Lenka Vaculikova - Academia.edu (original) (raw)

Papers by Lenka Vaculikova

Research paper thumbnail of Synthesis, characterization and catalytic activity of cryptomelane/montmorillonite composites

Applied Clay Science, Mar 1, 2021

Abstract Manganese oxides are considered to be highly effective catalysts for the oxidation of vo... more Abstract Manganese oxides are considered to be highly effective catalysts for the oxidation of volatile organic compounds (VOCs). A series of MnO2/montmorillonite composites was prepared to test their catalytic activity in the combustion of model compounds - toluene and ethanol. Several different types of montmorillonites (Mt), referred to as STx-1b, SWy-2, SAz-2, and Kunipia- F, were used to prepare the composites. The MnO2/Mt composites were synthetized in a weight ratio of 1:1, using the reaction between KMnO4 and HCl for the generation of the MnO2 component. Advanced techniques including XRD, SEM/EDS, IR spectroscopy, N2 adsorption/desorption, and H2 TPR were used for physico-chemical characterization of obtained materials. The MnO2 component precipitated as cryptomelane, the tunnel α-MnO2 structure. In catalytic tests, all composite samples were more active than the reference MnO2. The performance of composites in toluene oxidation was correlated with their reducibility. In the case of ethanol, it is suggested that catalytic activity is additionally affected by differences in the distribution of potassium between the Mt and the cryptomelane caused by the different cation exchange capacity (CEC) of montmorillonites. Lower CEC of clay mineral leads to a higher share of potassium in MnO2 enhancing thereby its basicity, which is favorable for ethanol combustion.

Research paper thumbnail of Mineralogical, Geochemical and Geotechnical Study of BCV 2017 Bentonite—The Initial State and the State following Thermal Treatment at 200 °C

Minerals

Bentonites are considered to be the most suitable materials for the multibarrier system of high-l... more Bentonites are considered to be the most suitable materials for the multibarrier system of high-level radioactive waste repositories. Since BCV bentonite has been proved to be an ideal representative of Czech Ca-Mg bentonites in this respect, it has been included in the Czech Radioactive Waste Repository Authority (SÚRAO) buffer and backfill R&D programme. Detailed knowledge of processes in the material induced by thermal loading provides invaluable assistance regarding the evolution of the material under repository conditions. Samples of both original BCV 2017 bentonite and the same material thermally treated at 200 °C were characterised by means of chemical analysis, powder X-ray diffraction, infrared spectroscopy, thermal analysis, cation exchange capacity, specific surface area (BET) measurements, the determination of the swell index, the liquid limit, the swelling pressure and water retention curves. The smectite in BCV 2017 bentonite comprises Ca-Mg montmorillonite with a sign...

Research paper thumbnail of Bentonite Modification with Manganese Oxides and Its Characterization

The paper describes the preparation of new composite based on relatively cheap natural materials ... more The paper describes the preparation of new composite based on relatively cheap natural materials from domestic deposits and synthetically prepared manganese oxides. At first the natural bentonite was simple chemically modified by natrification. In general, bentonite is a rock with dominant presence of clay minerals from the smectite group, mainly montmorillonite. The properties of bentonite result from the crystal structure of this group. The particles of montmorillonite have negative charges on their faces due to isomorphic substitutions in structure. The natrification salt Na2CO3 is used almost exclusively thanks to its financial accessibility. The significant changes of surface properties after the modification of bentonite were observed. Natrification increased the surface area of bentonite. Then the manganese oxides were precipitated on the surface of activated sodium bentonite particles. The structural changes of bentonite, before and after its modification, were studied by X-...

