. The contents of total alkaloids in 60% ethanol extract, 95% ethanol and water ethanol were 38.71, 52.25 and 60.50 mg/g, respectively. The 60% ethanol ex- tract had strong antibacterial activity against Streptococcus pneumoniae, Staphylo- coccus aureus and Escherichia coil; the water extractive had stronger antibacterial activity against Escherichia colr, 95% ethanol extract had weak antibacterial activity, with no inhibition of Pseudomonas aeruginosa. [Conclusion] This method is accurate, simple, with good repeatability, which can be used for the determination of alkaloids content of the climbing groundsel herb; there is no positive correlation between the content of total alkaloids in different solvent extracts of climbing groundsel herb and their antibacterial activity.
