为提高杂粮与小浆果的利用度,研究复配乳酸菌发酵芸豆-蓝靛果复合汁制备发酵液并优化其工艺参数。选取四种乳酸菌对芸豆-蓝靛果复合汁接种发酵,以活菌数为指标筛选复配乳酸菌后,进行单因素实验及响应面优化试验确定复合发酵液的工艺参数...为提高杂粮与小浆果的利用度,研究复配乳酸菌发酵芸豆-蓝靛果复合汁制备发酵液并优化其工艺参数。选取四种乳酸菌对芸豆-蓝靛果复合汁接种发酵,以活菌数为指标筛选复配乳酸菌后,进行单因素实验及响应面优化试验确定复合发酵液的工艺参数,并对其理化性质、生物活性及抗氧化能力进行检测。结果表明,筛选得到复配乳酸菌L1:L2等比例复配接种芸豆-蓝靛果复合汁,优化得到的复合发酵液的最优工艺参数为原料复配比例1:1、初始pH5.0、接种量2%、发酵温度34℃,此条件下复合发酵液的活菌数为9.89 lg CFU/mL。经检测,复合发酵液中总酚及黄酮含量均在16 h达到最高,分别为2204.96μg/mL和701.09μg/mL。抗氧化实验表明,在发酵过程中芸豆-蓝靛果复合汁的DPPH自由基清除率及ABTS+自由基清除率呈现先上升后缓慢下降的趋势,最高清除值为98.23%和93.77%,最优条件制备的芸豆-蓝靛果复合发酵液抗氧化能力较强。展开更多
Leaching kinetics of acid-soluble Cr（VI） in chromite ore processing residue （COPR） using hydrofluoric （HF） acid solution as a leaching agent was investigated for potential remediation of COPR with industrial was...Leaching kinetics of acid-soluble Cr（VI） in chromite ore processing residue （COPR） using hydrofluoric （HF） acid solution as a leaching agent was investigated for potential remediation of COPR with industrial waste water containing HF. The results show that HF can effectively destabilize the Cr（VI）-bearing minerals, resulting in the mobilization of Cr（VI） from COPR into the leachate. Particle size significantly influences the leaching of acid-soluble Cr（VI） from COPR, followed by leaching time, whereas the effects of HF concentration and leaching temperature are slight and the influence of stirring rate is negligible. The leaching process of acid-soluble Cr（VI） from COPR is controlled by the diffusion through the product layer. The apparent activation energy is 8.696 kJ/mol and the reaction orders with respect to HF concentration and particle size is 0.493 8 and -2.013 3, respectively.展开更多
Four new coordination polymers,{[Cd(mbtx)(4OHphCOO)]NO_(3)}n(1),{[Zn(mbtx)(1,4-bdc)_(0.5)(H_(2)O)_(2)]·(1,4-bdc)_(0.5)·4H_(2)O}n(2),{[Cd2(mbtx)(5NO_(2)-bdc)_(2)(H_(2)O)_(3)]·4.5H_(2)O}n(3),and{[Zn(H_(2)...Four new coordination polymers,{[Cd(mbtx)(4OHphCOO)]NO_(3)}n(1),{[Zn(mbtx)(1,4-bdc)_(0.5)(H_(2)O)_(2)]·(1,4-bdc)_(0.5)·4H_(2)O}n(2),{[Cd2(mbtx)(5NO_(2)-bdc)_(2)(H_(2)O)_(3)]·4.5H_(2)O}n(3),and{[Zn(H_(2)O)6][Zn_(2)(mbtx)_(2)(btc)_(2)(H_(2)O)_(4)]·2H_(2)O}n(4)(mbtx=1,3-bis(4H-1,2,4-triazole)benzene,4OHphCOO-=p-hydroxybenzoate,1,4-bdc2-=1,4-benzenedicarboxylate,5NO_(2)-bdc2-=5-nitro-isophthalate,btc3-=1,3,5-benzenetricarboxylate),were synthesized under room temperature condition and characterized by single-crystal X-ray diffraction,elemental analyses,and powder X-ray diffraction.Single-crystal X-ray structural analysis shows that complexes 1 and 3 are 2D networks.In 1,the adjacent 2D networks are linked to a 3D network byπ-πstacking interaction.2 and 4 exhibit 1D chains,and the 1D chains are connected into a 3D network byπ-πstacking interaction and intermolecular hydrogen bond.Luminescence and thermogravimetric analysis of the four complexes were discussed.CCDC:2416406,1;2416407,2;2416408,3;2416409,4.展开更多
