Marshal, Thank you very much for the article. Here are some comments on the study.
The sequence of events I as read them are: 1) 2 versions of silver nanoparticles were created. One using silver nitrate giving a range of particles from 2 to 18 nm and averaging 8.2 nm. This was called Solution A. The second used silver oxide as the source and had particle sizes similar to the silver nitrate version. This was called Solution B. The tests were performed using the silver nitrate based version. I see no instance where the silver oxide version (Solution B) was used. 2) A solution was also created using large commercially available silver particles (200 mesh). This was used only for the test demonstrating that bulk silver does not react with HCl. That is the test that involved 3 days of magnetic stirring. It showed no creation of silver chloride after the 3 days. 3) The concentration of the HCl used was approximately 18.5% HCl. 4)HCl was added to Solution A and a white product was formed immediately. X-ray powder diffraction (XRD) confirmed that little Ag+ remained in solution and that AgCl was created. This was further confirmed by a UV-vis absorption test that verified the disappearance of the Ag+ absorption peak at 302 nm. 5) The chemical reactivity of Ag nanoparticles in the polymer matrix has also been investigated. Figure 5 shows results similar to (4) above. AgCl was created. 6) The test mentioned in (2) above was performed verifying that bulk silver does not react with HCl. I would have to say that it appears to me that the tests did indeed demonstrate that Ag nanoparticles have an unusually high chemical nanoreactivity in the reaction with hydrochloric acid. And a surprisingly rapid conversion to silver chloride. - Steve N -----Original Message----- From: Marshall Dudley [mailto:mdud...@king-cart.com] Sent: Wednesday, September 29, 2010 10:23 AM To: silver-list@eskimo.com Subject: Re: CS>CS and killing of pathogens I now have the full article. Anyone wanting it please let me know and I will email it to you. There are some problems with their methodology. 1. They say they make CS by two methods, one which leaves a residue of silver nitrate in the solution, and the other which does not. I cannot find which one they used for the data they are producing. 2. They say that they remove all AgO2 from the non-nitrate solution by centrifuge. Fact is that it is impossible to removed dissolved silver oxide and silver hydroxide by centrifuge. 3. Their curve shows a rise on the front end which indicates silver oxide/hydroxide before adding HCl, but turns down after adding it, indicating that ionic silver was converted to silver 4. They say that adding HCl produced silver chloride immediately as evidenced by the solution turning milky, but that happens anyway with silver oxide or nitrate in the solution from reactions with them. 5. They assume that the loss of the colloid is by producing silver chloride instead of aggregation and precipitation when HCl is added. But it is known that changing the pH of a solution significantly from 7 will cause aggregation and precipitation. 5. Figure 5 shows a peak for colloidal silver of one size particle in (b). In (c) it shows some AgCl peaks and a significant broadening of the spectrum. This broadnening is I believe proof that instead of small consistent particles, it now has variable sized particles, as would be expected if the HCl was causing aggregation. There are too many holes in the paper for me to be convinced that they have not done junk science. I conclude from the data they have supplied that the ionic portion reacted with HCl and that the colloidal portion aggregated, which is exactly what I would have expected. Marshall -- The Silver List is a moderated forum for discussing Colloidal Silver. Rules and Instructions: http://www.silverlist.org Unsubscribe: <mailto:silver-list-requ...@eskimo.com?subject=unsubscribe> Archives: http://www.mail-archive.com/silver-list@eskimo.com/maillist.html Off-Topic discussions: <mailto:silver-off-topic-l...@eskimo.com> List Owner: Mike Devour <mailto:mdev...@eskimo.com>
