Looking Back

     The end of the semester is getting near, and it's time to reflect on the class as a whole.  If I had to explain the field of green chemistry to a friend, I would say that it is a relatively new field that is still expanding and growing its ideas, and it also strictly follows the twelve basic principles of green chemistry, including: "Safer Solvents and Auxiliaries", "Design for Degradation", and "Inherently Safer Chemistry for Accident Prevention."
     The "Safer Solvents and Auxiliaries" means to use as less chemicals that could potentially harm the environment and  human health as possible.  For example, many soaps are made up of chemicals that could be easily replaced with natural ingredients.  Therefore, natural soap is the perfect example for this principle.  Next time buying soap, look for the ingredients and see if they are natural!
     "Design for Degradation" means designing materials to be biodegradable whenever possible.  Many companies have been trying to go by this principle, including Lay's.  They have now created biodegradable bags!
     Last but not least, "Inherently Safer Chemistry for Accident Prevention" means that we should plan to minimize (or completely eliminate) any potential chemical accidents.  This is certainly true for nuclear power plants:  when designing them, we have to make sure that contains lots of backup to prevent any accidents.

Corn as a Chemical Feedstock

     Many experts today agree that we cannot solely rely on fossil fuels as a source of energy for cars.  Therefore, we should look for alternative fuels by experimenting with chemical and engineering sciences.   For instance, through the fermentation of yeast, corn produces ethanol.  Today, ethanol is an additive to gasoline.  Now when I look at the gas pump and see the "contains 10% ethanol" sign, I'll think of corn.

     Corn doesn't solely produce ethanol, however.  Corn can also produce acetone and butanol: these are "high-value industrial solvents."  Butanediol can also be produced from corn: it's "an industrial solvent and a precurser to synthetic rubber."  Others chemical feedstock derived from corn include lactic, acetic, and citirc acid.

     There is a big problem with producing a chemical from natural microorganisms: they are extremely slow to produce and the concentrations are really low.  For instance, the fermentation of yeast to produce ethanol takes about twenty-four to forty-eight hours and about ten percent of the entire final product is ethanol (and these numbers are even worse when producing acetone and butanol from corn).  This, in turn, makes production very expensive and time consuming.    This is where biochemical engineers come in, researchers at the University of Illinois have found a way to mutate corn and other chemical feedstock to be more efficient.

Source:

 https://netfiles.uiuc.edu/mcheryan/www/feedstoc.htm

Durham's Cogeneration Plant

     When I first started to read about the cogeneration plant at the University of New Hampshire in Durham, I thought it was the coolest thing!  The cogeneration plant is a heat and power facility that is taking methane gas from nearby landfills and turning it into electricity.  UNH will receive eighty percent of their power and heat from pure methane, and they are the first university to use gas as a source of power.

     First, the methane gas from the landfill is collected and transformed into its pure form (from the help of  TREE).  Then, the gas is transferred to the University's cogeneration plant by traveling 12.7 miles through pipes underground.  The plant then transforms the gas into energy.  By doing this, UNH will be saving money and reducing greenhouse gas emissions (by 21 percent an academic year).

     To me (as I am sure it is for other people) this is huge!  I would rather have cities powered by natural gas rather than nuclear energy.  In an event of a nuclear melt down, we have to be able to control and secure the condition before it turns into a threatening situation.  I don't care how secure people think nuclear power plants are--the minute it's not secure it becomes dangerous.  If the cogeneration plant were to malfunction some day, we would have nothing to worry about!  Natural gas has no threat to the environment or humans.  I think methane gas (if this cogeneration plant really proves to be efficient) should be the future heat and power source of homes (at least partially, like what UNH is doing)!

Sources:

http://unh.edu/news/cj_nr/2009/may/bp19ecoline.cfm

http://www.unh.edu/users/unh/admin/sustain/climate_ed/cogen_landfillgas.html

Carbon Monoxide: Air Pollutant

     When I first think of carbon monoxide, I think of the cars that we drive that give them off.  Carbon monoxide does not just come from the cars that we drive, however.  They can come from volcanic activities, any man-made fire, and the burning of fossil fuels.  The amount of carbon monoxide present in the air varies from place to place, but urban areas tend to have higher levels, and the exhaust from combustion engines are the primary reason for this.

     What can carbon monoxide do to you?  Carbon monoxide goes directly into people's bloodstream.  There are higher levels of CO in the bloodstream of people that live in urban areas.  The problem is that the presence of CO in the blood slows down oxygen activity.  Therefore, the higher the levels of CO present, the harder it is to breathe in general--especially if one is exercising.  People living in urban areas probably experience more chest pain, shortness of breath, and even heart problems due to the higher levels of carbon monoxide in the air.  And of course, extremely high levels of CO can kill anyone.

      One way the EPA and the US Department of Energy are working to reduce the levels of carbon monoxide is by creating alternative vehicles that will take in other fuels.  We already have hybrid (both electric and gas fueled) and plain electric cars.  There are these new vehicles that that in natural gas (such as methane) instead of gasoline or diesel as fuel.  These new vehicles reduce the emission of CO by 90 to 97 percent!  This is great because these are and will continue to be the cleanest vehicles on earth.  Hopefully we'll be seeing more and more of these vehicles overtime.