A new method of extracting chlorogenic acid from flos lonicerae, and treating the materials with enzyme before being extracted by ethanol is developed, and the optimum conditions are also investigated in detail. Three...A new method of extracting chlorogenic acid from flos lonicerae, and treating the materials with enzyme before being extracted by ethanol is developed, and the optimum conditions are also investigated in detail. Three important factors, enzyme dosage, treatment time and treatment temperature are adapted to optimize the extraction process. The experimental results show that the extract yield of flos lonicerae and chlorogenic acid can be obviously increased by the cellulase treatment, 61.5 mg chlorogenic acid is obtained from 1.00 g flos lonicerae at most. The optimal temperature of enzymatic treatment is 40 50 ℃. Compared with the use of single cellulase, the combined treatment of cellulase and pectinase increase the extract yield obviously but fail to improve that of chlorogenic acid.展开更多
PtRuIn/C electrocatalysts( 20% metal loading by weight) were prepared by sodium borohydride reduction process using H_2PtCl6·6H_2O,RuCl_3·xH_2O and InCl_3·xH_2O as metal sources,borohydride as reducing ...PtRuIn/C electrocatalysts( 20% metal loading by weight) were prepared by sodium borohydride reduction process using H_2PtCl6·6H_2O,RuCl_3·xH_2O and InCl_3·xH_2O as metal sources,borohydride as reducing agent and Carbon Vulcan XC72 as support. The synthetized PtRuIn/C electrocatalysts were characterized by X-ray diffraction( XRD),energy dispersive analysis( EDX),transmission electron microscopy( TEM),cyclic voltammetry( CV),chronoamperommetry( CA) and polarization curves in alkaline and acidic electrolytes( single cell experiments). The XRD patterns showPtpeaks are attributed to the face-centered cubic( fcc) structure,and a shift of Pt( fcc) peaks indicates that Ru or In is incorporated into Ptlattice. TEMmicrographs showmetal nanoparticles with an average nanoparticle size between 2.7 and 3.5 nm. Methanol oxidation in acidic and alkaline electrolytes was investigated at room temperature,by CV and CA. PtRu/C( 50 ∶ 50) shows the highest activity among all electrocatalysts in study considering methanol oxidation for acidic and alkaline electrolyte. Polarization curves at 80 ℃ showPtRuIn/C( 50 ∶ 25 ∶ 25)with superior performance for methanol oxidation,when compared to Pt/C,PtIn/C and PtRu/C for both electrolytes. The best performance obtained by PtRuIn/C( 50 ∶ 25 ∶ 25) in real conditions could be associated with the increased kinetics reaction and/or with the occurrence simultaneously of the bifunctional mechanism and electronic effect resulting from the presence of Ptalloy.展开更多
The main objective of this paper was to characterize the voltammetric profiles of the Pt/C,Pt/C-ATO,Pd/C and Pd/CATO electrocatalysts and study their catalytic activities for methane oxidation in an acidic electrolyte...The main objective of this paper was to characterize the voltammetric profiles of the Pt/C,Pt/C-ATO,Pd/C and Pd/CATO electrocatalysts and study their catalytic activities for methane oxidation in an acidic electrolyte at 25 ℃ and in a direct methane proton exchange membrane fuel cell at 80 ℃. The electrocatalysts prepared also were characterized by X-ray diffraction( XRD) and transmission electron microscopy( TEM). The diffractograms of the Pt/C and Pt/C-ATO electrocatalysts show four peaks associated with Pt face-centered cubic( fcc) structure,and the diffractograms of Pd/C and Pd/C-ATO show four peaks associated with Pd face-centered cubic( fcc) structure. For Pt/C-ATO and Pd/C-ATO,characteristic peaks