Researches from the National and University Library of Slovenia, the Faculty of Chemistry and Chemical Technology of the University of Ljubljana and the National Institute of Chemistry in Ljubljana published the article titled »Nano calcium carbonate vs nano calcium hydroxide in alcohols as a deacidification medium for lignocellulosic paper«.
Deacidification is still the dominant paper conservation intervention, since a large part of library and archive collections consists of books and other documents consisting of acidic paper. Therefore, new deacidification agents are being developed and studied ideally with only minor side effects. Commercially available nano calcium hydroxide dispersions for paper deacidification, and laboratory-prepared nano calcium carbonate dispersions in ethanol and 2-propanol were investigated and compared with respect to their effectiveness in increasing paper stability. Evaluation of changes in colour, molecular weight, pH and alkaline reserve in different lignocellulosic papers was performed.
Compared to untreated samples, our results indicate that all of the investigated deacidification treatments reduce the degradation rate of cellulose as determined by accelerated degradation. However, the treatments involving nano calcium hydroxides in alcohols noticeably affects the colour of treated lignocellulosic papers. According to the obtained results, nano calcium carbonate is therefore more suitable for deacidification of papers containing lignin.