How to produce electolyzed water?

Hello Members,
i want to produce electrolysed water (by electrolysis) where end product is HypoChlorous (chlorine) by adding NaCl...., which can be used as sanitizer,  i tried used regular 220V current but it does't bring any effect.
i want to know which is the optimum Voltage and amperage..., and suitable electrode for electolysis?

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I suggest using carbon electrodes, like those found inside carbon-zinc batteries, for both the anode and cathode electrode.

The actual potential needed is only a few volts, with current not greater than a few amperes.

Also I recommend using a bench type of regulated DC supply, one capable of supplying a few amperes constant current.

A DC supply capable of constant current is typically going to be more expensive, and harder to find, than the usual regulated DC supply, which supplies constant voltage. But I think you'll get more predictable results from your electrolysis experiment, whatever it is, if you can give the cell constant current.

Although, for some reason, the usual introductory electrolysis experiments, like those recommended by chemistry teachers, almost never use constant current. Instead they always use constant voltage. Maybe they do this because this kind of power supply is cheap, easy to find, easy to understand. For example, in Kevin Dunn's Caveman Chemistry, in the chapter on electrolysis, he uses a 6-volt lantern battery. A 5-volt DC adapter, like a cellphone charger, would probably work too.

Actually, the reason I am reminded of that one, is because that one was electrolysis of NaCl, in a cell without a separator, so the Cl2 gas (produced at the anode) and OH- (produced at the cathode) will react with each other,

Cl2 + 2OH− = Cl− + ClO− + H2O

to form chloride (Cl-) and hypochlorite (ClO-) , which is, I think what you, were asking about. Upon request, I can up some pictures the relevant pages from this book, just the ones pertaining to Dunn's setup for this experiment. I think he also used carbon electrodes from old batteries, and PET plastic bottles. He used PET plastic bottles for everything.

Also the Wikipedia page for Chloralkali Process,

https://en.wikipedia.org/wiki/Chloralkali_process

has a good overview of the reactions involved in the electrolysis of salt (NaCl) water. That article says it is necessary to keep the cell temperature less than 60 C, to avoid producing other chlorine oxyions, like chlorate (ClO3-). Of course if you actually want to create chlorate ion, then the cell needs to run hot.

Also, BTW, they've got a table of all the chlorine oxyanions, there's like four of them, here,

https://en.wikipedia.org/wiki/Hypochlorite#Other_o...

vinayanand (author)  Jack A Lopez2 years ago

Thank you Jack,

But, in some articles I read, they have produce acid (at anode) and alkali (cathode) by electrolysis (as you mentioned above) using membranes as separator. i want to produce same for my experiment cz it is more efficient than other sanitizer

If you want to make a cell with separate compartments, one for the
anolyte, one for the catholyte, this requires some kind of separator.

An ideal separator would allow specific ions to flow through, but prevent the mixing of the liquids from the two compartments.

In
industry, like at a factory that makes lye (NaOH), they use engineered
materials, like Nafion (r) membrane, and that stuff (looks like thin
plastic sheet) is pretty much ideal for separating aqueous NaCl.

For
a homemade two-compartment electrolysis cell, there are other
possibilities for the separator. For example, this instructable,
https://www.instructables.com/id/Make-Lye-From-Salt...

uses food ingredient gelatine (the kind used for making jelly and fruity desserts) as a separator.

Also I claim it is possible to make a two (or three) compartment cell from two (or three) plastic cups, connected by one (or two) pieces of wet string.

Water, and anything dissolved in it, will diffuse
through wet string. However, the ions in the wet string are strongly
motivated to move one way or the other, because when the cell is turned
on there is an electric field across the wet string. Because this
effect is only there when the cell is turned on, the string should be
lifted out when the cell is turned off, to prevent the contents of the
cups from mixing, diffusing into each other through the wet string.


I don't know if that makes sense, or not. I should maybe draw a picture of this. Or set one up, and take a picture of it.

vinayanand (author)  Jack A Lopez2 years ago

i tried, by connecting two beakers by glass tube filled with NaCl (similar to Galvanic cell), but current used is 220V , at this condition water in the test tube get heated but no Change in pH of beakers..,

For moment of ions reducing the Volt (to 15 V) and increasing the amperage (~12)is that much important............????

I don't quite follow what you're doing here, although it kind of sounds like you're just connecting mains power to salt water, which is probably a bad idea, for a couple of reasons.

The main bad thing is there is big danger of electric shock if you touch the salt water.

The other bad thing is mains power is AC, not DC, so the anode and cathode are switching places at 50 or 60 times a second, and that's not going to work for a cell for which you want separate anode and cathode compartments.

Also the voltage is much higher than needed for the electrolysis reaction.

