Ivana Sýkorová

Sorption of metal ions on lignite and the derived humic substances.

The study presents results of sorption of metal ions (Pb2+, Zn2+, Cu2+, and Cd2+) onto lignite mined in South Moravia, Czech Republic, and solid humic substances (humin and humic acid) derived from it. The efficiency of these sorbents has been studied as a function of contact time, solution pH, and metal concentration. The sorption efficiencies were higher for humin and lower for humic acid samples than for the original lignite. With its high sorption capacities of several mmol/g, particularly for Pb2+ and Cd2+, the South Moravian lignite can provide a cheap source material for preparation of sorbents utilizable in removal of toxic metals from wastewaters.

Geochemistry of Miocene lacustrine sediments from the Sokolov Coal Basin (Czech Republic)

Abstract Sediments of the upper part of the Sokolov Formation of the Sokolov Brown Coal Basin consist mostly of brown lacustrine clays and claystones enriched in organic matter (2–18% TOC). The lower portion of the stratigraphic profile is formed mostly by kaolinite–illite clays and claystones, while the montmorillonite content increases in the upper portion. The change in the lithology of sediments is caused by the gradual erosion of the weathering crust in the source areas of the clastic material. Inversion of the weathering profile during erosion is manifested geochemically in a decrease in the Al 2 O 3 /Na 2 O ratio and an increase in the SiO 2 /Al 2 O 3 , Na 2 O/K 2 O and K 2 O/TiO 2 ratios from the base to the top of the studied part of the Sokolov Formation. The amounts of trace elements (La, Ce, Nb, Zr, Cr, V, Sn) also decrease in the same direction. On the other hand, the amounts of Rb and Sr increase. The organic matter of the upper part of the Sokolov Formation consists primarily of Types I and II kerogen. Only near the base of the studied part of the formation, i.e., in the coal stringer, kerogen of Type III prevails. The extremely low degree of thermal maturity permits determination of the source of the organic matter and characterization of its accumulation environment. The organic material in the sediments is predominantly of algae origin. Relatively high amount of pentacyclic triterpanes of the hopane series indicates either the occurrence of cyanobacteria as primary producers or bacterial reworking during sedimentation and diagenesis. Organic matter accumulated under the conditions of a fresh-water lake or lake with slightly elevated salinity, in a dysoxic aqueous environment. The alternation of organic carbon-rich layers with layers low in organic matter is explained in terms of changes in the degree of dysoxia of the aqueous environment and a variation in the intensity of oxidation and mineralization of the organic material.

Dispersed organic matter from Silurian shales of the Barrandian Basin, Czech Republic: optical properties, chemical composition and thermal maturity

Abstract Samples of lower Silurian (Liten and Kopanina formations) dark shales from the Barrandian basin, Czech Republic, were examined using reflected light microscopy, Fourier-Transform infrared spectroscopy (FT-IR) and gas chromatography-mass spectrometry (GC-MS). The samples contained uniform assemblage of organic material that included dominant graptolites, chitinozoa, bitumens and minor anthracite to meta-anthracite rank particle of unknown origin. Two types of graptolite morphologies were recognized: a nongranular blocky type and a granular type. Bitumen is also common in these rocks and forms discrete, oval bodies resembling droplets or angular particles with granular internal fabrics. The thermal maturity of the sediments was examined by measuring random reflectance of organic particles. The variations in graptolite reflectance in between three localities in the western part of the basin were relatively minor, suggesting a similar level of diagenetic transformation. The values range from 0.78% to 1.53% R r . The reflectance of graptolites was correlated with the reflectance of chitinozoa and bitumen, and also indirectly with illite crystallinity data, which indicates thermal maturation levels in the high-temperature part of the oil window to the onset of wet gas/condensate zone. Mature petroleum that commonly impregnates veins crosscutting the sequence further supports a maturation level within the oil window. Graptolite and bitumen reflectance values markedly elevated above the regional diagenetic background were found in several centimeter-wide contact zones immediately adjacent to basalt sills that locally penetrate the Silurian strata. As shown by computer modeling, heating in the range of 600–800 °C, which lasted only several years, was sufficient to promote an increase in reflectance (up to 2–2.5% R r ) in the contact samples. With increasing thermal stress, the graptolite periderm undergoes progressive optical and structural changes being gradually converted into a highly condensed aromatic residuum structurally and chemically similar to highly matured kerogen. On a basin-wide scale, however, the overall impact of basalt intrusions on organic maturity of enclosing shales was minimal.

