This paper reports some ion-exchange column experiments, carried out to determine the breakthrough curves of137Cs and89Sr radioisotopes on a commercially available inorganic ion-exchange sorbent of the amorphous zirconium phosphate type. A dynamic capacity of about 3–4 meq·g–1 was observed.
Synthetic zeolites X & Y have been examined for their abilities to take in Co, Ni and Zn radioisotopes. Distribution coefficients (Kd) have been determined, with and without competing cations, and at various pH values. Elution studies on zeolites containing Co, Ni and Zn radioisotopes considered the effect of acid and alkaline conditions, calcination and cement encapsulation. Leach rates arising from these experiments have been calculated. The general conclusions can be drawn are that zeolites X & Y are suitable for decontamination of aqueous wastes containing Co, Ni and Zn. Cement encapsulation is appropriate but no advantage accrues from pre-calcination. Some comments on the likely mechanism of leaching losses have been made.
Samples of the natural zeolites chabazite, clinoptilolite and a clinoptilolite-rich tuff, were loaded with the isotope 137Cs. Composites of these labeled materials were made with cement and blast furnace slag. Standard leaching experiments were carried out with synthetic sea, ground and "pond" waters, as well as distilled water. Rates of leaching were calculated and compared to similar systems.
Authors:A. S. Rodríguez, B. López, L. Fucugauchi, and E. Martínez-Quiroz
A number of ammonium uranates have been obtained, all of them different in their X-ray diffraction patterns. This contribution attempts to demonstrate that different series of compounds can be produced depending on the preparation method. The ammonium uranates were precipitated from solutions of uranyl nitrate using gaseous ammonium to determine the effect of precipitation pH on their composition and morphology.
Authors:S. Rodríguez, A. Acosta, B. López, and L. Fucugauchi
An effective modification of the chemical processes has been obtained to dissolve uranium(IV) and extract it as uranium triperoxocomplex, which facilitates its manipulation and final conversion into uranium nitrate as a high purity concentrate.
Authors:H. Someda, M. Ezz El-Din, R. Sheha, and H. El-Naggar
Apricot stone shells were carbonized under certain chemical and thermal conditions to produce sorbents having a quantitative affinity to retain some radioactive nuclei. The sorbent shows a thermal stability upto 500 °C. The diffraction patterns clarify that the sorbent is mainly amorphous in structure. Carbon in these shells was elementally analyzed and the data reveal a predominant content of acidic surface centers with hydrophilic properties. The isoelectric point (pHPZC) was determined and found to be 4.2 implying the acidic nature of the sorbent surface. The sorption of Cs+, Co2+ and Eu3+ on the prepared sorbent was studied from aqueous solution under different variables and the sorption capacity had values from 0.23-1.15 meq/g.
Authors:Xiaofeng Zhang, Jianguo Ma, Junfa Qin, and Lun Xiao
Elements in two kinds of 30 traditional Chinese medicines were analyzed by PIXE method, and the data were treated by multivariate statistical methods. The results show that these two kinds of traditional Chinese medicines are almost separable according to their elemental contents. The results are congruous with the traditional Chinese medicine practice.
Since April 29, 1986, the radioactive contamination resulting from the accident of the Chernobyl reactor has been measured in various kinds of matrixes, with particular regard to Northern Italy. Here we present the data obtained for137Cs from several measurements effected on milk and dairy products over the period of one year. In particular, we have studied the transfer kinetics of137Cs from forage to milk by feeding dairy cows with forage of known activity and we have evaluated the body Cs absorption by measuring the percentages of Cs eliminated with milk as well as with urine and feces. Further, the decay rate of137Cs in milk has been assessed and the results of the kinetic, analysis are reported. We have also evaluated the efficacy of various clay materials in removing Cs from milk. Here we report the results of adsorption kinetics for the grey clay which resulted the most effective material.
Authors:S. Al Waér, B. Al Medehem, and V. Peretrukhin
A two-step chromatographic technique was elaborated to isolate144Ce,144Pr from a solution of uranium fission products in 6M HNO3. The oxidation to Ce(III) by bromate and selective adsorption of144Ce(IV) on anion exchange column were used to concentrate and purify144Ce. Some impurities of uranium,95Zr,95Nb,106Ru remain in144Ce solution after the first step of its isolation. The final purification is achieved by passing the 6M HNO3 solution of144Ce(IV) through the HDEHP-coated teflon column. The decontamination factors of144Ce from main fission products are given. 7.2 mCi of (144Ce+144Pr) are recovered from each gram of irradiated uranium trioxide with the yield greater than 99%. An improvement of known generator was carried out to elute a purer144Pr from maternal144Ce(IV) adsorbed on the anion exchange column.
Authors:P. Tölgyessy, M. Kollár, D. Vančo, and M. Piatrik
The effect of -radiation on waste water solutions containing 2-mercaptobenzothiazole and N-oxydiethylene-2-benzothiazolesulfenamide was studied by UV spectrosocopy, COD, BOD5 and TOC determination and Pitter's kinetic test of biodegradation. No improvement in biodegradability of model solutions was detected and in case of 2-mercaptobenzothiazole colloidal turbidity removable by coagulation appeared.