采用高效液相色谱-串联质谱(HPLC-MS/MS)技术研究了新型反相分配和强阳离子交换固相萃取柱的性能,确定了该新型固相萃取柱的最佳p H值、最佳流速、最大吸附容量及饱和吸附容量。研究了新型固相萃取柱对三聚氰胺在不同起始浓度下的吸附...采用高效液相色谱-串联质谱(HPLC-MS/MS)技术研究了新型反相分配和强阳离子交换固相萃取柱的性能,确定了该新型固相萃取柱的最佳p H值、最佳流速、最大吸附容量及饱和吸附容量。研究了新型固相萃取柱对三聚氰胺在不同起始浓度下的吸附动力学和不同温度下的吸附热力学性能,并对吸附等温线数据进行了拟合。结果显示:该新型固相萃取柱的最佳吸附p H值为5.0,最佳流速为1.0 m L/min,最佳洗脱体积为1.0 m L,最大吸附量为900μg。30℃下该萃取柱的饱和吸附容量为81.45μg/mg。该吸附过程符合准二级动力学吸附模型,吸附等温线符合Langmuir吸附模型,且该过程为自发进行的吸热反应。展开更多
Developing high-performance lithium ion batteries(LIBs)using manganese oxides as anodes is attractive due to their high theoretical capacity and abundant resources.Herein,we report a facile synthesis of hierarchical s...Developing high-performance lithium ion batteries(LIBs)using manganese oxides as anodes is attractive due to their high theoretical capacity and abundant resources.Herein,we report a facile synthesis of hierarchical spherical MnO2 containing coherent amorphous/crystalline domained by a simple yet effective redox precipitation reaction at room temperature.Further,flower-like CoMn2O4 constructed by single-crystalline spinel nanosheets has been fabricated using MnO2 as precursor.This mild methodology avoids undesired particle aggregation and loss of active surface area in conventional hydrothermal or solid-state processes.Moreover,both MnO2 and CoMn2O4 nanosheets manifest superior lithium-ion storage properties,rendering them promising applications in LIBs and other energy-related fields.展开更多
The development of stable and efficient visible light-absorbing oxide-based semiconductor photocatalysts is a desirable task for solar water splitting applications.Recently,we proposed that the low photocurrent densit...The development of stable and efficient visible light-absorbing oxide-based semiconductor photocatalysts is a desirable task for solar water splitting applications.Recently,we proposed that the low photocurrent density in film-based BiFeO_(3)(BFO)is due to charge recombination at the interface of the domain walls,which could be largely reduced in particulate photocatalyst systems.To demonstrate this hypothesis,in this work we synthesized particulate BFO and Mn-doped BiFeO_(3)(Mn-BFO)by the sol-gel method.Photocatalytic water oxidation tests showed that pure BFO had an intrinsic photocatalytic oxygen evolution reaction(OER)activity of 70μmol h^(-1) g^(-1),while BFO-2,with an optimum amount of Mn doping(0.05%),showed an OER activity of 255μmol h^(-1) g^(-1) under visible light(λ≥420 nm)irradiation.The bandgap of Mn-doped BFO could be reduced from 2.1 to 1.36 eV by varying the amount of Mn doping.Density functional theory(DFT)calculations suggested that surface Fe(rather than Mn)species serve as the active sites for water oxidation,because the overpotential for water oxidation on Fe species after Mn doping is 0.51 V,which is the lowest value measured for the different Fe and Mn species examined in this study.The improved photocatalytic water oxidation activity of Mn-BFO is ascribed to the synergistic effect of the bandgap narrowing,which increases the absorption of visible light,reduces the activation energy of water oxidation,and inhibits the recombination of photogenerated charges.This work demonstrates that Mn doping is an effective strategy to enhance the intrinsic photocatalytic water oxidation activity of particulate ferroelectric BFO photocatalysts.展开更多
Li4Ti5O12/C composite materials were synthesized by two-step solid state reaction method with glucose, sucrose, and starch as carbon sources, respectively. The effects of carbon sources on the structure, morphology, a...Li4Ti5O12/C composite materials were synthesized by two-step solid state reaction method with glucose, sucrose, and starch as carbon sources, respectively. The effects of carbon sources on the structure, morphology, and electrochemical performance of Li4Ti5O12/C composite materials were investigated by SEM, XRD and electrochemical tests. The results indicate that carbon sources have almost no effect on the structure of Li4Ti5O12/C composite materials. The initial discharge capacities of the Li4Ti1O12/C composite materials are slightly lower than those of as-synthesized Li4Ti5O12. However, Li4Ti5O12/C composite materials show better electrochemical rate performance than the as-synthesized Li4Ti5O12. The capacity retention （79%） of the Li4Ti5O12/C composite materials with starch as carbon source, is higher than that of Li4Ti5O12/C composite materials with glucose and sucrose as carbon source at current rate of 2.0C.展开更多
