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Earth Science

Taking Radioactive Contaminants From Water With Shells 50

RedEaredSlider writes "Crab shells may soon be used to take radioactive contaminants out of water. Joel Pawlak, an associate professor of forest biomaterials at North Carolina State University, has developed a material similar to foam rubber that absorbs water and attaches to molecules dissolved in it, leaving pure and potable water behind. The material is a combination of hemicellulose and chitosan. The first comes from wood and is extracted by the ton in the paper-making process. Chitosan is extracted from ordinary crustacean shells — primarily crab, shrimp and lobster — by treatment with hydrochloric acid and then sodium hydroxide."
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Taking Radioactive Contaminants From Water With Shells

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  • ... are planning a march on Washington to protest.

    Chitosan is extracted from ordinary crustacean shells — primarily crab, shrimp and lobster — by treatment with hydrochloric acid and then sodium hydroxide


    Hmmm . . . that is one treatment that I will try avoid, if possible . . .

    • by lxs ( 131946 )

      Almost sounds like an acid-base extraction. Is it an alkaloid?

      • A polysaccharide.
        • by lxs ( 131946 )

          So it is, but there is still that dangling amine group on the monomer which would be susceptible to acid base extraction if you'd find a suitable non polar solvent.

      • Re: (Score:2, Funny)

        by Anonymous Coward

        It's a polysaccharide, in which some of the saccharides are D-glucosamine, which is basic.

  • by narcc ( 412956 ) on Thursday April 14, 2011 @06:27AM (#35815974) Journal

    We've known for years that three shells is all you need to remove common contaminants. Now, if only someone would post instructions...

    • Oh crap, here we go with the three shells again....

  • If it works for radioactivity, could it work for almost anything? I mean could you literally put blood in one end and get clean water out the other? Not sure where I'm going with this but intersting...

    • You could put (say) blood in at one end and get potable water out at the other end, along with a plugged and useless filter and a significant quantity of "blood concentrate". This is generally true for all filtering systems, and the more effective the filter, the faster it happens.

      SOME (not all) filtering systems can be reverse-flushed to regenerate them, but for that, you need a supply of potable water to do the flushing with (otherwise you'fe got a filter contaminated on both sides.

      Things get more compl

  • So we're going to take parts of wildlife apart to clean the environment we destroyed to save the wildlife? Interesting... I'm a little curious how they'll COLLECT the shells. Are we going to buy the byproducts of a factory that produces frozen pre-made seafood?
    • Probably. Just look at how many crabs are eaten. Now look at how many of those sold have a shell still attached. It's turning waste from two different sources into a usable solution to a major problem - and one that's just become even more significant.
  • on how exactly they were going to remove radioactivity with a shell [], and if so, which [] one [] ? []

    • rm -rf radioactivity perhaps? Seriously, if you don't know the basics, do not post on slashdot!
      • It won't work without a forward slash. Forward slashes counteract radiactivity:

        rm -rf / radioactivity

  • I guess they'll be using the shell to BASH the radioactivity out.

    *ba da boom tish*

    Thank you, I'm here all week!

  • The summary sounds like a WoW quest. It should have ended with a "Lobuno, please could you get me 12 crab shells from the Abyss?". Sorry... too much WoW this last mon
  • by SEWilco ( 27983 ) on Thursday April 14, 2011 @07:32AM (#35816196) Journal
    Eat lobster and save the world!
  • I thought "This is the same way we're removing terrorists from Iraq!". But wait, different kind of shell...

  • I knew shell would save the world, but which one? csh, ksh, bash, zsh, ...
  • by _0xd0ad ( 1974778 ) on Thursday April 14, 2011 @08:43AM (#35816578) Journal

    Sounds like they're combining the properties of both a cationic and anionic polymer with the idea of maximizing the surface area on which the adhesion occurs (similar to activated carbon).

    Basically, in layman's terms... most things that dissolve in water form ions (either positively or negatively charged), which can be removed by their electrostatic adhesion to oppositely-charged ions. According to TFA, this polymer foam has both positively and negatively charged ions at its surface for the dissolved ions to adhere to (perhaps someone with more knowledge of organic chemistry could tell me if this is fairly unique? I've never heard of a polymer which was both cationic and anionic). Since the ions actually cling to its surface, the surface area should be maximized (the principle behind an activated carbon filter), which in this case they're doing by making it into a foam.

  • What they didn't tell you is that it will birth Lobersteron the Terrible! Sucking all that radiation into its carapace he will grow to the size of a large skyscraper and terrorize the countryside. Fortunately he will probably cross paths with Crabucon the Munificent and will duke it out, the loser slinking back into the ocean. Of course the urban devastation will be horrible, but whatcha gonna do... Hopefully it will be DJ'ed by the Beastie Boys.

  • There is no difference in removing radioactive materials from seawater than removing non-radioactive materials. Each atom of I-131 is exactly Iodine until that moment when it decides to decay and transform into Xenon-131, a stable isotope. This method may be useful only if it can remove contaminants at very low mass concentrations. The total amount of I-131 released at Fukushima is only around 100 grams, assuming the values in the news are correct. The reported concentration at one of the outfalls, at sever
  • I recently shifted from ordinary disposable filters (that cost an arm and a leg per year for the average family here in Europe) to a swiss-made ceramic-based one that can be cleaned after a while, and is expected to last years (I indeed used it for one year now without wear).
    I understand this method is more for bacterias etc. rather than ions, so maybe the crab-related thingie could be set just after ;-)
    For this now I also have a carbon flter that removes some ions (chlore among others) but certainly not ra

    • The principle here is not actual filtration (such as is done by your ceramic filters). It is actually the electrostatic attraction between charged ions. Rather than a lattice structure in which large impurities get "stuck", this is a surface to which impurities adhere. It's like fly-paper, or those cat-hair removers.

      Making it into a foam is not designed to trap the impurities, but rather to give the impurities a lot of surface area to stick to. The impurities don't get stuck because they can't find any open

  • Since this relies on chemical properties of dissolved radioactive elements, it shouldn't have any effect on deuterium and tritium bound up in water molecules. Deuterium isn't actually radioactive, but tritium is, so there could still be some radioactivity. I don't know how much tritiated water is likely to be contained in conatminated water, though (it might vary depending on the source), so it might not actually be that much of a problem.
  • by Dunbal ( 464142 ) *
    I want to take radioactive contaminants from water without shells in it.

"This is lemma 1.1. We start a new chapter so the numbers all go back to one." -- Prof. Seager, C&O 351