Research paper thumbnail of Pyrolytic Oils in Coal Flotation

  1. Doc. Ing., Ph.D.; VSB – Technical University of Ostrava, Faculty of Mining and Geology, Instit... more 1) Doc. Ing., Ph.D.; VSB – Technical University of Ostrava, Faculty of Mining and Geology, Institute of Clean Technologies for Extraction and Utilization of Energy Resources, 17.listopadu 15, 708 33 Ostrava-Poruba, Czech Republic; email: vladimir.cablik@vsb.cz 2) Dipl. Ing.; VSB – Technical University of Ostrava, Faculty of Mining and Geology, Institute of Environmental Engineering, 17.listopadu 15, 708 33 Ostrava-Poruba, Czech Republic 3) Ing.; VSB – Technical University of Ostrava, Faculty of Mining and Geology, Institute of Environmental Engineering, 17.listopadu 15, 708 33 Ostrava-Poruba, Czech Republic; email: mariana.herkova@vsb.cz 4) Ing.; VSB – Technical University of Ostrava, Faculty of Mining and Geology, Institute of Environmental Engineering, 17.listopadu 15, 708 33 Ostrava-Poruba, Czech Republic; email: jakub.halas@vsb.cz 5) Ing.; VSB – Technical University of Ostrava, Faculty of Mining and Geology, Institute of Clean Technologies for Extraction and Utilization of Energ...

Research paper thumbnail of Characterization and differentiation of kaolinites from selected Czech deposits using infrared spectroscopy and differential thermal analysis

Research paper thumbnail of Lithium and rubidium extraction from zinnwaldite by alkali digestion process: Sintering mechanism and leaching kinetics

International Journal of Mineral Processing, 2013

ABSTRACT Lithium and rubidium were extracted from zinnwaldite [KLiFe2 +Al(AlSi3)O10(F,OH)2] by (1... more ABSTRACT Lithium and rubidium were extracted from zinnwaldite [KLiFe2 +Al(AlSi3)O10(F,OH)2] by (1) its sintering with and CaCO3 powders and (2) water leaching the obtained sinters—the alkali digestion process. The experimental results showed that sintering proceeded in three partly overlapping stages: (1) decomposition of zinnwaldite at temperature up to 800 °C, (2) formation of new phases in the temperature range between 750 and 835 °C, and (3) formation of amorphous glassy phase at temperature above 835 °C. Densification of the reaction mixture occurred via a liquid phase sintering at temperatures above 750 °C and diffusion of calcium, potassium, silicon and rubidium resulted in the formation of the new phases. The decomposition of zinnwaldite and the formation of the new phases increased extraction of lithium and rubidium. The formation of glassy phase probably hindered extraction of lithium but did not affect that of rubidium because of its outward diffusion to sinter's surface. The optimal extraction efficiencies of 84% of lithium and 91% of rubidium were achieved at sintering temperature of 825 °C and leaching temperature of 95 °C. The good fit of the hyperbolic and uniform reaction models to the leaching data indicated that dissolution of lithium and rubidium proceeded through two stages. Application of the shrinking core model showed that dissolution of lithium was controlled by diffusion. The formation of a layer of Ca(OH)2 on surface of sinters apparently slowed and then terminated dissolution of lithium and rubidium in the later stage of leaching.

Research paper thumbnail of Identification of Clay Minerals and Micas in Sedimentary Rocks

Research paper thumbnail of Different level of fluorescence in Raman spectra of montmorillonites

Vibrational Spectroscopy, May 1, 2016

Research paper thumbnail of Organobeidellites for Removal of Anti-Inflammatory Drugs from Aqueous Solutions

Nanomaterials, Nov 17, 2021

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Sorption of Alkylammonium Cations on Montmorillonite

Research paper thumbnail of Composition of gypsum from the Kobeřice quarry (Czech Republic)

Research paper thumbnail of Characterization of Limestone from Cement Plant at Berbera (Republic of Somaliland)

Procedia Engineering, 2017

Abstract The results of physico-chemical characterization of limestone samples come from the Meso... more Abstract The results of physico-chemical characterization of limestone samples come from the Mesosoic limestone deposit areas in the region of Berbera (Republic of Somaliland) were reported in this paper. The chemical analysis was carried out by X-ray fluorescence analysis, FT-IR spectroscopy and thermal analysis. The physical characterization of limestone samples were performed in laboratory conditions. This investigation provided necessary data for subsequent utilization and exploitation of limestone in this region. The tested material is a good quality and purity. From the chemical composition point of view the tested limestone has a high content of about 96% CaCO3, with small amount of clay minerals and with traces of quartz, which corresponds to the medium purity limestone. It was confirmed, that this limestone is suitable for cement production. The density and porosity measurement indicated that the medium to high density limestone is very compact with porosity lower than 4%. These data very good corresponds to relatively high Young's modulus up to 48 200 MPa and maximum strength of 204 MPa.

