Most people know of connecting 3 nine volt batteries together to get 27 volts, and most have heard that 30 volts is the best voltage. But is this correct? The answer is no, it is not correct.
To understand why, it is necessary to realize several things.
1 ) Some definitions and terms:
- a) The Anode is the positively charged silver electrode.
- b) The Cathode is the negatively charged electrode (doesn't have to be silver).
- c) Positively charged ions are atoms or groups of atoms which do not have enough electrons to have a stable outer electron shells, while negatively charged ions are atoms or groups of atoms which have too many electrons to have stable outer electron shells.
- d) Electric field strength is determined by the voltage between the anode and cathode divided by the distance between them.
- e)Ag is the chemical symbol for silver
2 ) The battery's job is to create the electric field between the Cathode and Anode. What matters is how many volts there are from the battery
divided by the distance between the electrodes. It does this by removing some electrons from the Anode, and adding the exact same amount of extra electrons to the Cathode (initial current flow). Electrons move to or from the electrodes until their electric field exactly cancels out the battery voltage. Changing the distance between the electrodes changes the amount of electron surplus or deficit on the electrodes. Initially, the electrodes behave like and actually are a charging capacitor.
If you want a formula, it would be: e = kV/d
where e= field strength, k = a constant, V = voltage, and d = distance.
3 ) The shortage of electrons on the surface of the anode facing the cathode effectively causes metal ions at the surface of the anode to be formed
*. These Ag
+ ions are very reactive, meaning they want to chemically combine with something else which will restore their missing electrons. Initially, the only negative ion which should be in distilled water is the hydroxyl ion (OH
-).
4 ) The electric field forces negatively charged ions in the water toward the Anode, and positively charged ions to the Cathode. This allows a compatible negatively charged ion (the OH in this case) to react easily with the silver atom to produce a molecule of silver hydroxide (AgOH) which floats free into the water. When I say compatible, I mean it must produce a compound which is to some degree water soluble and ionizable.
When the AgOH leaves the Anode, it allows the battery to remove one more electron from the Anode.
The electrical current then depends upon the number of OH
- ions available and also the number of electrons removed from the Anode by the battery. This in turn depends on the voltage applied, the distance between the electrodes and how many OH
- ions have already been produced. (It also depends upon the surface area of the electrodes, but I am assuming here that electrode size is fixed.)
5 ) Only a very tiny amount of water molecules dissociate to provide H
+ and OH
- ions. This is why the CS process starts so slowly.
6 ) Once the AgOH enters the solution, it dissociates again into Ag
+ and OH
- ions.
7 ) The Ag
+ ions are now no longer electrically neutral and thus are attracted to the Cathode while the OH
- ions are again attracted to the Anode where they can grab another Ag. Some of the Ag ions reach the Cathode where they pick up an electron reverting the Silver ion to metallic silver. This is what creates the silver residue on the Cathode.
8 ) This process continues generating AgOH until the concentration of AgOH reaches saturation at which point it precipitates out becoming particles instead of ions. At this point the solution will exhibit the Tyndall effect and is now a colloid.
9 ) AgOH is an unstable compound which breaks down into Ag
2O (Silver Oxide) and hydrogen gas. The amount of material, being in the ppm range does not produce enough hydrogen to actually bubble out, so you will not see this. Silver oxide is what you make if you stick silver wires in distilled water and hook them up to a battery. Most people call it CS but it is not.
10) If the CS is made while the water is close to boiling temperature and/or you use a reducing agent, an additional reaction occurs which converts Ag
2O to pure metallic silver. This will have a straw yellow color which is the indicator you have made real CS.
**11) The point of this analysis is to show how and why battery voltage alone is a meaningless parameter. Use what you have in terms of power packs or batteries, and adjust the process by changing the spacing between the electrodes. Personally, I like higher voltage, which allows my electrodes to be farther apart resulting in less chance for the Cathode residue to short out to my Anode.
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*) This formation of metal ions on the positive terminal is the same effect that causes the copper wires on the positive post of a car battery to corrode over time, but not the negative one. The corrosion on the positive terminal of a car battery is always a blue or blue-green color which indicates a copper compound or a reddish brown color if the battery clamp is steel. Lead does not react readily with most anions (negative ions) but copper or iron does.
**) Whether Silver Oxide is better or Metallic CS is better is an unresolved issue. My personal preference is for the pure metallic CS, but apparently both are active bacteria killers. My biggest pet peeve is that many CS producers do not correctly identify what they have made, and thus perpetuate the confusion. If its clear and has a metallic taste, its ionic (Colloidal Silver Oxide) and should be denoted CSO. If its yellow colored, and has no metallic taste, its real CS (metallic).
Edited to correct spelling