I have done some experiments,recently, like last night, trying to make a two-compartment cell, for electrolysis of aqueous NaCl. I posted some pictures and notes on this here to your topic, but as a top level post, so it would not be buried here in a reply-to-a-reply-to-a-reply.

If you are interested more details I might be willing to write this up as a detailed instructable, but the time it would take for that to happen might be days, weeks. I dunno, basically when, or if, I get around to it.

Regrettably,,,, I do not believe Vinayanand knows what AC or DC means :-(

I wonder... Maybe I should include a link to allaboutcircuits, particularly the chapter on Safety,

http://www.allaboutcircuits.com/textbook/direct-cu...

vinayanand (author)  Jack A Lopez2 years ago

link showing err. Jack

The link works. I think the Instructables editor decided to truncate the part it shows to us, because it thinks overly long links are ugly, and look prettier as first 50 chars plus ellipsis (...)

+1

That Cl antidote is a whiff of dilute ammonia stored next to the full strength or concentrated ammonia and other reagents.

While collecting Cl gas in saltwater using an inverted bottle, my eyes really watery from what you called swimming room smell, I grab the ammonia and since really woozy decide to get a long strong whiff all well and good BUT it was the concentrated ammonia.........................................

My nostrils were clear all summer that year.

iceng iceng2 years ago

.

AC=> Alternating Current & Voltage changes polarity 50 times each second.

.

DC=> Direct Current & Voltage is always the same polarity like a Battery !

I did some experimenting, to see if I could get this "wet string" separator idea to work. I used carbon electrodes, which were part of the insides of two zinc-carbon AA batteres, in their former life. For the cell compartments I used small (approx 100 mL volume) plastic cups. For the separator, I tried wet cotton string, and I also tried strips of wet paper towel.

For the DC power supply, I used a lab bench type power supply with limits for voltage and current. I set the voltage limit at 20.0 volts, and I set the current limit at 0.1 ampere = 100 mA.

I bought this power supply, this company, for about 50 USD,
http://www.circuitspecialists.com/csi3003sm.html
But I have seen the same thing other places, like here,
http://www.mpja.com/0-30VDC-0-3A-Variable-Benchtop...


Anyway, I was initially thinking I could get this thing started by starting one of the compartments containing pure distilled water. I'm not sure if that won't work, but it takes a really long time to get started, since the conductivity of pure water is very low, so the initial current is also very low. I measured just 1 or 2 mA, at a potential of 20 V across the whole cell.

So, in the interest of getting this thing started in a reasonable amount of time, I decided to start over, using a two compartment cell, with salt water (with concentration of about 15g per 100 mL water) in both compartments.

The separator is some strips of paper towel, and this can be seen in the attached pictures. I think I used about 4 or 5 strips,each about 2 cm wide. This is the cheap brand paper towel, so each strip is very thin. They're all stacked on top each other. From looking at it, or looking at the picture, I can't see to count the number of strips in the stack, because the water has sort of merged them all together.

Once I had it setup I let it run overnight, which might have been a mistake, because when I came back to my experiment (about 8 hours later), the whole room smelled like a swimming pool; i.e. smelled strongly of chlorine.

The pictures you see were taken after the cell had been running for about six hours. The anode compartment has turned a yellow-green color. The cathode compartment is still clear, but there's some frothy white stuff around the cathode.

I tested each cell compartment with some strips of pH indicator paper, and it looks like the two compartments have very different pH. Guessing about 2-3 for the anode side, and about 10-11 for the cathode side.

nacl-electrolysis-w-paper-towel-separator-01.JPGnacl-electrolysis-w-paper-towel-separator-02.JPGnacl-electrolysis-w-paper-towel-separator-03.JPGnacl-electrolysis-w-paper-towel-separator-04.JPG
vinayanand (author)  Jack A Lopez2 years ago

Right, I tried the same by using whatman filter paper..., but used 220V- my fault again.., thanks a lot Jack & iceng for your suggestion on circuit type.., i forgotten those things which studied in +2..,

thank you

iceng2 years ago

Hope you know the antidote for Chlorine gas which high school chemistry taught young students of my time.

Every time current flows through salt water chlorine gas is liberated.

A first symptoms as I remember is a heavy head sinus cold and watery eyes.

iceng2 years ago

You want lower voltage DC

vinayanand (author)  iceng2 years ago
can you explain please..........,
i tried directly with 220V - water got heated but no change in pH,
so wat will be the optimum Volt and Ampere...,

30 Volts Direct Current from a variable power supply like a big Lionel train controller...

This one might be worth looking at,

https://www.instructables.com/id/Pocket-Sized-Water...

Again this is electrolysis of aqueous NaCl, with the goal of making hypochlorite (ClO-) ion.