Research paper thumbnail of Removal of amoxicillin and ampicillin using manganese dioxide/montmorillonite composite

Journal of Chemical Technology & Biotechnology

BACKGROUNDClay‐based materials represent great potential for the development of efficient and env... more BACKGROUNDClay‐based materials represent great potential for the development of efficient and environmentally friendly sorbents. The study focuses on a laboratory‐obtained manganese dioxide/montmorillonite (MnO2/MMT) composite for removal of two types of antibiotics – amoxicillin (AMX) and ampicillin (AMP) – from aqueous solution.RESULTSThe composite was successfully prepared using a reduction procedure involving the reaction between potassium permanganate (KMnO4) and hydrochloric acid (HCl) to form MnO2 followed by the addition of MMT. X‐ray analysis, scanning electron microscopy, X‐ray fluorescence and Fourier transform infrared spectroscopy were performed for characterization of physicochemical and structural properties, simultaneous thermogravimetry and differential scanning calorimetry for estimation of thermal stability and high‐performance liquid chromatography for determination of antibiotic equilibrium concentrations in aqueous solution. The precipitated MnO2 component, man...

Research paper thumbnail of Correction to: Removal of analgesics from aqueous solutions onto montmorillonite KSF

Journal of Thermal Analysis and Calorimetry, 2021

A correction to this paper has been published: https://doi.org/10.1007/s10973-021-10855-7

Research paper thumbnail of Identification of Clay Minerals and Micas in Sedimentary Rocks

Real possibilities of FTIR-spectroscopy application along with thermal analysis (TG/DTA) for exam... more Real possibilities of FTIR-spectroscopy application along with thermal analysis (TG/DTA) for examining clay minerals in rocks are presented. These methods were used for determination of mineral composition in sedimentary rock samples from the shaft No.4 Frenstat -West, Northern Moravia, CZ. Previously, the samples representing the basic clay mineral specimen were investigated by means of the following methods. In order to provide an adequate characterization of these samples, X-ray diffraction and X-ray fluorescence spectroscopy were utilized. As the individual clay minerals often occur in a form of mixed-layer clay minerals with various ratios of individual components, IR spectra and TG/DTA curves of mixtures (either natural or synthetic) were recorded, too. Clay minerals represented mainly by fine-crystalline illite (muscovite) with traces of kaolinite were predominant. Besides, carbonates (calcite, ankerite) and silica minerals occured in these samples, too. A presence of pyrites...

Research paper thumbnail of Hollandite and cryptomelane from Poniklá near Jilemnice, Czech Republic

Research paper thumbnail of Organobeidellites for Removal of Anti-Inflammatory Drugs from Aqueous Solutions

Nanomaterials, 2021

Diclofenac (DC) and ibuprofen (IBU) are widely prescribed non-steroidal anti-inflammatory drugs, ... more Diclofenac (DC) and ibuprofen (IBU) are widely prescribed non-steroidal anti-inflammatory drugs, the consumption of which has rapidly increased in recent years. The biodegradability of pharmaceuticals is negligible and their removal efficiency by wastewater treatment is very low. Therefore, the beidelitte (BEI) as unique nanomaterial was modified by the following different surfactants: cetylpyridinium (CP), benzalkonium (BA) and tetradecyltrimethylammonium (TD) bromides. Organobeidellites were tested as potential nanosorbents for analgesics. The organobeidellites were characterized using X-ray powder diffraction (XRD), Infrared spectroscopy (IR), Thermogravimetry and differential thermal analysis (TG/DTA) and scanning microscopy (SEM). The equilibrium concentrations of analgesics in solution were determined using UV-VIS spectroscopy. The intercalation of surfactants into BEI structure was confirmed both using XRD analysis due to an increase in basal spacing from 1.53 to 2.01 nm for ...

