----- Original Message ----- From: "coyote" <coy...@alltel.net>
Hi KD'C, Lot of ground you covered below! I have a shot at answering what I can, my comments prefaced with ***. > At 04:33 PM 4/5/00 +1200, you wrote: > >>From An earlier post of mine > > ## Thanks Ivan > I don't plan to start an arguement, I would just like this issue to be cleared up or at least expanded upon and open to discussion. The dogma just doesn't correlate with my personal observations. > Therefore, I question the dogma. [Defined as 'established pat answers'] > I've heard this theory endlessly repeated and worded as though it came from the same source, yet none of my chemist friends can go beyond, "I guess it's possible". Of course, they don't mess with CS, but you'd think they would have at least heard of this effect in use elsewhere. I have yet to find confirmation outside CS circles. ***No questions - no answers! Colloid chemistry is a complex field and only those involved know much about it. It is not surprising that many chemists no little of colloid properties. Indeed not many chemists know much about electrolysis. To make matters worse, metallic sols are an obscure subset of colloid science. There is not much call for nano-sized pure metal solutions, even though nano-sized metallic powders are showing new and exciting properties and are under active investigation and experimentation. There is some use for gold sols in marking organic molecules for measurement etc. and these sols do display the characteristics of changing colour with particle size.*** > > 2nd subject > According to my Dr/PHD chemist friend, there is a newish instrument out there that determines particle size using the Tyndal effect [another unheard of term , at least, in the pharmeceutical research area] > "I've never heard of the Tyndal effect, but I can tell you that our crystallographers use a "Lasex" particle size device which is a fiber optic cable that can be put into a suspension to determine average particle size, but only after it has been calibrated." ***The Tyndal effect is often included in the formal definitions of colloids vs solutions, but is only a minor effect which has been over shadowed by such effects as Raman scattering etc. which are the basis for many laser particle sizers. However, you will be hard pressed to find particle sizers that measure below 10nm, and even these are pretty sophisticated lab models. To measure below about 2nm is quite difficult and measuring the speed of particle travel is often employed.*** > Anyhow, please don't take offence. I don't have an ax to grind, just some logical holes to fill. Believers can believe what they want. > >======================== > > > >Ah, the question of colour never dies ;-) > > > >I can possibly be of help here, but let me say at the outset, > >that all CS within the accepted colour range (clear, through > >yellow-green, yellow and gold) exhibit very good antimicrobial > >properties. > ### I don't doubt that and never said that any color was "bad" or even that whatever produces the color is not effective. I simply don't know. > My rule is, if it looks yukky or weird, I fill a drain with it. I've filled a lot of drains. > > Silver nitrate is effective, no? > If sand were mixed in with CS, the CS would still be effective...and the sand harmless. But, neither sand or nitrates are Bredig sol pure metal colloids. > > > > >The colour of a colloid is dependant on the particle size, and > >how that affects the reflection, refraction and extinction of > >visible light. The smaller the particle size the smaller the > >wavelength of light it will absorb leaving its complimentary > >colour to be transmitted. > > > >Particles so small that they absorb UV light (outside the visible > >range) transmit the full visible spectrum and look colourless. As > >the particle size increases (by small amounts) so the wavelength > >of the absorbed light increases, and the transmitted > >complimentary light changes, as noted above. > ## This begs another question. > If the particle size is so small as to not transmit a color, how would a colorimeter possibly be used to accurately determine concentration? There is a direct contradiction here. ***Colorimeters use a complexing agent to bind with the specimen, the resultant colour density is measured.*** > Also, why does that color stick to the glass after storing for several weeks leaving the suspension clear yet still potent? > Do I have defective glass? Has anyone else noticed this? Honest, it happens without fail, for me at least. *** The colour is a property of the particles plating out upon the walls. The question is why do particles plate out at all ... the answer no doubt includes all sorts of reasons, including particle size, the charge of the particle, the particle makeup etc. I do not have this problem myself, but the vessels I use to generate in, do show plating on the walls.