Electrolysis to reduce water's saltiness?

[Phythochem]

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 which ones although) Cl^- would be trun into Cl_2(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

 

[Borek]

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.

 

[Phythochem]

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^-.

 

[Borek]

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).

 

[Phythochem]

Thanks for your answer I'll see where I can get with this !