Research paper thumbnail of Removal of analgesics from aqueous solutions onto montmorillonite KSF

Journal of Thermal Analysis and Calorimetry, 2021

Due to increasing consumption of analgesic drugs associated with their occurrence in wastewater, ... more Due to increasing consumption of analgesic drugs associated with their occurrence in wastewater, it is necessary to pay attention to find new accessible types of sorbents for effective drug removal. The objective of this work is the assessment of ability of commercial montmorillonites for the removal of drugs from aqueous solutions since these inexpensive materials exhibit both adsorption and ion exchange properties as well as environmental stability. The commercial montmorillonite KSF, primarily used as acidic catalyst, was used in both unmodified and cetyltrimethylammonium bromide (CTAB) modified form as potential sorbent for three analgesics: paracetamol (PAR), ibuprofen (IBU) and diclofenac (DC) from aqueous solutions. The samples were characterized by X-ray fluorescence (XRFS), X-ray powder diffraction (XRD), simultaneous thermogravimetry and differential thermal analysis (TG/DTA) and high-performance liquid chromatography (HPLC). XRD confirmed the intercalation of CTAB into the montmorillonite structure with the increasing of basal spacing. Thermal analysis also determined the presence of CTAB associated with increasing of the hydrophobicity accompanied by a decrease in dehydration temperature. Also, due to surfactant modification, the temperature of constitution water removal decreased. Adsorption experiments were carried out in a batch mode with different initial concentration of paracetamol, ibuprofen and diclofenac solutions. Montmorillonite samples especially in organically modified form demonstrated sufficient sorption ability of pharmaceuticals from aqueous solutions in the order diclofenac > ibuprofen > paracetamol.

Research paper thumbnail of Thermal analysis and FT-IR spectroscopy of synthetic clay mineral mixtures

Journal of Thermal Analysis and Calorimetry, 2020

Common clays and especially mixed-layered or interstratified clay minerals are generally mixtures... more Common clays and especially mixed-layered or interstratified clay minerals are generally mixtures of predominantly clay mineral along with minor quantity of another clay mineral, wherein the ratio of the components will determine the resulting properties of these clay materials. This study focuses on IR spectroscopy and TG/DTA analysis and their contribution to the identification of clay minerals in two-component mixtures. Identifying clay minerals in such mixtures by means of thermal analysis is often complicated by the similarity of the thermal effects of the individual clay components. Similarity in thermal behavior is mainly connected with the origin, chemical variability and crystal structure of phyllosilicates. The main problem is overlapping thermal effects of clay minerals or thermal effects related to accessory minerals (calcite, quartz, etc.) on DTA curve. A similar problem also appears in the identification of mixed clay mineral structures by infrared spectroscopy. There are also more or less overlapping absorption bands in the infrared spectra for the mixtures of clay minerals. In this paper, the prepared clay mixtures were supposed to partially simulate the natural mixed clay structures and a minimum content of detectable minerals in clay mixtures were determined according to characteristic peaks on the DTA curves and absorption bands in FT-IR spectra. The results of both methods showed that kaolinite is the most reliable detectable mineral. The detection limit for thermal analysis corresponds to 3% mass kaolinite in admixture with chlorite or montmorillonite, and 1% mass kaolinite for both of these mixtures is based on IR spectroscopy. In case of montmorillonite and chlorite, the identification by FT-IR spectroscopy shows detection limit only 30% mass in contrast to TG/DTA with the detection limit of 5% mass for montmorillonite and 5% mass or 10% mass for chlorite. The obtained results can be effectively used to solve problems in identification of clay minerals in sedimentary rocks, which is very important for subsequent applications in geotechnical, geothermal, and mining activities.

Research paper thumbnail of Characterization of Limestone from Cement Plant at Berbera (Republic of Somaliland)

Procedia Engineering, 2017

Abstract The results of physico-chemical characterization of limestone samples come from the Meso... more Abstract The results of physico-chemical characterization of limestone samples come from the Mesosoic limestone deposit areas in the region of Berbera (Republic of Somaliland) were reported in this paper. The chemical analysis was carried out by X-ray fluorescence analysis, FT-IR spectroscopy and thermal analysis. The physical characterization of limestone samples were performed in laboratory conditions. This investigation provided necessary data for subsequent utilization and exploitation of limestone in this region. The tested material is a good quality and purity. From the chemical composition point of view the tested limestone has a high content of about 96% CaCO3, with small amount of clay minerals and with traces of quartz, which corresponds to the medium purity limestone. It was confirmed, that this limestone is suitable for cement production. The density and porosity measurement indicated that the medium to high density limestone is very compact with porosity lower than 4%. These data very good corresponds to relatively high Young's modulus up to 48 200 MPa and maximum strength of 204 MPa.

