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Earth Technology

Easy-To-Clean Membrane Separates Oil From Water 39

ckwu writes: A steel mesh with a novel self-cleaning coating can separate oil and water, easily lifting oil from an oil-water mixture and leaving the water behind. Unlike existing oil-water separation membranes, if the coated mesh gets contaminated with oil, it can be simply rinsed off with water and reused, without needing to be cleaned with detergents. The team was able to use the mesh to lift crude oil from a crude oil-seawater mixture, showcasing the feasibility of oil-spill cleanup. The membrane could also be used to treat oily wastewater and as a protective barrier in industrial sewer outlets to avoid oil discharge.
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Easy-To-Clean Membrane Separates Oil From Water

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  • by TheNarrator ( 200498 ) on Thursday September 03, 2015 @06:35PM (#50454275)

    I bet a lot of people who have contaminated well water thanks to fracking are going to love this!

    • If fracking contaminated well water with oil, I'm sure they would. Unfortunately, the claim is that fracking contaminates well water with fracking compounds used by the driller, not the oil. This does them no good at all.

      • If fracking contaminated well water with oil, I'm sure they would. Unfortunately, the claim is that fracking contaminates well water with fracking compounds used by the driller, not the oil. This does them no good at all.

        Quite right... the water wells are seldom contaminated with oil. Salty production water, carcinogenic solvents, and as yet mystery fracking chemicals are much more common invaders of the fresh water table due to drilling activities.

        Every well drilled for oil/gas exploitation travels through the water table to get to the energy reservoir. There is an industry practice of casing these wells with concrete to below where the water table ends, altruistically protecting the water table from the well.

        Consider th

  • Okay oil sticks to mesh coated with a phosphorylcholine-based polymer membrane. Sounds not-cheap. Next you wash the oil build-up off with water. This happens because the polymer has an affinity for water. Next...what comes next? Where does the oil-water mixture go? Is it shipped to a facility that can properly treat it or are they simply moving the problem to another location?
    • You sell it to McDonalds for French Fry grease.

    • This would work if the filter takes out more oil than it requires to wash it off. Oil sticks to polymer, other oil is attracted to the oil skin more than the water and the skin grows. Forced water overcomes the polymer bias. The resultant sludge is then treated like water polluted oil instead.

  • by IonOtter ( 629215 ) on Thursday September 03, 2015 @07:19PM (#50454493) Homepage

    US law requires that all oil collected by vacuum ships be brought to a processing facility, where 100% of all oil must be removed prior to the water being discharged.

    During the Deepwater Horizon disaster, there were serious delays in the US accepting offers of help from the Netherlands and other nations. Most of them came with a price tag, but the Dutch offered three sets of Koseq Rigid Sweeping Arms for free. Because they were only 98% efficient, and they were initially refused.

    However, common sense (and desperation) won out in the end, and we started accepting all the offers for free equipment that came in, including the Dutch offer.

    Reference article []

    • by 93 Escort Wagon ( 326346 ) on Thursday September 03, 2015 @10:55PM (#50455329)

      You might want to re-read your "reference article" all the way through, including the editorial comment after the article's end. It doesn't seem to contain the details you state.

    • And who got those ridiculous, expensive laws passed, that were designed to screw companies over? Why, environmentalists, of course. Is anyone surprised?
    • The rule for shipboard oily water separators for most of us is that the oil content of discharge has to be less than 15ppm. OWS discharge monitoring devices generally suck because they use an optical detection system to ensure the 15ppm and they go off on rusty water just the same as oily water. However, if you're a tanker, life is better. As per 33 CFR 157.37 [] a tanker 50 miles from shore can discharge oily mixture into the sea while underway so long as the oil content doesn't exceed 30 liters per nautical
      • Of course a nice work around for oily water separation is to just take that dirty bilge water and slowly inject it into the hot part of your diesel fired incinerator. 20ppm into the water isn't allowed, but if all those hydrocarbons get converted to CO2, there's no regulation on that discharge.
  • How It Works (Score:5, Informative)

    by chill ( 34294 ) on Thursday September 03, 2015 @07:19PM (#50454497) Journal

    The coating lives water and repels oil. Pull it thru an oil-water mix and the water flows thru the holes but the oil doesn't.

    Pull it out and it contains a puddle of oil. Rinse it with a little water and the oil comes right off, ready for reuse.

    This isn't that uncommon in these types of filters. What is new is that this works dry. Other filters of this type have to be thoroughly wet before they work. This one is oleophobic when dry as well. So no fancy prep to get it to work.

  • > if the coated mesh gets contaminated with oil

    If I filter oil, the mesh gets oily. What's the reason for the 'if'?

  • by Anonymous Coward

    Wasn't this necessity already solved by a competition a few years back? There was an X-prize competition where several groups tested methods of removing oil from seawater. The winner by a large margin (industry standard was 1,100 gallons per minute, goal of competition was 2,500 gpm, they achieved almost twice that) was a simple concept of large rotating grooved disks of plastic, the oil would adhere to the plastic long enough to be scraped off and diverted to a holding tank. It removed far more oil than

  • Something for me to skim oil off of my soup with?

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