Hexachlorobenzene (HCB), a representative of hydrophobic organic chemicals (HOC), belongs to the ... more Hexachlorobenzene (HCB), a representative of hydrophobic organic chemicals (HOC), belongs to the group of persistent organic pollutants (POPs) that can have harmful effects on humans and other biota. Sorption processes in soils and sediments largely determine the fate of HCB and the risks arising from the compound in the environment. In this context, especially HOC–organic matter interactions are intensively studied, whereas knowledge of HOC adsorption to mineral phases (e.g., clay minerals) is comparatively limited. In this work, we performed batch adsorption experiments of HCB on a set of twelve phyllosilicate mineral sorbents that comprised several smectites, kaolinite, hectorite, chlorite, vermiculite, and illite. The effect of charge and size of exchangeable cations on HCB adsorption was studied using the source clay montmorillonite STx-1b after treatment with nine types of alkali (M+: Li, K, Na, Rb, Cs) and alkaline earth metal cations (M2+: Mg, Ca, Sr, Ba). Molecular modeling...
The effect of different terminations of cluster models was shown on the quantum-chemically calcul... more The effect of different terminations of cluster models was shown on the quantum-chemically calculated atomic charges, bonding population analysis and harmonic vibrational frequency of the inner OH group. As the basic model was proposed 32 atomic cluster of the brucite sheet in lizardite layer. The calculations were performed using Hartree-Fock method and 3-21G atomic basis set (HF/3-21G).
Atrazine (A) is one of the most applied herbicides and has a negative impact on the environment a... more Atrazine (A) is one of the most applied herbicides and has a negative impact on the environment and health. Density functional theory (DFT) and experimental methods were used in the study of the immobilization of atrazine in two smectites, montmorillonite (Mt) and beidellite (Bd), as well as in their organically modified structures. Four systems were examined: A-Mt and A-Bd, as well as the structures modified by tetramethylphosphonium cation (TMP), A-TMP-Mt and A-TMP-Bd. The calculations revealed a flat arrangement of the atrazine in the interlayer space of both smectites with higher stability of beidellite structures. The presence of the TMP cation increased the fixation of atrazine in both organically modified smectites. The calculated vibrational spectra allowed a detailed analysis of the overlapping bands observed in the experimental FTIR spectra and their correct assignment. Further, selected FTIR bands unambiguously assigned to atrazine and both smectites served for the estima...
Essential focus of the study has been to acquire thermoanalytical events, incl. enthalpies of dec... more Essential focus of the study has been to acquire thermoanalytical events, incl. enthalpies of decompositions -∆H, of natural minerals of calcium-silicate-sulfate-aluminate hydrates. The thermoanalytical curves of thaumasite and ettringite are fully in line with that reported in reference sources. The values of ∆H calculated from DSC curves in the intervals of key decomposition steps ranging from 50 to 250 °C, achieve (1215 ± 60) J g -1 for thaumasite and (930 ± 40) J g -1 for ettringite. The differing values of decomposition enthalpies ∆H, as presented by various research groups, are indicated and critically discussed in the paper.
ABSTRACT The pressure-induced A-B phase transition of synthetic Rb-tetra-ferri-annite (Rb-TFA) mi... more ABSTRACT The pressure-induced A-B phase transition of synthetic Rb-tetra-ferri-annite (Rb-TFA) mica was studied theoretically by means of Density Functional Theory (DFT) method. The calculations show that Rb-TFA keeps a Franzini A-type structure up to at least 5.39 GPa of pres-sure, whereas at higher pressure, it transforms to a Franzini B-type structure. The negative value of the tetrahedral rotation angle a = -4.68° has appeared at 5.56 GPa of calculated pressure. This result is in a relatively good agreement with experimentally estimated phase transition area in the range of 3.36-3.84 GPa. The energy difference between the A and B structures is very small (DE = 8 kJ/ mol). The detailed analysis of the optimized structural data shows minimal changes in the structure of Rb-TFA after the pressure-induced phase transition.
Abstract The title compound, [Cu(5-Mesal)2(denia)2 (H2O)2] (5-Mesal = 5-methylsalicylato, denia =... more Abstract The title compound, [Cu(5-Mesal)2(denia)2 (H2O)2] (5-Mesal = 5-methylsalicylato, denia = N,N-diethylnicotinamide) crystallizes in the triclinic unit cell. Crystal structure was solved from the laboratory powder diffraction data. Each copper(II) atom is situated on an inversion centre and is coordinated by two O atoms from two 5-Mesal ligands [Cu—O 2.00(3) Å], two N atoms from two denia ligands [Cu—N 2.05(2) Å], and two water molecules [Cu—Ow 2.80(3) Å] in a highly distorted octahedral geometry. In the crystal structure, intermolecular O—H … O hydrogen bonds link the molecules into chains extended in direction [1 –1 0]. The optimization in solid state with DFT/plane-waves approach revealed the large value of Cu—Ow bond length [2.793 Å].
Crystal structure of the title compound was solved from the laboratory powder diffraction data in... more Crystal structure of the title compound was solved from the laboratory powder diffraction data in the
... The aims of this study were to obtain accurate structural information on the dimethyl sulfoxi... more ... The aims of this study were to obtain accurate structural information on the dimethyl sulfoxide (DMSO) and dimethylselenoxide (DMSeO) kaolinite intercalates, paying close attention to the hydrogen-bond geometries, and to provide a detailed interpretation of the individual ...