Research paper thumbnail of Synthesis, characterization and catalytic activity of cryptomelane/montmorillonite composites

Applied Clay Science, Mar 1, 2021

Abstract Manganese oxides are considered to be highly effective catalysts for the oxidation of vo... more Abstract Manganese oxides are considered to be highly effective catalysts for the oxidation of volatile organic compounds (VOCs). A series of MnO2/montmorillonite composites was prepared to test their catalytic activity in the combustion of model compounds - toluene and ethanol. Several different types of montmorillonites (Mt), referred to as STx-1b, SWy-2, SAz-2, and Kunipia- F, were used to prepare the composites. The MnO2/Mt composites were synthetized in a weight ratio of 1:1, using the reaction between KMnO4 and HCl for the generation of the MnO2 component. Advanced techniques including XRD, SEM/EDS, IR spectroscopy, N2 adsorption/desorption, and H2 TPR were used for physico-chemical characterization of obtained materials. The MnO2 component precipitated as cryptomelane, the tunnel α-MnO2 structure. In catalytic tests, all composite samples were more active than the reference MnO2. The performance of composites in toluene oxidation was correlated with their reducibility. In the case of ethanol, it is suggested that catalytic activity is additionally affected by differences in the distribution of potassium between the Mt and the cryptomelane caused by the different cation exchange capacity (CEC) of montmorillonites. Lower CEC of clay mineral leads to a higher share of potassium in MnO2 enhancing thereby its basicity, which is favorable for ethanol combustion.

Research paper thumbnail of Mineralogical, Geochemical and Geotechnical Study of BCV 2017 Bentonite—The Initial State and the State following Thermal Treatment at 200 °C

Minerals

Bentonites are considered to be the most suitable materials for the multibarrier system of high-l... more Bentonites are considered to be the most suitable materials for the multibarrier system of high-level radioactive waste repositories. Since BCV bentonite has been proved to be an ideal representative of Czech Ca-Mg bentonites in this respect, it has been included in the Czech Radioactive Waste Repository Authority (SÚRAO) buffer and backfill R&D programme. Detailed knowledge of processes in the material induced by thermal loading provides invaluable assistance regarding the evolution of the material under repository conditions. Samples of both original BCV 2017 bentonite and the same material thermally treated at 200 °C were characterised by means of chemical analysis, powder X-ray diffraction, infrared spectroscopy, thermal analysis, cation exchange capacity, specific surface area (BET) measurements, the determination of the swell index, the liquid limit, the swelling pressure and water retention curves. The smectite in BCV 2017 bentonite comprises Ca-Mg montmorillonite with a sign...

Research paper thumbnail of Bentonite Modification with Manganese Oxides and Its Characterization

The paper describes the preparation of new composite based on relatively cheap natural materials ... more The paper describes the preparation of new composite based on relatively cheap natural materials from domestic deposits and synthetically prepared manganese oxides. At first the natural bentonite was simple chemically modified by natrification. In general, bentonite is a rock with dominant presence of clay minerals from the smectite group, mainly montmorillonite. The properties of bentonite result from the crystal structure of this group. The particles of montmorillonite have negative charges on their faces due to isomorphic substitutions in structure. The natrification salt Na2CO3 is used almost exclusively thanks to its financial accessibility. The significant changes of surface properties after the modification of bentonite were observed. Natrification increased the surface area of bentonite. Then the manganese oxides were precipitated on the surface of activated sodium bentonite particles. The structural changes of bentonite, before and after its modification, were studied by X-...

