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.

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/

Water fluoridation is a double edged sword.  In the U.S. fluoride has been added to most water streams in order to help prevent tooth decay.  (I should mention fluoride naturally occurs in a lot of drinking water sources throughout the world).  However fluoride can be damaging to bones at higher doses and it can even be fatal if you take in large quantities of it.

The desiccant activated alumina plays a very important role in reducing fluoride levels in water.  By doing this activated alumina leaves enough fluoride in water for people to receive its potential health benefits while at the same time it makes sure that health damaging amounts of fluoride do not remain in drinking water.

In 1994 the World Health Organization recommended that fluoride levels in water should be contained from 0.5-1mg/L.  Fluoride levels above 1mg should undergo defluoridation, which can be done three different ways: with chemicals and precipitation, with membrane based technologies, or with ion exchange and adsorption.

A lot of times these methods are used in combination.  For example, when fluoride levels are above 15ppm using lime which falls under the chemicals and precipitation category should be used because they can handle the high levels of fluoride.  Once that level is lowered using lime, activated alumina, which falls under the adsorption category, should be used to reduce to the fluoride content to below 1ppm since activated alumina can purify water up to 99%.

How does Activated Alumina work in removing fluoride from water?

Activated alumina adsorbs fluoride because fluoride is attracted to alumina.  It wants to make aluminum fluoride which it does once it comes into contact with activated alumina.  The alumina fluoride will remain stuck to the alumina beads so long as the pH level of the water remains below 6.  If water’s pH remains lower than a 6 the effectiveness of activated alumina starts to be reduced.  It can also allow aluminum to get in your water, although aluminum does not typically dissolve in water.

Note: Reverse osmosis is used to remove aluminum from water and so can certain distillers.  Aluminum does not typically get into water because water has a difficult time dissolving it.

It’s recommended that you pre-treat activated alumina with aluminum sulfate before you use it in order to improve the first adsorption runs.  After pretreatment it’s important to remember that adsorption reactions with activated alumina are  flow-rate dependent.  Although activated can handle high flow rates and still work, its adsorption capacity is reduced and this could lead to having to do additional cycles.  Doubling the flow rate allowed 33% more fluoride through the activated alumina beds, thus reducing activated alumina effectiveness in adsorbing fluoride.

There is a possibility of other ions interfering with the adsorption process when working with activated alumina, this is due to water in the U.S. containing other ions.  These ions are usually sodium chloride, sodium sulfate, and sodium bicarbonate.  Sodium chloride and sodium sulfate do not interfere with the adsorption process, but sodium bicarbonate can reduce the capacity of activated alumina between 33% and 70%.

Activated alumina like most desiccants can be regenerated.   Sodium hydroxide, aluminum sulfate, or sulfuric acid are applied to a lye solution with the activated alumina, allowing the adsorbent to be regenerated.  Once regenerated activated alumina can continue to be re-used, and when used properly activated alumina can last years.

Activated alumina is essential in removing fluoride in water up to 99% and making water safe for people to drink.

Sources:

http://www.watersanitationhygiene.org/References/EH_KEY_REFERENCES/WATER/Water%20Quality/Fluoride/Defluoridation%20Using%20Activated%20Alumina%20%28UNICEF%29.pdf

http://www.bibliotecapleyades.net/salud/salud_fluor23.htm

World Health Organization: http://whqlibdoc.who.int/trs/WHO_TRS_846.pdf

http://www.tramfloc.com/tf133.html

Double Flow Rate = 33% decrease in adsorption capacity, reverse osmosis, and ions.  http://www.purewateroccasional.net/newnewsletter8.html

Water below pH of 6 reduces effectiveness of Activated Alumina http://greenlivingqa.com/content/fluoride-filtration-using-alum

This is the final blog article that discusses ethanol’s ability to produce energy gains.  The previous two articles focused on proving that ethanol is currently producing positive energy gains and proving that the primary research done by David Pimentel (research that claims ethanol is producing a net energy loss) is very flawed.

Ethanol has been producing positive energy gains for the past couple of decades as well as reducing the amount of energy needed to produce ethanol.  Technology has improved the efficiency of ethanol plants currently and will continue to do so as we move towards the future. In addition to improving the technology in ethanol production, ethanol also produces a number of co-products besides fuel that also increase the total energy yields of ethanol plants.  Both of these factors play a large role in ethanol producing positive energy gains.

Technology has improved many different areas in ethanol production.  Studies show that it took 5.8 gallons of water to produce 1 gallon of ethanol in 1998, in 2010 it took 2.7 gallons of water to produce 1 gallon of ethanol.  This in turn helped to improve the BTU’s of ethanol produced ratio to BTU’s of energy used to produce ethanol.  Positive ethanol energy gains have increased from 1.37 BTU’s of energy in 1996 to 2.3 BTU’s of energy in 2005.

Note: BTU stands for British Thermal Unit, it measures how much energy is required to heat 1lb of water (or .11 gallons of water) from 39 degrees Fahrenheit.  1BTU=1055 Joules of Energy

In the 2010 NREL  report Current State of the U.S. Ethanol Industry ethanol producers had reduced water consumption by 26.6% from the years 2001 to 2006.  The report went on to say a typical sized ethanol plant uses as much water as town of 5,000 people or as much water as an average sized golf course.

Dr. Steffen Mueller at the University of Illinois at Chicago has researched how ethanol plants have become more energy efficient.   Her study found ethanol plants have been able to reduce the amount of electricity they use by 32% from the years 2001 to 2008.

Meuller’s study also found that dry mill ethanol plants had reduced thermal energy by 28% since 2001.  Dry mill ethanol plants were using  26,000 BTU’s of energy on average to produce a gallon of ethanol.  A gallon of ethanol yields approximately 77,000 BTU’s of energy.

