Sciencemadness Discussion Board

Electrostatic and electrolysis

Toshiro - 18-3-2010 at 10:15

Hello everyone i have a question please , Do you think an electrostatic machine is able to produce hydrogen and oxygen using electrolysis of water ? Apparently wikipedia here http://en.wikipedia.org/wiki/Timeline_of_hydrogen_technologi... is talking about two men Jan Rudolph Deiman and Adriaan Paets van Troostwijk who used an electrostatic machine for the first electrolysis of water , i think its false and impossible , because an electrostatic machine is not powerfull enough what do you think ?

unionised - 18-3-2010 at 11:16

It would be a spectacularly inefficient way to do it but I guess it's possible in theory.

JohnWW - 18-3-2010 at 11:41

I have a secondhand copy (found in a local bookshop) of "Electrostatics And Its Applications" by A D Moore (editor) (Wiley-1973), long out-of-print and widely sought for (a leading book on the subject), which may shed some light on it. I will be scanning it to image files and uploading it soon, including extensive annotations that I and a previous owner have made in the margins.

[Edited on 19-3-10 by JohnWW]

Toshiro - 18-3-2010 at 12:39

Thanks a lot JohnWW , i'm extremely curious ( a little sceptical in the same time ) about this book :o
In fact i think its more than inefficient unionised :P..

Xenoid - 18-3-2010 at 13:50

I'm not sure what the problem is here!

The item states they used a Leyden Jar, this is a simple capacitor, they may have used several in parallel. Even if the "electrostatic device" was only producing, say 10uA, it would be possible to store up enough charge to electrolyse water, especially at several thousand volts. A few milliamps should be enough to observe electrolysis in action using fine wires.

woelen - 18-3-2010 at 23:59

Voltage is not determining how much water is electrolysed, it is the product of current and time (or more general: integral of current over time) which tells how much hydrogen+oxygen is formed.

So, it does not really matter how many thousands of volts you have, a few volts does the job equally well.

[Edited on 19-3-10 by woelen]

Xenoid - 19-3-2010 at 00:19

Quote: Originally posted by woelen  

So, it does not really matter how many thousands of volts you have, a few volts does the job equally well.


Not if the water was low in electrolytes, and near non-conducting!

What I was implying was that because a high voltage was available there would have been no problem with conductivity and relatively pure water could have electrolysed.

woelen - 19-3-2010 at 03:05

Yes, you're right, at very low conductivity it might have helped that the voltages in those old times were very high. Probably they just could observe some slight bubbling, but the observing capabilities of those old-time scientists were remarkable and such tiny effects certainly could not pass by unnoticed.

12AX7 - 19-3-2010 at 06:53

Without water purification systems, they might've pulled water from a well. I don't think conductivity is going to be a problem.

Some of the more precise measurements might've used distilled water, in which case the electrolytes will be small indeed, mostly sodium due to the glassware. Still, 18.2Mohm-cm is enough resistivity to sink miliamps at tens of kV, so even if it's ionically pure, it hardly matters. In fact, that just means it leaks away slower, which gives a more efficient connection than sparking to it (both methods always conserve charge, so it still doesn't matter).

Tim

[Edited on 3-19-2010 by 12AX7]

chief - 19-3-2010 at 09:02

They can only mean a multi-electrode-effect:
==> Dispersing water into lots of droplets
==> and each of those acting as a double-electrode ..., just like it's possible to hang lots of electrodes into an electrolyte and attach only the 2 outermost onto the Voltage ...

Then the Voltage is divided by the number of the cells ..., in case of a car-battery the 12 V are divided by the 6 cells, giving 2 V per cell,
==> and in case of the static electrolysis the 50 kV may be divided by 30000 dispersed droplets, giving the right voltage per droplet ...

The benefit would be, that only a small electrode-surface-area would be needed (platinum or whatever), most of the electrode-surface would be made of water ... (no parasitical by-reactions or whatever)
==> and so the efficiency might go up because of the absence of overpotentials etc., and also maybe because a droplet would just act as a charge-carrier as long as the voltage would be too low for electrolysis ...




[Edited on 19-3-2010 by chief]

12AX7 - 19-3-2010 at 16:50

That wouldn't explain the conclusion that charge efficiency is ~100%. If such an effect were occuring, it would be significantly higher.

Tim

JohnWW - 19-3-2010 at 18:57

Here are some items of relevance here:

http://www.electrostatic.com/research/pdfs/c77role.joap145.0... 1,408 Kb - Role of Joule heating in the electrostatic spraying of liquids , by J M Crowley (1976)

Electrostatic spray nozzle system - U$ Patent 4004733:
http://www.freepatentsonline.com/4004733.html

Drop deflection device and method for drop marking systems - U$ Patent 4845512:
http://www.patentstorm.us/patents/4845512/description.html

Experimental Design of High Volume Electrostatic Charger - Aerosol:
http://www.informaworld.com/smpp/6084615-80283083/ftinterfac...
DOI: 10.1080/02786829708965443
Aerosol Science and Technology, Volume 26, Issue 5 1997 , pages 433 - 446
(requires log-in access at an university library with a paid subscription - someone please oblige)

Charged Plumes
http://www.nature.com/nature/journal/v266/n5598/abs/266116c0...
(ditto - someone please oblige)

Toshiro - 19-3-2010 at 21:40

Hi everyone , thanks for all the very interressant answers we have here , apparently its possible , please if you have more links about electrolysis of water from electrostatic generators , post here on my topic , thanks a lot my friends :)