Deacidification of acidic books and paper by means of non-aqueous dispersions of alkaline particles: A review focusing on completeness of the reaction

Abstract

Deacidification refers to chemical treatments meant to slow down the acid hydrolysis and embrittlement of books and paper documents that had been printed on acidic paper. From the early 1800s up to about 1990, papermakers used aluminum sulfate, an acidic compound, in most printing papers. Certain deacidification methods use non-aqueous media to distribute alkaline mineral particles such as MgO within the pages of the treated books. Evidence is considered here as to whether or not the proximity of alkaline particles within such documents is sufficient to neutralize the acidic species present. Because much evidence suggests incomplete neutralization, a second focus concerns what to do next in cases where books already have been treated with a non-aqueous dispersion system. Based on the literature, the neutralization of acidic species within such paper can be completed by partial moistening, by high humidity and pressure, by water condensation, as well as by optional treatments to enhance paper strength and a final drying step.

Preparation and characterisation of hydrotalcites colloid dispersions suitable for deacidification of paper information carriers

“…The surface pH values of the modified papers were usually in the acid range. In some cases, the pH values were ≥ 6 which are promising values for the deacidification of acidic papers, the pH of which is usually around 4 (Hubbe et al 2017). The use of sols appears to be a more suitable form of application, and, of course, the more suitable ratio of magnesium and aluminium is 5:1.…”

Decoupling hydrolysis and oxidation of cellulose in permanent paper aged under atmospheric conditions

“…For example, Horst showed a decrease of the pH from 10 to 7 during 50 years of natural ageing, whereas some AR still remained (Horst et al, 2020). Moreover, several studies point out the question of diffusion and reactivity of AR since the particles are heterogeneously distributed in the paper (Bégin et al, 1998;Hubbe et al, 2017). As a result, they could diffuse and react slower than the production of acids.…”

“…These institutions follow climate guidelines for the conservation of their paper-based documents and can resort to treatments to tackle both chemical and mechanical degradation. In particular, several deacidification treatments that leave an alkaline reserve have been proven effective for hindering the decrease of pH of paper, a threatening issue for paper degradation (Arney et al, 1980;Barrow & Sproull, 1959;Hubbe et al, 2017). In a review article, Baty mentioned that these treatments are even more effective on least degraded papers (Baty et al, 2010).…”

Reversible Deacidification and Preventive Conservation of Paper-Based Cultural Relics by Mineralized Bacterial Cellulose

“…Moreover, minimum intervention and reversibility are two important criteria to be considered during paper deacidification . The common paper deacidification methods include gaseous and liquid (in aqueous or organic solution) processes. ,− In gaseous deacidification, amine compounds are important alkaline agents, including ammonia, hexamethylene tetramine, and morpholine . Additionally, nonamine agents like diethyl zinc are also developed and used .…”