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- Author or Editor: Yibei Fu x
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Abstract
The extraction behavior of perrhenate with crown ethers has been studied and methods for the separation and determination of rhenium have been developed. Perrhenate anion can be quantitatively extracted into nitrobenzene by benzo-15-crown-5 (B15C5) from 2M potassium hydroxide and back-extracted by sodium phosphate buffer solution. The molar ratio of B15C5 to KReO4 in the extracted species is probably 2
1. Rhenium was satisfactorily determined by neutron activation method in rock samples.
Abstract
The extraction behavior of rubidium with a crown ether has been studied and methods for the separation and determination of rubidium have been developed. Rubidium was separated with tetraphenylborate from sample solution, and then quantitatively extracted into nitrobenzene by 18-crown-6 from 0.05 mol/l picric acid (pH 6) and back-extracted by 6 mol/l hydrochloric acid. Rubidium was determined by the neutron activation method in rock samples.
Abstract
The reduction kinetics of pertechnetate by thiocyanate in perchloric acid is studied by spectrophotometric method. The effect of the concentrations of pertechnetate, hydrogen ion and thiocyanate on the reaction rate is investigated. The kinetic expression at 25°C is: −dC VII/dt=(2.2±0.4)·10−3 [TcO4 −]1.1 [H+]3.2 [SCN−]3.3 The effect of temperature on the reaction rate is studied. The activation energy is 91 kJ/mol. The possible mechanism of the reaction is discussed.
Abstract
Polyether-urethane samples were irradiated at the dose range from 10 to 2000 kGy by 2 MeV electron beams. Volatile species from the polymer degradation were analyzed quantitatively and qualitatively with GC/MS. Thermal properties and micro-phase separation of the samples were examined by TG and the morphology was studied by TEM and SEM. The results show that the irradiated polyether-polyurethane evolves CO2, H2, CH4 and C2H6, etc. The thermal stabilities between the hard and soft segments in the irradiated samples are different. At high doses, the phase separation in the sample is predominant and the hard segment of sample is more stable. The dose rate affects the soft segment of the irradiated sample much more.
Abstract
A method of determination of trace gold and iridium in steel is presented. The samples were preconcentrated with an anion exchanger. The chemical recoveries were determined by an isotope tracer technique using198Au and192Ir.