Sources:

http://www.epa.gov/airquality/carbonmonoxide/health.html

http://www.afdc.energy.gov/afdc/vehicles/natural_gas_emissions.html

http://en.wikipedia.org/wiki/Carbon_monoxide

Green Agriculture

     Before the civil war, Virginia's driving economy was tobacco.  Everyone knows now that tobacco sucks the nutrients right out of the soil.  As a result, this makes the soil unsuitable for growing crops.  When Virginians first started growing tobacco, they began to see that growing tobacco in one spot for a long period of time had an effect on their quality overtime.  Eventually, they figured out a very practical, efficient, and green way to grow tobacco.

     Since there was no such thing as fertilizers back then, someone came up with the brilliant idea of rotating the tobacco by using different sections of the land every few years.  The first four years of growing tobacco was done in one section of the land.  When those years were up, they'd plant tobacco in another section and so on.  By the time the farmers came back to the first section of the land, the soil had enough time to recover from it's lack of nutrients.  This eventually led to the idea of crop rotation.

     Crop rotation was used by farmers and gardeners for a very long time to reduce infertile soil, diseases, and buildup of pests.  It is a three year rotation of crops.  For instance, you grow a certain type of crops for the first year, then a different type for the second year, and for the last year you let the soil recover for the next year.  Then the cycle begins again.  Another more modern type of crop rotation is having roots (potatoes), legumes (beans), alliums, and brassicas.  You can rotate these plants around every couple of years or so (by using different section of land) because every type of plant has a different role to play with the soil.  For instance, legumes--such as beans-- have a type of bacteria in their roots that can produce nitrogen (acting as a natural fertilizer) and roots--such as carrots- serve as a type of anti-bacterial in the soil (helps kill any potential disease or pest).  Rotating these crops around can produce a nice and healthy soil.

     This type of agriculture has definitely grown overtime, and it is very green!  It doesn't get any greener than this.  If you haven't clicked on the link above ("modern type of crop rotation") you should now.  It'll help you understand the modern crop rotation better.  It's highlighted in white.

Sources:

My knowledge of what I learned in history and botany class.

http://www.thegardenerscalendar.com/Guides/story.asp?nid=2677

Fertilizers and the Environment

     The topic of this blog is biological interaction with environmental chemicals.  Took me a little while to figure out what I was going to write about, but I finally stumbled upon fertilizers and the impact they can have on the environment around us.  There are two kinds of fertilizers: organic and inorganic.  I have decided to discuss about inorganic fertilizers and how it affects the environment.

     Many inorganic fertilizers are usually synthesized in the lab.  For instance using the "Haber-Bosch Process" produces ammonia as the end product.  The ammonia is added to fertilizers as feedstock and this becomes the inorganic fertilizer. I don't know about you, but ammonia in soil raises big red flags in my mind. The use of inorganic fertilizers have been increasing steadily in the last fifty years or so.  These synthesized fertilizers are mostly used to treat corn, barley, and even soy.  They can have beneficial effects when used in moderate amounts.

     Using excessive amounts of inorganic fertilizers can have some devastating effects, however.  "Over-fertilization" can throw off nutrient levels in the soil and it eats away the minerals that crops need. Using too much inorganic fertilizer can also cause something called "fertilizer-burn", where roots dry out and if not treated right away can cause the plant to die.

     The disadvantages of inorganic fertilizers are much worse than the disadvantages of organic fertilizers.  The biggest disadvantage that the organic fertilizers is that using too much of it could cause the plant to catch some form of disease.  Comparing it to inorganic fertilizers this is not that bad.  The problem is that it is much more expensive that inorganic fertilizers.  Because it is cheaper,  buyers tend to go for the inorganic fertilizers.  This is really unfortunate since organic fertilizers have a lot more benefits than the non-organic fertilizers.  The disadvantages are even better (if that makes any sense).

Source:

 http://en.wikipedia.org/wiki/Fertilizer

Water as a Green Solvent

     For this week, our class has to provide an example of when water is used as a green solvent.  Before I give my example, I would like to explain why water is a very good (if not the best) green solvent. Water is extremely safe to work with, it is beneficial to the environment, it is simple, and even cheap!  When you think that water couldn't get any better, it's physical properties top it off; water's temperature is very easy to control since it has very specific heat, water has very high surface tension (this is why water feels wet), and it allows molecules to move freely.

      An example where water is used as a green solvent is in sewer systems.  It starts when we flush the toilet.  The waste then goes to a large sewage system where it will undergo the first step of the treatment.  The first step involves the water sitting still, which allows the solids to sink (since they are heavier than water) and the scum to rise.  The solids are then removed and later end up in landfills.  The first stage removes about fifty percent of the solids and bacteria in the water.  The second stage removes about ninety percent of solids of and organic materials with the help of bacteria.  The water is constantly in motion, and this allows the bacteria to move around and eat anything in it's path.  The last stage includes the use of Chlorine to completely clean the water by killing any remaining bacteria and other wastes.

     The sewer example shows that water is very easy to work with to remove waste.  This process applies to many principles of green chemistry.  By using water we are avoiding chemicals that can potentially harm the environment, this process recycles water, it is very easy to monitor, and we do not have to worry about any chemical accidents!  Water is the greenest solvent anybody could ever use.  Because of this, water should be used whenever possible!

Sources:

http://www.slideshare.net/balmukund/water-a-green-solvent-with-a-diference

http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/S/SewageTreatment.html

http://en.wikipedia.org/wiki/Sewage_treatment