Fukushima Nuclear Disaster Overview

On March 11, 2011 a 9.0 Earthquake, the fourth largest on record since 1900, occurred in the Pacific Ocean causing a series of large tsunamis to strike the eastern coast of Japan.  Now called the Tohoku earthquake, it (and the subsequent tsunamis) caused one of the worst natural disasters on record with over 15,361 people killed, a million buildings damaged or destroyed, and a financial cost of $235 billion dollars (the most expensive natural disaster on record).

In addition to the large amount of damage caused by this natural disaster, it also caused one of the greatest man made disasters on record at Fukushima.  Japan, a country that heavily relies on nuclear power, had a number of nuclear plants that were built near the eastern coast when the tsunamis struck.  Fortunately Japan, a country that sits near two fault lines and has a history with experiencing earthquakes, had containment measures set in place for just such an occurrence.  Once powerful enough earthquake tremors are recorded near Japan’s nuclear plants, they begin to shutdown and cool off.  For the most part this worked, except at Fukushima.

At Fukushima the plants power failed during the earthquake, so the emergency power system along with the emergency cooling condensers had to be used.  Less than half an hour after the emergency systems turned on, tsunamis began to strike the coast near the Fukushima power plant.  A seawall 19 feet high was put in place around the plant to protect it against tsunamis.  The waves from the tsunamis that hit Fukushima were over 46 feet tall, rendering the seawall worthless.  After crashing over the seawall, this wave not only destroyed backup power to the plant but also wiped out key equipment that was part of the emergency core cooling system.

The destruction of key cooling equipment by the tsunami triggered full meltdowns of reactors 1, 2, and 3, thus beginning what we now call the Fukushima Nuclear Disaster.  After the earthquakes subsided, cleanup began and radioactive damage was assessed.  High levels of  Caesium-134, Caesium-137, and some other radioactive isotopes were detected around the nuclear plant and in the ocean.   Currently efforts are on-going to clean up the radioactive waste as a result from the meltdowns.

Molecular Sieve and Zeolites Role in Clean Up

The Fukushima disaster is only the second nuclear disaster (the first was Chernobyl)  to receive a 7 on the International Nuclear Event Scale (INES), the highest disaster rating a nuclear event can be rated.  The clean up process will see new technological developments as well tried and true methods during the clean up of radioactive waste.

One method that’s currently being used, and was used in the past, is using zeolites.  Shortly after the disaster, the Japanese government began to order the dropping of zeolites in the oceans surrounding the disaster site.  The Japanese government is hoping that zeolites (the one’s that the Japanese government are using have specialized in nuclear waste processing), will help to slow down radioactive contamination of the ocean.  Zeolites had previously been used in the clean up of the 1979 Three Mile Island Nuclear Disaster in the United States.

Although dropping zeolite in the ocean seems like a desperate attempt to contain the disaster, Japan is also utilizing  molecular sieve in the clean up process, too.  The molecular sieve in use was specifically designed to capture Caesium, and is being used to treat radioactive wastewater that is on the disaster site. Since the disaster began over 43 million gallons of wastewater have been treated with this molecular sieve at Fukushima.

Experts expect the Fukushima disaster clean up to last decades.  As the clean up continues adsorption technology will continue to play an important role in cleaning up the oceans, environment, and reducing the amount of damage that will be done to our atmosphere.

Sources:

https://share.sandia.gov/news/resources/news_releases/fukushima_cleanup/

http://www.japannewstoday.com/?tag=fukushima-zeolite-absorbs-radiation

http://www.emfnews.org/Fukushima-Decontamination-and-Zeolite.html

http://www.world-nuclear.org/info/fukushima_accident_inf129.html

http://earthquake.usgs.gov/earthquakes/eqarchives/poster/2011/20110311.php

The Far Reaching Effect Zeolite Has On Everyday Human Lives

Some of the natural occurring forms of zeolite that can be seen on Earth.

Before reading this article here are four questions to consider:

1. Have you ever drank a glass of tap water?
2. Have you ever been to a hospital and seen someone receive medical oxygen?
3. Do you heat up your home with gas?
4. Have you ever washed your clothes with laundry detergent?

The majority of people in Western society would have to answer yes to at least one of these questions, if not all of them.  These are just but a few of the many diverse  medical, practical, and  luxury based purposes and products that zeolites have made possible for humans in everyday life.  This broad spectrum of uses makes zeolite one of the most widely used minerals on Earth, yet most people have never heard of it before.  So the question is, what is zeolite and where does it come from?

