Molecular Sieve is Playing an Important Role in Redefining Contemporary Knowledge of Early Human History

Radioactive carbon dating was a technique developed by Willard Libby in 1949 (a discovery that won him the Nobel Prize in Chemistry over a decade later) that can be used to date carbon based materials up to 60,000 years.  This number is significant because it allows scientists to date all of civilized human history and even some early human history and the history of our common ancestors. Carbon dating can also be used to learn valuable things about what the environment and climate were like in the past, too.

Carbon dating works by measuring the isotopes carbon-14 and carbon-12 or 13 in any fossil.  When people, plants, or anything that is carbon based is alive, it is able to generate carbon-14, when it dies it stops generating carbon-14.

Carbon-14 decays though, while Carbon-12 and 13 do not decay.  Carbon-14 has a half life of 5,730 years, which means due to radioactive decay the amount of carbon-14 in an object will be half of what it was in 5,370 years.  Carbon-12 and 13 do not decay so the ratio of the decaying carbon-14 needs to be compared to carbon-12 or 13  to determine how old the object is.

However, recently studies have shown that samples that go through standard carbon dating tests have accuracy issues when the sample is older than 30,000 years.  This is due to 98% of the carbon-14 already having decayed and because carbon-14 molecules from surrounding soil or other carbon based items start to seep into the fossils.  This combination of events can throw off carbon dating by thousands of years.

Tom Higham, an archeologist working for the University of Oxford, is modifying the carbon dating process.  Tom has been using molecular sieve to remove extra C02 and other carbon chains that are contaminating samples and are distorting the test results.

The graphic below shows how some fossils in Europe have been re-dated using molecular sieve.

Note: 13X molecular sieve is frequently used to remove C02 and other large hydrocarbons from the air, and this is most likely the type of molecular sieve being used to improve fossil dating. 

Using molecular sieve in carbon dating has improved the dating of fossils and items over 30,000 years old.  The improvements in the accuracy of these tests could redetermine historical dates/events that are currently being contested; such as when the first humans entered Europe and whether humans came into contact with neanderthals.  As more carbon dating studies are conducted we may see contemporary knowledge of early human history be redefined.

Sources:

http://www.nature.com/news/archaeology-date-with-history-1.10573

http://planetearth.nerc.ac.uk/features/story.aspx?id=833

http://science.howstuffworks.com/environmental/earth/geology/carbon-142.htm

Molecular Sieve Basics: Crystals Help Determine the Pore Size of Molecular Sieve

This article is a kind of a continuation on an article we wrote in 2011 that discusses the pores sizes of molecular sieve.

Molecular sieve are crystalline metal aluminosilicates that belong to the zeolite family.  That means that the molecules and atoms that make up a molecular sieve are made out of alumina, silicon, and oxygen and because they are crystalline they have a strong degree of order in the way they are laid out.

Molecular sieves specialize in separating very small molecules and atoms apart from one another.  Being part of the zeolite family, molecular sieve has a three dimensional network of pores which can adsorb molecules of a specific size.  The pores on a molecular sieve is what makes sieve special, this is because they can separate any substance down to the 1/10,000,000,000th of a meter, or an Angstrom.  There are four standard pore sizes that a molecular sieve can have:

• 3A, 3 Angstrom pore size
• 4A, 4 Angstrom pore size
• 5A, 5 Angstrom pore size
• 13X, 10 Angstrom pore size (depending on the manufacturer the pore size may be either 8 or 9 Angstrom)

The pores on molecular sieve could have one of two structure types: A structure or X structure.  3A, 4A, and 5A are made from an A structure while 13X is made from an X structure.  The A structure is smaller and more square-shaped than the X structure which is larger and circle shaped.

Aluminum Hydroxide, Sodium Hydroxide, Sodium Bicarbonate, and clay are used in the sieve manufacturing process, when the process is created this combination of material will make 4A molecular sieve when created with a type A structure or 13X molecular sieve when created with a type X structure.

