George Martin wrote: > > I've always suspected that the color was due to > oxidation but have absolutely no evidence that this is the > case.
Haven't got this all figured out either, George, but I'll offer a few of my thoughts abd observations on the subject: The 'selective' reflection of yellow light more than other colors is a known characteristic of very small particle size Ag. This in and of itself does not tell the whole story, but is a valid observation on it's own. [Yellow coler=light reflected off very fine particle size silver.] I have a set of silverware that I've noticed > exhibits the same sort of color change as it oxidizes. If > this was the case I would expect to see a greater color > change (more rapid oxidation) with the larger particle > sizes (greater surface area per particle). One other > anecdotal input...if I place a recently cleaned piece in my > mouth I don't get the same taste as I get from a heavily > tarnished piece. To me the tarnished piece tastes close to > the metallic taste I get from the darker colored CS. The 'Blue Bloods' of previous times derived their Argyria from eating with all silver utinsels, resulting in their bluish grey skin tone, as I understand it. Oxidized silver particles on the surface of the silverware may be more easily dislodged from the surface, since their bonding is no longer completely to the other non-oxidized silver atoms of the main piece. This is evidenced by the fact that it is easy to remove the oxides by either polishing or a chemical dip. The taste of the tarnished silverware is possible because these oxidized particles can separate from the surface and interact with your taste buds; the recently cleaned piece does not have free particles to do so.... Now if you can tell me the difference in taste between tarnished particles (oxidized) and non-tarnished particles, we'll be able to use the taste test for more than just detecting separate particles in general. I have experimented with placing a silver electrode from my Zapper - the positively charged external one- under my tongue and near the gum next to a problem tooth; very much a metalic taste quickly. (Yes, I know all of the cautions reguarding peroxide generation, etc.... friend killed out a long standing sinus infection by this same method, however, and was happy to live with the trade-offs in the process.) > For those of you who may take exception to this > just tell me one thing... what is the process that > prevents the silver from oxidizing in the presence of the > oxygen in the water? Here is more undefined ground - I'll offer an observation I believe is relevant, and a theory for which I as yet do not have complete proof; it's not easy to phrase the wording, and I won't try to go into an in-depth explaination... While the generator is running (in a DC system) you will observe that the Anode (positive electrode) darkens. Oxidation of the silver Anode itself is likely what we are observing in this darkening, as oxygen is drawn to / generated at the surface of the strongly positively charged silver anode. An oxygen atom, when in contact with the positively charged anode, can do either of two things; <1> it can combine with other oxygen atoms and be evolved as oxygen gas bubbles, which we can observe with the naked eye at higher current flow levels; <2> it can combine with an atom of silver in the surface matrix of the silver anode, resulting in a non-charges silver oxide particle that will stay weakly bonded to the surface of the anode unless otherwise 'disturbed'; hence, the 'darkening' of the anode, as silver oxide is generally greyish-black (reflects no light) rather than yellow, if I understand it correctly. Silver Ions, on the other hand, are by their individual positive charge, rapidly repelled from the vicinity of the anode, and drawn towards the negatively charged cathode. If they make contact there, they will gain an electron and lose their charge, being reduced to metalic silver (the greyish 'sludge' you see forming on the surface of the cathode.) Will silver ions oxidize in the water between the two actively charged electrodes? This is the core of the question that I can not definitely answer, but I suspect that IF oxygen is to bond to silver atoms while the electrodes are charged, it may be far more likely to do so with atoms of silver still in the surface of the anode, rather than with free ions of silver suspended in the water... Someone else may be able to tell us exactly why this might be tha situation. I'm sure there's more to the story, but I'll stop here. Hope these thoughts help. Bruce K. Stenulson Applied Technology http://web.idirect.com/~showcase/althealth > > Regards, > George Martin > > On Fri, 10 Apr 1998 14:04:35 -5, M. G. Devour wrote: > > >On 8 Apr 98 at 21:29, Paul Novak wrote: > > > >> My CS batches normally start out a very pale straw color and > >> end up after 5-7 days a rich, but light amber ... I've followed > >> the discussion on the scattering of light and its relationship to > >> the colloid's color. My question then is this: If the color of my > >> colloid is deepening over time, what is this telling me about the > >> particles of silver??? > > > >I have observed a similar thing, with my somewhat higher > >concentration CS starting out a rich amber and darkening over 24 > >hours or so to a deep honey or even burgundy color. > > > >It does change color rapidly as it cools to room temperature. But > >then it continues to change for a while longer. > > > >The stuff is still effective, though, so I don't know that anything > >is wrong with it. > > > >It is a good question and I do not have an answer for you, Paul. > > > >Be well, > > > >Mike D. > > > >[Mike Devour, Citizen, Patriot, Libertarian] > >[[email protected] ] > >[Speaking only for myself... ] > > > > > >-- > >The silver-list is a moderated forum for discussion of colloidal silver. > > > >To join or quit silver-list or silver-digest send an e-mail message to: > >[email protected] -or- [email protected] > >with the word subscribe or unsubscribe in the subject: line. > > > >To post, address your message to: [email protected] > > > >List maintainer: Mike Devour <[email protected]> > > > > > > -- > The silver-list is a moderated forum for discussion of colloidal silver. > > To join or quit silver-list or silver-digest send an e-mail message to: > [email protected] -or- [email protected] > with the word subscribe or unsubscribe in the subject: line. > > To post, address your message to: [email protected] > > List maintainer: Mike Devour <[email protected]> -- The silver-list is a moderated forum for discussion of colloidal silver. To join or quit silver-list or silver-digest send an e-mail message to: [email protected] -or- [email protected] with the word subscribe or unsubscribe in the subject: line. To post, address your message to: [email protected] List maintainer: Mike Devour <[email protected]>
