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[Klinger01]

Hello Everyone 

 

I am currently investigating the use of electrolysis of sea water to produce Hydrogen and Oxygen gas, as sea water is arguably the most available substance besides air. 

 

One of the issues I am facing is that the chloride concentration of the water is too high for the anode reaction to yield any oxygen. I am looking for way to remove the majority of the chloride ions from the water without too much energy input as this would make the whole process very inefficient. 

 

I have read on less reliable sites that air stripping can be used to remove chloride ions from water however I have not been able to find any source to verify this. Can air stripping be used for this purpose or are there any other methods that would work effectively on a large scale without disrupting the electrolysis of the water.

 

Thank you in advance.

[thorium90]

The Chloride ion has a size of 175pm. I highly doubt air stripping can remove chlorides in sufficient degree from the seawater concentration of 3.5%...

Removing dissolved solids such as chloride ions is much more difficult than removing suspended particle, since these are actually ions inside the liquid. Therefore removal of dissolved solids is energy intensive. As such, I believe it would take more energy to remove the chlorides  and to apply electrolysis to get the hydrogen than the energy you would get from the resultant hydrogen that is produced. I'm very sure it would not be energy favourable...

 

Anyhow, the most common way is by reverse osmosis membrane. Note that it is just as energy intensive as any other dissolved solids separation method.