On this page:
Kharkov National University - Zeolite as Decontaminant
Global Security Newswire - Zeolite as Buffer Zone
Sacbee - Zeolite as Natural Filter for Radioactive Particles
Geocities - Zeolite Removes Toxic Cations
News in Focus - Zeolite Helps Clean Up Radioactive Liquid
Rota Mining - Zeolite as Barrier for Radioactive Waste
US Army - Zeolite in Decontamination Kits
Anne Galarneau - Zeolites at the Dawn of the 21st Century
The following is an excerpt from a research paper by A. Yu. Lonin and , A.P. Krasnopyorova of the National Science Center "Kharkov Institute of Physics and Technology", 61108, Kharkov, Ukraine.
To read the full article follow this link:
Kharkov National University, Kharkov, Ukraine (April 2, 2007)
The possibility of using zeolites in decontaminants applied for cleaning up radioactively contaminated working clothes and surfaces is studied. It has been established that zeolites can be used for decontamination of working clothes, as well as, working surfaces presented by metals, ceramic tile, wood coated with paint or varnish, glass. The data on dfferent zeolite-based decontaminant in comparison with a known detergent "Zashchita" are given.
During employment of nuclear power objects one of the methods providing the safety of personnel is radioactive decontamination of working clothes and surfaces followed by the radioactive waste utilization and disposal. Formerly, for decontamination of working surfaces and materials one used different reagents selected with taking into account the properties of surfaces and materials subjected to processing. For equipment decontamination used are alkali, permanganate of potassium and oxalic acid. Decontamination of rooms is performed by means of the water solution of oxalic acid with addition of hexameta-phosphate and sulphonol. For decontamina tion of working clothes and footwear one uses the solutions containing salt-forming components: oxalic acid, sodium carbonate, sodium phosphate and detergents (sulphonol, soap).
Solutions, obtained after decontamination have had a large volume and required an additional treatment in the process of radwaste utilization and disposal [1-3].
In recent years, adsorption agents are widely used for radioactive decontamination. They are specifed by the universal use in regard to working surfaces and materials and allow one to reduce substantially the decontamination sinks. At the most part of Ukrainian APPs ones use for decontamination of equipment, rooms and personnel an ion-exchange resin-based detergent "Zashchita" (produced in Russia). However, the use of adsorption agents has some
- low decontamination coefficient;
- presence of an abrasive effect for chrome-plated surfaces and surfaces of glass and organic glass;
- necessity in the additional charge for waste utilization associated with ion-exchange resin decomposition and subsequent immobilization of radioactive waste.
A material, used in this work, was natural zeolite - clinoptilolite and synthetic zeolites. The choice of zeolites was determined by the following factors:
Firstly, the authors of [1,2] regarded the ion-exchanging and adsorptive properties of zeolites considering a possibility of using them for decontamination.
Secondly, it was taken into account that the mining of natural zeolites, the resources of which in Ukraine are rather ample, is considerably cheaper than the production of ion-exchange resins .
Thirdly, Russia is carrying out a research into the use of clinoptilolite for radioactive waste utilization. At the State Scienti¯c Center "Academician A.I.Leypunsky Institute for Energy Physics" a method of liquid radioactive waste condensation and reprocessing with the use of clinoptilolite as a sorbent was developed. Clinoptilolite is a component of the film-forming mixture, applied for radioactive decontamination of the constructional material surface, offered by the Academician A.A.Bochvar Research Institute of Inorganic Materials [4-6].
The purpose of this work was to create for decontamination of working clothes, equipment and rooms, a domestically produced zeolite-based decontaminant, having a high decontamination coefficient and being cheaper, in comparison with existing analogues, as well as, to develop a simplified utilization method.
The proposed composition of the decontaminant is characterized by the low cost since it contains a natural component clinoptilolite, the resources of which in Ukraine are very ample. Besides, the open mining of this mineral considerably reduces the manufacturing cost of the detergent. The solutions obtained after decontamination with the use of zeolite occupy a much smaller volume than the solutions obtained after application of the decontaminant "Zashchita". Moreover, these detergents provide appreciably lower expenses for radwaste utiliza123tion and disposal (clinoptilolite is strongly immobilized by radionuclides and can be utilized as a base for radionuclide disposal). Proposed compounds for zeolite-based decontamination have no limitations as for chrome-plated surfaces and surfaces of glass and organic glass due to the absence of an abrasive effect. The zeolite-based decontaminant is applicable for repeated decontamination of multiply contami-
nated fabric surfaces.