Zeolite is a natural occurring group of microporous aluminosilicates that are found here, naturally on Earth. Their widespread use amounted to just under 3,000,000 tons of Zeolite being mined around the world in 2010.

Zeolites are naturally formed under low grade metamorphic conditions.  Low grade metamorphism occurs naturally in the cavities of volcanic rocks, where at temperatures between 200 -320 degrees Celsius, and while under low pressure, zeolites can be formed.  However they have been synthetically formed by humans as well, allowing the creation of a wide variety of different zeolites with many different uses.

Note: Some of the most recently created zeolite was made on-board the Columbia Space Shuttle.The reason for creating zeolite in space is to minimize nucleation effects and eliminate sedimentation.

There are 45 different minerals that are classified as zeolites but they only have three different structure types.  These three structures include chain structure, sheet structure, and framework structure.  Chain structure has crystal pores that form prism shaped crystals, sheet structure has crystal pores that are flat, and framework crystal pores have relatively equal sized pore dimensions.

As of November 2011 there are 201 different frameworks (pore classifications) for each of the three different structure types that have been discovered or synthesized by humans.  This combination of having variable structures and having many different pore (framework) sizes and shapes give zeolite the ability to perform many different tasks because of all of the different variations it can be produced in.

How does zeolite work?

Zeolite is microporous.  On its surface are millions of tiny pores that adsorb different materials which is based on the size and shape of the pore and what type of mineral the zeolite is.  Zeolite is also used to make other adsorbents like molecular sieve which is very effective at separating and purify chemicals.  These tiny pores can filter out material that is not needed for a specific application.

Molecular sieve (pictured above) is one of the products that is created and designed from the structure of zeolite.

Referring to the questions asked at the beginning:

Have you ever drank a glass of tap water?

In the case of tap water, zeolite or molecular sieve collects contaminants in water and removes them so you can drink it.

Have you ever been to a hospital and seen someone receive medical oxygen?

Medical oxygen requires pure 100% oxygen before it can be used.  This pure oxygen is frequently made by removing the other elements like nitrogen and argon from the air that occurs naturally here on Earth.  In this case a 13X molecular sieve is used to remove all other components (that are not oxygen) in our atmosphere so that pure oxygen can be made and administered to patients.

Do you heat up your home with gas?

When natural gas (which is turned into the gas that heats your home) is first harvested from the Earth, it is harvested with a lot of other different elements that could be dangerous for human consumption.  Water also needs to be removed from natural gas streams and again these processes require the use of zeolite based molecular sieve.

Have you ever washed your clothes with laundry detergent?

Laundry detergent uses zeolite as a water softener by removing calcium and magnesium from water.  These elements can interfere with the cleaning benefits that the soaps in the laundry detergent provide.

These are only a few of the many different functions zeolites can provide a person, but there importance in the development of technology and in our everyday lives is undeniable.

Sources:

Metamorphism: http://www.tulane.edu/~sanelson/geol111/metamorphic.htm

Zeolite grown in space: http://www.tubitak.gov.tr/tubitak_content_files//spaceworkshop/presentations/Bac.Nurcan.pdf

Zeolite structures: http://www.galleries.com/Zeolite_Group

Zeolite production: http://minerals.usgs.gov/minerals/pubs/commodity/zeolites/mcs-2011-zeoli.pdf

Amount of Zeolite mined: http://minerals.usgs.gov/minerals/pubs/commodity/zeolites/mcs-2011-zeoli.pdf

More Structures: http://www.iza-structure.org/

A Look Into How Military’s Use Desiccants in Gas Masks and Medical Equipment

Desiccants are used all over the world and military’s around the world are no exception.

The first widespread use of desiccants by any military occurred during the First World War.  This war is famous for the use of chemical gases as a weapon, and armies that were afflicted with a barrage of gas containing shells needed protection in order to avoid being poisoned.

This led to the first gas masks being mass produced.  The material in the gas mask canisters that absorbed potential toxins was silica gel, and this helped to reduce the effects of poisonous gas attacks that opposing armies faced throughout the remainder of the war.

During 1915 ,while World War I was on-going, Russian scientist Nikolay Zelinsky improved upon the gas mask by creating a filter that used activated carbon, another desiccant.  Today activated carbon is the standard desiccant used in most modern gas masks.

