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- Author or Editor: V. Mikulaj x
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Abstract
A continuous extraction device for preconcentration of metals with light phase internal recycle has been developed. This system was used for preconcentration of cobalt and uranium from 20–30 dm3 samples with 10.8 dm3/hours feed rate. The emulsion membranes were created of surfactants and LIX 64 N (for cobalt) or di-2ethylhexyl-phosphoric acid (for uranium) as a carrier to control stability and permeability for long time periods. The results from continuous extraction of cobalt and uranium using the device constructed have shown the possibility to reach 100–200-fold preconcentration of metals with high yield (min. 92%).
Abstract
Membrane extraction is treated as an analogue of solvent extraction in three-phase distribution systems. Its advantages and drawbacks are discussed with respect to separation and preconcentration of radionuclides, fission products of uranium and uranium itself.
Determination of plutonium-239,240 in environmental samples from surroundings of the Atomic Power Station Jaslovské Bohunice
Determination of plutonium in Manivier and Dudváh river
Abstract
Specific activity of239,240Pu in contaminated soils from the bank of Manivier channel was determined to be in the range of 5–40 Bq·kg–1 and for soils from the bank of Dudvah river 0.6–8 Bq·kg–1. The ratio of239,240Pu/137Cs found in the samples is about 1·10–4, which is very close to the ratio found in the pulp of high activity concentrate in the collecting tank of nuclear power plants (NPP).
Abstract
Radiolytical decomposition of phenol was investigated at60Co gamma irradiation (1–2 Gy·s–1, 
10 kGy) of pre- and continuously aerated aqueous solutions at concentrations of phenol 1–100 mg· ·dm–3 and in the presence of sodium hydroxide, sulphuric acid, sodium and ferrous sulphate, formaldehyde, 2-propanol,n-hexane, xylene, benzene, and commercial gasoline. From the decomposition rate at doses 50–400 Gy, a phenomenological model of linear relation between the dose acquired for 37% decomposition (D
37), initial concentration (g·m–3) of phenol (p
0) and of an admixture (s
0) was confirmed in the formD
37=52f
tr(p
0+f
eq
s
0), wheref's are constants which can be attributed to the relative transformation resistance of phenol towards the OH radicals in given matrix (f
tr, for pure waterf
tr=1) and relative acceptor capacity of competing substrate (f
eq). In real wastewaters, the efficient decrease of phenols content may be substantially lower than that in model solutions, obviously due to radiation oxidation of aromates, as proved by irradiation of aqueous solutions of benzene. Technical and economical feasibility of the process is discussed.
