Evaluation of the effectiveness and compatibility of nanolime for the consolidation of earthen-based murals at Mogao Grottoes

Abstract

• First time use nanolime for the conservation of Chinese earthen-based murals. • One treatment increases surface cohesion with acceptable color change. • Interaction mechanism between nanolime and pigments particles was investigated. • One treatment with nanolime decreases the pore diameter while keeps the porosity. Mogao Grottoes is a World Cultural Heritage site with splendid ancient murals and sculptures which record the culture and history of the Silk Road. To consolidate these earthen-based murals with multilayer structure, nanolime were synthesized with anion exchange method and the effectiveness and compatibility of using it for the conservation of Dunhuang murals were evaluated. For mural samples, the nanolime treatment increases the surface cohesion and hardness while changing the colors in an acceptable range, in the meantime decreases the pore diameter while keeping the porosity equivalent. To the best of our knowledge, this is the first time nanolime was used for the restoration of earthen-based murals.