3A and 5A molecular sieve are made once they are ion exchanged with the originally cre

ated 4A sieve.  4A molecular sieve is ion exchanged with potassium to create 3A sieve, the potassium molecules are larger than the sodium molecules they were exchanged with shrink the pore size.  5A sieve is created when 4A sieve is ion exchanged with calcium, calcium molecules are exchanged in a 1:2 ratio.  Every calcium molecule removes two sodium molecules thus increasing  the size of the pore.

The various pore sizes of molecular sieve offer a great variety of services to anyone looking to separate different combinations of molecules from one another.

Oxygen Therapy Relies on Purified Oxygen

On earth oxygen occupies approximately 21% of the air in our atmosphere (the other 78% is nitrogen and 1% is argon, carbon dioxide and other gases).  In medical situations you may need a higher concentration of oxygen than what is available in our current living conditions.  This is where 13X molecular sieve and Lithium LSX are used, they purify oxygen.  13X and Lithium LSX do this by adsorbing nitrogen, argon, and the other gases from natural air leaving you with pure oxygen.

Oxygen is the third most common element found in the universe (only hydrogen and helium are more abundant) and it is the element that is most commonly associated with life on our planet.  Technology has allowed us to make oxygen industrially but it can also be used medically.  Higher purities of oxygen are needed in the medical world for both chronic conditions and emergency medical situations and 13X molecular sieve and Lithium SLX both play crucial roles in purifying oxygen so that they can be used medically.

Oxygen in the medical world is primarily used in oxygen therapy.  Oxygen therapy helps treat chronic conditions like chronic obstructive pulmonary disease (COPD) with the most common COPD being emphysema.  Pure 100% oxygen has also been shown to be able to stop the onset of cluster headaches so long as pure oxygen is administered before the peak of the attack occurs.  Cluster headaches are medically believed to be one of the most painful experiences a human being can endure and pure oxygen can help release the tension of the blood vessels that are constricting the nerves, thus relieving a person from tremendous pain.

Oxygen therapy can be essential in saving lives during emergency medical situations and is frequently used during resuscitation. Oxygen tanks and liquid oxygen are usually used during these situations and the oxygen stored in these devices must be purified, which again is the responsibility of molecular sieve.

One of the most common devices used for medical oxygen purification is an oxygen concentrator, which is type of portable oxygen generator that can be used at home as well as in a hospital.  These devices use either 13X molecular sieve or Lithium LSX to purify their oxygen.  The difference between Lithium LSX and 13X is that the Low Sodium X in Lithium LSX has been lithium exchanged.  Both are used in portable oxygen generators but Lithium LSX is used in smaller generators while 13X is used in larger generators.

The oxygen generators range from 100 liter/minute to 3 liters/minute and can be found everywhere from hospitals to MASH units in Iraq or Afghanistan to someone afflicted with COPD. Technology in the medical world has improved to the point that some of these pressure swing units that purify the oxygen can be made so small that they can be worn on a belt, inside a backpack or be plugged into a 12 volt power source.  They can also run on lithium batteries or be plugged into a 120 volt source allowing them to run in a home, field hospital or a domestic hospital.

13X molecular sieve and Lithium LSX have improved our quality of life by allowing oxygen to be purified and used for various forms medical treatment.  This life saving technology is available due to the abilities of  molecular sieve and the scientists and engineers who continue to improve our way of life.

13X Molecular Sieve is Crucial to Making Steel

13X molecular sieve has many different applications and can complete a large variety of tasks.  One industry 13X molecular sieve can be used in is in the steel industry.  Before explaining 13X’s role in the steel industry, here is brief overview that describes how steel is created.

Steel is made from iron and this is done by removing iron’s impurities like silica, phosphorus, and sulfur.  Steel must also have a consistent concentration of carbon (between 0.5% and 1.5%).

Modern steel making has been done using the Bessemer Process (Developed by Henry Bessemer) or one of its modern variants.  The Bessemer Process was developed in 1858 and it was designed to use oxygen to generate steel at a faster rate.  Since separated oxygen was difficult to produce during Bessemer’s time, the patent to this process went mostly unused until the mid 20^th century when new improvements in oxygen generating technology were developed.