The following articles discuss zeolites as being the last defence against radioactive contamination of ground water supply at Yucca Mountain.
This article was taken from
http://www.nti.org/d_newswire/issues/newswires/2002_3_13.html, a link which no longer works.
Global Security Newswire by National Journal Group
Daily News on Nuclear, Biological and Chemical Weapons, Terrorism and Related Issues
The tests determined that, while there would be movement of the rock due to the heat, the water itself would be drawn away from the canisters, in effect creating ““a buffer zone,”” he said.
Researchers also examined how the alternating layers of volcanic and nonvolcanic rock that make up Yucca Mountain would block the movement of water through the mountain. If any water were able to penetrate down into the ““drifts,”” or underground tunnels cut into Yucca Mountain where the waste canisters would be stored, it would then have to corrode through a thick titanium drip shield placed over the canisters, Rowe said. He added that if the water could corrode its way through the shield, it would then have to corrode its way through the storage canisters themselves.
In that situation, most of what little water that would reach the spent-fuel itself would be evaporated by the heat generated by the waste before it could dissolve any radionuclides and carry them down into the water table, Rowe said. Water would then have to make its way through the floor of the storage tunnels and through a layer of zeolites –– minerals that can either filter out radionuclides or slow down their process through the rock layer.
Rowe was shocked at claims made by Yucca Mountain opponents that the mountain was in effect a sieve and water would easily flow through the mountain and carry radioactive contaminants into the ground water supply (see GSN, Feb. 6).
“It doesn't look like any sieve I’ve ever seen,” he said.
The following article was taken from:
http://www.sacbee.com/24hour/healthscience/story/419320p-3342057c.html, the link no longer works.
Groundwater discussions touch on Yucca Mountain
By SCOTT R. BURNELL, UPI Science News
Published 6:31 p.m. PDT Thursday, May 30, 2002
The controversial proposed nuclear waste storage site at Nevada's Yucca Mountain made its way Thursday into discussions at the American Geophysical Union's spring meeting, as four out of 12 visual presentations in an AGU session on groundwater field testing touched on Yucca to some degree.
Leslie countered some DOE statements concerning a possible barrier to the spread of any contamination. Below the level where waste would be stored, several sedimentary layers contain crystals called zeolites, which act as a natural filter for radioactive particles, DOE personnel have said.
Some zeolites lie in fractured areas, Leslie explained, where groundwater might flow too fast to allow the filtering to occur. The zeolites have only limited effectiveness against the most hazardous isotopes, he said.
Another link which is no longer available:
Zeolites, naturally occurring cation-exchangers, are suitable substitute for the removal of toxic cations from different streams of wastewater. Among the natural zeolites, clinoptilolite seems to be the most efficient ion-exchanger for the removal of heavy metal cations from industrial wastewater as well as dangerous and toxic radioisotopes from nuclear waste streams.
Follow this link to read a News in Focus article about zeolite's use in helping to clean up radioactive waste in Japan.
The following is an article by Rota Mining Corporation, Turkey
RADIOACTIVE WASTE TREATMENT
Natural zeolite has a high ion exchange capacity and a particular affinity for heavy metal cations. It can absorb elements such as strontium 90, caesium 137 and other radioactive isotopes from solution and hold them in its 3 dimensional crystal framework. Zeolites react readily with cement and glass systems thus allowing the radioactive waste to be entrapped and contained safely. Zeolites are physically robust and resistant to nuclear degradation, and they are less expensive than organic ion exchange resins.
Sorbent Barriers For Radioactive Waste
Permeable barriers incorporate sorbent materials, including zeolite, to selectively contain contaminants that are percolating from shallow land burial sites of low-level radioactive waste. The zeolites are combined with clays and other materials that retard the migration of leachate for a period long enough to allow exchange and/or decay of radioactive ions.
ZEOLITE MINERAL AGAINST RADIOACTIVE POLLUTION
Zeolites are hydrated aluminosilicates in crystal structures, capable of absorbing many different types of gases, odors, moisture, petrochemicals, ammonia, heavy metals, low-level radioactive elements and a multitude of various solutions. In the USA and Great Britain zeolite are routinely applied for the decontamination of radioactive wastewater to remove Cs and Sr radioisotopes. However, these are small-scale operations compared to the extensive use of natural zeolites at Chernobyl disaster in 1986.
