Calcium hydroxide nanoparticles from solvothermal reaction for the deacidification of degraded waterlogged wood

Abstract

The proposed solvothermal reactions can be used to produce stable and highly concentrated calcium hydroxide nanoparticle dispersions in alcohols, needing no further purification before the application. This process has also the advantage to be upscalable to industrial level. Both pH and DTG measurements showed that the newly developed dispersions can homogenously penetrate inside the wood up to 20cm, neutralizing acidity and creating an alkaline buffer inside the wooden matrix, to hinder the degradation of residual cellulose.

Nano Ca(OH)2synthesis using a cost‐effective and innovative method: Reactivity study

“…The reduction in particle dimensions to a sub-micrometric scale can also lead to higher reactivity, such as the faster carbonation process of mortars prepared by aged lime putty compared with mortars containing commercially available, hydrated lime. [19][20][21][22][23] Moreover, Ca(OH) 2 is rarely the only product of the reaction, requiring time-consuming purification. 18 Currently, typical procedures adopted to prepare submicrometric (or nano-sized) and plate-like Ca(OH) 2 particles consist of wet chemical methods, carried out at high temperature and/or at high pressure, in aqueous, alcohol or organic solvents.…”

A stabilizer-free non-polar dispersion for the deacidification of contemporary art on paper

“…About fifteen years ago, the use of dispersions of alkaline nanoparticles, mainly calcium and magnesium hydroxide in short-chain alcohols, was proposed as an efficient way for the deacidification and pH control of several cellulose-based works of art [13][14][15]. Since then, several systems have been formulated and applied to paper [16,17], iron gall inked manuscripts [18][19][20] and archeological wood [21][22][23]. Nanoparticles high reactivity grants a fast neutralization of acidity, providing a neutral environment due to the conversion of hydroxides into carbonates, which are milder alkaline species.…”

“…Calcium metal and n-propanol were used to prepare n-propoxide, which turned to hydroxide after hydrolysis, in a one-pot process described elsewhere [17,23]. Nanoparticles were then dried under vacuum and dispersed in cyclohexane using an ultrasonic bath at a concentration of 1 g/L.…”

Tuning the Dimensionality of Nano Ca(OH)2 with Surfactants for Wall Painting Consolidation

“…However, the disadvantages of this method include an elevated temperature and the time‐consuming dropwise addition of alkali liquid into a CaCl 2 or Ca(NO 3 ) 2 aqueous solution . For the heterogeneous synthesis methods, CaO, Ca 2 H 2 or calcium metal as precursors have been reported to prepare Ca(OH) 2 . Nevertheless, these methods require an extremely long time of aging (such as five years), a high cost, or a complicated purification process due to impurities.…”

“…[19][20][21] For the heterogeneous synthesis methods, CaO, Ca 2 H 2 or calcium metal as precursors have been reported to prepare Ca(OH) 2 . [19,22] Nevertheless, these methods require an extremely long time of aging (such as five years), a high cost, or a complicated purification process due to impurities. Therefore, developing a facile and economical method to prepare nanosized Ca(OH) 2 for application in the conservation of cultural heritage is critical.…”