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Yes (11)
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THE PHOTOCATALYTIC ABATEMENT OF NOX IMISSIONS USING COMMERCIAL FUNCTIONAL COATING WITH POROUS MORPHOLOGY
Žouželka, Radek
2016 - English
Titanium dioxide is the most important photocatalysts used for purifying applications. It was the purpose of this study to investigate the photocatalytic activity of commercial Protectam FN (R) containing TiO2 nanoparticles towards NO and NO2. Experiments on concrete as a support for photocatalyst were carried out in two types of reactors with laminar and turbulent flow under ´´real world setting´´ conditions of temperature, relative humidity, irradiation and pollutant concentrations. The results showed that photocatalytic process significantly reduced both nitrogen oxides in the air. The decrease in the total concentration of nitrogen oxides on contact with the photocatalytic surface reached 20-50 %, i.e. at a concentration of 100 ppb the decrease in NO and NO2 was 20-50 ppb. The nitrogen oxides were oxidized up to their highest oxidation state, nitric acid ( or nitrates) and undesirable nitrous acid was not formed at all. The experimental study conducted showed that the photocatalytic oxidation on the surface of the photocatalytic Protectam FN (R) coating is an effective method for the removal of nitrogen oxides from contaminated air.
Keywords:
TiO2; NOx; imissions; photocatalysis; air purification
Available at various institutes of the ASCR
THE PHOTOCATALYTIC ABATEMENT OF NOX IMISSIONS USING COMMERCIAL FUNCTIONAL COATING WITH POROUS MORPHOLOGY
Titanium dioxide is the most important photocatalysts used for purifying applications. It was the purpose of this study to investigate the photocatalytic activity of commercial Protectam FN (R) ...
Possibilities of Hollow Fiber Microextraction and Voltammetric Detection of Homovanillic acid
Hrdlička, V.; Barek, J.; Navrátil, Tomáš
2016 - English
The contribution deals with hollow fiber liquid phase microextraction (HF-LPME) of homovanillic acid (HVA) and its subsequent voltammetric detection. In HF-LPME, HVA is extracted from acidic sample through thin supported liquid membrane into basic aqueous acceptor solution. Since common electrode materials such as gold, platinum or glassy carbon are only able to detect HVA under acidic or neutral conditions, a new method was developed, utilizing silica gel modified carbon paste electrode (CPE). Reached limit of detection in a 10 μL drop of the HVA extract of pH 13 was 1·10-5 mol L-1.
Keywords:
Hollow-fibers; Liquid phase microextraction; voltammetry
Available at various institutes of the ASCR
Possibilities of Hollow Fiber Microextraction and Voltammetric Detection of Homovanillic acid
The contribution deals with hollow fiber liquid phase microextraction (HF-LPME) of homovanillic acid (HVA) and its subsequent voltammetric detection. In HF-LPME, HVA is extracted from acidic sample ...
Metalothioneiny u drobných volně žijících savců jako bioindikátor znečištění životního prostředí
Křivská, D.; Šestáková, Ivana
2016 - Czech
Metalothioneiny (MT) jsou cysteinem bohaté nízkomolekulární proteiny, schopné vázat esenciální i toxické kovy. Jejich syntéza je indukována přítomností zejména kadmia a zinku, ale také dalších kovů jako Pb, Ni, Hg, Ag a i jinými faktory (např. stres, kortikoidy) 1. Pro práce věnující se studiu biologických funkcí metalothioneinů jako homeostáze, prevence oxidačního stresu, detoxifikace či studie vlivu znečištění životního prostředí na různé živočichy je důležitý celkový obsah metalothioneinů v jednotlivých tkáních 2. U vodních organismů, zejména Mytilus galloprovincialis 3 a Ruditapes decussatus 4 je obsah MT užíván jako bioindikátor znečištění mořské vody a je proto snaha mít obdobnou možnost pro zjišťování kontaminace půdy a životního prostředí. Animals living in the contaminated areas are exposed to elevated concentrations of risk elements. Příbramsko is one of most contaminated sites in Czech Republic. This area is loaded with sources of geological and metallurgical industry influence resulting in extremely high Pb, Cd, and Zn contents in soil. We analyzed eighteen subjects trapped on selected locations, belonging to the species Apodemus sylvaticus and Microtus arvalis. By differential pulse voltammetry and modified Brdička reaction, concentrations of metallothionein (MT) in their livers were measured. The influence of field sample treatment on resulting voltammetric record has been demonstrated. Differences of MT concentrations were found between species and among places of trapping.