Hexachlorobenzene (HCB), a representative of hydrophobic organic chemicals (HOC), belongs to the ... more Hexachlorobenzene (HCB), a representative of hydrophobic organic chemicals (HOC), belongs to the group of persistent organic pollutants (POPs) that can have harmful effects on humans and other biota. Sorption processes in soils and sediments largely determine the fate of HCB and the risks arising from the compound in the environment. In this context, especially HOC–organic matter interactions are intensively studied, whereas knowledge of HOC adsorption to mineral phases (e.g., clay minerals) is comparatively limited. In this work, we performed batch adsorption experiments of HCB on a set of twelve phyllosilicate mineral sorbents that comprised several smectites, kaolinite, hectorite, chlorite, vermiculite, and illite. The effect of charge and size of exchangeable cations on HCB adsorption was studied using the source clay montmorillonite STx-1b after treatment with nine types of alkali (M+: Li, K, Na, Rb, Cs) and alkaline earth metal cations (M2+: Mg, Ca, Sr, Ba). Molecular modeling...
The effect of different terminations of cluster models was shown on the quantum-chemically calcul... more The effect of different terminations of cluster models was shown on the quantum-chemically calculated atomic charges, bonding population analysis and harmonic vibrational frequency of the inner OH group. As the basic model was proposed 32 atomic cluster of the brucite sheet in lizardite layer. The calculations were performed using Hartree-Fock method and 3-21G atomic basis set (HF/3-21G).
Atrazine (A) is one of the most applied herbicides and has a negative impact on the environment a... more Atrazine (A) is one of the most applied herbicides and has a negative impact on the environment and health. Density functional theory (DFT) and experimental methods were used in the study of the immobilization of atrazine in two smectites, montmorillonite (Mt) and beidellite (Bd), as well as in their organically modified structures. Four systems were examined: A-Mt and A-Bd, as well as the structures modified by tetramethylphosphonium cation (TMP), A-TMP-Mt and A-TMP-Bd. The calculations revealed a flat arrangement of the atrazine in the interlayer space of both smectites with higher stability of beidellite structures. The presence of the TMP cation increased the fixation of atrazine in both organically modified smectites. The calculated vibrational spectra allowed a detailed analysis of the overlapping bands observed in the experimental FTIR spectra and their correct assignment. Further, selected FTIR bands unambiguously assigned to atrazine and both smectites served for the estima...
Essential focus of the study has been to acquire thermoanalytical events, incl. enthalpies of dec... more Essential focus of the study has been to acquire thermoanalytical events, incl. enthalpies of decompositions -∆H, of natural minerals of calcium-silicate-sulfate-aluminate hydrates. The thermoanalytical curves of thaumasite and ettringite are fully in line with that reported in reference sources. The values of ∆H calculated from DSC curves in the intervals of key decomposition steps ranging from 50 to 250 °C, achieve (1215 ± 60) J g -1 for thaumasite and (930 ± 40) J g -1 for ettringite. The differing values of decomposition enthalpies ∆H, as presented by various research groups, are indicated and critically discussed in the paper.
ABSTRACT The pressure-induced A-B phase transition of synthetic Rb-tetra-ferri-annite (Rb-TFA) mi... more ABSTRACT The pressure-induced A-B phase transition of synthetic Rb-tetra-ferri-annite (Rb-TFA) mica was studied theoretically by means of Density Functional Theory (DFT) method. The calculations show that Rb-TFA keeps a Franzini A-type structure up to at least 5.39 GPa of pres-sure, whereas at higher pressure, it transforms to a Franzini B-type structure. The negative value of the tetrahedral rotation angle a = -4.68° has appeared at 5.56 GPa of calculated pressure. This result is in a relatively good agreement with experimentally estimated phase transition area in the range of 3.36-3.84 GPa. The energy difference between the A and B structures is very small (DE = 8 kJ/ mol). The detailed analysis of the optimized structural data shows minimal changes in the structure of Rb-TFA after the pressure-induced phase transition.
Abstract The title compound, [Cu(5-Mesal)2(denia)2 (H2O)2] (5-Mesal = 5-methylsalicylato, denia =... more Abstract The title compound, [Cu(5-Mesal)2(denia)2 (H2O)2] (5-Mesal = 5-methylsalicylato, denia = N,N-diethylnicotinamide) crystallizes in the triclinic unit cell. Crystal structure was solved from the laboratory powder diffraction data. Each copper(II) atom is situated on an inversion centre and is coordinated by two O atoms from two 5-Mesal ligands [Cu—O 2.00(3) Å], two N atoms from two denia ligands [Cu—N 2.05(2) Å], and two water molecules [Cu—Ow 2.80(3) Å] in a highly distorted octahedral geometry. In the crystal structure, intermolecular O—H … O hydrogen bonds link the molecules into chains extended in direction [1 –1 0]. The optimization in solid state with DFT/plane-waves approach revealed the large value of Cu—Ow bond length [2.793 Å].
Crystal structure of the title compound was solved from the laboratory powder diffraction data in... more Crystal structure of the title compound was solved from the laboratory powder diffraction data in the
... The aims of this study were to obtain accurate structural information on the dimethyl sulfoxi... more ... The aims of this study were to obtain accurate structural information on the dimethyl sulfoxide (DMSO) and dimethylselenoxide (DMSeO) kaolinite intercalates, paying close attention to the hydrogen-bond geometries, and to provide a detailed interpretation of the individual ...
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Papers by Eva Scholtzová