A skutterudite-related antimonide, CoFe3Sb12,was prepared with vacuum melting.XRD analysis showed the material contained Sb, FeSb2, CoSb2 and CoSb3 phases.The electrochemical properties of the ball-milled CoFe3Sb12-10...A skutterudite-related antimonide, CoFe3Sb12,was prepared with vacuum melting.XRD analysis showed the material contained Sb, FeSb2, CoSb2 and CoSb3 phases.The electrochemical properties of the ball-milled CoFe3Sb12-10wt% graphite composite were studied using pure lithium as the reference electrode. A maximal lithium inserting capacity of about 860 mAh/g was obtained in the first cycle.The reversible capacity of the material was about 560mAh/g in the first cycle and decreased to ca.320 mAh/g and 250 mAh/g after 10 and 20 cycles respectively.Ex-situ XRD analyses showed that the antimonides in the pristine material were decomposed after the first discharge and that antimony was the active element for lithium to insert into the host material.展开更多
In this work, SiO2 nanoplates with opened macroporous structure on carbon layer （C-mSiO2） have been obtained by dissolving and subsequent ingrowing the outer solid SiO2 layer of the aerosol-based C-SiO2 double-shell...In this work, SiO2 nanoplates with opened macroporous structure on carbon layer （C-mSiO2） have been obtained by dissolving and subsequent ingrowing the outer solid SiO2 layer of the aerosol-based C-SiO2 double-shell hollow spheres. Subsequently, triple-shell C-mSiO2-C hollow spheres were successfully prepared after coating the C- mSiO2 templates by the carbon layer from the carbonization of sucrose. When being applied as the anode material fur lithium-ion batteries, the C-mSiO2-C triple-shell hollow spheres deliver a high capacity of 501 mA. h.g- 1 after 100 cycles at 500 mA.g-1 （based on the total mass of silica and the two carbon shells）, which is higher than those of C-mSiO2 （391 mA.h.g 1） spheres with an outer porous SiO2 layer, C-SiO2-C （370 mA-h.g-1） hollow spheres with a middle solid Si02 layer, and C-SiO2 （319.8 mA·h-g-1） spheres with an outer solid SiO2 layer. In addition, the battery still delivers a high capacity of 403 mA· h· g- 1 at a current density of 1000 mA· g- 1 after 400 cycles. The good electrochemical performance can be attributed to the high surface area （246.7 m2·g- 1 ） and pore volume （0.441 cm3· g-1） of the anode materials, as well as the unique structure of the outer and inner carbon layer which not only enhances electrical conductivity, structural stability, but buffers volume change of the intermediate SiO2 layer during repeated charge-discharge processes. Furthermore, the SiO2 nanoplates with opened macroporous structure facilitate the electrolyte transport and electrochemical reaction.展开更多
The cost of raw materials has the largest contribution to the final price of biodiesel produced by traditional routes, currently adopted in most industrial scale processes. That contribution comes from the need to use...The cost of raw materials has the largest contribution to the final price of biodiesel produced by traditional routes, currently adopted in most industrial scale processes. That contribution comes from the need to use edible and noble oils, with low acidity, such as soybean oil. This work proposes＇the use of Macauba oil, a vegetable oil in focus in the State of Minas Gerais, Brazil, in which the current extractive yield generates a raw material with high acidity, therefore, not suitable to be used in biodiesel production. To make it technically feasible, a cationic exchange resin, the Purolite CT275DR, was used as a catalyst for esterification reaction with samples of Macauba oil, aiming to reduce its acidity. The resin can be reused, regenerated and easily removed from the reaction product, reducing costs with catalyst and purification stages. As a result of this work, in a sample of oil with an initial acidity of about 10% m/m were achieved acidity reductions up to 97% by using cationic resins as catalyst, demonstrating its potential use in the oil pretreatrnent step. Additionally, the data collected during all the analysis made it possible to define the chemical kinetic of the esterification reaction.展开更多