Research paper thumbnail of Pyrolytic Oils in Coal Flotation

  1. Doc. Ing., Ph.D.; VSB – Technical University of Ostrava, Faculty of Mining and Geology, Instit... more 1) Doc. Ing., Ph.D.; VSB – Technical University of Ostrava, Faculty of Mining and Geology, Institute of Clean Technologies for Extraction and Utilization of Energy Resources, 17.listopadu 15, 708 33 Ostrava-Poruba, Czech Republic; email: vladimir.cablik@vsb.cz 2) Dipl. Ing.; VSB – Technical University of Ostrava, Faculty of Mining and Geology, Institute of Environmental Engineering, 17.listopadu 15, 708 33 Ostrava-Poruba, Czech Republic 3) Ing.; VSB – Technical University of Ostrava, Faculty of Mining and Geology, Institute of Environmental Engineering, 17.listopadu 15, 708 33 Ostrava-Poruba, Czech Republic; email: mariana.herkova@vsb.cz 4) Ing.; VSB – Technical University of Ostrava, Faculty of Mining and Geology, Institute of Environmental Engineering, 17.listopadu 15, 708 33 Ostrava-Poruba, Czech Republic; email: jakub.halas@vsb.cz 5) Ing.; VSB – Technical University of Ostrava, Faculty of Mining and Geology, Institute of Clean Technologies for Extraction and Utilization of Energ...

Research paper thumbnail of Characterization and differentiation of kaolinites from selected Czech deposits using infrared spectroscopy and differential thermal analysis

Research paper thumbnail of Lithium and rubidium extraction from zinnwaldite by alkali digestion process: Sintering mechanism and leaching kinetics

International Journal of Mineral Processing, 2013

ABSTRACT Lithium and rubidium were extracted from zinnwaldite [KLiFe2 +Al(AlSi3)O10(F,OH)2] by (1... more ABSTRACT Lithium and rubidium were extracted from zinnwaldite [KLiFe2 +Al(AlSi3)O10(F,OH)2] by (1) its sintering with and CaCO3 powders and (2) water leaching the obtained sinters—the alkali digestion process. The experimental results showed that sintering proceeded in three partly overlapping stages: (1) decomposition of zinnwaldite at temperature up to 800 °C, (2) formation of new phases in the temperature range between 750 and 835 °C, and (3) formation of amorphous glassy phase at temperature above 835 °C. Densification of the reaction mixture occurred via a liquid phase sintering at temperatures above 750 °C and diffusion of calcium, potassium, silicon and rubidium resulted in the formation of the new phases. The decomposition of zinnwaldite and the formation of the new phases increased extraction of lithium and rubidium. The formation of glassy phase probably hindered extraction of lithium but did not affect that of rubidium because of its outward diffusion to sinter's surface. The optimal extraction efficiencies of 84% of lithium and 91% of rubidium were achieved at sintering temperature of 825 °C and leaching temperature of 95 °C. The good fit of the hyperbolic and uniform reaction models to the leaching data indicated that dissolution of lithium and rubidium proceeded through two stages. Application of the shrinking core model showed that dissolution of lithium was controlled by diffusion. The formation of a layer of Ca(OH)2 on surface of sinters apparently slowed and then terminated dissolution of lithium and rubidium in the later stage of leaching.

Research paper thumbnail of Identification of Clay Minerals and Micas in Sedimentary Rocks

Research paper thumbnail of Different level of fluorescence in Raman spectra of montmorillonites

Vibrational Spectroscopy, May 1, 2016

Research paper thumbnail of Organobeidellites for Removal of Anti-Inflammatory Drugs from Aqueous Solutions

Nanomaterials, Nov 17, 2021

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Sorption of Alkylammonium Cations on Montmorillonite

Research paper thumbnail of Composition of gypsum from the Kobeřice quarry (Czech Republic)

Research paper thumbnail of Characterization of Limestone from Cement Plant at Berbera (Republic of Somaliland)

Procedia Engineering, 2017

Abstract The results of physico-chemical characterization of limestone samples come from the Meso... more Abstract The results of physico-chemical characterization of limestone samples come from the Mesosoic limestone deposit areas in the region of Berbera (Republic of Somaliland) were reported in this paper. The chemical analysis was carried out by X-ray fluorescence analysis, FT-IR spectroscopy and thermal analysis. The physical characterization of limestone samples were performed in laboratory conditions. This investigation provided necessary data for subsequent utilization and exploitation of limestone in this region. The tested material is a good quality and purity. From the chemical composition point of view the tested limestone has a high content of about 96% CaCO3, with small amount of clay minerals and with traces of quartz, which corresponds to the medium purity limestone. It was confirmed, that this limestone is suitable for cement production. The density and porosity measurement indicated that the medium to high density limestone is very compact with porosity lower than 4%. These data very good corresponds to relatively high Young's modulus up to 48 200 MPa and maximum strength of 204 MPa.

