Preparation of MgO/CaCO₃ nanocomposites and their deacidification properties for paper documents

Acidification is an important factor in the damage of paper documents. At present, it is recognized that deacidification is an effective means to solve the problem. In this work, aiming at the problems of the traditional single deacidification agent, such as uncontrollable alkali strength, insufficient alkaline reserve, uneven deacidification effect, and high local alkalinity, MgO/CaCO₃ nanocomposites were prepared as a new paper deacidification agent. The composites combined the immediate and efficient deacidification of MgO and the long-term mild deacidification of CaCO₃. The morphologies and structures of MgO/CaCO₃ nanocomposites were characterized by TEM and XRD. When applied to the deacidification of paper documents, the MgO/CaCO₃ nanocomposites showed excellent deacidification performances and high alkaline reserve. The alkali strength of the MgO/CaCO₃ nanocomposites can be controlled by adjusting the ratio of MgO to CaCO₃ so that the pH value and alkaline reserve of the paper after deacidification are within a reasonable range.