The objective of this research was to investigate the optimum condition for treatment of textile industrial wastewater from water jet loom machine by chemical coagulation and electrocoagulation methods. The variables ...The objective of this research was to investigate the optimum condition for treatment of textile industrial wastewater from water jet loom machine by chemical coagulation and electrocoagulation methods. The variables of chemical coagulation method were type and amount of chemicals, pH and stirring rate. For electrocoagulation method, the variables were electrode materials, electric potential and contact time. It was found that the optimum condition of chemical coagulation method was 10% （w/w） of aqueous solution of aluminum sulphate 80 mL and 0.01% （w/w） of aqueous solution of coagulant aids, cationic polymer 32 mL per 4 L of wastewater at oH 8. The mixture solution was rapidly stirred with 120 rpm for 1 min and then slowly stirred with 20 rpm for 20 rain. The removal efficiency of turbidity, COD and oil content were 88.88%, 85.20% and 77.72%, respectively. For electrocoagulation method, the optimum condition was using aluminum electrode with 35 V and 150 min of contact time. The removal efficiency of turbidity, COD and oil content were 98.86%, 91.63% and 89.84%, respectively. It can be concluded from this study that the textile industrial wastewater treatment from water jet loom machine with electrocoagulation method is more efficient than that with chemical coagulation method.展开更多
目的:建立一种重组高密度脂蛋白(reconstituted high density lipoprotein,rHDL)载p53基因纳米粒的制备方法。方法:采用阳离子脂质材料包裹、压缩p53基因,形成复合物,考察其粒径、电位、体外稳定性;薄膜分散法制备rHDL载基因纳米粒,并研...目的:建立一种重组高密度脂蛋白(reconstituted high density lipoprotein,rHDL)载p53基因纳米粒的制备方法。方法:采用阳离子脂质材料包裹、压缩p53基因,形成复合物,考察其粒径、电位、体外稳定性;薄膜分散法制备rHDL载基因纳米粒,并研究rHDL载基因纳米粒的粒径、电位、形态、包封率和血清稳定性。结果:选用双十八烷基二甲基溴化铵(dimethyldioctadecylammonium bromide,DODAB)压缩p53基因形成DODAB/p53复合物;在最优N/P比时,该复合物粒径为(102.0±0.7)nm,电位为(10.50±0.75)mV,复合物仅在高浓度肝素条件下出现解聚,且其血清稳定性良好。rHDL能有效包载上述复合物形成rHDL载基因纳米粒,该纳米粒粒径为(104.3±5.8)nm,电位为(-10.70±3.24)mV,外观呈球形结构,p53基因包封率为78.09%,且血清稳定性良好。结论:成功制备了rHDL载p53基因纳米粒,且该纳米粒具有良好的理化性质及体外稳定性,为其后期体内外抗肿瘤作用的研究打下了实验基础。展开更多
文摘采用高效液相色谱-串联质谱(HPLC-MS/MS)技术研究了新型反相分配和强阳离子交换固相萃取柱的性能,确定了该新型固相萃取柱的最佳p H值、最佳流速、最大吸附容量及饱和吸附容量。研究了新型固相萃取柱对三聚氰胺在不同起始浓度下的吸附动力学和不同温度下的吸附热力学性能,并对吸附等温线数据进行了拟合。结果显示:该新型固相萃取柱的最佳吸附p H值为5.0,最佳流速为1.0 m L/min,最佳洗脱体积为1.0 m L,最大吸附量为900μg。30℃下该萃取柱的饱和吸附容量为81.45μg/mg。该吸附过程符合准二级动力学吸附模型,吸附等温线符合Langmuir吸附模型,且该过程为自发进行的吸热反应。
基金Project(JCYJ20170817110251498)supported by the Basic Research Project of the Science and Technology Innovation Commission of Shenzhen,ChinaProject(2016TQ03C919)supported by the Guangdong Special Support for the Science and Technology Leading Young Scientist,ChinaProject(21603094)supported by the National Natural Science Foundation of China
文摘Developing high-performance lithium ion batteries(LIBs)using manganese oxides as anodes is attractive due to their high theoretical capacity and abundant resources.Herein,we report a facile synthesis of hierarchical spherical MnO2 containing coherent amorphous/crystalline domained by a simple yet effective redox precipitation reaction at room temperature.Further,flower-like CoMn2O4 constructed by single-crystalline spinel nanosheets has been fabricated using MnO2 as precursor.This mild methodology avoids undesired particle aggregation and loss of active surface area in conventional hydrothermal or solid-state processes.Moreover,both MnO2 and CoMn2O4 nanosheets manifest superior lithium-ion storage properties,rendering them promising applications in LIBs and other energy-related fields.
