Re: Eliminating CaCO3 in buffer in "achival" watercolor papers
Thanks Ryuji, The Na4EDTA way seems interesting, since I have plenty of that on hand... Regards, Loris. 12 Ağustos 2008, Salı, 9:11 pm tarihinde, Ryuji Suzuki yazmış: > In order to wash out calcium, I suggest an alkaline solution > of potassium sodium tartrate, an alkaline solution of > potassium sodium saccharate, an alkaline solution of sodium > gluconate or Na4EDTA solution. These would be my first > choice. Besides, though less effectively, you could use an > alkaline solution of sodium citrate. > > As a starting point, I'd suggest 1% of any of the above agent > and 1% sodium hydroxide, and soak the paper in the solution > with intermittent agitation until you find the paper has lost > the calcium salt, as determined by test prints or whatever > means you prefer. Na4EDTA does not need additional NaOH and it > may be effective at an even lower concentration. However, EDTA > is not biodegradable (and in some areas of Germany and perhaps > other areas, EDTA pollution is a problem). > > Once you treat the paper, you may wish to rinse off the > chelating agent and also neutralize the paper to the acidic > side. I suggest to use a dilute solution of acetic acid for this.
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