Uptake Of Thorium Research Articles

Selective recovery of uranium and thorium ions from dilute aqueous solutions by animal biopolymers.

Selective actinide ion recovery from dilute, aqueous, multication waste streams is an important problem. The recovery of uranium (U) and thorium (Th) by various animal biopolymers was examined. Of four species of biopolymers tested, a high uptake of uranium and thorium was found in hen eggshell membrane (ESM) and silk proteins, with the maximum uranium and thorium recovery exceeding 98% and 79%, respectively. The uptake of U and Th was significantly affected by the pH of the solution. The optimum pH values were 6 and 3 for the uptake of U and Th, respectively. The effect of temperature differed with the metal. The uptake of U decreased with increasing temperature (30-50 degrees C), whereas the Th uptake increased with increasing temperature. Selective recovery of U and Th from dilute aqueous binary and multimetal solutions was also examined. ESM and silk proteins tested were effective and selective for removing each metal by controlling the pH and temperature of the solution. In multimetal systems, the order of sorption of ESM proteins was preferential: U > Cu > Cd > Mn > Pb > Th > Ni > Co > Zn at pH 6 and Th > U > Cu > Pb > Cd > Mn > Co > Ni = Zn at pH 3. These biopolymers appear to have potential for use in a commercial process for actinide recovery from actinide-containing wastewater.

Thorium(IV) sorption on ignited Sarcotragus muscarum, its kinetic and thermodynamic parameters

The uptake of thorium from aqueous systems by ignited Sarcotragus muscarum(L. Schmidt, 1864), collected from Kusadasi Region at Southwest of Turkeyas an adsorbent has been investigated. The thorium(IV) uptake was studiedas a function of pH, ion concentration and temperature. At the determinedoptimum conditions, the sorption of thorium on ignited sponge follows a Langmuir-typeisotherm. We assumed that this phenomenon can be a sorption process. Kineticof thorium sorption was investigated at different time intervals at 25, 50and 70 °C. The reaction rate and diffusion constants were calculated forthese temperatures. The activation energy and .H° were found to be –19.04and –5.22 J/mol, respectively.

A case study on uptake of thorium from soil to plant by using X-ray fluorescence spectrometry

A case study was carried out to determine the uptake of thorium from soil to plant by using X-ray fluorescence technique. The radioecological experiment was undertaken to provide plant/soil concentration ratio (CR) data for thorium using 2 types of plant (barley and common vetch)×4 levels of Th(0, 1500, 3000,4500ppm)×2 types of soil (acidic and alkaline) with different configuration parameters. The calibration of the analytical method for thorium on dry basis of samples is described by using109Cd excitation source. The results indicated that theCR values decreased with the corresponding Th concentration in soils with a 1000 fold range and differed among soil and plant types.

Accumulation of Some Heavy Metals onAspergillus flavus

Uranium and thorium were found to be accumulated extracellularly on the surface of Aspergillus flavus. The rate and the extent of accumulation were subjected to variations in environmental parameters such as pH, temperature and the interference of certain anions and cations. The rates of uranium and thorium uptake by Aspergillus flavus were increased by chemical pretreatment of the cells. Accumulated uranium and thorium were removed chemically from Aspergillus flavus cells. The rate of uptake of uranium and thorium at 25°C±3°C was found to be extremely rapid at pH values of 4·5±0·2 and 2·5±0·2 respectively. Electron microscopic examinations showed that uranium and thorium were accumulated in a dense layer around the surface of Aspergillus flavus cells. © 1997 SCI.

Accumulation of Some Heavy Metals on Aspergillus flavus

Uranium and thorium were found to be accumulated extracellularly on the surface of Aspergillus flavus. The rate and the extent of accumulation were subjected to variations in environmental parameters such as pH, temperature and the interference of certain anions and cations. The rates of uranium and thorium uptake by Aspergillus flavus were increased by chemical pretreatment of the cells. Accumulated uranium and thorium were removed chemically from Aspergillus flavus cells. The rate of uptake of uranium and thorium at 25°C±3°C was found to be extremely rapid at pH values of 4·5±0·2 and 2·5±0·2 respectively. Electron microscopic examinations showed that uranium and thorium were accumulated in a dense layer around the surface of Aspergillus flavus cells. © 1997 SCI.

