Measurements of the magnetic properties and total contents of Cu, Cd, Pb and Fe in 30 automobile emission particulate samples indicated the presence of magnetic particles in them. The values of frequency dependent sus...Measurements of the magnetic properties and total contents of Cu, Cd, Pb and Fe in 30 automobile emission particulate samples indicated the presence of magnetic particles in them. The values of frequency dependent susceptibility （Xfd） showed the absence of superparamagnetic （SP） grains in the samples. The IRM20mT （isothermal remanent magnetization at 20 mT） being linearly proportional to SIRM （saturation isothermal remanent magnetization） （R^2=0.901）, suggested that ferrimagnetic minerals were responsible for the magnetic properties of automobile emission particulates. The average contents of Cu, Cd, Pb and Fe in automobile emission particulates were 95.83, 22.14, 30.58 and 34727.31 mg/kg, respectively. Significant positive correlations exist between the magnetic parameters and the contents ofPb, Cu and Fe. The magnetic parameters of automobile emission particulates reflecting concentration of magnetic particles increased linearly with increase of Pb and Cu content, showed that the magnetic measurement could be used as a preliminary index for detection of Pb and Cu pollution.展开更多
The functions of rare earth metals in the automobile emission purification catalysts were reviewed, and it was clarified that with precious metals resources using up gradually emission regulations becoming more and mo...The functions of rare earth metals in the automobile emission purification catalysts were reviewed, and it was clarified that with precious metals resources using up gradually emission regulations becoming more and more strict, rare earth metals will play more and more important roles in the high performance, and in low price automobile emission purification catalysts, they can not be substituted by other elements, for example, precious metals.展开更多
基金Project supported by the National Natural Science Foundation of China (No. 40371056)the Foundation for the Author of NationalExcellent Doctoral Dissertation of China (No. 200149)
文摘Measurements of the magnetic properties and total contents of Cu, Cd, Pb and Fe in 30 automobile emission particulate samples indicated the presence of magnetic particles in them. The values of frequency dependent susceptibility （Xfd） showed the absence of superparamagnetic （SP） grains in the samples. The IRM20mT （isothermal remanent magnetization at 20 mT） being linearly proportional to SIRM （saturation isothermal remanent magnetization） （R^2=0.901）, suggested that ferrimagnetic minerals were responsible for the magnetic properties of automobile emission particulates. The average contents of Cu, Cd, Pb and Fe in automobile emission particulates were 95.83, 22.14, 30.58 and 34727.31 mg/kg, respectively. Significant positive correlations exist between the magnetic parameters and the contents ofPb, Cu and Fe. The magnetic parameters of automobile emission particulates reflecting concentration of magnetic particles increased linearly with increase of Pb and Cu content, showed that the magnetic measurement could be used as a preliminary index for detection of Pb and Cu pollution.
文摘The functions of rare earth metals in the automobile emission purification catalysts were reviewed, and it was clarified that with precious metals resources using up gradually emission regulations becoming more and more strict, rare earth metals will play more and more important roles in the high performance, and in low price automobile emission purification catalysts, they can not be substituted by other elements, for example, precious metals.