of cassiterite( SnO_2) phase are observed,which are associated with Sb-doped SnO_2( ATO) used as supports for electrocatalysts. Cyclic voltammograms( CV) of all electrocatalysts after adsorption of methane show that there is a current increase during the anodic scan. However,this effect is more pronounced for Pt/C-ATO and Pd/C-ATO. This process is related to the oxidation of the adsorbed species through the bifunctional mechanism,where ATO provides oxygenated species for the oxidation of CO or HCO intermediates adsorbed in Pt or Pd sites. From in situ ATR-FTIR( Attenuated Total Reflectance-Fourier Transform Infrared) experiments for all electrocatalysts prepared the formation of HCO or CO intermediates are observed,which indicates the production of carbon dioxide. Polarization curves at 80 ℃in a direct methane fuel cell( DMEFC) show that Pd/C and Pt/C electroacatalysts have superior performance to Pd/C-ATO and Pt/C-ATO in methane oxidation.展开更多
Production of ursolic acid, the anti-hepatitis effective composition from natural plant,Sambucus chinensis Lindl.was carried out and the scale-up preparation technology was studied.Extraction of the herb Sambucus chin...Production of ursolic acid, the anti-hepatitis effective composition from natural plant,Sambucus chinensis Lindl.was carried out and the scale-up preparation technology was studied.Extraction of the herb Sambucus chinensis Lindl.was extracted in reflux with 7 volume times of refluxing ethanol at 80℃ for 1 h for two times.The extract was purified with a selt-made specific impurity remover “YCXY-1” to yield ursolic acid of high purity.A new “Extraction/Gelation” technology for the production of ursolic acid was developed. The specific impurity remover “YCXY-1” showed high effectiveness in purification. The purity of the mass-produced ursolic acid was up to 99.8%. The chemical structure of the product was confirmed by the physicochemical constants and spectroscopic identification. The production of high-purity ursolic acid was optimized with natural plant as raw material and with only ethanol as extracting solvent. The difficulties such as isolation and impurity removal were addressed effectively. The novel technology is reasonable, convenient, practical, low-cost, high-yield, suitable for mass production.展开更多
PdAuIr/C-Sb2O5·SnO2electrocatalysts with Pd∶Au∶Ir molar ratios of 90∶5∶5,70∶20∶10 and 50∶45∶5 were prepared by borohydride reduction method.These electrocatalysts were characterized by EDX,X-ray diffracti...PdAuIr/C-Sb2O5·SnO2electrocatalysts with Pd∶Au∶Ir molar ratios of 90∶5∶5,70∶20∶10 and 50∶45∶5 were prepared by borohydride reduction method.These electrocatalysts were characterized by EDX,X-ray diffraction,transmission electron microscopy and the catalytic activity toward formic acid electro-oxidation in acid medium investigated by cyclic voltammetry(CV),chroamperometry(CA)and tests on direct formic acid fuel cell(DFAFC)at 100℃.X-ray diffractograms of PdAuIr/C-Sb2O5·SnO2electrocatalysts showed the presence of Pd fcc phase,Pd-Au fcc alloys,carbon and ATO phases,while Ir phases were not observed.TEM micrographs and histograms indicated that the nanoparticles were not well dispersed on the support and some agglomerates.The cyclic voltammetry and