Note: Dry mill ethanol plants represent over 90% of the current ethanol plants in operation in the United States.  The remaining 10% are called Wet Mill Plants.

These improvements in technology have helped to increase ethanol’s energy outputs.  In addition to improvements in technology ethanol production allows the production of co-products.  These products which can also be factored into ethanol total production include:

• Distiller’s Grains -These are used as animal feed.  28% of corn used to produce ethanol is recycled and reused as animal feed.   Ethanol production currently gets around 16lbs of distiller grains from each bushel of corn. (1 bushel of corn = 56lbs).
• Carbon Dioxide – This is another by-product of ethanol production.  During the distillation process C02 is produced, this gas is usually resold to soda companies or any other company that produces carbonated beverages.

All of these technological trends show that ethanol is creating energy gains.  As the ethanol industry continues to grow the technology to produce ethanol will continue to get more efficient which will give the world a renewable, effective, and efficient energy source.

Sources:

Pimentel/Patzek Article Oil Ties and Arguments  http://www.biofuelsjournal.com/articles/ethanol_industry_refutes_david_pimentel_s_study_showing_negative_energy_balance_for_ethanol-27165.html

2002 U.S. Department of Agriculture Study http://journeytoforever.org/ethanol_energy.html

Pimentel Claims: http://www.freelists.org/post/biofuels-forum/Key-Differences-between-PimentelPatzek-Study-and-Other-Studies,1

http://journeytoforever.org/biofuel_library/PimentelComments4_5_05.pdf

National Renewable Energy Laboratory See Section 7.1 Net Energy Balance http://www.nrel.gov/analysis/pdfs/doe-02-5025.pdf

USDA Switchgrass yields http://www.scientificamerican.com/article.cfm?id=grass-makes-better-ethanol-than-corn

U.S. Ethanol Distiller Grains http://growthenergy.org/images/reports/ethanol_livestock.pdf

Dry Mill Ethanol Efficiency Gains http://www.ethanolrfa.org/exchange/entry/from-farm-to-biorefinery-ethanol-production-efficiency-improves/

Dry Mill Ethanol Efficiency (Thermal Energy) http://www.ethanolrfa.org/news/entry/dry-mill-ethanol-production-shows-significant-improvements-in-efficien/

2.1.1.1 DGS in the U.S. http://www.transportation.anl.gov/pdfs/AF/527.pdf

Part 2: Disputing Pimentel’s Ethanol Research

This is the second article in a three part series that focuses on debunking the myth that ethanol production creates a net energy loss.

Last weeks article focused on this myth’s origin and its strongest supporters  David Pimentel and Tad Patzek.  This week will focus on debunking the some of the inconsistencies found in their research compared to the results of other studies done on ethanol energy outputs, and it will discuss some of the key energy omissions from Pimentel’s/Patzek’s 2001 study.

Below is  a  list of the Pimentel Study’s most glaring problems along with rebuttals to why they are problems.

1. Pimentel – Ethanol production yields a 29% loss in energy when produced from corn
•    The U.S. National Renewable Energy Lab found a producing ethanol yielded a 30% gain in Energy when comparing 1BTI of fossil fuel to 1BTU ethanol.  This study was done shortly after Pimentel’s Study.
•    In the National Renewable Energy Laboratory (NREL) 2010 report Current State of the U.S. Ethanol Industry the NREL finds the following
1.  The net energy balance of corn ethanol has increased from 1.76 BTU’s to 2.3 BTU’s since 2004.
2.  For every BTU of energy required to make ethanol, 2.3
   BTU’s of energy are produced.
3. Over the past 20 years ethanol yields have increased over 10% and corn yields have increased 39%.
2. Pimentel – Between 45% to 57% more energy would be lost in producing ethanol from wood or switchgrass
•    The United States Department of Agriculture conducted a study on switchgrass and found that it had a 540% energy yield, meaning it produced 540% more energy than it took to produce it.
3. Pimentel’s study uses outdated information or incorrect  data
•    Pimentel uses data for corn yields that exists before 1992.
•    Pimentel uses values for measuring energy to produce ethanol that were used in the 1980′s.
•    Pimentel uses 1990 world-wide values, not recent U.S. values for his figures determining how much energy is needed to produce fertilizer.
4. Pimentel’s study omits crucial data that could help determine ethanol’s energy production
•    Pimentel does not factor in dried distiller grains into ethanol’s energy output.  1/3 of all ethanol produced gets reused as distiller grains, which in turn is used to make animal feed.  This is huge source of energy not included in Pimentel’s study.

Pimentel’s study has many flaws making it an unreliable source of information.  His findings have been discredited by many scientists and government agencies within the U.S.  Next week will be part three of this series which will discuss the energy ethanol is currently producing and what the ethanol industry is expected to produce.

Sources:

Pimentel/Patzek Article Oil Ties and Arguments  http://www.biofuelsjournal.com/articles/ethanol_industry_refutes_david_pimentel_s_study_showing_negative_energy_balance_for_ethanol-27165.html

2002 U.S. Department of Agriculture Study http://journeytoforever.org/ethanol_energy.html

Pimentel Claims: http://www.freelists.org/post/biofuels-forum/Key-Differences-between-PimentelPatzek-Study-and-Other-Studies,1

http://journeytoforever.org/biofuel_library/PimentelComments4_5_05.pdf

National Renewable Energy Laboratory See Section 7.1 Net Energy Balance http://www.nrel.gov/analysis/pdfs/doe-02-5025.pdf

USDA Switchgrass yields http://www.scientificamerican.com/article.cfm?id=grass-makes-better-ethanol-than-corn

U.S. Ethanol Distiller Grains http://growthenergy.org/images/reports/ethanol_livestock.pdf