Suzana Erić

The influence of building materials on salt formation in rural environments

Blocks of limestone and sandstone used in walls of the Manasija Monastery complex showed damage caused by the efflorescence and subflorescence of different salts in a low-pollution rural environment. In addition to common salts such as thenardite, thermonatrite, trona and gypsum, a small amount of eugsterite and darapskite was also present. Although these sodium and sodium–calcium salts formed where cement mortar was used for repairs, the lithological type and chemical composition of the substrate also had an influence on the development of distinct salts. The interaction between limestone and sandstone (substrates) and a solution rich in sodium (without calcium) was successfully simulated in the laboratory. The presence of gypsum and sodium–calcium sulphate, as experimental products, solely on the limestones indicated that, in addition to the cement-mortar solution, part of the calcium required for the formation of calcium and double sodium–calcium salts could occur from this substrate.

Biogenesis of secondary mycogenic minerals related to wall paintings deterioration process

Present study addresses potential of fungal strains, isolated from deteriorated mural paintings and surrounding air environment of the Church of the Holy Ascension in Veliki Krčimir (Serbia), to precipitate mycogenic minerals, when cultivated on agarized B4 medium. Utilizing culture-based isolation methods, 38 filamentous fungi were obtained in total, 23 from mural paintings and 15 from air, respectively, mainly ascomycetes, while Bjerkandera adusta and Thanatephorus cucumeris were only basidiomycetes. A total of 31 of 38 fungal isolates, more than 80%, were able to form minerals of different morphologies and variable size, determined via SEM-EDS and XRPD, to be either calcite or calcite and weddellite association. Among screened fungi, all Penicillium, Chaetomium and Cladosporium isolates, as well as most of the Aspergillus isolates (8/11) precipitated minerals, whereas cultures of Bionectria, Bjerkandera, and Seimatosporium isolates lacked any observable crystal forms. With the exception of two Alternaria alternata strains, no apparent disparity in potential to precipitate minerals in general, or form particular crystal phase was documented among the air and mural paintings isolates. Possible mechanisms of fungal mineralization of calcite and weddellite are further proposed. In addition to providing experimental evidence for fungal induced precipitation of oxalate and carbonate minerals, presented data suggest that fungal activity could be an important factor in a weathering process affecting cultural heritage exhibited and stored in inadequate conditions. Implementation of B4 plate assay for screening of mineralization potential of the isolated fungi could be used to assess biodegradative risk mycobiota pose to the mural paintings, so appropriate conservation measures may be utilized.

Diffuse reflectance spectra of methylene blue adsorbed on different types of clay samples

Abstract Diffuse reflectance (DR) spectra in the visible (VIS) and near-infrared (NIR) region of methylene blue (MB) adsorbed on clay samples of different mineral composition and varying MB/clay ratios were analyzed. This type of investigation is not affected by unadsorbed MB molecules and can be used in clay-mineral determination. When the MB dye/clay loading was increased, enhancement of bands in the DR-VIS and DR-NIR was observed. The distribution of various MB aggregates was interpreted according to mineral composition and MB loading. The NIR spectrum of H2O overtone provides insights about the intercalated MB aggregation, consistent with VIS spectra. Critical MB concentration for formation of dimeric structure was between 0.7 and 1.75 mmol/100 g followed with suppression of monomers. Different orientations of vectors of polarized light allowed calculations of the possible orientation and tilting angle of MB molecules on the surface of the clay particles in accordance with XRD data.

Origin of Fluorine in Mineral Waters of Bujanovac Valley (Serbia, Europe)

