Synthesis and X-Ray Diffraction Analyses of Calcium Hydroxide Nanoparticles in Aqueous Suspension

Abstract

Calcium hydroxide nanoparticles in aqueous suspensions (also called nanolime) were successfully employed in Cultural Heritage conservation thanks to the ability of favoring re-adhesion of the pictorial layer on original carbonatic substrates or allowing to a better superficial cohesion and protection of treated stones. In this work, we have synthesized nanolime particles in aqueous suspension by two different methods. The produced particles were characterized in the laboratory, in terms of structural and morphological features, by means of X-Ray diffraction powder (XRD) and by transmission electron microscopy (TEM), respectively. Nanoparticles were crystalline, regularly shaped, hexagonally plated and with side dimensions generally ranging from 300 nm to 30 nm or less. Crystal structure of nanolime particles directly in the aqueous suspension, has been also analyzed by synchrotron diffraction from X-ray synchrotron radiation (SR-XRD); data have been analyzed by means of the Rietveld method and we have investigated the structure of Ca(OH) 2 particles in suspension in terms of cell parameters, atomic coordinates, bond lengths and angles.

Synthesis of Nano Calcium Hydroxide in Aqueous Medium

“…The first generic feature is the inevitable presence of the carbonation process irrespective of whether a surfactant and/or an airtight container are used . The carbonation process almost invariably happens independent of whether nonaqueous or nonaqueous along with aqueous or an aqueous medium is utilized. The almost generic presence of calcium hydroxide and calcium carbonate phases is a consequence of the carbonation process and definitely does not happen as events independent of the carbonation process .…”

“…The carbonation process almost invariably happens independent of whether nonaqueous or nonaqueous along with aqueous or an aqueous medium is utilized. The almost generic presence of calcium hydroxide and calcium carbonate phases is a consequence of the carbonation process and definitely does not happen as events independent of the carbonation process . So far, in literature, there is no detailed report on XRD‐based quantitative as well as electron microscopy‐based structural analysis of the calcium hydroxide and calcium carbonate phases.…”

“…The additional presence of an aqueous medium is also reported. There is only a singular attempt to synthesize CHNPs in completely aqueous medium . Moreover, about 84% of the reported cases utilize one or the other variant of the chemical precipitation (CP) technique at either room temperature or high temperature …”

Nanotechnologies in Cultural Heritage - Materials and Instruments for Diagnosis and Treatment

“…It has been found that well-crystallized products with a low degree of sintering have been obtained, but relatively high calcination temperatures were required and the application of this long-term treatment, 4 h, was to obtain a finished product with the desired parameters [3]. Both X-ray diffraction and infrared spectroscopy showed the high degree of purity of the reaction products [54]. The study of SEM and AFM images was very consistent with the results obtained by other analysis techniques: thermal analysis [46].…”

Performance evaluation of commercial nanolime as a consolidant for friable lime-based plaster

“…Although various synthesizing methods of nanolime have been designed since (Giorgi et al, 2000;Salvadori and Dei, 2001;Nanni and Dei, 2003;Rodgriguez-Navarro et al, 2005;Ciliberto et al, 2008;Daniele et al, 2008;Liu et al, 2010;Nasillo et al, 2011;Daniele and Taglieri, 2012;Taglieri et al, 2013;Rodgriguez-Navarro et al, 2013;Poggi et al, 2014;Taglieri et al, 2014;Taglieri et al, 2015), researchers agree there are two basic methods for producing nanolime particles. One mechanically breaking the calcium hydroxide particles into nanoscale particles, while the other produces nanolime using a homogeneous phase or heterogeneous phase synthesizing method (Rodriguez-Navarro et al, 2013).…”