CS>Cathodic Silver? From: Matthew McCann Date: Wed, 12 Jan 2005 11:33:24 http://escribe.com/health/thesilverlist/m76896.html
> It is commonly accepted that the silver that goes into aqueous > suspension/solution we call EIS comes from the anode, i.e. the > positively charged electrode. Yes. A silver atom gives up an electron at the anode and becomes a positive ion in solution: Ag - e --> Ag+(s) > To test this, I replaced the silver anode with a strip of titanium > and kept a silver Maple Leaf as the cathode (the negatively > charged electrode) and electrolyzed at a current of around 100 > microamperes for about two and a half days. The electrodes were > spaced about 3 inches apart. This gives fairly low current density which is ideal for silver electrolysis. > The result was a definite cleaning action on the lower half of the > coin cathode (submerged) in comparison to the upper half of the > coin (unsubmerged.) The cleaning action was most noticeable on the > milled edging. Yes. Water molecules are ionized at the cathode to form hydroxide and hydronium ions: H2O + e --> H3O + OH(-) The hydronium ion reacts with silver oxides on the cathode and converts them to ions: AgOH + H3O --> Ag(+) + 2H2O Ag2O + H3O --> 2Ag(+) + H2O + OH(-) The cleaning action is most noticeable on sharp edges due to the current concentration at discontinuities. > A tyndall effect also became noticeable, in comparison to the > distilled water not used in the electrolysis. Due to the high concentration of ions, some of the silver ions react with hydroxyl ions and form silver oxides: Ag(+) + OH(-) --> AgOH The silver hydroxide dissociates to form silver oxide: 2AgOH --> Ag2O + H2O Another path is 2Ag(+) + 2OH(-) --> Ag2O + H2O The oxides are close to each other and may agglomerate due to van Der Waals forces. When the particles become larger than about 63nm, they start to become visible in a red laser beam. > I don't think it was due to titanium coming off the anode, since > titanium metal is very difficult to corrode even by electrolysis. Yes, you are correct. All the action occurs at the cathode. > This doesn't make much sense if we assume that silver must > necessarily come off as positively charged particles. Yes, it must. The only way for silver to enter solution in dw is as positively charged ions. Either from giving up an electron at the anode, or by reacting with hydronium at the cathode as described above. > It might make sense if we allow for silver to come off as > solid-state nanocrystals. No, silver is insoluble in dw. > After all, metallic silver conductors can take a negative charge > as well as a positive charge. Current flow in metals is by free electrons. This is completely different from ion drift in solutions. > Has anybody noticed anything like this using other non-silver > inert metals like gold, platinum or stainless steel being used as > the anode? Yes, anyone who uses low current density will find the cathode is cleaned during the brew. However, black oxides may form on the anode. These are removed when the electrodes are swapped on the next brew. > Thanks in advance for your input. > Best regards, > Matthew Mike Monett -- The Silver List is a moderated forum for discussing Colloidal Silver. Instructions for unsubscribing are posted at: http://silverlist.org To post, address your message to: [email protected] Silver List archive: http://escribe.com/health/thesilverlist/index.html Address Off-Topic messages to: [email protected] OT Archive: http://escribe.com/health/silverofftopiclist/index.html List maintainer: Mike Devour <[email protected]>