Selective biosorption of thorium ions by an immobilized mycobacterial biomass

The biosorption of thorium and uranyl ions by cells of Mycobacterium smeamatis has been studied as a function of initial cation concentration. A similar sorption saturation level was observed for both ions. For immobilized cells, optimal conditions of metal ion retention were found for a bacterial mass/support concentration ratio of 1/6. However, selective uptake of thorium was manifest in solutions of the mixed cations. X-ray diffraction studies of the heat-dried biomasses loaded with cations showed that uranyl-loaded samples present a distinct pattern typical of ammonium uranyl phosphate, whereas thorium-loaded samples are amorphous. The microorganism used appears to have useful properties for applications in connection with separation and concentration of natural radioelements under conditions of high dilution.

Removal of thorium from simulated acid process streams by fungal biomass

Biomass from several fungal species removed thorium from solution in 1M HNO(3), pH 0-1. Thorium uptake was saturable with increasing thorium concentration, although the equilibria did not correspond to a simple ad sorption isotherm. Thorium uptake was altered by the biomass concentration, the uptake per unit biomass being reduced at high biomass concentrations. The presence of Al(3+) and Fe(3+) only slightly inhibited uptake of thorium while Ca(2+), Mg(2+), and Na(+) had no effect. Thus fungal biomass appears capable of removing thorium from solution under chemical conditions existing in acid waste liquors. Thorium uptake was increased by pretreatment using detergent and also, in the case of filamentous fungi, varied with the culture conditions, which implies that the thorium uptake characteristics of fungal biomass are able to be manipulated by these or similar means for optimum performance.

Uptake and intracellular compartmentation of thorium in saccharomyces cerevisiae

When Saccharomyces cerevisiae was cultured in the presence of thorium, the element was accumulated by the cells and was visible in electron micrographs as electron dense granules. When thorium was present during exponential growth, these granules were located mainly in the vacuole, with some present in the cytosol. Where thorium was present only during the stationary phase, there appeared to be greater thorium deposition in the cell wall than during exponential growth and some vacuolar deposits were also evident. Thorium uptake by exponential-phase cells was not stimulated by glucose and was thus independent of metabolic energy.

Observations on the bioaccumulation potential of thorium and uranium in rainbow trout (Salmo gairdneri).

Preliminary studies are reported to determine if uptake of uranium and thorium occurs at significant rates in rainbow trout. Also assessed is how soluble and particulate partitioning affects the uptake behavior of these actinides. (JMT)

Comparative Uptake of Uranium, Thorium, and Plutonium by Biota Inhabiting a Contaminated Tennessee Floodplain

AbstractThe uptake of 238U, 232Th, and 239Pu from soil by rescue, grasshoppers, and small mammals was compared at the contaminated White Oak Creek floodplain in East Tennessee. Comparisons of actinide uptake were based on analyses of radionuclide ratios (U/Pu and Th/Pu) in soil and biota. U:Pu ratios in small mammal carcasses (shrews, mice, and rats) and bone samples from larger mammals (rabbit, woodchuck, opossum, and raccoon) were significantly greater (P ±0.05) than U/Pu ratios in soil (based on 8M HNO3 extractable). There was no significant difference between Th/Pu ratios in animals and soil. The order of actinide accumulation by biota from the site relative to contaminated soil was U > Th ≈ Pu.