文摘The development of stable and efficient visible light-absorbing oxide-based semiconductor photocatalysts is a desirable task for solar water splitting applications.Recently,we proposed that the low photocurrent density in film-based BiFeO_(3)(BFO)is due to charge recombination at the interface of the domain walls,which could be largely reduced in particulate photocatalyst systems.To demonstrate this hypothesis,in this work we synthesized particulate BFO and Mn-doped BiFeO_(3)(Mn-BFO)by the sol-gel method.Photocatalytic water oxidation tests showed that pure BFO had an intrinsic photocatalytic oxygen evolution reaction(OER)activity of 70μmol h^(-1) g^(-1),while BFO-2,with an optimum amount of Mn doping(0.05%),showed an OER activity of 255μmol h^(-1) g^(-1) under visible light(λ≥420 nm)irradiation.The bandgap of Mn-doped BFO could be reduced from 2.1 to 1.36 eV by varying the amount of Mn doping.Density functional theory(DFT)calculations suggested that surface Fe(rather than Mn)species serve as the active sites for water oxidation,because the overpotential for water oxidation on Fe species after Mn doping is 0.51 V,which is the lowest value measured for the different Fe and Mn species examined in this study.The improved photocatalytic water oxidation activity of Mn-BFO is ascribed to the synergistic effect of the bandgap narrowing,which increases the absorption of visible light,reduces the activation energy of water oxidation,and inhibits the recombination of photogenerated charges.This work demonstrates that Mn doping is an effective strategy to enhance the intrinsic photocatalytic water oxidation activity of particulate ferroelectric BFO photocatalysts.
基金Project(2007BAE12B01) supported by the National Key Technology Research and Development Program of China
文摘Li4Ti5O12/C composite materials were synthesized by two-step solid state reaction method with glucose, sucrose, and starch as carbon sources, respectively. The effects of carbon sources on the structure, morphology, and electrochemical performance of Li4Ti5O12/C composite materials were investigated by SEM, XRD and electrochemical tests. The results indicate that carbon sources have almost no effect on the structure of Li4Ti5O12/C composite materials. The initial discharge capacities of the Li4Ti1O12/C composite materials are slightly lower than those of as-synthesized Li4Ti5O12. However, Li4Ti5O12/C composite materials show better electrochemical rate performance than the as-synthesized Li4Ti5O12. The capacity retention （79%） of the Li4Ti5O12/C composite materials with starch as carbon source, is higher than that of Li4Ti5O12/C composite materials with glucose and sucrose as carbon source at current rate of 2.0C.
文摘A skutterudite-related antimonide, CoFe3Sb12,was prepared with vacuum melting.XRD analysis showed the material contained Sb, FeSb2, CoSb2 and CoSb3 phases.The electrochemical properties of the ball-milled CoFe3Sb12-10wt% graphite composite were studied using pure lithium as the reference electrode. A maximal lithium inserting capacity of about 860 mAh/g was obtained in the first cycle.The reversible capacity of the material was about 560mAh/g in the first cycle and decreased to ca.320 mAh/g and 250 mAh/g after 10 and 20 cycles respectively.Ex-situ XRD analyses showed that the antimonides in the pristine material were decomposed after the first discharge and that antimony was the active element for lithium to insert into the host material.
