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Porosity of different rocks in relation to capturing/moving of gases and liquids
Řimnáčová, Daniela; Vöröš, Dominik; Natherová, Vendula; Přikryl, R.; Lokajíček, Tomáš
2022 - English
Variability in the porosity of natural rocks and waste have been investigated in relation to the influence on the\npermeability of gases and water. The samples were of sedimentary or igneous rocks, carbon-rich rocks, and solid\nporous waste material after thermal conversion. Using mercury intrusion porosimetry, porosity values and pore\nsize distribution varied with the origin of materials. These results have been compared and a connection between\nthe origin and porosity of material was observed. Total porosity values of selected samples ranged from ca. 0.2%\nfor granite to 55% for waste porous material. Lower porosity values demonstrate the connectivity between\nmesopores or micropores and are related to the capturing of greenhouse gases, while higher porosity is caused\npredominantly by the presence of macropores and coarse pores, which serve as pathways for permeability of\ngases and liquids.
Keywords:
gas adsorption; porosity; rocks; waste materials
Fulltext is available at external website.
Porosity of different rocks in relation to capturing/moving of gases and liquids
Variability in the porosity of natural rocks and waste have been investigated in relation to the influence on the\npermeability of gases and water. The samples were of sedimentary or igneous rocks, ...
Geopolymers: The influence of alkaline activator cations on efflorescence
Novotná, Martina; Polonská, A.; Šídlová, M.; Perná, Ivana
2021 - English
This paper describes the effect of the type of cations in the alkaline activator on geopolymer properties and especially on the formation of efflorescence. The susceptibility to the formation of efflorescence is discussed according to the standard ČSN 72 1565-13. Cations in alkaline activators influence the mineralogical type of efflorescence: Li+ and Na+ cations form carbonates (Li2CO3 and Na2CO3, respectively), whereas K+ cations form sulphate (K2SO4). The mechanical properties, workability and pore structure of the geopolymer composites have been determined. Alkaline activators with sodium and potassium ions reach higher mechanical strength than those containing lithium cations. For lithium alkaline activators, there was a noticeable difference in the properties between the SiO2/Li2O ratios 1.8 and 2.6. Based on the properties of the mentioned geopolymer composites with various alkaline cations, it is possible to use lithium alkaline activators in geopolymer technology.
Keywords:
geopolymer; efflorescence; alkaline activator cations; properties
Available in digital repository of the ASCR
Geopolymers: The influence of alkaline activator cations on efflorescence
This paper describes the effect of the type of cations in the alkaline activator on geopolymer properties and especially on the formation of efflorescence. The susceptibility to the formation of ...
Three-dimensionally ordered micromesoporous carbon as adsorbent for CO2 capture
Vorokhta, Maryna; Řimnáčová, Daniela; Pilař, Radim
2019 - English
In this work, ordered three-dimensionally micromesoporous carbon composed of large spherical mesopores 13 nm in diameter and small micropores with a mean micropore width of 1.46 nm, connecting the main spheres, was synthesized and investigated for CO2 capture ability at temperatures of 25°C, 35°C and 50°C, and at pressures up to 6.5 MPa. Because of the big pore volume occupying 3.62 cm3/g, composed of mesopores and micropores, the carbon sample showed very high adsorption capacity at high pressures. The highest CO2 adsorption capacity of 24.03 mmol/g was obtained at 25°C and at 5.5 MPa. As the temperature increased, the CO2 adsorption capacity decreased to 13.34 mmol/g at 50°C and at 6.5 MPa. The Freundlich fittings of the measured adsorption isotherms at pressures up to 2 MPa showed very high correlation coefficients. The estimated isosteric heats of adsorption in the range of 5.62-6.90 kJ/mol indicated a physical adsorption process, and suggested a stronger interaction between CO2 molecules than between CO2 molecules and the surface of the carbon sample.
Keywords:
3DOmm carbon; CO2 adsorption; Freundlich fit; Isosteric heat
Fulltext is available at external website.
Three-dimensionally ordered micromesoporous carbon as adsorbent for CO2 capture
In this work, ordered three-dimensionally micromesoporous carbon composed of large spherical mesopores 13 nm in diameter and small micropores with a mean micropore width of 1.46 nm, connecting the ...
Adsorption study of waste materials as potential adsorbents for pollutant removal and storage
Řimnáčová, Daniela; Vorokhta, Maryna; Vöröš, Dominik; Borecká, Lenka; Bičáková, Olga
2019 - English
The study shows how changing the experimental conditions during carbonization of a waste material such as sewage sludge influences textural properties and the CO2adsorption capacity of final carbonized productsin their potential use for removaland storage of pollutantssuch as carbon dioxide. The CO2adsorption measurements were done with gravimetric and manometric sorption devices in a wide range of pressures and temperatures. Further, CO2adsorption capacities of other materialssuch as activated carbon prepared from black carbon and a Czech Silurian shalewere compared toadsorption capacities of the studied carbonized sewage sludge. These two compared materials were chosen according to their compositionsand porosity.The porosityof the studied materials was determined from the N2sorption isotherms and measurements of their skeletal density with He.The adsorption capacity depended on the ratio of micropores and mesopores in the carbonized sewage sludge, because CO2fillsmicropores and mesopores at lowand highpressures, respectively, and was decreasing with the temperature increase atconstant pressure.The adsorption capacity of the carbonized sewage sludgewas increased by increase inthe carbonization temperature.The obtained adsorption capacities showed that the carbonization of sewage sludge can lead to preparation of perspective adsorbents for CO2capture and storage.