The activated carbon filters in gas masks didn’t start getting used until after World War II.  During this war silica gel was replaced as the primary adsorbing material in gas mask by asbestos… which the world learned after the war caused serious illnesses like mesothelioma and malignant lung cancer.

This paved the way for modern gas masks which use activated carbon filters in combination with aerosol filters to keep soldiers safe.  Activated carbon has a larger surface area than silica gel and can adsorb more potentially dangerous airborne chemicals, thus making it more effective filter.

Besides being used in gas masks, desiccants have recently found a new use in military medical technology.

Zeolites have been attached to gauze and recently been used by the U.S. military to help reduce the blood flow in wounded soldiers and civilians.  The pores in the zeolites are small enough to adsorb the water out of the bloodstream leaving only cells and platelets.

Platelets circulate throughout our blood stream looking to clot blood.  With all the water absorbed out of the bloodstream, thanks to the zeolites, the blood is allowed to clot a lot faster.  This has helped save many lives because it greatly speeds up the time for a wound to close and stop bleeding and it also reduces the chance of wound becoming infected.

The success of zeolites in gauze has allowed this product to be used in the commercial medical market and it is now being used by law enforcement and emergency response units.

What Is It and How Does It Separate Oxygen from Nitrogen

What is carbon molecular sieve?

Carbon molecular sieve is an adsorbent that fuses the ideas behind both activated carbon and zeolites into one product.  Activated carbon is known for its high porosity and zeolites are known for their ability to be crafted into highly specialized adsorbents called molecular sieve.  Carbon molecular sieve is a product that brings the benefits of both of these products together.

Carbon molecular sieve is made out of coal (the same material most activated carbon is made out of) and it specializes in adsorbing material under 10 angstroms, something activated carbon can not do accurately.  The smallest pore size created for carbon molecular sieve is 4A, but it exists in a 5A, and 10A (or 13X) as well.

Carbon molecular sieve specializes in separating oxygen from nitrogen, an important part in natural gas processing. This process is done with a PSA (Pressure Swing Adsorption) device in two phases.  The first phase sees the gas enter the PSA generator and the oxygen is adsorbed while the nitrogen passes through because the nitrogen molecules are too large and are used as a separate product.  The second phase sees the oxygen slowly released from the sieve at low pressures and thereby regenerating it so that the separation process can be repeated.

Carbon molecular sieve is used in this situation as opposed to activated carbon because the physical size between oxygen (0.28nm×0.40nm) and nitrogen (0.30nm×0.41nm) molecules are so close.  The pore sizes on carbon molecular sieve are able to accommodate these small size differences, where as activated carbon would just end up adsorbing both of them.

Molecular sieve isn’t used because it is a polar adsorbent, meaning its surface area attracts other polar molecules.  Oxygen is a non-polar molecule and would be attracted to other non polar surfaces.  Carbon molecular sieve is one of the few non-polar adsorbents out there which is why it is chosen over molecular sieve for this application.

In addition to separating nitrogen from oxygen carbon molecular sieve can be used for metal heat treatment, electron production, and as preservative in food products.

…and Oxygen and Carbon Compound Adsorbents?

Absorption and adsorption are two natural occurring processes that are similar, but are not the same.  Here is a basic breakdown of how they are different:  absorption occurs when one material’s physical state is absorbed into another material’s physical state, while adsorption occurs when one material physically sticks to another material without changing it’s physical state.

Absorption occurs when a gas turns into a liquid, or a liquid into a solid, etc.  This is what separates it from adsorption, the physical state of the molecules have changed.  For example if you were to drink a glass of milk, your body would absorb it into your digestive system and eventually into your bloodstream.  The earth absorbs the suns rays and has converted its energy into the life sustaining planet we live on today.  The roots of plants absorb water when it rains converting into the energy it needs to survive.  All of these examples feature one material’s phase being turned into another.

Adsorption occurs when liquid or gas molecules stick to the side of surface, preserving their physical state.  This is useful for separating certain molecules from one another.  Adsorbents are most commonly found as carbon compounds or oxygen compounds.

Oxygen compound adsorbents are used to make products like silica gel which works to absorb moisture and reduce humidity levels or zeolites which can be tailored to specifically remove certain molecules from the air like carbon dioxide.

Carbon compound adsorbents like activated carbon can be effectively used to treat waste water and gas.  Contaminates will get stuck to the pores that are found all over the surface area of activated carbon while the water filters through.

Absorption and adsorption are both sorption processes, they both take in a substance or hold it in place and that is how they are related and why the are so similar, the process, however, is different.