Production of alcohol dispersion containing calcium hydroxide and magnesium hydroxide nanoparticles for dolomite formation and consolidation

Download
2021-2-12
Karahan Dağ, Fulya
Dolostone (CaMg(CO3)2 - calcium magnesium carbonate) has been a commonly-used building stone in the construction of many historical structures since the ancient periods. Those structures show deterioration problems in time and need conservation treatments. Repairs with incompatible materials are known to damage the original stone. In the context of dolomite conservation, there is a necessity to develop a consolidation material and treatment method that is compatible with the dolomite. The study aims to consolidate the dolostone by synthesizing dolomite within its deteriorated parts. For that purpose, alcohol dispersion of Ca(OH)2 and Mg(OH)2 nanoparticles was produced from the dolostone itself. This dispersion was allowed to react with CO2 in a desiccator. The carbonation process was followed in petri dishes prior to consolidation treatment. It is found that the carbonation process is affected by relative humidity (RH) and CO2 partial pressure (pCO2) in the desiccator, and Mg:Ca ratio of the dispersion. The most effective dolomite formation is achieved by the carbonation process of Ca(OH)2 and Mg(OH)2 nanoparticles under high RH (90-95%) and high CO2 partial pressure (pCO2 ~ 0.4 atm) conditions in ethanol dispersion where Mg:Ca ratio is ~1. It is important not to disturb that system in the desiccator at least for 10 days for dolomitization. The carbonation products formed in petri dishes were followed by means of XRD, FTIR, and SEM analyses. Afterwards, the deteriorated dolostone sample was treated with alcohol dispersion of Ca(OH)2 and Mg(OH)2 nanoparticles, and kept in a desiccator under high RH and high CO2 partial pressure conditions for carbonation. The formation of dolomite aggregates having 100-200 nm size within the matrix of dolostone was confirmed by SEM analysis. Average UPVdirect value of the treated dolostone sample increased from ~1844 m/s to 2158 m/s. The carbonation products could join two broken dolostone pieces together, which shows its strong adhesion property. The production of this specific nano-consolidation material from the dolostone itself, the description of the consolidation treatment for dolostone, and the success in dolomite synthesis in the laboratory under the appropriate carbonation conditions are expected to provide an important contribution to stone conservation practices

Suggestions

Assesing the Usage of Calcium and Magnesium Hydroxide Nanoparticles as Consolidant for Dolostones.
Karahan Dağ, Fulya; Tavukçuoğlu, Ayşe (2018-12-01)
Dolostone has been abundantly used in the construction of monuments during archaeological periods in Anatolia. Several of those monuments have some decay problems to be assessed and need conservation treatments to be developed. In the study, it was aimed to prepare a nanodispersive solution from the dolostone itself and follow its carbonation mineral phases in order to obtain a compatible consolidation treatment for dolostone. A mixture of calcium and magnesium hydroxide nanodispersive solution in ethyl alc...
Determination of Nitrate and Nitrite by Ion-Selective Electrodes in Relation to Gypsum Formation on Some Travertine Buildings in Polluted Atmosphere of Ankara
Göktürk, E. H.; Al-badawi, M. B.; Aygün, S.; Caner, E. N. (Informa UK Limited, 1990-9)
Gypsum formation on calcareous building stones in the polluted atmosphere of cities is thought to be accelerated by the presence of nitrogen-containing compounds. A reliable method for nitrate and nitrite determinations is proposed and the presence of nitrogen compounds is discussed in relation to their possible influence on gypsum formation. Investigations on nitrate and nitrite determinations with ionselective electrodes have been carried out along with gypsum determinations on the samples taken from alte...
The influence of seawater carbonate chemistry, mineralogy, and diagenesis on calcium isotope variations in Lower-Middle Triassic carbonate rocks
Lau, Kimberly V.; Maher, Kate; Brown, Shaun T.; Jost, Adam B.; Altıner, Demir; DePaolo, Donald J.; Eisenhauer, Anton; Kelley, Brian M.; Lehrmann, Daniel J.; Paytan, Adina; Yu, Meiyi; Carlos Silva-Tamayo, Juan; Payne, Jonathan L. (2017-11-05)
The geological calcium cycle is linked to the geological carbon cycle through the weathering and burial of carbonate rocks. As a result, calcium (Ca) isotope ratios (Ca-44/Ca-40, expressed as delta Ca-44/40) can help to constrain ancient carbon cycle dynamics if Ca cycle behavior can be reconstructed. However, the delta Ca-44/40 of carbonate rocks is influenced not only by the delta Ca-44/40 of seawater but also by diagenetic processes and fractionation associated with carbonate precipitation. In this study...
PREPARATION AND CHARACTERISTICS OF CO-DOPED HYDROXYAPATITE BIOMIMETIC COATINGS ON PRETREATED Ti6Al4V ALLOY
Hacioglu, Tugce; Tezcaner, Ayşen; Abbas, Sherif; Evis, Zafer (World Scientific Pub Co Pte Lt, 2020-11-01)
In this study, bismuth + carbonate co-doped and pure hydroxyapatites (HAp) were coated on rough surfaces of Ti6Al4V plates by biomimetic method. Prepared samples were investigated with SEM, EDS, FTIR, XRD and ICP. Furthermore, mechanical scratch tests, profilometer tests and in vitro cell studies were carried out. In order to explore the antibacterial characteristics of the coating, the survival rate of a bacteria named Staphylococcus epidermidis was determined. Structural investigations showed that HAp nuc...
Production of in situ aluminum-titanium diboride master alloy formed by slag-metal reaction
CHANGIZI, Ahmad; Kalkanlı, Ali; SEVINC, NACİ (Elsevier BV, 2011-01-12)
Al-TiB(2) master alloys have received much attention in recent years owing to their potential as efficient grain refiners for aluminum foundry alloys. In this study, the process of production of master alloys was investigated to develop a low cost method, namely, slag-metal reaction. This method can be used to fabricate Al-TiB2 master alloy in situ from the TiO(2)-H(3)BO(3)-Na(3)AlF(6) and Al system. Since the price of the raw materials is low and the technology is simple, the processing technique appears t...
Citation Formats
F. Karahan Dağ, “Production of alcohol dispersion containing calcium hydroxide and magnesium hydroxide nanoparticles for dolomite formation and consolidation,” Ph.D. - Doctoral Program, Middle East Technical University, 2021.