Details

Učinki organskih kislin na propadanje različnih vrst karbonatnih kamnin uporabljenih v kulturni dediščini
ID Ščuka, Mojca (Author), ID Vrabec, Mirijam (Mentor) More about this mentor... This link opens in a new window, ID Dolenec, Sabina (Comentor)

.pdfPDF - Presentation file, Download (4,42 MB)
MD5: 0B6FB1C47C50963B653893653FB4A377

Abstract
Magistrsko delo obravnava vpliv organskih kislin (oksalne, glukonske, citronske in jabolčne) na pet vrst karbonatnih kamnin slovenske kulturne dediščine (lipiški apnenec, sivi lesnobrdski apnenec, litotamnijski apnenec, škofjeloški konglomerat in sedovški peščenjak). Kamnine so bile izpostavljene raztopinam kislin različnih koncentracij (0,1 %, 1 % in 5 %) v obdobju 28 dni. Meritve pH-vrednosti in prevodnosti raztopin so omogočile spremljanje kemijskih reakcij, medtem ko so rentgenska praškovna difrakcija (XRD) in vrstična elektronska mikroskopija (SEM) razkrile mineralne in mikrostrukturne spremembe. Rezultati kažejo, da nizke koncentracije kislin (0,1 %) večinoma ne povzročijo opaznih sprememb, razen pri oksalni kislini, kjer nastajajo netopni kalcijevi oksalati, ki ohranjajo nizko pH-vrednost raztopine. Višje koncentracije (1 % in 5 %) povzročijo intenzivnejše reakcije, kot so raztapljanje kamnin, izločanje CO2 in tvorba kalcijevih soli, pri čemer citronska kislina še posebej izstopa zaradi obsežne tvorbe kalcijevega citrata. Najbolj dovzetne kamnine za raztapljanje sta bili sedovški peščenjak in litotamnijski apnenec, kar lahko pripišemo večji poroznosti in specifični površini kamnin. Škofjeloški konglomerat, z raznoliko sestavo in neenotno teksturo, se raztaplja selektivno. PH-vrednosti raztopin so se večinoma povečevale z razvojem reakcij, razen pri oksalni kislini, kjer so netopni oksalati ohranjali kislost. Prevodnost raztopin je bila odvisna od vrste kisline, saj vsaka sprošča specifične količine ionov. Zaradi kompleksnih reakcij se prevodnost raztopin različno spreminja, kar zahteva dodatne raziskave. Raziskava poudarja pomen razumevanja vpliva organskih kislin na kamnine, saj so te interakcije ključne za ohranjanje slovenske kulturne dediščine, kjer so karbonatne kamnine pogosto izpostavljene naravnim biološkim vplivom mikroorganizmov.

Language:Slovenian
Keywords:organske kisline, karbonatne kamnine, raztapljanje kamnin, kulturna dediščina, mikroorganizmi
Work type:Master's thesis/paper
Organization:NTF - Faculty of Natural Sciences and Engineering
Year:2025
PID:20.500.12556/RUL-167462 This link opens in a new window
Publication date in RUL:23.02.2025
Views:84
Downloads:22
Metadata:XML DC-XML DC-RDF
:
Copy citation
Share:Bookmark and Share

Secondary language

Language:English
Title:Effects of organic acids on deterioration of various carbonate rocs used in cultural heritage
Abstract:
The master's thesis examines the impact of organic acids (oxalic, gluconic, citric and malic acid) on five types of carbonate rocks significant to Slovenia's cultural heritage (Unified Lipica limestone, grey Lesno Brdo limestone, lithothamnian limestone, Škofja Loka conglomerate and Sedovec sandstone). The rocks were exposed to acid solutions of varying concentrations (0.1%, 1%, and 5%) over a period of 28 days. Measurements of pH values and solution conductivity enabled the monitoring of chemical reactions, while X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) revealed mineralogical and microstructural changes. The results show that low acid concentrations (0.1%) generally do not cause significant changes, except in the case of oxalic acid, where insoluble calcium oxalates form, maintaining a low pH value in the solution. Higher concentrations (1% and 5%) result in more intense reactions, such as rock dissolution, CO₂ release, and the formation of calcium salts, with citric acid particularly standing out due to extensive calcium citrate production. The most susceptible rocks to dissolution were Sedovec sandstone and lithothamnian limestone, attributed to their higher porosity and specific surface area. Škofja Loka conglomerate, with its heterogeneous composition and uneven texture, dissolves selectively. The pH values of the solutions generally increased as the reactions progressed, except with oxalic acid, where insoluble oxalates preserved the acidity. The conductivity of the solutions depended on the type of acid, as each released specific amounts of ions. Due to complex reactions, the conductivity of solutions varies differently, necessitating further research. This research highlights the importance of understanding the effects of organic acids on rocks, as these interactions are crucial for preserving Slovenia's cultural heritage, where carbonate rocks are often exposed to natural biological influences from microorganisms

Keywords:organic acids, carbonate rocks, rock dissolution, cultural heritage, microorganisms

Similar documents

Similar works from RUL:
Similar works from other Slovenian collections:

Back