基金Supported by the National Science Funding for Distinguished Young Scholars of China(21125628)National Natural Science Foundation of China(21476044)the Fundamental Research Funds for the Central Universities(DUT15QY08)
文摘In this work, SiO2 nanoplates with opened macroporous structure on carbon layer （C-mSiO2） have been obtained by dissolving and subsequent ingrowing the outer solid SiO2 layer of the aerosol-based C-SiO2 double-shell hollow spheres. Subsequently, triple-shell C-mSiO2-C hollow spheres were successfully prepared after coating the C- mSiO2 templates by the carbon layer from the carbonization of sucrose. When being applied as the anode material fur lithium-ion batteries, the C-mSiO2-C triple-shell hollow spheres deliver a high capacity of 501 mA. h.g- 1 after 100 cycles at 500 mA.g-1 （based on the total mass of silica and the two carbon shells）, which is higher than those of C-mSiO2 （391 mA.h.g 1） spheres with an outer porous SiO2 layer, C-SiO2-C （370 mA-h.g-1） hollow spheres with a middle solid Si02 layer, and C-SiO2 （319.8 mA·h-g-1） spheres with an outer solid SiO2 layer. In addition, the battery still delivers a high capacity of 403 mA· h· g- 1 at a current density of 1000 mA· g- 1 after 400 cycles. The good electrochemical performance can be attributed to the high surface area （246.7 m2·g- 1 ） and pore volume （0.441 cm3· g-1） of the anode materials, as well as the unique structure of the outer and inner carbon layer which not only enhances electrical conductivity, structural stability, but buffers volume change of the intermediate SiO2 layer during repeated charge-discharge processes. Furthermore, the SiO2 nanoplates with opened macroporous structure facilitate the electrolyte transport and electrochemical reaction.
文摘The cost of raw materials has the largest contribution to the final price of biodiesel produced by traditional routes, currently adopted in most industrial scale processes. That contribution comes from the need to use edible and noble oils, with low acidity, such as soybean oil. This work proposes＇the use of Macauba oil, a vegetable oil in focus in the State of Minas Gerais, Brazil, in which the current extractive yield generates a raw material with high acidity, therefore, not suitable to be used in biodiesel production. To make it technically feasible, a cationic exchange resin, the Purolite CT275DR, was used as a catalyst for esterification reaction with samples of Macauba oil, aiming to reduce its acidity. The resin can be reused, regenerated and easily removed from the reaction product, reducing costs with catalyst and purification stages. As a result of this work, in a sample of oil with an initial acidity of about 10% m/m were achieved acidity reductions up to 97% by using cationic resins as catalyst, demonstrating its potential use in the oil pretreatrnent step. Additionally, the data collected during all the analysis made it possible to define the chemical kinetic of the esterification reaction.
文摘The objective of this research was to investigate the optimum condition for treatment of textile industrial wastewater from water jet loom machine by chemical coagulation and electrocoagulation methods. The variables of chemical coagulation method were type and amount of chemicals, pH and stirring rate. For electrocoagulation method, the variables were electrode materials, electric potential and contact time. It was found that the optimum condition of chemical coagulation method was 10% （w/w） of aqueous solution of aluminum sulphate 80 mL and 0.01% （w/w） of aqueous solution of coagulant aids, cationic polymer 32 mL per 4 L of wastewater at oH 8. The mixture solution was rapidly stirred with 120 rpm for 1 min and then slowly stirred with 20 rpm for 20 rain. The removal efficiency of turbidity, COD and oil content were 88.88%, 85.20% and 77.72%, respectively. For electrocoagulation method, the optimum condition was using aluminum electrode with 35 V and 150 min of contact time. The removal efficiency of turbidity, COD and oil content were 98.86%, 91.63% and 89.84%, respectively. It can be concluded from this study that the textile industrial wastewater treatment from water jet loom machine with electrocoagulation method is more efficient than that with chemical coagulation method.
文摘目的:建立一种重组高密度脂蛋白(reconstituted high density lipoprotein,rHDL)载p53基因纳米粒的制备方法。方法:采用阳离子脂质材料包裹、压缩p53基因,形成复合物,考察其粒径、电位、体外稳定性;薄膜分散法制备rHDL载基因纳米粒,并研究rHDL载基因纳米粒的粒径、电位、形态、包封率和血清稳定性。结果:选用双十八烷基二甲基溴化铵(dimethyldioctadecylammonium bromide,DODAB)压缩p53基因形成DODAB/p53复合物;在最优N/P比时,该复合物粒径为(102.0±0.7)nm,电位为(10.50±0.75)mV,复合物仅在高浓度肝素条件下出现解聚,且其血清稳定性良好。rHDL能有效包载上述复合物形成rHDL载基因纳米粒,该纳米粒粒径为(104.3±5.8)nm,电位为(-10.70±3.24)mV,外观呈球形结构,p53基因包封率为78.09%,且血清稳定性良好。结论:成功制备了rHDL载p53基因纳米粒,且该纳米粒具有良好的理化性质及体外稳定性,为其后期体内外抗肿瘤作用的研究打下了实验基础。
