Re: Eliminating CaCO3 in buffer in "archival" watercolor papers
From: BOB KISS <bobkiss@caribsurf.com> Subject: RE: Eliminating CaCO3 in buffer in "archival" watercolor papers Date: Sat, 16 Aug 2008 10:39:52 -0400 > A late question: What concentration of Na4 EDTA do you > recommend to remove the CaCO3? This should be determined experimentally, but I'd start with 1%. If you want to do this right, this is how I would do: 1. Establish a measurement method for calcium in paper. 2. Run parallel treatments; one piece in water, other sets in each of the treatment solutions. 3. Find the effective range of concentrations, pH, etc., and give enough safety margin. 4. Find the working capacity of the solution. 5. Publish results. EDTA is a very good start for research purpose, but I'm a bit leery of adapting it to production work, because it is very nondegradable and stay in the surface water for a VERY LONG TIME, and it started to cause problems. If you dump EDTA into sewer system, it goes right through the treatment plants and gets dumped to the ocean. At least, EDTA solution should be reused until it becomes ineffective, to minimize the quantity. -- Ryuji Suzuki "Strange how people who suffer together have stronger connections than people who are most content." (Bob Dylan, Brownsville Girl, 1986)
|