EVALUATION OF NATURAL ION EXCHANGERS FOR THE REMOVAL OF RADIOACTIVE ISOTOPES FROM LIQUID EFFLUENTS

2002 ◽  
Vol 1 (4) ◽  
pp. 577-588
Author(s):  
Eveline Popovici ◽  
Igor Cretescu ◽  
Elena Botezatu ◽  
Gabriela Soreanu ◽  
Alina Mihaela Hanu ◽  
...  
Keyword(s):  
Radioactive Isotopes ◽  
Ion Exchangers

Comparison of some organic and inorganic ion exchangers concerning the sorption of Ce(III), Te(IV), Zr(IV), Hf(IV) and Nb(V)

2018 ◽  
Vol 106 (3) ◽  
pp. 207-216 ◽  
Author(s):  
Fatma H. El-Sweify ◽  
Ehab A. A. El-Shazly ◽  
Shreen M. Salama
Keyword(s):  
Organic Anion ◽  
Aqueous Media ◽  
Fission Products ◽  
Ionic Species ◽  
Mineral Acid ◽  
Lanthanide Ions ◽  
Radioactive Isotopes ◽  
Ion Exchangers ◽  
Inorganic Ion Exchangers ◽  
Inorganic Ion

AbstractThe sorption behaviors of Ce(III), as a representative of trivalent lanthanide ions, and Te(IV), Zr(IV) and Nb(V) as fission products representatives, as well as Hf(IV), from various aqueous media on some synthesized inorganic exchangers, as well as commercially available organic ion exchangers were studied and compared. Organic cation exchanger Dowex-50WX8 and organic anion exchangers AG-1X8 and AG-2X8 were utilized. Synthesized inorganic ion exchangers were zirconium titanium phosphate (ZrTiP) of different Zr:Ti mole ratios and ceric tungstate (CeW). The sorption was carried out from mineral acid solutions as well as EDTA and DTPA solutions. The radioactive isotopes,95Zr,95Nb,123mTe,141Ce and181Hf were used to trace the sorption behaviors of the corresponding elements, which were studied in mixtures of them. The differences between the sorption behaviors of the studied metal ionic species on both kinds of ion exchangers were interpreted and discussed in this work.

Bioavailability of Vitamin B12

2010 ◽  
Vol 80 (45) ◽  
pp. 330-335 ◽  
Author(s):  
Lindsay Helen Allen
Keyword(s):  
Vitamin B12 ◽  
Vitamin B12 Deficiency ◽  
The Elderly ◽  
Radioactive Isotopes ◽  
Animal Source Foods ◽  
Dietary Requirements ◽  
In Vivo Labeling ◽  
B12 Deficiency ◽  
Vitamin B12 Malabsorption

Vitamin B12 deficiency is common in people of all ages who consume a low intake of animal-source foods, including populations in developing countries. It is also prevalent among the elderly, even in wealthier countries, due to their malabsorption of B12 from food. Several methods have been applied to diagnose vitamin B12 malabsorption, including Schilling’s test, which is now used rarely, but these do not quantify percent bioavailability. Most of the information on B12 bioavailability from foods was collected 40 to 50 years ago, using radioactive isotopes of cobalt to label the corrinoid ring. The data are sparse, and the level of radioactivity required for in vivo labeling of animal tissues can be prohibitive. A newer method under development uses a low dose of radioactivity as 14C-labeled B12, with measurement of the isotope excreted in urine and feces by accelerator mass spectrometry. This test has revealed that the unabsorbed vitamin is degraded in the intestine. The percent bioavailability is inversely proportional to the dose consumed due to saturation of the active absorption process, even within the range of usual intake from foods. This has important implications for the assessment and interpretation of bioavailability values, setting dietary requirements, and interpreting relationships between intake and status of the vitamin.

DEMINERALIZATION OF WATER WITH MIXED-LAYER ION-EXCHANGERS

2013 ◽  
Vol 12 (1) ◽  
pp. 137-145 ◽  
Author(s):  
Iuliana Rogoveanu Radosavlevici ◽  
Dan Niculae Robescu
Keyword(s):  
Mixed Layer ◽  
Ion Exchangers

Superposition of Potential Chemical Polluants and Radioisotopes and Their Influence Upon the Environment and Living Organisms

2017 ◽  
Vol 68 (9) ◽  
pp. 2189-2195
Author(s):  
Valeriu V. Jinescu ◽  
Simona Eugenia Manea ◽  
George Jinescu ◽  
Vali Ifigenia Nicolof
Keyword(s):  
Solid Waste ◽  
Critical Energy ◽  
Radioactive Isotopes ◽  
Nuclear Facility ◽  
Chemical Pollutants ◽  
Living Organisms

Following the activities developed in a nuclear facility result gaseous and liquid radioactive effluents and radioactive solid waste. All these waste contain radioactive isotopes which are potentially pollutants for the environment. In the same time chemicals are, also, pollutants. According to the legislation, discharging of chemicals and radioactive liquid and gaseous effluents into the environment, should meet the requirements of the unrestricted discharge. However, what happens when several pollutants superpose: only chemical pollutants, or only radioactive pollutants, or chemical and radioactive pollutants? Such problems have been solved in this paper on the basis of the principle of critical energy.

Multipurpose filters with ion-exchanger for the equalization of ammonia peaks

1995 ◽  
Vol 32 (7) ◽  
pp. 199-206 ◽  
Author(s):  
Martin Oldenburg ◽  
Ivan Sekoulov
Keyword(s):  
Operation Time ◽  
Ion Exchanger ◽  
Filter Medium ◽  
Nitrification Rate ◽  
Ion Exchangers ◽  
Flow Rates ◽  
Hydraulic Loading ◽  
Influent Concentration

In this study the use of zeolites as ion-exchangers for equalization of ammonia peak loadings in aerated biological activated filters was investigated. For this use zeolites were mixed with a filter medium and the nitrifying filter was loaded with ammonia peaks for two hours at different flow rates. It could be demonstrated that during the phase of higher inflow concentrations the zeolite was collecting ammonia. When the influent concentration decreased ammonia was desorbed from the zeolite and could be nitrified by the bacteria growing on the filter medium. It was shown that additional zeolites can equalize variations of ammonia, especially in filter units which are working at a high nitrification rate and which are very sensitive to varying influent conditions. During the operation time of the filter no separation of the zeolite by higher hydraulic loading or by backwashing could be recognized. So the upgrading of nitrifying filters with zeolite represents an additional security for effluents containing oscillating ammonia concentrations.

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