The finishing.com Hotline: Serious Education ... plus the most fun you can have in metal finishing. Ted Mooney, Webmaster
Ceramic water purifier using reduced silver nitrate
Q. I live and work in Indonesia and we are trying to develop a low cost silver-ceramic water filtration system using crushed clay brick soaked in a silver nitrate solution, then packed into a PVC pipe system. We then run salt water through the filter to form a silver chloride precipitate within the filter media.
Initially the filters were 100% effective in removing coliform bacteria from water however, over time the silver chloride precipitate appears to be slowly leaching out of the filter thus rendering the filters ineffective. Instead of salting the silver nitrate to form silver chloride, I am searching for a simple chemical process to reduce the silver nitrate within the ceramic particles which would produce either silver metal or ionic silver which might possibly bond or ionically "attach" to the ceramic particles and thus remain within the filter indefinitely. Is this possible? If so, how can we achieve this?Glen Eitemiller
A. There are a number of ways to reduce silver nitrate to metallic silver, but with a ceramic substrate I would try the traditional method of "silvering" a mirror by using an aldehyde to reduce the silver ions to silver metal. See:
http://www.chymist.com/silver%20flask.pdf and or:
Google "making a silver mirror" for additional information and videos.
analytical sensors - Wisconsin Rapids, Wisconsin, USA
January 29, 2012
Long time, and please update me on your news! There seems to be a lot of filter activity in Indonesia! I was there in 2008, getting some people in Jogjakarta started with the production of candle filters, but now I'm understanding that there are several groups that are working on the packed particle beds. We first did the PPBs, working in Nepal, in 2002.
- Alfred, New York USA