Keywords:
CO2 adsorption; high pressure; porous materials
Fulltext is available at external website.
Adsorption study of waste materials as potential adsorbents for pollutant removal and storage
The study shows how changing the experimental conditions during carbonization of a waste material such as sewage sludge influences textural properties and the CO2adsorption capacity of final ...
The processing of stabilized sewage sludge by high-temperature slow pyrolysis and gasification
Bičáková, Olga; Čimová, Nikoleta; Vöröš, Dominik; Náhunková, Jana; Řimnáčová, Daniela
2019 - English
One of the most challenging type of waste is sewage sludge, which is a heterogeneous suspension containing organic and inorganic substances and pathogenic organisms. This work focuses on an effective application method for the sewage sludge, which is usually deposited in landfills or co-incinerated in power plants. High temperature pyrolysis and gasification at 700–900 °C were applied to the samples of stabilized sewage sludge. The samples with a constant weight of 100 g were heated in a stationary bed, with the rate of batch heating being monitored. During the heating process, volatile products were released and the composition of the gaseous products developed during the heating was analyzed. Afterwards, the mass balance of the resulting products was evaluated. The elemental and textural analyses of the products were performed. Furthermore, it has been found that the solid residue has a porous texture and properties suitable for the removal and capture of pollutants. \n
Keywords:
Sewage sludge; pyrolysis; gasification; mass balance
Fulltext is available at external website.
The processing of stabilized sewage sludge by high-temperature slow pyrolysis and gasification
One of the most challenging type of waste is sewage sludge, which is a heterogeneous suspension containing organic and inorganic substances and pathogenic organisms. This work focuses on an effective ...
Valley evolution of the Biala Lądecka drainage network during late Cenozoic, Lower Silesia, Poland
Stemberk, Jakub; Štěpančíková, Petra; Tábořík, Petr; Coubal, Miroslav
2017 - English
Biala Lądecka (Biala Kłodzka) river is located in Lower Silesia (Poland) and its valley separates Góry Złote Mts.\n(Rychlebské hory Mts.) on the NE from Góry Bialskie Mts. on the SW. We conducted geomorphic investigations on the Biala\nLądecka river basin, in order to determine if Quarternary tectonic activity at the Bělský fault (or near Marginal Sudetic fault) is\ncontributing to the river’s asymmetry. Our research was focused on analysis of selected landforms, DEM parameters,\nmorphometric indexes and their spatial distribution which could potentially indicate recent tectonic activity in the area. At\nselected places geophysical measures were used to discover proper location and structure of Bělský fault or presence of\nsuggested morpholineaments. Preliminary results suggest a Quaternary tectonic activity for the Bělský fault. Moreover we tried\nto clarify nowadays stress regime in study area based striae measurement on fault planes and precise monitoring of selected\nfaults using TM-71 device.
Keywords:
Poland - Czech border; NE Europe; stable continental areas; Biala Lądecka river; Bělský fault; morphometric indexes; DEM analysis
Fulltext is available at external website.
Valley evolution of the Biala Lądecka drainage network during late Cenozoic, Lower Silesia, Poland
Biala Lądecka (Biala Kłodzka) river is located in Lower Silesia (Poland) and its valley separates Góry Złote Mts.\n(Rychlebské hory Mts.) on the NE from Góry Bialskie Mts. on the SW. We conducted ...
Late Quaternary activity of slow-slip intraplate Mariánské Lázně fault as revealed by trenching and shallow geophysical survey; Bohemian Massif (Czech Republic, central Europe)
Štěpančíková, Petra; Fischer, T.; Hartvich, Filip; Tábořík, Petr; Rockwell, T.; Stemberk, Jakub; Široký, J.; Sana, Hamid
2017 - English
The NNW-SSE trending Mariánské Lázně Fault (MLF) zone is situated in the western part of the Bohemian Massif (Czech\nRepublic, central Europe) where it intersects NE-trending Cenozoic Eger rift. The northern segment of the MLF controls the\nmorphologically pronounced mountain front of Krušné hory Mts. and eastern limit of Cenozoic Cheb basin, which is famous for\nearthquake swarms (max. ML=4.6) and CO2 emanation. We performed 2D and 3D geophysical survey (electric resistivity\ntomography, ground penetration radar) and 3D trenching to look for large surface-rupturing prehistoric earthquake responsible\nfor pronounced moutain range front. Seven excavated and six hand-dug trenches revealed a complex geology and deformation\nat the study site probably as a result of right-lateral transpression during Late Quaternary. Two Holocene earthquakes 1150-590\nBC and 780-1000 AD were inferred from 14C dating of faulted Holocene colluvium with corresponding magnitudes Mw=6.7-7.0.\nThe latter one is the youngest documented surface-rupturing event in central Europe.\n
Keywords:
paleoseismic trenching; historic earthquake; Cheb basin; Mariánské Lázně fault; Bohemian Massif
Fulltext is available at external website.
Late Quaternary activity of slow-slip intraplate Mariánské Lázně fault as revealed by trenching and shallow geophysical survey; Bohemian Massif (Czech Republic, central Europe)
The NNW-SSE trending Mariánské Lázně Fault (MLF) zone is situated in the western part of the Bohemian Massif (Czech\nRepublic, central Europe) where it intersects NE-trending Cenozoic Eger rift. The ...
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