chroamperometry studies showed that PdAuIr/C-Sb2O5·SnO2(50∶45∶5)had superior performance toward formic acid electro-oxidation at 25℃compared to PdAuIr/C-Sb2O5·SnO2(70∶20∶10),PdAuIr/C-Sb2O5·SnO2(90∶5∶5)and Pd/C-Sb2O5·SnO2electrocatalysts.The experiments in a single DFAFC also showed that all PdAuIr/C-Sb2O5·SnO2electrocatalysts exhibited higher performance for formic acid oxidation in comparison with Pd/C-Sb2O5·SnO2electrocatalysts,however PdAuIr/C-Sb2O5·SnO2(90∶5∶5)had superior performance.These results indicated that the addition of Au and Ir to Pd favor the electro-oxidation of formic acid,which could be attributed to the bifunctional mechanism(the presence of ATO,Au and Ir oxides species)associated to the electronic effect(Pd-Au fcc alloys).展开更多
文摘为提高杂粮与小浆果的利用度,研究复配乳酸菌发酵芸豆-蓝靛果复合汁制备发酵液并优化其工艺参数。选取四种乳酸菌对芸豆-蓝靛果复合汁接种发酵,以活菌数为指标筛选复配乳酸菌后,进行单因素实验及响应面优化试验确定复合发酵液的工艺参数,并对其理化性质、生物活性及抗氧化能力进行检测。结果表明,筛选得到复配乳酸菌L1:L2等比例复配接种芸豆-蓝靛果复合汁,优化得到的复合发酵液的最优工艺参数为原料复配比例1:1、初始pH5.0、接种量2%、发酵温度34℃,此条件下复合发酵液的活菌数为9.89 lg CFU/mL。经检测,复合发酵液中总酚及黄酮含量均在16 h达到最高,分别为2204.96μg/mL和701.09μg/mL。抗氧化实验表明,在发酵过程中芸豆-蓝靛果复合汁的DPPH自由基清除率及ABTS+自由基清除率呈现先上升后缓慢下降的趋势,最高清除值为98.23%和93.77%,最优条件制备的芸豆-蓝靛果复合发酵液抗氧化能力较强。
基金Project(2009FJ1009) supported by Major Program of Hunan Provincial Science and Technology, ChinaProject(2005CB6237) supported by the National Basic Research Program of China
文摘Leaching kinetics of acid-soluble Cr（VI） in chromite ore processing residue （COPR） using hydrofluoric （HF） acid solution as a leaching agent was investigated for potential remediation of COPR with industrial waste water containing HF. The results show that HF can effectively destabilize the Cr（VI）-bearing minerals, resulting in the mobilization of Cr（VI） from COPR into the leachate. Particle size significantly influences the leaching of acid-soluble Cr（VI） from COPR, followed by leaching time, whereas the effects of HF concentration and leaching temperature are slight and the influence of stirring rate is negligible. The leaching process of acid-soluble Cr（VI） from COPR is controlled by the diffusion through the product layer. The apparent activation energy is 8.696 kJ/mol and the reaction orders with respect to HF concentration and particle size is 0.493 8 and -2.013 3, respectively.
文摘Four new coordination polymers,{[Cd(mbtx)(4OHphCOO)]NO_(3)}n(1),{[Zn(mbtx)(1,4-bdc)_(0.5)(H_(2)O)_(2)]·(1,4-bdc)_(0.5)·4H_(2)O}n(2),{[Cd2(mbtx)(5NO_(2)-bdc)_(2)(H_(2)O)_(3)]·4.5H_(2)O}n(3),and{[Zn(H_(2)O)6][Zn_(2)(mbtx)_(2)(btc)_(2)(H_(2)O)_(4)]·2H_(2)O}n(4)(mbtx=1,3-bis(4H-1,2,4-triazole)benzene,4OHphCOO-=p-hydroxybenzoate,1,4-bdc2-=1,4-benzenedicarboxylate,5NO_(2)-bdc2-=5-nitro-isophthalate,btc3-=1,3,5-benzenetricarboxylate),were synthesized under room temperature condition and characterized by single-crystal X-ray diffraction,elemental analyses,and powder X-ray diffraction.Single-crystal X-ray structural analysis shows that complexes 1 and 3 are 2D networks.In 1,the adjacent 2D networks are linked to a 3D network byπ-πstacking interaction.2 and 4 exhibit 1D chains,and the 1D chains are connected into a 3D network byπ-πstacking interaction and intermolecular hydrogen bond.Luminescence and thermogravimetric analysis of the four complexes were discussed.CCDC:2416406,1;2416407,2;2416408,3;2416409,4.