This paper deals with mineral and thermomineral water occurrences of the Bujanovac valley in south eastern part of Serbia related to granitoides of the Bujanovac massif along both the margin and the floor of the valley. In past decades (1966–2010) numerous hydrogeological, hydrogeochemical and geophysical explorations were carried out. One of results of these explorations is the completion of test holes and exploratory—production wells. They provide groundwater for three water bottling factories: “Heba”, “Bivoda”, “Prohor” as well as the “Vrelo Bujanovac Banja Spa Centre” for rehabilitation, treatment, and prevention. All stated consumers use the same mineral water aquifer. The content of fluoride in the majority of examined mineral waters is higher than 4 mg/1, whereby they are singled out as typical fluoride waters. The content of calcium ions in them amounts 80 mg/1, and the values of the saturation index in relation to calcium fluoride (SI) range from 0.4 to 0.7 mg/1, which points to mineral waters saturated in relation to fluorite. However, in the study area, there are mineral water occurrences with the content of fluoride significantly lower than in the majority of analysed waters representing hydrochemical anomalies. These waters occur as hydrochemical anomalies in marl and sandstone wherein Secondary mineral water aquifers, originating from cracked granite of the Bujanovac massif, are formed. When mineral waters from granite (with the increased content of fluoride) reach these secondary aquifers, the content of fluoride ions lowers to about 1 mg/1, which is of great significance from the point of view of mineral water utilisation as table bottled water. In this paper, it is proved that, in addition to the presence of some minerals as basic fluorine bearers, the role of the lithological environment where the natural process of defluoridation occurs is significant, which is confirmed by the revitalization of the A-4 well. The paper deals with mineral water deposits of the Bujanovac valley, and the natural way of lowering of fluorine content in the given waters.

Ti-in-biotite geothermometry in non-graphitic, peraluminous metapelites from Crni vrh and Resavski humovi (Central Serbia)

Ti-in-biotite geothermometry in non-graphitic, peraluminous metapelites from Crni vrh and Resavski humovi (Central Serbia) The study discusses the application of the Ti-in-biotite geothermometer of Henry et al. (2005) to the example of biotites from non-graphitic peraluminous micaschists of Central Serbia. Three petrographically different micaschists were distinguished on the basis of the following mineral assemblages: CV1 (St-Grt-Bt-Ms-Pg-Pl-Qtz), CV2 (Grt-St-Ky-Bt-Ms-Pl-Qtz) and RH (Grt-St-Bt-Ms-Pl-Qtz). Applying different geothermobarometers it was estimated that the studied micaschists were metamorphosed at average temperatures and pressures of 530 °C and 520 MPa (CV1incl), 580 °C and 670 MPa (CV1), 630 °C and 700 MPa (CV2) and 550 °C, 680 MPa (RH). The average temperatures obtained by the Ti-in-biotite method revealed uniform values for CV1 and CV2 micaschists and these values are very similar to the temperatures obtained by other methods. In contrast, the application of Ti-in-biotite geothermometer for RH micaschist yields the temperature difference of 85-110 °C. The variability of temperature is interpreted as a result of a positive correlation of Ti contents and XMg values in RH biotite, which is in disagreement with the principles of the Ti-in-biotite method. The positive Ti-XMg correlation is a result of the compositional variability shown by RH biotites from different samples, which can possibly be related to compositional inhomogeneities of the pelitic protolith. On the other hand, the Ti-in-biotite geothermometer for CV2 biotite gave very uniform temperatures despite variable Ti contents (Ti = 0.260, sd = 0.018 apfu). This is explained as result of the low sensitivity of Ti-in-biotite geothermometer for high Ti concentrations (> 0.25 apfu).

Preparation, characterization and antimicrobial activity of inclusion complex of biochanin A with (2‐hydroxypropyl)‐β‐cyclodextrin

An inclusion complex of biochanin A (BCA) with (2‐hydroxypropyl)‐β‐cyclodextrin (HP‐β‐CD) was prepared in the ethanol solution to improve its water solubility.

Scanning electron microscopy coupled with energy dispersive spectrometric analysis reveals for the first time weddellite and sylvite crystals on the surface of involucral bracts and petals of two Xeranthemum L. (Compositae) species

In this work, weddellite and sylvite crystals are identified for the first time on the involucral bracts and petals of Xeranthemum annuum and Xeranthemum cylindraceum using scanning electron microscopy coupled with energy dispersive spectrometric (SEM-EDS) analysis. Well-developed crystals of weddellite (CaC2O4·2H2O) occur in the form of a tetragonal bipyramid (hhl), rarely in combination of a bipyramid and tetragonal prism (h00). Indumentum of involucral bracts of X. cylindraceum consists of nonglandular and glandular trichomes. Sylvite (KCl) crystals are observed only on the petal surface of X. cylindraceum. The crystals of sylvite occur in the form of perfect cubes (hexahedrons), but some crystals are deformed, i.e., partially elongated. Taxonomic significance of investigated microcharacters as well as the use of SEM-EDS analysis in taxonomic studies of plants are discussed.