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Electrolysis to reduce water's saltiness?

  1. Feb 12, 2018 #1
    Hi

    I wonder if we can reduce the quantity of salt (mostly Cl- and Ca2+) from water by electrolysis and still be safe to drink. I know that with inert electrods (not sure wich ones although) Cl- would be trun into Cl2(g) and I'm concerned by its toxicity even though it's going in the air. But I'm don't know what's going on about the Calcium: if it can be precipitated or if I can't get rid of it and will just need to adjust the pH.

    Thanks
     
  2. jcsd
  3. Feb 12, 2018 #2

    Borek

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    Staff: Mentor

    Won't work.

    If you wait long enough Cl2 will be gone. However, you won't get rid of calcium this way, you will just produce hydrogen (think about it: even if you were able to deposit metallic calcium on the electrode surface it will immediately react with water, in reality water just reacts first and the net effect - gaseous hydrogen and unchanged calcium in the solution - is the same). Plus, removed Cl- will be replaced by OH-, making water alkaline and even less drinkable.
     
  4. Feb 12, 2018 #3
    Oh yes I see, that's why I thought about adjusting the pH. But do you think using a chelator such as sodium citrate could help ? I mean having sodium in solution is still better than calcium in term of taste and quantity of OH-.
     
  5. Feb 12, 2018 #4

    Borek

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    Staff: Mentor

    You need both calcium and sodium, not sure why you want to get rid of Ca. pH has nothing to do with the Ca2+ presence (that is, some waters can have some correlation, but it is not absolute).
     
  6. Feb 12, 2018 #5
    Thanks for your answer I'll see where I can get with this !
     
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