[en] The invention relates to the sewage treatment, in particular to the sewage biological treatmen from radioactive waste, namely from uranium. The process dor sewage biological treatment from uranium includes cultivation in the sewage of the aquatic plants Lemna minor and Spirulina platensis. The plants cultivation is carried out in two stages. In the first stage for cultivation is used Lemna minor in the second stage - Spirulina platensis . After finishing the plant cultivation it is carried out separation of their biomass. The result of the invention consists in increasing the uranyl ions by the biomass of plants cultivated in the sewage

[en] This paper deals with a study on the radiolysis of water in the presence of certain oxides: BeO, SiO₂, TiO₂, ZrO₂ acting as catalysts for the hydrogen production. A radionuclide of ⁶⁰Co with an activity of about 5x10⁴ Ci was employed as an irradiation γ source. A considerable increase (up to ten times or more) of the amount of hydrogen resulting from the radiolysis of water in the presence of the above mentioned oxides was noticed in comparison with a reference sample, irradiated under the same experimental conditions, but without any catalyst. The radiolysis products have been identified by means of a method based on mass spectrometry

[en] It was recently shown that the calcination at 1000 C in Ar of a gel formed from the reaction of uranyl nitrate and citric acid yields nanometric UO₂ clusters, completely embedded and well-dispersed in a carbon matrix. Uranium carbide powders with high sinterability are then easily obtained from the carbothermal reduction of such precursor by a further heat treatment in vacuum at temperatures of 1200-1600 C for few minutes. Here we report the first results of our investigation on the possibility to obtain the nitride form from the same precursor, by conducting the last step in a nitrogen-containing atmosphere, and on the granulation of such powders by a novel electro-dropping method. The work is being performed within the EU-funded FREDMANS Project. (authors)

[en] This paper is a continuation of some earlier studies concerning the use of radioisotopes in the kinetic study of the crystal formation and growth in gels, when radioactive cations such as: ⁶⁰Co²⁺, ¹³⁴Cs⁺, ²⁰⁴Tl⁺, ⁵⁵⁺⁵⁹Fe³⁺, ⁵¹Cr³⁺ were used in the presence of different anions. ''U'' shaped tubes made of PVC, with the interior diameter of 1.5 cm, the length of the horizontal branch of 8 cm and the length of the vertical branches of 7 cm, were used for the radiokinetic study of the crystals growing in polyvinyl alcohol (PVA) 11% and 13% hydrogels. The tubes filled with hydrogels were kept at a constant temperature of 4 C. Then, in each tube were introduced the solutions that contained the reagents. In one of the vertical branches of the tube were introduced 8 ml of the radioactive solution of 10^-2M ⁶⁰CoCl₂, with a specific activity of 3.7.10⁴ Bq/ml, and in the other vertical branch, were introduced 8 ml from aqueous solutions of K₂C₂O₄, KI or KSCN respectively, all having a concentration of 10^-2M. (orig.)

[en] Bioaccumulation of some radioactive ions from contaminated waste solutions, on hydrophytic vegetal organisms is discussed. In order to follow the distribution of radioactive ions ¹³⁷Cs⁺, ⁶⁰Co²⁺ and ⁵¹Cr³⁺ in various cell components extracted from Spirulina platensis, Porphiridium cruentum, Scenedesmus quadricauda, Lemna minor, Elodea canadensis, Pistia stratiotes and Riccia fluitans, the plants were cultivated in radioactive solutions. The resulting complexes were extracted with acetone or acetic acid and separated chromatographically. The results show an intense activity of the polysaccharide and lipoid fractions in the bioaccumulation process. The bioaccumulation varies in the series: Spirulina > Scenedesmus > Porphiridium > Riccia > Pistia > Lemna ≥ Elodea for ¹³⁷Cs⁺ and ⁶⁰Co²⁺; Spirulina > Porphiridium > Scenedesmus > Riccia > Pistia > Lemna > Elodea for ⁵¹Cr³⁺. (author)

[en] Radiolytic decomposition of water under the action of gamma rays in the presence of some zeolites such as ZSM-5, SAPO-5 and MOR was studied. The irradiation was performed using a gamma ⁶⁰Co source at an activity of 3^.10⁴ Ci and dose rate 8.3 KGy/h. The stable products of radiolysis as well as the other chemical species were identified by mass spectrometry. The calculated radiochemical yield decreased in order: H-ZSM-5 > Na-ZSM-5 > H-SAPO-5 > MOR and was higher in the presence of these catalysts than in their absence

[en] The microporous titanosilicate ETS-10 synthesized from gel with following molar composition: 1.0 Na₂O : 1.49 SiO₂ : 0.2 TiO₂ : 0.6 KF : 1.28 HCl : 39.5 H₂O was subjected to sorption of radioactive cations ¹¹⁵Cd²⁺, ²⁰⁴Hg²⁺, ⁶⁰Co²⁺ and ¹³⁷Cs⁺ (M) from aqueous solution, in the absence of ionic competition. The uptake of these cations on the ETS-10 was compared by means of the distribution coefficient (K_d) versus contact time and sorption capacity (R) at equilibrium. The FT-IR spectra of M-ETS-10 sorption products exhibit a modification of the absorption band, principally at 381 cm^-1. (author)

[en] The present study follows the extent of translocation radioactivity from the substrates of the Crucea uranium mining area to the macromycetes spontaneously occurred during June-October 2008. To this end, radioactivity measurements (gross α + β and ¹³⁷Cs) on both macromycetes and their substrates were made. The resultants obtained were confirmed by FT-IR spectroscopy, evidencing the presence of characteristic bands around of 910 cm^-1, corresponding to the asymmetric stretching vibration of the uranyl unit and to the interaction between the UO₂²⁺ ions and the group belonging to various cellular components. (author)

[en] This study investigates the corrosion of OL-37, OL-60 and 316L type steel samples immersed in acidic media (HCl, HClO₄, H₂SO₄ and HNO₃), based on a new radioactive tracer method. This procedure, used for the determination of the global rate constant of metal corrosion reaction, is based on the screening of β^--rays emitted by ²⁰⁴Tl⁺ radionuclides, present in the aggressive medium of the iron ions which are formed during the process. The global rate constants of corrosion reaction decrease, for a certain metallic sample, in the series HCl > HClO₄ > H₂SO₄ > HNO₃, and increase with the concentration of the used acid. For a given aggressive solution, the corrosion process decreased with the decreasing of the carbon amount in each steel sample. (orig.)

[en] In order to clean some low radioactive contaminated waters containing beta + gamma-active cations (⁵⁵⁺⁵⁹Fe³⁺, ⁶⁰Co²⁺, ⁶⁵Zn²⁺ and ¹³⁷Cs⁺), calix[4]arene and p-(tert-butyl)calix[4]arene have been used. Experiments have been performed in the absence of ionic competition, at 4 deg C, 22 deg C and 40 deg C. Whatever the temperature and the sorbent used, the yield of retaining the beta + gamma-active cations varies as follows: ⁵⁵⁺⁵⁹Fe³⁺ > ⁶⁰Co²⁺ > ⁶⁵Zn²⁺ > ¹³⁷Cs⁺. (author)