Toxicologically important trace elements and organic compounds investigated in size-fractionated urban particulate matter collected near the Prague highway

Urban particulate matter was collected in the most exposed area of Prague, near a busy highway, in order to provide petrographic and chemical characterization useful for health impact assessment in that locality or other applications. Samples were collected from filters of the air conditioning system in two years, 2009 and 2010, and sieved into four grain-size fractions: 0.507-0.119 mm, 0.119-0.063 mm, <0.063 mm and sub-fraction <0.025 mm. Methods of destructive and non-destructive analyses were used for the determination of total analyte (As, Cd, Cr, Mn, Ni, Pb, Zn) contents. Labile forms of some toxicologically important analytes were tested in 2 M HNO(3) extracted solutions. A composition of inorganic and carbonaceous particles of natural and anthropogenic origin and their morphology were studied by optical and electron microscopy. Organic solvent extracts of the samples were analyzed using gas chromatography to compare the organic compound distribution in fractions. Only slight differences between 2009 and 2010 years are visible. The relatively high extractable part of most investigated elements confirms mobility and potential availability to organisms. The changes can be recognized in the petrographic and organic composition in samples from both years, which were likely the result of various inputs of source materials. Specific organic marker compounds indicate contribution from fossil fuels, plant materials and bacteria.

Carbon air pollution reflected in deposits on chosen building materials of Prague Castle.

Thin black surface layers or black coloured gypsum crusts can be observed on stones of many buildings and sculptures around the world. The black weathered stone and mortar surface from selected sections of the Prague Castle were studied by microscopic methods, GC/MS and pyrolysis-GC/MS analysis. Microscopically, we found an authigenic gypsum formation with an outer layer of an admixture of fine grains of quartz, clay minerals, thermally altered clay minerals, fly ash, and carbonaceous particles of natural and anthropogenic origin particularly chars, cokes, soots. Noncarbonate C content ranged between 0.8% and 4.3%. Phtalates dominated in extracts from the samples and benzonitrile had the greatest abundance in the pyrolysis products. The identified organic particles and compounds are known to result from human activities.

Relationship between properties and conversions of North Bohemian coals during coal/oil coprocessing

Abstract Eleven low rank coals from North Bohemian mines were comprehensively characterized by using a number of analytical methods. Along with common proximate and ultimate analysis, spectroscopic techniques, porosity measurement, extractability and swelling in organic solvents were used. Although coals were of similar geological origin, some of their characteristics largely differed from one coal to another. Coals were coprocessed with petroleum vacuum residue at 440°C for 1 h and yields of reaction products and coal conversions were determined. Despite the differences in composition and properties, the coals provided similar conversions and yields of distillable reaction products. A small positive effect on coal conversion was found for ash content and microporosity of coals. However, a small negative effect was found for carbon content, optical reflectance and solvent extractability of coals.

Petrological and spectroscopic structural characteristics of Bohemian and Moravian coals and their possible relation to gas proneness

Abstract Optical and infra-red microscopy, diffusion reflectance infra-red spectrometry and solid-state nuclear magnetic resonance spectrometry (13C CP/MAS NMR) were applied to the determination of the degree of coalification and structural characteristics of lignite and bituminous coal from deposits in the Czech Republic. Structural parameters such as the aliphatic and aromatic contents and carbonyl contents of coal and coal macerals could be valuable tools for determination of gas proneness, e.g. the CH2/CH3 ratio derived from infra-red spectroscopy. Aromaticity, fa, determined by 13C CP/MAS NMR, is shown to be a valuable parameter reflecting the degree of coalification, particularly for low and middle rank coal, thus supplementing data derived from the vitrinite reflectance Ro and (H/C)at ratio data. The maceral group of huminite/vitrinite mirrored similar changes with increasing coalification degree as the parent coal. The structure of two macerals of the liptinite group, sporinite and cutinite, was investigated for bituminous coal, and the aromatic and oxygen group contents were higher in cutinite than in sporinite.

