What are we really making when we say we are making CS? Updated 4/6/2011

[Kephra]

Well, that depends on the method we use.  Here are the  main methods I hear of people using:

I) Distilled water + silver electrodes at room temperature.

In this method, free hydroxyl ions in the water initially react with the positive silver electrode to make silver hydroxide (AgOH) which dissolves into the water.  Silver hydroxide is unstable and rapidly decomposes to silver oxide Ag₂O. 

2AgOH --> Ag₂O + H₂O

Silver Oxide is slightly soluble in water, and after electrolyzing for a while you have an ionic silver solution, not colloidal silver.  You can prove that silver ions exist at this point by adding a small amount of table salt as a test.  The salt will form silver chloride which will precipitate out to form a cloudy liquid because the solubility of silver chloride is 8 times less than silver oxide.¹

If the electrolysis is continued, the silver oxide will reach saturation, and then will start to precipitate as colloidal silver oxide.  At this point, the solution will start to show the Tyndall effect. This is not strictly colloidal silver, although it does have anti-microbial properties according to the EPA²  Silver oxide is what gives CS its metallic taste which is another indication you have made silver oxide instead of colloidal silver.

This is what most people make and call colloidal silver. 

II) High Temperature Colloidal Silver method

If the same method as above is performed while the water is boiling, an additional reaction happens.  Silver Oxide reduces to metallic silver at 100 deg Centigrade in the absence of free oxygen³. This makes a straw colored colloidal silver product.

The spontaneous reaction that reduces the silver oxide to silver is:
2Ag₂O --> 4Ag + O₂

The result is then a solution containing very little silver oxide (ionic silver) and a majority of metallic silver particles.  This can also be tested by the addition of some salt.  Unlike the CS made at room temperature, this CS does not turn cloudy with the addition of chloride ions showing that it contains few silver ions.  This is true colloidal silver.

III) Distilled water + salt + silver anode.

Some people add a little table salt to jump start the electrolysis process.  This method produces silver chloride, which has very low solubility and thus produces a cloudy solution.  Silver chloride is very photosensitive, and is used in the production of photographic paper.  When ingested, silver chloride ions travel into the skin, and are photo reduced by sunlight to metallic silver which then becomes trapped in the skin and cannot be removed.  This causes the skin discoloration called Argyria as the amount of silver trapped in the skin increases over time.  Ingesting silver chloride is definitely not a good idea. 

IV) Distilled hot water + electrolyte + silver anode + reducing agent + constant current

With the addition of a reducing agent, such as corn syrup, glucose, fructose, sodium citrate, or maltodextrin; it is permissible to add a very small amount of either table salt or sodium hydroxide as an electrolyte provided that you use a constant current power source.

In this procedure, the salt is used to increase the conductivity of the water enough so that the constant current source can supply full current from the start. The salt does create some silver chloride, which normally would be a bad result, but the reducing agent will remove it at the end leaving metallic silver particles.  A side benefit of using salt or sodium hydroxide is that the sodium ions are selectively reduced at the cathode, preventing most of the silver from plating out.  This makes the electrodes run much cleaner, and wastes much less silver.  The electrolysis of salt (sodium chloride) also produces enough sodium hydroxide to active a sugar based reducing agent such as corn syrup. 

A constant current regulator is required so that the electrolysis can be timed, allowing the amount of silver in the solution to be known fairly accurately.  This allows the reducing agent to be added after the electrolysis is complete, thereby preventing the reducing agent itself to be electrolyzed. 

The amount of electrolyte used is fairly critical, and must be measured accurately.


Which method is better?

Definitely not III, with salt.  Ingesting silver chloride is simply asking for trouble in my opinion.

Method I, the most common way of making CS would seem to be safe however it probably does not remain silver oxide when ingested.  The stomach is a chloride rich environment which will convert silver oxide to silver chloride as soon as it is swallowed.  Do people take enough silver oxide to be a problem?  I don't know. Perhaps silver chloride is not readily absorbed by the body, but then why is that the people who developed argyria use salt to make their CS?  Maybe its simply the dosage.

Method II was my personal preference until I developed method IV, as I know the true CS will not react with stomach acid to make silver chloride, and it has an excellent shelf life, even when exposed to light.  I have a sample over 2 years old in a clear glass bottle exposed to light every day, and it has not yet degraded.

At this time, I believe that Method IV is superior, as it produces pure metallic silver with no ionic silver in the product.  In addition, it:

• Is very fast.  With 15 ma current, a 250ml batch takes only 5 minutes
• Minimizes silver usage by preventing excessive silver from plating onto the cathode
• Can Use commonly available reagents -- Table salt, and Corn Syrup
• Produces no toxic byproducts -- only a small amount of sugar and sodium is left
• All ionic content is quickly reduced to metallic.
• Maximizes battery life if using 9 volt batteries

-----------------------------------------

1) Solubility of silver species
Silver Oxide            0.00250 g/100 ml (20C)
Silver Chloride           0.00052 g/100 ml (20C)

2) US EPA Registration Review Schedule: Antimicrobial Pesticides of October, 4, 2006

3) I first discovered this when attempting to make CS using one submerged silver electrode, and one silver electrode suspended 1/8th inch above the water.  I then applied 4000 volts from a transformer to create a plasma arc from the suspended electrode to the water surface.  This created a clear CS (as tested by the salt method).  I noticed that after a time, a yellow to brown layer would form at the top of the solution as it heated up from the plasma arc.  As the arc continued to heat the solution, the brown layer would grow further down from the top.  I did not know why until recently when I found reference to the decomposition of silver oxide to pure silver at boiling temperature in the absence of oxygen.

Edit 04/6/2011:  Added method IV to reflect recent findings.

[Kephra]

Older replies moved to the Archive section.  You can find them here --> http://www.cgcsforum.com/index.php/topic,281.0.html

[l337acc]

What about using sodium bicarbonate (baking soda) instead of table salt? Also, what is the difference between your typical 9v battery and constant current?

[Kephra]

Carbonates will not work.  The carbonate ions form silver carbonate which it totally insoluble, and only collects on the anode instead of entering in solution.  Salt (sodium chloride) works because it forms silver chloride which is partially soluble, and enters into solution.

A battery is essentially a constant voltage source.  The amount of silver coming off the anode is proportional to current, but the current changes as the process runs because the resistance of the water changes.  As more ions enter the solution, the conductivity goes up, and the resistance goes down.  Ohms law is Current = Voltage divided by Resistance, so with a constant voltage and decreasing resistance, the current will go up.

 A constant current supply sense the current and reduces the voltage to maintain the current at the regulators setpoint.   This keeps the process from running away, and allows the amount of silver to be calculated based on current and time. 

[Lifechanger]

Very helpful - we are lucky to have you running this forum - Regards

[rumblefrost]

Kephra, What are your thoughts on using Ascorbic acid?

[Kephra]

I tried vitamin C a long time ago, and indeed it did work as a reducing agent.  I used the sodium salt though sodium ascorbate to reduce gold.  As a reducing agent, the ascorbate become oxidized to dehydroascorbic acid (DHA).  Luckily, the human body is very good at reducing DHA back to ascorbic acid.  DHA can pass the blood brain barrier where ascorbic acid cannot.  Apparently this is a good thing, as the brain has a high concentration of ascorbic acid even though it does not pass the blood-brain barrier. 

Some photographers use vitamin C as a film developer.  Film developers are silver reducing agents.

But I don't remember what happened with silver.  I think I just looked for something better that would produce higher ppm, and lower turbidity.  So far, that is cinnamon.