The effects of the calorimetric buffer solutions were investigated while the two colorimetric reactions of AI-ferron complex and Fe-ferron complex occurred individually, and the effects of the testing wavelength and t...The effects of the calorimetric buffer solutions were investigated while the two colorimetric reactions of AI-ferron complex and Fe-ferron complex occurred individually, and the effects of the testing wavelength and the pH of the solutions were also investigated. A timed complexatian colorimetric analysis method of Al-Fe-ferron in view of the total concentration of {AI + Fe} was then established to determine the species distribution of polymeric Al-Fe. The testing wavelength was recommended at 362 net and the testing pH value was 5. With a comparison of the ratios of n(Al)/n(Fe), the standard adsorption curves of the polymeric Al-Fe solutions were derived from the experimental results. Furthermore, the solutions' composition were carious in both the molar n(Al)/n(Fe) ratios, i.e. 0/0, 5/5, 9/1 and 0/10, and the concentrations associated with the total ( Al + Fe which ranged from 10(-5) to 10(-4) mol/L..展开更多
This article focused on the influences of fulvic acid and humic acid on aluminum speciation in drinking water. Factors including the concentration of residual chlorine and pH value had been concerned. Aluminum species...This article focused on the influences of fulvic acid and humic acid on aluminum speciation in drinking water. Factors including the concentration of residual chlorine and pH value had been concerned. Aluminum species investigated in the experiments included inorganic mononuclear, organic mononuclear, mononuclear, polymer, soluble, and suspended forms. It was found that the effects of fulvic acid and humic acid on aluminum speciation depended mainly on their molecular weight. Fulvic acid with molecular weight less than 5000 Dalton had little influence on aluminum speciation; while fulvic acid with molecular weight larger than 5000 Dalton and humic acid would increase the concentration of soluble aluminum significantly even at concentration below 0.5 mg/L （calculated as TOC）. Aluminum species, in the present of fulvic acid with molecular weight larger than 5000 Dalton and humic acid, were more stable than that in the present of fluvic acid with molecular mass less than 5000 Dalton, and varied little with reaction time. Within pH range 6.5-7.5, soluble aluminum increased notably in water with organic matter. As the concentration of residual chlorine increased, the effects of fulvic acid and humic acid became weak. The reactions between humic acid, fulvic acid with large molecular weight, and aluminum were considered to be a multi-dentate coordination process. With the consideration of aluminum bioavailability, reducing the concentration of fulvic acid and humic acid and keeping the pH value among 6.5-7.5 were recommended during drinking water treatment.展开更多
The exergy analysis and finite time thermodynamic methods had been employed to analyze the compound condensation process (CCP). It was based on the air-cooling heat pump unit. The cooling capacity of the chiller unit ...The exergy analysis and finite time thermodynamic methods had been employed to analyze the compound condensation process (CCP). It was based on the air-cooling heat pump unit. The cooling capacity of the chiller unit is about 1 kW, and the work refrigerant is R22/R407C/R410A/CO2. The MATLAB/SIMULINK software was employed to build the simulation model. The thermodynamic simulation model is significant for the optimization of parameters of the unit, such as condensation and evaporation temperature and mass flow of the sanitary hot water and size of hot water storage tank. The COP of the CCP of R410A system is about 3% - 5% higher than the CCP of the R22 system, while CCP of the R407C system is a little lower than the CCP of R22 system. And the CCP of CO2 trans-critical system has advantage in the hot supply mode. The simulation method provided a theoretical reference for developing the production of CCP with substitute refrigerant R407C/R410A/CO2.展开更多
基金TheNationalNaturalScienceFoundationofChina (No .2 96 770 0 4)
文摘The effects of the calorimetric buffer solutions were investigated while the two colorimetric reactions of AI-ferron complex and Fe-ferron complex occurred individually, and the effects of the testing wavelength and the pH of the solutions were also investigated. A timed complexatian colorimetric analysis method of Al-Fe-ferron in view of the total concentration of {AI + Fe} was then established to determine the species distribution of polymeric Al-Fe. The testing wavelength was recommended at 362 net and the testing pH value was 5. With a comparison of the ratios of n(Al)/n(Fe), the standard adsorption curves of the polymeric Al-Fe solutions were derived from the experimental results. Furthermore, the solutions' composition were carious in both the molar n(Al)/n(Fe) ratios, i.e. 0/0, 5/5, 9/1 and 0/10, and the concentrations associated with the total ( Al + Fe which ranged from 10(-5) to 10(-4) mol/L..
基金supported by the National Natural Science Foundation of China (No.50838005)the Changjiang Scholars and Innovative Research Team in University(No.IRT0853)the American Aluminum Foundation
文摘This article focused on the influences of fulvic acid and humic acid on aluminum speciation in drinking water. Factors including the concentration of residual chlorine and pH value had been concerned. Aluminum species investigated in the experiments included inorganic mononuclear, organic mononuclear, mononuclear, polymer, soluble, and suspended forms. It was found that the effects of fulvic acid and humic acid on aluminum speciation depended mainly on their molecular weight. Fulvic acid with molecular weight less than 5000 Dalton had little influence on aluminum speciation; while fulvic acid with molecular weight larger than 5000 Dalton and humic acid would increase the concentration of soluble aluminum significantly even at concentration below 0.5 mg/L （calculated as TOC）. Aluminum species, in the present of fulvic acid with molecular weight larger than 5000 Dalton and humic acid, were more stable than that in the present of fluvic acid with molecular mass less than 5000 Dalton, and varied little with reaction time. Within pH range 6.5-7.5, soluble aluminum increased notably in water with organic matter. As the concentration of residual chlorine increased, the effects of fulvic acid and humic acid became weak. The reactions between humic acid, fulvic acid with large molecular weight, and aluminum were considered to be a multi-dentate coordination process. With the consideration of aluminum bioavailability, reducing the concentration of fulvic acid and humic acid and keeping the pH value among 6.5-7.5 were recommended during drinking water treatment.
文摘The exergy analysis and finite time thermodynamic methods had been employed to analyze the compound condensation process (CCP). It was based on the air-cooling heat pump unit. The cooling capacity of the chiller unit is about 1 kW, and the work refrigerant is R22/R407C/R410A/CO2. The MATLAB/SIMULINK software was employed to build the simulation model. The thermodynamic simulation model is significant for the optimization of parameters of the unit, such as condensation and evaporation temperature and mass flow of the sanitary hot water and size of hot water storage tank. The COP of the CCP of R410A system is about 3% - 5% higher than the CCP of the R22 system, while CCP of the R407C system is a little lower than the CCP of R22 system. And the CCP of CO2 trans-critical system has advantage in the hot supply mode. The simulation method provided a theoretical reference for developing the production of CCP with substitute refrigerant R407C/R410A/CO2.
