Bookbinding and the Conservation of Books
A Dictionary of Descriptive Terminology

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non-aqueous deacidification

A method of deacidifying paper which utilizes alcohol, or some other non-aqueous solvent, for the deacidifying chemical. Aqueous methods cannot be used to treat archival materials in cases in which the ink is susceptible to the action of water; therefore, in such cases a non-aqueous method is essential. One such method involves treating the document with a solution prepared by dissolving 19 gm of crystalline barium hydroxide octahydrate (Ba(OH) 2 . 8H 2 O) in one liter of methyl alcohol (which corresponds to a 1% solution of barium hydroxide as a free base). The normal procedure is non-commingled to immerse the document in the solution, but it may be brushed or sprayed on if the document is too fragile for immersion. While drying, any excess barium hydroxide is converted into barium carbonate (BaCO 3 ) by the action of atmospheric carbon dioxide, giving a final pH of approximately 8.0. Another method is to treat the document with a 1.0 to 1.5% solution of magnesium methoxide in methyl alcohol. In this process the magnesium methoxide is converted by the moisture in the paper into magnesium hydroxide (Mg(OH 2 ) , which is the effective deacidifying agent. Excess magnesium hydroxide is converted into magnesium carbonate (MgCO 3 ) by the action of carbon dioxide in the atmosphere. The final pH is approximately 8.5 to 9.0. See also: ALKALINE RESERVE ;DEACIDIFICATION ;DOUBLE DECOMPOSITION ;VAPOR-PHASE DEACIDIFICATION .

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