Research paper thumbnail of Removal of amoxicillin and ampicillin using manganese dioxide/montmorillonite composite

Journal of Chemical Technology & Biotechnology

BACKGROUNDClay‐based materials represent great potential for the development of efficient and env... more BACKGROUNDClay‐based materials represent great potential for the development of efficient and environmentally friendly sorbents. The study focuses on a laboratory‐obtained manganese dioxide/montmorillonite (MnO2/MMT) composite for removal of two types of antibiotics – amoxicillin (AMX) and ampicillin (AMP) – from aqueous solution.RESULTSThe composite was successfully prepared using a reduction procedure involving the reaction between potassium permanganate (KMnO4) and hydrochloric acid (HCl) to form MnO2 followed by the addition of MMT. X‐ray analysis, scanning electron microscopy, X‐ray fluorescence and Fourier transform infrared spectroscopy were performed for characterization of physicochemical and structural properties, simultaneous thermogravimetry and differential scanning calorimetry for estimation of thermal stability and high‐performance liquid chromatography for determination of antibiotic equilibrium concentrations in aqueous solution. The precipitated MnO2 component, man...

Research paper thumbnail of Correction to: Removal of analgesics from aqueous solutions onto montmorillonite KSF

Journal of Thermal Analysis and Calorimetry, 2021

A correction to this paper has been published: https://doi.org/10.1007/s10973-021-10855-7

Research paper thumbnail of Identification of Clay Minerals and Micas in Sedimentary Rocks

Real possibilities of FTIR-spectroscopy application along with thermal analysis (TG/DTA) for exam... more Real possibilities of FTIR-spectroscopy application along with thermal analysis (TG/DTA) for examining clay minerals in rocks are presented. These methods were used for determination of mineral composition in sedimentary rock samples from the shaft No.4 Frenstat -West, Northern Moravia, CZ. Previously, the samples representing the basic clay mineral specimen were investigated by means of the following methods. In order to provide an adequate characterization of these samples, X-ray diffraction and X-ray fluorescence spectroscopy were utilized. As the individual clay minerals often occur in a form of mixed-layer clay minerals with various ratios of individual components, IR spectra and TG/DTA curves of mixtures (either natural or synthetic) were recorded, too. Clay minerals represented mainly by fine-crystalline illite (muscovite) with traces of kaolinite were predominant. Besides, carbonates (calcite, ankerite) and silica minerals occured in these samples, too. A presence of pyrites...

Research paper thumbnail of Hollandite and cryptomelane from Poniklá near Jilemnice, Czech Republic

Research paper thumbnail of Organobeidellites for Removal of Anti-Inflammatory Drugs from Aqueous Solutions

Nanomaterials, 2021

Diclofenac (DC) and ibuprofen (IBU) are widely prescribed non-steroidal anti-inflammatory drugs, ... more Diclofenac (DC) and ibuprofen (IBU) are widely prescribed non-steroidal anti-inflammatory drugs, the consumption of which has rapidly increased in recent years. The biodegradability of pharmaceuticals is negligible and their removal efficiency by wastewater treatment is very low. Therefore, the beidelitte (BEI) as unique nanomaterial was modified by the following different surfactants: cetylpyridinium (CP), benzalkonium (BA) and tetradecyltrimethylammonium (TD) bromides. Organobeidellites were tested as potential nanosorbents for analgesics. The organobeidellites were characterized using X-ray powder diffraction (XRD), Infrared spectroscopy (IR), Thermogravimetry and differential thermal analysis (TG/DTA) and scanning microscopy (SEM). The equilibrium concentrations of analgesics in solution were determined using UV-VIS spectroscopy. The intercalation of surfactants into BEI structure was confirmed both using XRD analysis due to an increase in basal spacing from 1.53 to 2.01 nm for ...