228Ra and 228Th in coastal waters

Typically, the waters above the continental shelf contain higher concentrations of 228 Ra but lower concentrations of 228 Th than do the surface waters of the open ocean. The vertical profiles of 228 Ra concentration in the shelf waters of the Middle Atlantic Bight suggest that the shelf sediments are the chief source of 228 Ra, but that the sediments of bays and estuaries are a significant secondary source. In the mid-shelf and outer shelf waters of the Bight, the 228 Ra concentration increases and the 228 Th/ 228 Ra activity ratio decreases from the region bordering Nova Scotia to the region uust north of Cape Hatteras. The mean residence time of thorium in the surface waters of the Bight, calculated from the 228 Th/ 228 Ra activity ratios, ranges from 4 months in the slope waters and outer shelf waters and 1·5 months in the inner shelf waters of the region bordering Nova Scotia to 1·5 months in the slope waters, 20 days in the outer shelf waters and 10 days in the inner shelf waters of the region just north of Cape Hatteras. The vertical profiles of 228 Th concentration in the surface mixed layer and thermocline of the open ocean qualitatively resemble the profiles of concentrations of nutrients, such as phosphate. The process most likely to produce the observed rapid transport of thorium out of the surface waters probably involves uptake of thorium by phytoplankton, ingestion of the phytoplankton by zooplankton, and inclusion of the thorium in rapidly settling fecal pellets.

Fast and simple radiochemical method for the separation of uranium, thorium and lanthanum

The concept of using paper chromatography on papers impregnated with liquid anion or cation exchangers is extended to the separation of trace elements through filtration on filter papers loaded with suitable extractant. The uptake of uranium, thorium and lanthanum from HCl and HNO3 media of different molarities by a filter paper treated with tri-octyl amine (TOA) is investigated. The effect of the different parameters on the uptake of the studied elements is experimented. A simple and fast radiochemical procedure is developed for the separation of La, Th and U from each other.

234Th 238U radioactive disequilibrium in the surface layer of the ocean

234Th produced from 238U within sea water was found to be in radioactive disequilibrium with respect to its progenitor nuclide 238U in the surface layer of the ocean. The median value for 234Th 238U activity ratio is 0.80 in the upper 200 m layer. A box-model calculation gives a removal residence time of thorium of about 0.38 yr. This suggests that 234Th is scavenged from the surface layer by the uptake of thorium by biota.

Anion Exchange Behaviour of Yttrium

IN a recent paper1, we have reported the uptake of thorium on a strong-base anion exchange resin from sulphate and carbonate solutions. It was also observed in this laboratory that a trace amount of yttrium-90 was adsorbed on such resin from ammonium sulphate, sulphuric acid and sodium carbonate solutions.

Adrenal influences on distribution of injected colloidal thorium.

A chemical analysis was made of the influence of adrenalectomy upon the distribution of intravenously administered colloidal thorium dioxide (thorotrast) in spleen, liver, lymph nodes, lung, blood and urine of the adult rat. Adrenalectomy resulted in a decrease in the uptake of thorium by the spleen; this occurred as early as 2 hours and was maintained for at least 48 hours after its administration. The blood levels decreased quickly; only slight amounts remained after 2 hours. No significant differences were noted in thorium concentration within the livers of normal and adrenalectomized rats at 2, 4, 8, 24 and 48 hours after its injection. The lungs and lymph nodes (at 2 hr.) of adrenalectomized rats accepted slightly greater amounts of the metal than similar organs in control rats. Thorium was excreted in urine in slight amounts; but adrenalectomy resulted in a slightly greater excretion of ThO2/gm dried urine. Although the concentrating activity of spleen was much greater than the liver, the total amount of thorium deposited in the liver was larger. The quantities of thorium recovered from the normal rats were always greater than those from adrenalectomized animals, by a difference almost identical with that found between the spleens from normal and operated animals. The relatively large differences in thorium uptake by the spleens of normal and adrenalectomized animals cannot be accounted for by the differences in thorium deposition in other organs studied and by elimination in the urine. The discrepancy is probably explained on the basis of differential entry of thorium into tissues other than those examined in the present study.

Isolation of thorium B (lead)-binding substance from the erythrocytes of rabbit blood.

THE distribution of lead in blood fractions has been investigated by several workers. Recent studies made by using lead salts labelled with thorium B1,2, and with radium D3, showed that the lead is mainly held by the erythrocytes. The present communication deals with the isolation of the component mainly responsible for the uptake of thorium B by the erythrocytes.