ZEOLITE Mineral Barriers Against Radioactive Pollution in CHERNOBYL
During the Chernobyl disaster, thirty to forty times the radioactivity of the atomic bombs dropped on Hiroshima and Nagasaki were released. The main radioactive isotopes from the Chernobyl accident were 137Cs, 134Cs, 90Sr, and 89Sr. The details of zeolite applications at Chernobyl remain rather obscure because of a secrecy problem still remaining after disintegration of the former Soviet Union.
About 500,000 tons of zeolite rocks, mainly containing clinoptilolite, were processed at various deposits in Ukraine, Georgia, and Russia specifically for use at Chernobyl.
The majority of the zeolites were used for the construction of protective barriers and for agricultural applications in polluted areas.
Decontamination of potable water of the Dnieper river by using a combination of dust-like clinoptilolite and aluminum sulfate followed by filtration through clinoptilolite layers led to a drastic decrease of radioactivity.
In addition, filters of clinoptilolite tuffs were suggested to extract radionucleides from the drainage water of the encapsulated Chernobyl nuclear power plant.
Filtration reduced 137Cs by 95% and 90Sr by 50-60%. After one year the filters carrying a radioactivity of 10-5 Ci/kg were exchanged and buried. To reduce Cs radionucleides in cow milk in Bulgaria 10% clinoptilolite was added to the cow feed resulting in 30% Cs reduction in the milk. For Cs decontamination of children chocolate and biscuits were prepared containing 2-30 wt.% pure and powdery clinoptilolite. In Western Europe clinoptilolite was tested to reduce radionucleide levels in soil, plants, sheep, broiler chicken, and fruit juice.
The following article mentions that zeolites are used by the US Army in their decontamination kits. The link no longer works.
Newsletter Volume 1 Number 2 Spring 2000
DOD Decontamination Science and Technology Program
by John Weimaster, PhD, US Army Soldier, Biological Chemical Compound, Aberdeen Proving Ground, Edgewood Area, Maryland; and John Ontiveros, PhD and Mr Imran Baig, Battelle Edgewood Operations, Bel Air, Maryland
Current and Future Programs
The main thrust for 2000 is the JSSED-Block I Program. This program addresses the need to decontaminate CB agents from sensitive equipment such as avionics, electrical, electronic and environmental systms equipment. This program is scheduled for transitioning in FY01. Figure 1 summarises the planned DoD decontamination acquisition programs and the anticipated dates for transition from research to engineering.
Figure 1 - Decontamination Key Tech Base Transition Program
The JSSED-Block II/III Program emphasises decontamination of vehicle and aircraft interiors and also addresses the need for “on-the-move” decontamination. The Superior Decontamination Solution (SDS) Program consists of a series of projects that target the replacement of DS2 and the development of other decontamination solutions. The Next Generation Decontamination Kit encompasses the new category of solid decontaminants such as reactive sorbents (e.g. zeolites and nanoparticles). These will serve as a product improvement to replace the current developmental sorbent in the M295 Decontamination Kit and also have other applications. To conclude Figure 1, there are several issues, such as the environmental fate of agents and the behaviour of agents on surfaces, that impact all programs and these are collectively reported represented in the category Decon Studies and Program Issues.
The multi-fold responsibilities of the Joint Science and Technology Panel for Chemical and Biological Defense are strongly directed to the goal of achieving innovative and effective decontamination techniques for the future. Four transition milestones will occur over the next five years. The transfer of technologies to engineering development will provide new capabilities where none existed before. Continual awareness of valid ongoing projects will lead to effective collaboration, the judicious use of resources and concurrent investigation of promising technologies.
Next Generation Decontamination Kits
Destructive adsorption: a new approach to reactive sorbent for immediate decontamination: to prepare a reactive sorbent for immediate decontamination. This requires an initial preparation of inorganic substrates impregnated with oxides of transition state metals and a subsequent characterization of their reactivity to chemical war fare agents and simulants. This approach may have application in the JSSED-Block II/III Program mentioned earlier.
This is a link to a very technical and lengthy report on zeolite, titled Zeolites and Mesoporous Materials at the Dawn of the 21st Century by Anne Galarneau. If the link does not work copy the address into your browser address box.
http://books.google.com.au/books?id=huA0TXmmYXkC&pg=PA21&lpg=PA21&dq=radioactive+decontamination+zeolite&source=bl&ots=99hHC_-A0_&sig=n0qY2hNn4v-2FcvdAxA-idpLVMk&hl=en&ei=ckeiTcqJLIT6vwPIn8iTBQ&sa=X&oi=book_result&ct=result&resnum=3&ved=0CCgQ6AEwAg#v=onepage&q=radioactive decontamination zeolite&f=false