Detergent and Oil Spills
Name: Gina H.
Date: Saturday, October 12, 2002
Why does dish detergent clean oiled wildlife so well?
Why not use dish detergent to clean up an oil spill?
The detergent emulsifies the oil and enables it to be rinsed away. Do a
web-search for the word "micelle." It is a term used to describe the manner
in which oil and water (which do not mix) can become compatible long enough
for water to remove oil from a soiled material.
By the way, wildlife cleaned by detergents do not always survive the treatment
because it damages the animal's/bird's fur/feathers by removing naturally
present protective oils native the soiled creature.
Why it is not used to clean up oil spills: It is used in a very limited way.
However, detergents are relatively costly and many oil spills are simply far
too large to be addressed by application of any detergent.
Dish detergent cleans oiled wildlife by normal detergent action: the
oil-loving "tails" of the detergent molecules cluster around oil globules,
and the water-loving "heads" of the detergent molecules face into the water
solution so that the oil droplets are carried away in the water.
The problem with trying to clean up an oil spill this way is that this soapy
water with oil droplets dispersed in it is waste. The detergent does not
destroy the oil, it just disperses it in water. So what can you do with all
this oil-carrying water? If there is an oil spill in the ocean, the most
important thing to do is keep the oil as contained as possible so that it
doesn't foul many surfaces or living things. Adding detergent to an oil
spill would actually make it harder to contain.
Richard E. Barrans Jr., Ph.D.
Director of Academic Programs
PG Research Foundation, Darien, Illinois
Detergent breaks up the puddle of oil into very small bits by
surrounding it with molecules of water soluble compounds. When the water
soluble compounds are dissolved in water they take the oil with them.
This just spreads the oil around.
With an oil spill you want to actually remove most of the oil from the
environment rather than dispersing it. You would pick up as much oil as
possible and when that was done you might use a detergent to disperse
what was left. (Note: This is not to say that is what is actually done
with oil spills -- there are probably much more effective and less
damaging ways of treating them.)
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Update: June 2012