文摘A new method of extracting chlorogenic acid from flos lonicerae, and treating the materials with enzyme before being extracted by ethanol is developed, and the optimum conditions are also investigated in detail. Three important factors, enzyme dosage, treatment time and treatment temperature are adapted to optimize the extraction process. The experimental results show that the extract yield of flos lonicerae and chlorogenic acid can be obviously increased by the cellulase treatment, 61.5 mg chlorogenic acid is obtained from 1.00 g flos lonicerae at most. The optimal temperature of enzymatic treatment is 40 50 ℃. Compared with the use of single cellulase, the combined treatment of cellulase and pectinase increase the extract yield obviously but fail to improve that of chlorogenic acid.
文摘PtRuIn/C electrocatalysts( 20% metal loading by weight) were prepared by sodium borohydride reduction process using H_2PtCl6·6H_2O,RuCl_3·xH_2O and InCl_3·xH_2O as metal sources,borohydride as reducing agent and Carbon Vulcan XC72 as support. The synthetized PtRuIn/C electrocatalysts were characterized by X-ray diffraction( XRD),energy dispersive analysis( EDX),transmission electron microscopy( TEM),cyclic voltammetry( CV),chronoamperommetry( CA) and polarization curves in alkaline and acidic electrolytes( single cell experiments). The XRD patterns showPtpeaks are attributed to the face-centered cubic( fcc) structure,and a shift of Pt( fcc) peaks indicates that Ru or In is incorporated into Ptlattice. TEMmicrographs showmetal nanoparticles with an average nanoparticle size between 2.7 and 3.5 nm. Methanol oxidation in acidic and alkaline electrolytes was investigated at room temperature,by CV and CA. PtRu/C( 50 ∶ 50) shows the highest activity among all electrocatalysts in study considering methanol oxidation for acidic and alkaline electrolyte. Polarization curves at 80 ℃ showPtRuIn/C( 50 ∶ 25 ∶ 25)with superior performance for methanol oxidation,when compared to Pt/C,PtIn/C and PtRu/C for both electrolytes. The best performance obtained by PtRuIn/C( 50 ∶ 25 ∶ 25) in real conditions could be associated with the increased kinetics reaction and/or with the occurrence simultaneously of the bifunctional mechanism and electronic effect resulting from the presence of Ptalloy.
基金The project was supported by the FAPESP(2014/09087-4,2014/50279-4).