*** > > > >Colour depth, ie the strength of a particular colour, is directly > >proportional to the concentration of the solution (as you > >surmise). This relationship (Beer-Lambert Law) is exploited by > >colorimeters and spectroscopy in determining concentration of > >solutions. > >####I have watched unregulated batches go from clear to light yellow to reddish to brown to deep brown to black. I have run clear batches of CS that had various colors of deposits, stirred it up and got yellowish or brown as a result. The yellow deposits are not easily seen unless illuminated from below. They tend to appear under the pole that collects silver fuzz. > No question in my mind that depth of color indicates concentration of "something", but what something? > A dark color like red or blue in sufficient concentration will appear black. A color like yellow can easily be 'swamped out' by a dark color but whatever it is could be of a different density more easily suspended in a liquid. > ...so, perhaps it is uncharged silver oxide particles that clump together into differing sizes that account for the various colors as per the theory, whereas the silver particles produced by a constant current should all be the same size as well as being mostly seperated by thier charge and not tending to clump. *** Yes, I have seen the rainbow also and have deliberately run until I have a murky grey evil looking brew<g>. I have stained the bench green, yellow, purple and red. But to answer some of your questions (hopefully) I'll paste some of a previous post: [It seems clear that the colour of colloids is both a function of particle size and light absorption. The particle size would seem to influence which wavelength is absorbed, and so which is transmitted , reflected and scattered. The concentration effects the colour depth as per Beer's Law. From: http://www.svpvril.com/Tyndall.html If the particles are much less than 0.1 micron in size, they may be difficult to discern even with an ultra-microscope, but the beam of rays passing through the liquid will still be observed. Finally, if the particles are as small as 1 millimicron, the light scattering becomes so insignificant that this phenomenon also disappears and the liquid appears quite homogeneous or, as we say, "optically void." Such, for instance, are ordinary solutions of various substances. From: http://chemwww.bham.ac.uk/research_labs/Research_Profiles/gbpeacock/co lloidal.htm Colloidal, Nanoparticulate Gold For a long time now, one of the fundamental scientific conundrums has been the crossover between discreet molecules and bulk solids. The behaviours of both are well known and studied, but the intermediate ground - particles which are neither molecules, nor solids - is more of a wilderness. This is the area of clusters, nanoparticles and colloids - entities with dimensions of the order of a few nanometers - containing a finite number of atoms. One of the most striking examples of finite-size effects is the vivid red colour of colloidal gold, used since ancient times for colouring jewellery and staining glass. The colour arises from a collective oscillation of electrons within the finite-sized fragments of metallic gold. Nanoparticles of gold remain suspended in water by Brownian motion, although their charged surface means that they are severely solvated, and almost certainly have other ions associated with these otherwise unstable clusters. From: http://mole.chm.bris.ac.uk/goodwin/simon.htm Semiconductor Nanoparticles My Ph.D. research centres upon the formation and growth of colloidal nano-particles within complex surfactant media. There are many industrial applications for ultra-small colloidal particles. For example, nano-particles have been incorporated in printing inks. In fact, colloidal particles could be used for virtually anything coloured (paints, cosmetics, lipsticks, see 9/9/95 issue of New Scientist). The colour is changed by tuning the size and size distribution of the colloidal particles. It is the optical properties of nano-particles that are of particular interest here. Precise control of the colloids' scattering and absorbance properties may be achieved by their growth in surfactant media From: http://www.sciencedaily.com/releases/1998/11/981123081416.htm Microbiologist Develops Method For Dyeing Fabrics With Gold "The reagents reduce metallic ions, which are then formed into particles and grown," Todd explains. "By controlling their size, we can vary the color. "The particles are so small they can't be seen with a microscope," he adds. "But they produce a bright signal with a very small amount of metal. And since metals can be combined into alloys, different combinations can produce a variety of colors."] It must be remembered that colloids exist in a state of tenuous equilibrium, dependent on the balance of the forces of dispersion and the forces of attraction. And it does not take much to alter this balance. Colloids do not exist as single atoms (or ions) but discrete groups of these. It is thought that the groups of atoms form fractal arrangements, which means definite steps in size and stability. It is my view that when CS is formed with a low current density, the atoms form small groups, and become solvated quickly, resisting further grouping of these groups into larger fractals. Mechanical dispersion helps in this regard. In this way, there is little fallout, and minimal dendrite formation on the cathode. One can generate clear sols of high concentration in this manner, that are very stable. > I get a distinct feeling of seperate issues being lumped together and called the same thing. > :-) Ever notice the FDA doing this? To them, Bredig sol silver colloid, mild silver protien, various silver salts and compounds [including 'gag' silver cyanide] are all the same thing. Similarly, I never hear of pure silver in suspensions being mentioned as being a seperate issue from silver oxides which are near impossible to 'not' produce in low voltage systems. > One pole produces hydrogen that usually bubbles off. [If it doesn't