Radioactive Strontium-90 removal

Some zeolites have a strong affinity for particular cations. Clinoptilolite (HEU) is a naturally occurring zeolite which sequesters caesium, and is used by British Nuclear Fuels (BNFL) to remove Cs from radioactive waste, exchanging its own Na ions for the radioactive Cs cations. Similarly, zeolite A can be used to recover radioactive strontium. Zeolites were heavily used in the clean up operations after the Chernobyl and Three Mile Island incidents. 

Dozol, J.-F., Casas i Garcia, J., and Sastre, A. M. Applications of Crown-Ethers to Cesium and Strontium Removal from Marcoule Reprocessing Concentrate, in New Separation Chemistry Techniques for Radioactive Waste and Other Specific Applications, Cecille, L., Casarci, M., and Pietrelli, L. (Eds.), Elsevier Applied Science, Amsterdam, 1991, pp. 173-185. 

Synthetic and natural zeolites have also been intensively investigated. They are inexpensive and widely available sorbents that should be employable for strontium recovery. Some of these sorption materials, such as type A zeolites and natural chabazite are known to be effectively employed for the removal of radioactive strontium from technological solutions [246, 247] so contaminated. 

Radioactive (Strontium) Sr-90 Removal Using C20 ODPPA (2-Octyldodecyl Phenylphosphonic Acid) Extractant... 

Experiments carried out on laboratory animals have shown that (radioactive) strontium is rapidly deposited in the skeleton, from which it is only slowly removed in the normal process of metabolism. Once ingested, of the total amount in vertebrate animals or humans more than 99 % of the strontium is localized in bone and connective tissue, which in total is about 320 mg for a 70-kg adult. For herbivorous animals the bone strontium level is higher than that present in humans, probably due to the higher dietary intake of strontium from plant material. Retention of strontium in the human body after oral doses of 100-250 mg has amounted to 12-24% in a month (Harrison et al. 1955). More strontium is absorbed by persons on a low calcium intake than on a high calcium intake. Animal as well as human studies have demonstrated that the intestinal absorptions of strontium and calcium are comparable, which led to the hypothesis that these elements share a common carrier system in the intestinal wall (Reid etal. 1986). Stron-... 

As a means of removing radioactive strontium (stron-tium-90) from milk that has been contaminated by the element. 

Non-radioactive Sr-87 Removal We have synthesized a family of new extractants, alkyl phenylphosphonic acids, for strontium removal by SLMs with strip dispersion (Ho, 2001b, 2003 Ho and Wang, 2002). The extractants synthesized were 2-butyloctyl phenylphosphonic acid (Cl2 BOPPA), 2-hexyldecyl phenylphosphonic acid (C16 HDPPA), 2-octyldecyl/2-hexyldodecyl phenylphosphonic acid (C18 ODPPA/ HDPPA), and 2-octyldodecyl phenylphosphonic acid (C20 ODPPA). 

Researchers claim that lonsiv TIE-96 can remove 99.9% of the plutonium, strontium, and cesium from waste solutions, allowing for wastes to be divided into separate low-level and high-level radioactive waste streams, where they can be safely and efficiently processed for disposal. 

Herbst, R.S., Law, J.D., Todd, T.A. et al. 2002. Universal solvent extraction (UNEX) flowsheet testing for the removal of cesium, strontium, and actinides elements from radioactive, acidic dissolved waste. Solvent Extr. IonExch. 20 (4—5) 429 445. 

An example of removing multiple interfering elements is strontium purification in the presence of fission products. Ferric ion is added as a holdback carrier for the rare earths (and other radionuclides) and then precipitated as Fe(OH)3, the scavenger that carries these radioactive impurities. This or any other step can be repeated for enhanced removal of impurities. 

Crown ethers are also used to remove radioactive elements from radioactive waste. For example, radioactive cesium and strontium can be extracted using specialized derivatives of 18-crown-6. 

Samples (156) were taken from 54 reference lithic pieces that represented five rock types. These samples were analyzed at the SLOWPOKE Reactor Facility of the University of Toronto. They were irradiated for 1 min at 2 kW, or for 1 or 2 min at 5 kW (depending on their radioactivity level in preliminary tests). Upon removal from the reactor, the samples, which weighed between 0.1 and 0.3 g, were left to decay for 18 min and were counted for 5 min with a Ge(Li) y-ray detector coupled to a multichannel analyzer. Trace element concentrations were calculated with the comparator method (7). The 15 elements examined were barium, titanium, sodium, aluminum, potassium, manganese, calcium, uranium, dysprosium, strontium, bromine, vanadium, chlorine, magnesium, and silicon. The first seven of these elements were the most useful in the differentiation of major rock types. 

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