Composition and properties of North Bohemian coals

Abstract This work presents the mean chemical, micropetrographic, surface and other characteristics of coal seams from western, central, and eastern parts of the North Bohemian brown coal basin. Attention was especially paid to the elemental composition, ash content, content and forms of sulphur, occurrence of syngenetic and epigenetic sulphides, maceral composition, and degree of gelification and decomposition of components in the huminite maceral group. Some other coal characteristics were also assessed, such as pore texture, extractability and solvent swelling of the coals. The coals examined were huminitic with a variable xylite and detrite content. Huminite reflectance varied between 0.33 and 0.39%. Substantial differences in pore texture of the coals were found in the range of meso- and macropores. These differences largely affected the extractability of the North Bohemian coals. The coals also exhibited extremely high swelling ratios in basic solvents, such as pyridine.

Mercury contamination of stream sediments in the North Bohemian Coal District (Czech Republic): Mercury speciation and the role of organic matter

Industrial expansion in the North Bohemian Coal District over the past decades has had an adverse effect not only on stream sediments but also on the freshwater system. So far mercury occurrence has not been properly investigated in the area. In response to this situation, the present study applies mercury quantification and speciation in order to predict the possible mobility of mercury. The enrichment factor (EF) and sediment quality guidelines (SQGs) were used to calculate the degree of mercury contamination. An automatic mercury analyser was employed to detect the total mercury content (Hg-T) and Thermal Desorption technique was used to identify mercury species. All the sediment samples were assessed with the contamination degree which increased to very severe in stream sediments in the middle section of the river course. Mercury species identified were chiefly the insoluble forms Hg-FeS2 and HgS. Lignite components and combustion residues were identified as the primary source of Hg contamination in the area.

Hypogene Features in Sandstones: An Example from Carboniferous Basins of Central and Western Bohemia, Czech Republic

Concave and cavernous forms including rising wall channels, rising sets of coalesced copula, ceiling half-tube channels, separate ceiling copula, ceiling chimneys, and half-spherical upward-convex arches locally occur in surface outcrops of Carboniferous arkose sandstones in central and western Bohemia. Many of these negative forms conventionally described as tafoni and/or honeycombs have been traditionally interpreted as products of various exogenous weathering processes. Based on the line of indirect evidence, we propose an alternative interpretation in which these features represent transitional and outlet members of the morphologic suite of rising flow (MSRF), indicative of their subsurface hypogene origin. The negative forms are commonly associated with bedding planes and subvertical fractures mineralized with goethite and jarosite. The reflectance of coal particles embedded in sandstone along mineralized bedding planes (0.91–1.03% R r ) is appreciably higher with respect to those of adjacent unaltered arkose host rocks (0.61–0.85% R r ), pointing to the thermal overprint by hot fluids. Moreover, the walls of many cavities are covered by sandy-disintegrated alterite locally mineralized with gypsum, dickite, goethite, authigenic quartz, pickeringite, and bischofite. We suggest that these phenomena, including the origin of characteristic concave forms and mineralogical alterations of arkose host rocks, may have been due to warm, CO2-saturated and possibly H2S-rich brines that ascended from the deepest stratigraphic units of the Carboniferous succession via the network of subvertical tectonic fractures and migrated laterally outward along permeable bedding planes. As indicated by the apatite fission track analysis and wider geological observations, the alteration of arkose sandstones probably occurred at relatively shallow depth of burial, during the Tertiary uplift of the Bohemian Massif 15–20 Ma ago. In this environment, the alteration may have been accelerated by the effects of mixing corrosion where heated deep basinal fluids interacted with shallower interstratal waters. When the uplifted sandstone sequences eventually reached the surface, the hypogene cavities and altered cliff walls were subjected to subaerial weathering and fluvial erosion processes the effects of which were superimposed on older hypogene features.