Two level deacidification mathematical model for the description of transport of solid alkaline particles and diffusion of ions in a treated acid paper

Abstract

The industrial progress in papermaking in the early 19th century led to the technologies resulting in more acidic papers, which was caused mainly by exploitation of alum (KAl(SO4)2) and rosin. Papers prepared by such technologies have degraded more quickly. From the 1930 various deacidification and preservation processes with basic agents have been developed. The most widespread deacidification process is with the aerosol (spray system) consisting of microscale particles MgO and perfluoroheptane (PFH) as a carrier (the so-called Bookkeeper process). The shortcomings of this process are low dissolution of solid MgO particles and transport to the interior of acidic paper. We have developed a theoretical two-level model of the Bookkeeper process suitable for prediction of deacidification extent. The model involves both the dissolution/reaction of the solid particles and transport of solvated ions and solid particles inside the bulk of paper. The developed model coincides with the results of the performed deacidification experiment. The model is also in good agreement with the Lucas-Washburn equation which is usually used for description of the penetration of a deacidifying agent into the paper.