Selectively Functionalized Zeolite NaY Composite Materials for High-Efficiency Multiple Protection of Paper Relics

As an important carrier of information and culture, paper-based books and relics often suffer from many damages because of their fragile and environmentally sensitive intrinsic structure. Hence, a safe, durable, and multifunctional protection method is highly anticipated. In this work, we have pioneered the use of NaY zeolite as an open framework container to selectively load one or more functional object species with a sustained release effect for paper preservation. Based on this strategy, a series of MgO-modified NaY with an adjustable basic oxide amount was obtained, and it appears that with the coating of such composite materials, paper degradation can be effectively controlled by slowing down the acidification and maintaining a desired and moderate pH value between 7.53 and 9.11. Moreover, by cofunctionalization with Ag species, the coated paper can further tolerate the erosion of several typical ancient book fungi, such as Aspergillus niger, Trichoderma viride, and Paecilomyces variotii. Further, it is worth mentioning that the coating of functional NaY not only makes little aberration to the original chromatic property and water wettability of paper but also triggers no color changes of alkali-sensitive pigments (fading or blanching), as the side effects because of the introduction of overstrong alkalinity usually caused by traditional deacidification agents can be avoided. These unique characteristics are promising for the functional zeolite composites in the intelligent protection of paper-based materials and relics.