[Amby (OP)]

Hi,
I am new at all this.
I have found articles saying electrolysed water is a more efficient cleaning product than bleach,it is safe, it is drinkable, non harmful to human, won't bleach clothes or damage /irritate skin/eyes etc...therefore I want to try to make some and use it in a mister machine I bought online, to disinfect ourselves and clothing prior to entering our home .

I am using a bucket with 10 liters of tap water mixed with 1 kg of cooking salt, with two copper rods and a 12 volt, 10 Amps battery charger.

First try: the water turned blue and only at the negative anode I could see some bubbling occurring.

I checked the PH after one hour - equal to 9 (which is not good as it needs to be around 3 - 3.5).

1) Am I going the right way to produce the kind of electrolysed water I am seeking?
2) Is the blue color due to the copper or byproduct such as hydrogen, oxygen, chlorine?
3) how do i get the PH more acidic to a bout 3/3.5?

I would really appreciate some feedback / suggestions.
Thanks
Amby

[evan_au]

I checked the PH after one hour - equal to 9 (which is not good as it needs to be around 3 - 3.5).

1) Am I going the right way

Neutral water has a pH of 7.
Water with salt in it has a pH around 7.

If you want to reach pH of 3, and you have reached a pH of 9, you are going in the wrong direction.

Query: How do you know that a pH of 3-3.5 makes a good disinfectant?
- What do you want to disinfect (eg Coronavirus?)
- Note that a pH of 3 will cause corrosion of many metal objects

Note: If your target is Coronavirus, good old soap and water is an excellent disinfectant, since it dissolves the virus coat, and won't harm you or the things you wash down.

[Bored chemist]

Using copper electrode will just lead to the electrodes being corroded.
Platinum is good, carbon is sort-of useable.
These are possibly the best way to do it.
https://en.wikipedia.org/wiki/Mixed_metal_oxide_electrode

[alancalverd]

For a simple, organic, natural pH3, try adding lemon juice or cider vinegar to tap water.

If I was a real fraudster I'd add "no chemicals" - as if the phrase could ever be true of anything - and "no fossil-fuelled  electricity was used in making this product".

Calverd's Magic pH3 solution may not kill any bugs but it tastes great on fish & chips, salads, or even with gin, so it will make you happy.

[Edwina Lee]

For use by the general public, the obvious choice for electrodes is graphite (conductive carbon with lots of hexagonal plane arrangement): get it from a pencil.
What was the chemistry with the copper electrodes?
The electrolyte contains Na⁺ Cl ^- from salt, H ⁺ OH ^- from water. Cu ⁺⁺ from the copper electrode.
At the cathode, -ve charges go into the water: -ve + H ⁺ -> H, 2H-> H₂ gas; 
At the anode, +ve charges go into the water:
Cu ⁺⁺ ;
OH ^- - -ve -> OH, 2(OH) ->  H₂O + O; then either  -> H₂O₂ (disinfectant)
or 2O -> O₂ gas

The Cu ⁺⁺ makes the water go green, displace H₂ gas, and create 2(OH ^- ) in water hence the pH goes up.

With carbon electrodes, you might get 
At the anode, 2(OH ^- ) - 2(-ve) -> H₂O + O -> H₂O₂ (disinfectant) or O₂ gas
At the cathode, H⁺ + -ve -> H;  2H -> H₂ (gas)

But what would happen to the pH?
(Just testing my knowledge of school chemistry)

[Hansens]

Electrolysed water (electrolyzed water, EOW, ECA, electrolyzed oxidizing water, electro-activated water or electro-chemically activated water solution) is produced by the electrolysis of ordinary tap water containing dissolved sodium chloride. ... The resulting water can be used as a disinfectant.

[alancalverd]

You could just buy some sodium hypochlorite (15% solution costs about £2 per liter - ask for "patio cleaner" at your local hardware store, or get water treatment tablets from a camping shop) and save yourself the bother of electrolysis.   

If you can persuade the President of the USA that drinking patio cleaner will keep him safe from COVID, you may be in the running for a Peace Prize.

[Bored chemist]

Electrolysed water is hydrogen and oxygen.

[alancalverd]

I think they are actually talking about electrolysed brine

https://www.sciencedirect.com/topics/engineering/sodium-hypochlorite
12.15 Sodium Hypochlorite Production by Electrolysis. Sodium hypochlorite can be produced by the electrolysis of brine (a solution of sodium chloride) (Section 11.14). On-site generation (Plate 19(c)) produces a weak hypochlorite (<10 g/l) solution that is easy to handle and avoids many of the safety hazards associated with the use of purchased liquefied chlorine and bulk sodium hypochlorite.

rather than water.

Pointless, as bleach is so cheap, but if you use AC rather than DC you may corrode the electrodes less - or use graphite electrodes.

[Bored chemist]

Pointless,

No.
There's a really good reason for it.
I will let you work out what that reason is.