The primary modern improvement of Bessemer’s Process uses a basic oxygen furnace instead of a open-hearth furnace to create steel.  A basic oxygen furnace blows high purity oxygen (95%+ pure) through molten iron which lowers carbon, silicon, manganese, and phosphorus levels in iron thus helping to convert it to steel.  The oxygen furnace works approximately 10 times faster than its older counterpart.

Note: Sulfur and phosphorus levels are further reduced by chemical cleaning agents called fluxes in the steel making process.

It’s safe to say that oxygen is a key component to producing steel, and creating pure oxygen is where 13X molecular sieve becomes useful.  Pure oxygen is usually created using the Pressure Swing Process to separate ambient air into two streams.  One stream contains nitrogen, carbon dioxide, and other impurities while the other stream contains over 95%+ pure oxygen.  (The remaining 5% of air in the oxygen stream are noble gases, for example elements like helium).

Pure oxygen that is created from the Pressure Swing Process is then fed into steel furnaces under high pressure to oxidize the impurities inherent in iron.

Cryogenic oxygen generators are also used to purify oxygen for steel production.  These cryogenic generators also require air to be pretreated by molecular sieve in order to remove impurities that are commonly attached to oxygen.

Manufacturing high quality steel requires the use of the Pressure Swing Process or a cryogenic oxygen generator and both require the use of molecular sieve. Without sieve modern high quality steel manufacturing would be impossible today.

Sources:

Smil, Vaclav (2006). Transforming the twentieth century: technical innovations and their consequences, Volume 2. Oxford University Press US

http://science.howstuffworks.com/iron4.htm

Molecular Sieve 3A, 4A, 5A, and 13X…

What’s the difference?

So what’s the difference between all of these molecular sieve types?  – The difference is the size of the pores that come on each molecular sieve bead.  The A in 3A stands for Angstrom,a unit of measurement named after Swedish scientist Anders Jonas Angstrom who was looking for a unit of measurement small enough to measure spectral lines (beams of light).  An angstrom is equal 1/10 of a nanometer, or 1/10,000,000,000 of a meter, so when speaking of 3A sieve it refers to the size of the pore on the bead which is 3 angstroms or 3/10,000,000,000 of a meter.  (On a side note here 13X equals 10A).

So why would someone chose 3A over 4A? – The answer depends on what you are trying to accomplish with your molecular sieve.  For example 3A vs 4A, ethanol producers try to make ethanol that is over 99% pure ethanol.  Traditional distillation methods only give them a 95% ethanol purity rate, while the remaining 5% of the substance  is mostly water.  In short they need to separate the final 5% of the water from the ethanol.  Ultimately the choose a 3A molecular sieve here is why.

For this example 3A sieve works best because the size of water molecule is approximately 2.8 angstrom and the size of an ethanol molecule is 3.8 angstrom.  The 3A sieve adsorbs all of the water molecules because they are small enough to fit inside the pores.   The ethanol molecules, which are too large to fit in the pores, are free to pass by thus separating water from ethanol.  If this person were to use 4A, 5A, or 13X sieve it would not work because the pore sizes are large enough to adsorb both the ethanol and water molecules, and thus no separation would occur.

Generally speaking 3A sieve is used for purifying methanol and ethanol.  4A is used for removing C02  and ammonia from natural gas streams as well as being a desiccant for refrigerants, medicines, and electrical components.  5A is used for sweetening natural gas and purifying hydrocarbon gas and liquid streams.  13X (which is really 10 Angstrom) is a multipurpose sieve, it can adsorb the all the particles that previous 3 sieves can adsorb, but it is usually used to sweeten natural gas streams and purify petrochemical liquids and gases.  Ultimately the pore size of sieve can have a very specific use like 3A or it can have wide range of uses like 13X, it all depends on what you wish to accomplish.