Research paper thumbnail of Removal of analgesics from aqueous solutions onto montmorillonite KSF

Journal of Thermal Analysis and Calorimetry, 2021

Due to increasing consumption of analgesic drugs associated with their occurrence in wastewater, ... more Due to increasing consumption of analgesic drugs associated with their occurrence in wastewater, it is necessary to pay attention to find new accessible types of sorbents for effective drug removal. The objective of this work is the assessment of ability of commercial montmorillonites for the removal of drugs from aqueous solutions since these inexpensive materials exhibit both adsorption and ion exchange properties as well as environmental stability. The commercial montmorillonite KSF, primarily used as acidic catalyst, was used in both unmodified and cetyltrimethylammonium bromide (CTAB) modified form as potential sorbent for three analgesics: paracetamol (PAR), ibuprofen (IBU) and diclofenac (DC) from aqueous solutions. The samples were characterized by X-ray fluorescence (XRFS), X-ray powder diffraction (XRD), simultaneous thermogravimetry and differential thermal analysis (TG/DTA) and high-performance liquid chromatography (HPLC). XRD confirmed the intercalation of CTAB into the montmorillonite structure with the increasing of basal spacing. Thermal analysis also determined the presence of CTAB associated with increasing of the hydrophobicity accompanied by a decrease in dehydration temperature. Also, due to surfactant modification, the temperature of constitution water removal decreased. Adsorption experiments were carried out in a batch mode with different initial concentration of paracetamol, ibuprofen and diclofenac solutions. Montmorillonite samples especially in organically modified form demonstrated sufficient sorption ability of pharmaceuticals from aqueous solutions in the order diclofenac > ibuprofen > paracetamol.

Research paper thumbnail of Thermal analysis and FT-IR spectroscopy of synthetic clay mineral mixtures

Journal of Thermal Analysis and Calorimetry, 2020

Common clays and especially mixed-layered or interstratified clay minerals are generally mixtures... more Common clays and especially mixed-layered or interstratified clay minerals are generally mixtures of predominantly clay mineral along with minor quantity of another clay mineral, wherein the ratio of the components will determine the resulting properties of these clay materials. This study focuses on IR spectroscopy and TG/DTA analysis and their contribution to the identification of clay minerals in two-component mixtures. Identifying clay minerals in such mixtures by means of thermal analysis is often complicated by the similarity of the thermal effects of the individual clay components. Similarity in thermal behavior is mainly connected with the origin, chemical variability and crystal structure of phyllosilicates. The main problem is overlapping thermal effects of clay minerals or thermal effects related to accessory minerals (calcite, quartz, etc.) on DTA curve. A similar problem also appears in the identification of mixed clay mineral structures by infrared spectroscopy. There are also more or less overlapping absorption bands in the infrared spectra for the mixtures of clay minerals. In this paper, the prepared clay mixtures were supposed to partially simulate the natural mixed clay structures and a minimum content of detectable minerals in clay mixtures were determined according to characteristic peaks on the DTA curves and absorption bands in FT-IR spectra. The results of both methods showed that kaolinite is the most reliable detectable mineral. The detection limit for thermal analysis corresponds to 3% mass kaolinite in admixture with chlorite or montmorillonite, and 1% mass kaolinite for both of these mixtures is based on IR spectroscopy. In case of montmorillonite and chlorite, the identification by FT-IR spectroscopy shows detection limit only 30% mass in contrast to TG/DTA with the detection limit of 5% mass for montmorillonite and 5% mass or 10% mass for chlorite. The obtained results can be effectively used to solve problems in identification of clay minerals in sedimentary rocks, which is very important for subsequent applications in geotechnical, geothermal, and mining activities.

Research paper thumbnail of Characterization of Limestone from Cement Plant at Berbera (Republic of Somaliland)

Procedia Engineering, 2017

Abstract The results of physico-chemical characterization of limestone samples come from the Meso... more Abstract The results of physico-chemical characterization of limestone samples come from the Mesosoic limestone deposit areas in the region of Berbera (Republic of Somaliland) were reported in this paper. The chemical analysis was carried out by X-ray fluorescence analysis, FT-IR spectroscopy and thermal analysis. The physical characterization of limestone samples were performed in laboratory conditions. This investigation provided necessary data for subsequent utilization and exploitation of limestone in this region. The tested material is a good quality and purity. From the chemical composition point of view the tested limestone has a high content of about 96% CaCO3, with small amount of clay minerals and with traces of quartz, which corresponds to the medium purity limestone. It was confirmed, that this limestone is suitable for cement production. The density and porosity measurement indicated that the medium to high density limestone is very compact with porosity lower than 4%. These data very good corresponds to relatively high Young's modulus up to 48 200 MPa and maximum strength of 204 MPa.