Authors:T. Oi, Y. Kikawada, T. Honda, T. Ossaka, and H. Kakihana
Determination of the lanthanoids, thorium and uranium in silicate rocks has been investigated by neutron activation analysis (NAA). Seven or eight lanthanoids and thorium and uranium were determined by non-destructive instrumental NAA. The numbers of the lanthanoids determined were increased and errors on the final values were reduced by pre-irradiation treatments, which included a coprecipitation process with aluminium as collector to remove the alkali metals and halogens and a solvent extraction process to eliminate iron. The necessity of scandium removal was indicated.
A locally produced mordenite type synthetic zeolite and its modified form obtained by the treatment with dilute hydrochloric
acid were tested for their cesium uptake characteristics. The two zeolites were compared with other commercially available
synthetic zeolites with respect to their ability to sorb radiocesium from dilute nitric acid solution. The effects of the
changes in the composition of the solution including the concentration of nitric acid, sodium and cesium on the uptake of
cesium were investigated. The results can be used in the removing processor radiocesium from different types of nuclear plant
effluents by these zeolites.
Authors:R. C. Eerlingen, H. Jacobs, H. Van Win, and J. A. Delcour
Gelatinisation temperatures as a function of moisture content were determined for potato starch. The native starch was then hydrothermally treated at a temperature 3% (Kelvin degrees) below the gelatinisation peak temperature and at moisture levels varying from 20 to 67% (by weight). Gelatinisation temperatures, temperature ranges and enthalpy values were affected for all treated samples. However, two sample populations could be distinguished: those samples treated under ‘limited’ moisture conditions and other samples treated in the presence of ‘extragranular’ moisture. A two-step hydrothermal treatment further increased the gelatinisation temperature, but the effect of the second step was small in comparison to that of the first.
Some physico-chemical properties and reactivity in their reduction with hydrogen of NiO—Y2O3 mixed oxides prepared in a dry way have been studied using isothermal thermogravimetry in the range of 320–410°C and temperature-programmed reduction. It was found that addition of small amounts of chloride and acetate anions retarded the reduction of nickel oxide and accelerated the reduction of mixed oxides. The presence of oxalate and formate ions manifests itself by a small positive effect. Introduction of platinum activator or heat treatment of the samples in various atmospheres led to a pronounced increase in the reduction rate. The efficiency of the spill-over effect increases with increasing proportion of non-reducible Y2O3. The pre-irradiation of the samples by accelerated electrons and gamma rays at a dose of 1 MGy results in a negative kinetic effect only with the samples containing an excess of nickel oxide.
Authors:A. S. Al-Hobaib, D. M. Al-Dhayan, K. M. Al-Sulaiman, and A. A. Al-Suhybani
Sand filters are used as a filter bed in many ground water treatment plants to remove the physical contaminants and oxidation
products. A build-up of radioactivity may take place on the granules, where iron and manganese oxides are deposited and form
thin films on the surface of sand filter. The oxides of iron and manganese play an important role in adsorbing radium from
ground water. The disposal of those granules makes a significant problem. A batch technique is used for solubilization of
radium from sand filters in the presence of some organic acids, which act as reducing agents. These acids are formic acid,
acetic acid, benzoic acid, succinic acid, oxalic acid, phthalic acid, and adipic acid. The data were obtained as a function
of acidity, temperature, contact time and liquid/solid ratio particle size and shaking speed. It was found that oxalic acid
was the best for radium removal. The effectiveness of these acids on radium removal was as follows: oxalic acid > phthalic
acid > adipic acid > succinic acid > formic acid > acetic acid. The maximum removal obtained was 69.9% at 1M oxalic acid at
8 ml/g ratio. Reaction kinetics and mechanism parameters of the dissolution process were studied and compared with other published
The interactions between MoO3 and Sb2O3 or α-Sb2O4 taking place in the solid state in air during high-temperature as well as mechanochemical treatments have been investigated.
The high-energy ball milling of MoO3 with Sb2O3 converts α-Sb2O3 to β-Sb2O3 and leads to formation of Sb2MoO6 and Sb4Mo10O31 phases. They are the final products of thermal synthesis in an inert atmosphere but not in air. The solid solution of MoO3 in β-Sb2O4 was obtained in high-temperature reaction of MoO3 with Sb2O3 or α-Sb2O4 as well as by milling of mixture MoO3/α-Sb2O4 for 14 h. The milling resulted in higher than 3 mol% solubility of MoO3 in β-Sb2O4. The constructed phase diagram of MoO3–α-Sb2O4 system is presented.
Radiometric X-ray fluorescence analysis was used for the determination of Mn, Fe, Cu, Zn and Pb in wastewater and sludges from three wastewater treatment plants in Bratislava (SR). Metals were determined in wastewaters after preconcentration by 8-hydroxyquinoline and in sludges by drying and pressing to pellets.238Pu and109Cd was used for excitation of fluorescence radiation.
Authors:Zsanett Bodor, Bianka Pergel, and Csilla Benedek
., 2009; Kaszab et al., 2017 ). The properties of honeys also vary according to their exposure to heat. Heat treatment of the honey can influence its composition and physicochemical properties ( Bodor et al., 2019; Božiková et al., 2018 ). The proper