bubble off, it may trap silver ions on the bubble surface and form that grey fur.] The other pole produces pure oxygen and it's rare to see the oxygen bubble off. Where does it go? It instantly combines with silver ions accounting for the black stuff. [silver oxide] If it's not all on the rods or on the glass, where is it? There is only one other place it can be...in the water. If colored matter is mixed in water, you get colored water. If it has no charge to keep it suspended..... > Other observation of tarnish on silver tells me that silver oxides can take on several colors including all those mentioned above. Granted, there may be numerous chemicals floating around in the air to account for that color variation. Perhaps no relationship? *** Firstly, the tarnish found on silver in air is not silver oxide, but silver sulphide. Silver is stable in oxygen and water. Secondly, the reason that there are no observable oxygen gas bubbles at the anode is because there is none. The reduction potential (the energy required to remove an electron) of silver in water is 0.79V, the reduction potential water into oxygen gas is 0.815V which requires slightly more energy, but in fact electrolising water requires an overvoltage of about 0.6v which means the actual voltage reqired to produce oxygen is double that required to produce silver ions. Under a low current the reaction is that which requires the least energy. Silver is oxidised preferentialy to water. The situation is different at the cathode, hydrogen gas is produced at 0.41v but needs an overpotential of about 0.3v, netting just over 7v under but very close to that required by silver. Therefore you will see hydrogen gas bubbles but not oxygen. Silver is much more likely to form silver hydroxide than silver oxide in any event, and it is likely that there is a small amount of this present in the solution.*** > By all indications I find it likely that, if the theory is accurate, it's being applied to the wrong particle and make no mistake, there are 'at least' two distinct and different molecular structures, quite easily observable, present in low voltage CS production. Their location and concentration varies. > > A note on HVAC. If the electrodes are open to the atmosphere you'll get ozone [which will oxidize silver ions even more violently than pure oxygen], nitric acid [if there is moisture and atmospheric nitrogen present and since the discharge is into water...moisture is present.], hydrogen and oxygen become a part of the nitric acid. So, there will also be some silver nitrate made. ***Only if the electrodes arc and ionise the air.*** > If the electrodes are submerged in water, they still produce ozone, oxygen and hydrogen but little or no nitric acid. If there is no current control, all this stuff emulsifies into a sludge which very quickly turns black. [I have a HVAC generator that does just that in less than 4 minutes] > I understand that the leading HVAC unit isolates the electrodes from the atmosphere and doesn't allow direct contact with water. A Very good idea that probably makes very good CS. *** Again, the electrodes must arc to create ozone or H202, this is acutally closer to Bredig's system than most realise, he arced submerged DC electrodes, if my source is correct. I know of no HVAC colloidal silver generator whose electrodes do not contact the water, at least after start up. Ozone doesn't do anything to silver ions, these are already oxidised and the energy required to remove a further electron from the Ag+ is more than ozone can supply. However both ozone and H2O2 will oxidise metallic silver, producing water and O2 gas in the process. An interesting experiment, and one which should put to rest the idea of silver oxide inclusion (I think) is to add a few ml of H2O2 to some yellow CS, if there are any metallic silver particles they will be oxidised to Ag+ amid much bubbling and the colloid will probably become clear, as the large particles are oxidised and broken into small ionic ones. The H2O2 when applied to ionic yellow colloid with little metallic inclusion will have no reaction and not lose colour, H2O2 being stabilised by silver ions and probably visa versa.*** > Again, please don't take it personally, but the theory seems only to cover part of the question in a manner that implies a statement like "We don't know how to get rid of that yellow or brown color so we're going to find a way to say it's the greatest thing on Earth" and the rest goes unaddressed almost as though it were swept under the carpet. ***Yes well, don't get me wrong... we have talked about this in the past, and the consensus would be, that colloidal silver is quite safe and effective as a clear solution or as a light golden one, with clear being the one to strive for. Even if silver oxide is present it does not present any more of a risk than does silver. Hey, no offence taken... nice to meet you!*** > Well, owning a new Caddy with tinted roll up windows and air conditioning might be nice, but it doesn't make the traffic go away no matter what the dealer tells you. > [So much for lurking] > k...@czen/KD'C > Ivan. -- 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: silver-list-requ...@eskimo.com -or- silver-digest-requ...@eskimo.com with the word subscribe or unsubscribe in the SUBJECT line. To post, address your message to: silver-list@eskimo.com Silver-list archive: http://escribe.com/health/thesilverlist/index.html List maintainer: Mike Devour <mdev...@id.net>
