Radioactive metal removal

The vendor claims that CORPEX chemicals are more effective than other existing chelants in removing heavy metals and radioactive metal ions because of their unique molecular structures and enhanced solubility in water. They are effective over a wide range of temperatures (from freezing to boiling) and variable pH (from 1 to 14). The chemicals can be oxidized after the cleaning process and no undesirable residues are left—only water, carbon dioxide, carbon monoxide, and nitrogen. 

Fe(Hedta), Na2Fe(edta) Zn2+, Mn2+, Mg2 edta complexes see Chapter 62.1) (iv) removal of poisoning or radioactive metal ions from the body (Cd2+ NaCa(edta) Pb2+ Na3Ca(dtpa) see Chapter 62.2). Complexones have been used in the form of " Tc complexes to obtain scintigraphic imaging of human organs in diagnostic nuclear medicine (see Chapter 65). 

Silver removal from the liver by biliary excretion was demonstrated by Scott and Flamilton (1950). Control rats and rats with ligated bile ducts were administered radioactive metallic silver by intramuscular injection. In rats with ligated bile ducts, excretion of silver in the feces was 19%, compared to 97% in controls. Deposition in the liver of rats with ligated bile ducts was 48% and 2.5% in the gastrointestinal tract compared to 0.36% and 1.12%, respectively in the controls (Scott and Flamilton 1950). Klaassen (1979b) determined that biliary excretion accounted for between 24% and 45% of the silver administered to rats. The concentration of silver in the bile was estimated to be... 

Now it is difficult to conceive any field of human activity where PCMU are not used. Among them are health care and pharmacology (administering of desired metals into the organism, such as iron in the case of asiderotic anemia, as well as removal of harmful, particularly radioactive metals) atomic industry and hydrometallurgy (concentration and separation of rate metals and radioactive isotopes), chemistry and catalysis (preparation of highly effective immobilized catalysts) etc. 

Pamukcu and Wittle [138] removed radioactive metals (Sr, Cs, and U) in clay or clay-sand mixtures. An 80% removal was observed at the cathode chamber for Sr and Cs for 24 48 h durations of treatment. Only 20% of the uranium was transferred to the cathode compartment because of precipitation and speciation of this metal in the soil. Chromium, which was present as an anionic species, migrated to the anode, where a 30% removal was achieved. 

Applications technologies in metal ion, inorganic species, hydrocarbons separations, biochemical and biomedical applications, and fine particles preparation using ELM are reviewed. Commercial applications include the removal of zinc, phenol, and cyanide from wastewaters. Potential applications in wastewater treatment, biochemical processing, rare earth metal extraction, radioactive material removal, and nickel recovery are described. 

The last example shows that it is also feasible to use SLMs to remove and recover efficiently radioactive metals from nuclear process effluent. By using a microporous hydrophobic polypropylene hoUow-fiber supported Hquid membrane (HFSLM) consisting of extractant, tri-w-butyl phosphate (TBP) as carrier diluted with w-dodecane, actinides such as uranium (U) and plutonium (Pu) were removed [188]. It was concluded after modeling and evaluation of the process conditions that it is possible to remove more than 99% of U(VI) and Pu(IV) from process effluent in the presence of fission products when stripping reagent 0.1 M hydroxylamine hydrochloride in... 

Offgas treatment is extensive and involves use of sintered metal filters, quench systems, venturi scrubbers, a condenser, a mist eliminator, an offgas heater, parallel HEPA filters, a carbon filter for radioactive iodine removal, a baghouse, and a selective catalytic reduction unit a packed tower scrubber system is used as a backup. 

Important data on the efficiency of oral AC in heavy metal removal have been obtained after the Chernobyl nuclear power plant accident on April 26 1986. During the first 7 days after the accident significant amounts of radionuclides were released from the nuclear reactor to the environment, which required extensive measures and man-power to prevent further spretiding of the radioactive contamination and clean-up of the contaminated territories [49,50]. The military personnel who worked in the Chemolyl exclusion zone, known as liquidators because they liquidated the consequences of this disaster, were exposed to elevated levels of radioactivity. Although these levels could not cause the radiation sickness disease, they were sufficiently high to affect health of liquidators particularly if the radionuclides became incorporated in the body... 

As the total weight of the radioactive fission elements is proportional to that of the 94 at the time of fission, it mig t be assumed that the amount of these fission elements and of 94 present in metal removed from the 75... 

Two Other areas also must be included in any discussion of metals removal by flotation. These are (1) the concentration of trace level elements from seawater—studied extensively by Zeitlin and coworkers at the University of Hawaii—and (2) applications in radioactive waste treatment. 

The most direct but by no means the sole therapeutic use of chelating agents aims at the removal of toxic (stable or radioactive) metals from the body or at the treatment of diseases (e.g. haemochromatosis, Wilson s disease) which are related to an excessive storage of particular metal ions. Of the vast number of compounds which have been tested from this point of view, we shall cite only those which have proved to be of significant clinical value (1) ethylenediamine-tetra-acetic acid (EDTA), which has been or should be replaced by its more effective derivative (2) diethylenetriamine-pentaacetic acid (DTPA) (3) D-penidllamine and (4) desferrioxamine B. EDTA and DTPA are effective in removing almost all metals which are important in toxicology whereas the action of desferrioxamine B is limited to Fe alone, and D-penicillamine is superior to other chelators in mobilizing Cu, Co, and Hg" ". ... 

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