Barium Hydroxide Nanoparticle–Phosphoric Acid System for Desalination and Consolidation of Tomb Murals

Abstract

Tomb murals are an important component of cultural heritage, but the extant majority of burial murals are severely damaged. There are various causes behind the deterioration of tomb murals, among which the detrimental effects of sodium sulfate on murals are some of the most difficult to treat. In the past decades, the application of alkaline earth metal hydroxides (such as Ba(OH)2, Ca(OH)2, and Ma(OH)2) for the conservation and consolidation of murals has become more common. However, there are some problems, such as large particles, poor permeability, and potential for surface whitening. In response to this issue, we investigated a facile method for the synthesis of nano barium hydroxide (N-Ba(OH)2), from which we developed a barium hydroxide nanoparticle–phosphoric acid (N-Ba(OH)2/H3PO4) multisite in situ consolidation system. The results show that N-Ba(OH)2/H3PO4 consolidation material has good permeability and mechanical properties compared with commercial Ba(OH)2 and other common consolidation materials. This material performs very well in both salt resistance and desalination tests, the color difference change is minimal, and the technique is suitable for the practical manipulation of outdoor artifact conservation work. Recently, it has even been used in the desalination and consolidation of tomb murals in Jiangxi, China, the results of which opened a new way of thinking about the long-term conservation of tomb murals.