文摘The main objective of this paper was to characterize the voltammetric profiles of the Pt/C,Pt/C-ATO,Pd/C and Pd/CATO electrocatalysts and study their catalytic activities for methane oxidation in an acidic electrolyte at 25 ℃ and in a direct methane proton exchange membrane fuel cell at 80 ℃. The electrocatalysts prepared also were characterized by X-ray diffraction( XRD) and transmission electron microscopy( TEM). The diffractograms of the Pt/C and Pt/C-ATO electrocatalysts show four peaks associated with Pt face-centered cubic( fcc) structure,and the diffractograms of Pd/C and Pd/C-ATO show four peaks associated with Pd face-centered cubic( fcc) structure. For Pt/C-ATO and Pd/C-ATO,characteristic peaks of cassiterite( SnO_2) phase are observed,which are associated with Sb-doped SnO_2( ATO) used as supports for electrocatalysts. Cyclic voltammograms( CV) of all electrocatalysts after adsorption of methane show that there is a current increase during the anodic scan. However,this effect is more pronounced for Pt/C-ATO and Pd/C-ATO. This process is related to the oxidation of the adsorbed species through the bifunctional mechanism,where ATO provides oxygenated species for the oxidation of CO or HCO intermediates adsorbed in Pt or Pd sites. From in situ ATR-FTIR( Attenuated Total Reflectance-Fourier Transform Infrared) experiments for all electrocatalysts prepared the formation of HCO or CO intermediates are observed,which indicates the production of carbon dioxide. Polarization curves at 80 ℃in a direct methane fuel cell( DMEFC) show that Pd/C and Pt/C electroacatalysts have superior performance to Pd/C-ATO and Pt/C-ATO in methane oxidation.
文摘Production of ursolic acid, the anti-hepatitis effective composition from natural plant,Sambucus chinensis Lindl.was carried out and the scale-up preparation technology was studied.Extraction of the herb Sambucus chinensis Lindl.was extracted in reflux with 7 volume times of refluxing ethanol at 80℃ for 1 h for two times.The extract was purified with a selt-made specific impurity remover “YCXY-1” to yield ursolic acid of high purity.A new “Extraction/Gelation” technology for the production of ursolic acid was developed. The specific impurity remover “YCXY-1” showed high effectiveness in purification. The purity of the mass-produced ursolic acid was up to 99.8%. The chemical structure of the product was confirmed by the physicochemical constants and spectroscopic identification. The production of high-purity ursolic acid was optimized with natural plant as raw material and with only ethanol as extracting solvent. The difficulties such as isolation and impurity removal were addressed effectively. The novel technology is reasonable, convenient, practical, low-cost, high-yield, suitable for mass production.
基金the Laboratório de Microscopia do Centro de Ciências e Tecnologia de Materiais(CCTM) by TEM measurements,FAPESP(2011/18246-0,2012/03516-5) and CNPQ(150639/2013-9)for the financial support
文摘PdAuIr/C-Sb2O5·SnO2electrocatalysts with Pd∶Au∶Ir molar ratios of 90∶5∶5,70∶20∶10 and 50∶45∶5 were prepared by borohydride reduction method.These electrocatalysts were characterized by EDX,X-ray diffraction,transmission electron microscopy and the catalytic activity toward formic acid electro-oxidation in acid medium investigated by cyclic voltammetry(CV),chroamperometry(CA)and tests on direct formic acid fuel cell(DFAFC)at 100℃.X-ray diffractograms of PdAuIr/C-Sb2O5·SnO2electrocatalysts showed the presence of Pd fcc phase,Pd-Au fcc alloys,carbon and ATO phases,while Ir phases were not observed.TEM micrographs and histograms indicated that the nanoparticles were not well dispersed on the support and some agglomerates.The cyclic voltammetry and chroamperometry studies showed that PdAuIr/C-Sb2O5·SnO2(50∶45∶5)had superior performance toward formic acid electro-oxidation at 25℃compared to PdAuIr/C-Sb2O5·SnO2(70∶20∶10),PdAuIr/C-Sb2O5·SnO2(90∶5∶5)and Pd/C-Sb2O5·SnO2electrocatalysts.The experiments in a single DFAFC also showed that all PdAuIr/C-Sb2O5·SnO2electrocatalysts exhibited higher performance for formic acid oxidation in comparison with Pd/C-Sb2O5·SnO2electrocatalysts,however PdAuIr/C-Sb2O5·SnO2(90∶5∶5)had superior performance.These results indicated that the addition of Au and Ir to Pd favor the electro-oxidation of formic acid,which could be attributed to the bifunctional mechanism(the presence of ATO,Au and Ir oxides species)associated to the electronic effect(Pd-Au fcc alloys).
