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://en.wikipedia.org/wiki/Sewage_treatment
No comments:
Post a Comment