This is an article by Matej Vakula for Community Science Forum Issue #1 on DYI Oil Testing. Buy a copy in the Public Lab Store.
As an Oil Sheen Testing fellow I am looking for the most effective, safe and DIY approachable ways to collect oil sheens and possibly separate oil from water. My fellowship started in October and right now it is about to end. I developed and tested three collection methods. Besides that in mid February I organized a successful sheen collection and oil testing workshop at Newtown Creek in Greenpoint, Brooklyn. During this workshop we discovered a large oil spill in the Dutch Kills area of the Creek.
I am working with my mentor Gretchen Gehrke. I am also trying to recreate research results done by Ethan Bass on product oil (crude, motor, etc) dilutions in mineral oil and how it affects spectra measured by our DIY spectrometer.
The first oil (sheen) collection method is the “Freezing Method” which I developed during earlier stage of the fellowship. It is based on freezing the sample - oil and water mixture. This method is so far the most successful. I was able to recover roughly 2/3 (max) of the product with slightly different results for different oils.
The fact why we are not able to recover more of the product is due to two different factors. First because part of the total amount of oil simply stays in the frozen water. This most likely depends on the viscosity of the particular oil. Another more serious factor is that when spilled in water, only some compounds of oil create a sheen. The rest, separates from the sheen, mixes with water and does not surface. This might somewhat influence the measured spectra and I am continuing testing it, but overall I was able to tell differences and similarities between most of the measured oils.
Another collection method is using the PIG Oil Only absorbent mats. They have slow oil absorbance on water, but I am able to recover trace amounts of product oil which need to undergo a further concentration process which can be done using 91% Isopropyl Alcohol.
The Isopropyl concentration method (suggested by Matt Pendergraft) is needed also for the fourth collection method - using the Coast Guard Oil Spill Sampling Kit which had been more successful than the PIG Mats.
Hey mlamadrid, the "freezing" method can work as long as you you drop the temp down to -20C, or you can use a clevenger apparatus, which is a glass separating pear shaped funnel.
Pass the oil through a bed of sodium sulphate in the funnel, the water will be absorbed by the sodium sulphate and the oil will pass down thru the funnel.
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