mgperrault <[email protected]> wrote: > Why do the grey whiskers get formed on the electrode?
> If you put a barrier, I used a paper towel, you see they form on > the paper. Shaking it loose, it fell to the bottom. Adding > hydrogen peroxide dissolved it to a clear seemingly fine batch. >max No one has answered your question. Strange. The gray whiskers that form on the cathode are pure silver. They are silver ions from the anode, or positive electrode. They have accepted an electron from the cathode to become a neutral silver atom. What happens next depends on the current density. At very low current, such as used in the SilverCell process, the silver forms a fuzz around the electrode and grows tiny whiskers at the bottom. At higher currents, a silver sludge forms at the bottom of the U, assuming you are using a U-shape electrode. At higher currents, such as most cs generators use, the ion density is high enough for silver hydroxide to form in the thin Nernst Diffusion layer next to the cathode. This forms a soft black/brown deposit on the electrode and sends some into the dw. It agglomerates later and causes a characteristic yellow tint to the cs. The color is independent of the size of the particles. Silver is one of the privileged few metals that react to light through plasmon absorbance. This resonates with the blue light and removes it from the spectrum. This leaves red and green, which combine to form yellow. The yellow portion remains yellow, of course. This results in the characteristic yellow tint to the cs, which has been described variously as pale straw, yellow, or gold. If you ingest the cs, the silver hydroxide is converted back into silver ions, which then combine to form silver chloride. You can read more at http://www.mail-archive.com/[email protected]/msg145180.html When you add H2O2, the cs may turn clear. It can also turn white, brilliant yellow, black, and probably other colors. The colors are probably caused by contamination in the H2O2. Silver is a catalyst for H2O2 and causes it to decompose. The equation is 2H2O2 --> 2H2O + O2 However, hydrogen peroxide requires a stabilizer to prevent decomposition. The clear color results from the stabilizer in the H2O2 reacting with the silver hydroxide and producing silver ions. For food grade H2O2, the stabilizer is phosphoric acid. For pharmaceutical grade, the stabilizer is a different acid. The bottle should say "Do Not Ingest", or Poison, or somesuch. They mean it. The additive is toxic. Don't drink it. In the case of food grade H2O2, the phosphoric acid works in conjunction with the H2O2 to dissolve silver metal into ions. Here's how it works. Phosphoric acid, H3PO4, has three hydrogen ions available to ionize. It loses the first one quite readily. (Thanks to Wilco Oelen of sci.chem for this description) H3PO4 <--> H(+) + H2PO4(-) This makes hydronium ions (H3O+) available in the solution. If H2O2 containing H3PO4 is applied to silver metal, we get the following: 2Ag + H2O2 + 2H(+) --> 2Ag(+) + 2H2O Which is what you want to do. There is another side reaction that uses the catalytic reaction to turn H2O2 into oxygen and water: 2H2O2 (plus silver catalyst) --> 2H20 + O2 A similar reaction occurs with the silver hydroxide. I can post it if you wish. You cannot measure the conductance of the clear cs with a pwt. The phosphoric acid will dominate the measurement. But you can use the Salt Test to verify you still have silver ions in solution. You can read more on my Yahoo forum at http://health.groups.yahoo.com/group/silvercentral/message/560?l=1 Does this answer your question? I would not use a paper towel or any other kind of paper in cs. The paper-making process leaves various chemical residues that can combine with the silver ions and remove them from the solution. Recall that you are working with ppm levels of silver ions. Very few chemistry labs work sith such small concentrations. The contamination problem is just too expensive to try to to control. However, we have no choice. We must learn how to identify and eliminate as much as possible all the different kinds of contamination, and keep them from ruining or cs. This is not an easy problem, especially when most people claim the contamination does not exist. Please ignore such misinformed opinions. Thanks, Mike Monett -- The Silver List is a moderated forum for discussing Colloidal Silver. Rules and Instructions: http://www.silverlist.org Unsubscribe: <mailto:[email protected]?subject=unsubscribe> Archives: http://www.mail-archive.com/[email protected]/maillist.html Off-Topic discussions: <mailto:[email protected]> List Owner: Mike Devour <mailto:[email protected]>