Keywords:
Small terrestrial mammals; Příbram region; Brdička reaction
Available at various institutes of the ASCR
Metalothioneiny u drobných volně žijících savců jako bioindikátor znečištění životního prostředí
Metalothioneiny (MT) jsou cysteinem bohaté nízkomolekulární proteiny, schopné vázat esenciální i toxické kovy. Jejich syntéza je indukována přítomností zejména kadmia a zinku, ale také dalších kovů ...
Závislost vodivosti pyridiniových molekul na jejich struktuře
Lachmanová, Štěpánka; Hromadová, Magdaléna; Kolivoška, Viliam; Pospíšil, Lubomír; Gasior, Jindřich; Mészáros, G.; Lainé, P. P.
2016 - Czech
Vývojáři elektronických součástek stojí před palčivým problémem. Podle Moorova zákona 1, empirického pravidla odhadujícího možnosti v miniaturizaci elektronických součástek, již brzy nebude možné pokračovat ve zvyšování výkonu elektronických zařízení při zachování jejich rozměrů. Současná věda navrhuje hned několik možných směrů, jak nahradit doposud sloužící technologie na bázi křemíku. Jednou z nich je vývoj a použití specializovaných molekul 2. The derivates of pyridinium belong to promising group of molecules applicable in molecular electronics. For this purpose, four expanded branched pyridinium compounds were synthetized and the influence of the molecular structure on their electrochemical properties and single-molecule conductances has been studied. The highest values of conductance provided compounds 9-(pyridin-4-yl)benzo[c]benzo[1,2]quinolizino[3,4,5,6-ija][1,6]naphthyridin-15-ium tetrafluoroborate and 3,5-dimethyl-2´,6´-diphenyl-[4,1´:4´,4´´-terpyridin]-1´-ium tetrafluoroborate. By the electrochemical reduction both of these compounds received two electrons in two separated one-electron steps. On the other hand, the compounds 2´,6´-diphenyl-[4,1´:4´,4´´-terpyridin]-1´-ium tetrafluoroborate and 2,6-diphenyl-4-(4-(pyridin-4-yl)phenyl)-[1,4´-bipyridin]-1-ium tetrafluoroborate are reduced by different mechanism and their conductance was lower.
Keywords:
single molecule conductance; expanded pyridinium derivatives; scanning tunneling microscopy break junction
Available at various institutes of the ASCR
Závislost vodivosti pyridiniových molekul na jejich struktuře
Vývojáři elektronických součástek stojí před palčivým problémem. Podle Moorova zákona 1, empirického pravidla odhadujícího možnosti v miniaturizaci elektronických součástek, již brzy nebude možné ...
Oxidation of Bioflavonoids in Respect to their Chemical Structure
Sokolová, Romana; Ramešová, Šárka; Kocábová, Jana; Degano, I.
2016 - English
The electrochemical oxidation of flavone luteolin, flavanone taxifolin and flavonols derived from quercetin was studied by cyclic voltammetry. Only small differences in the chemical structure of bioflavonoids resulted in extremely variable oxidation pathways and products. Products of oxidation and further decomposition were determined by HPLC-ESI-MS/MS and HPLC-DAD.
Keywords:
oxidation; flavonoids; voltammetry
Available at various institutes of the ASCR
Oxidation of Bioflavonoids in Respect to their Chemical Structure
The electrochemical oxidation of flavone luteolin, flavanone taxifolin and flavonols derived from quercetin was studied by cyclic voltammetry. Only small differences in the chemical structure of ...
Voltammetric Behavior of Explosive Potassium Salt of 2,4-Dinitrobenzofuroxan\non Electrodes with Mercury Surface
Šelešovská, R.; Sokolová, Romana; Matyáš, R.; Janíková, L.
2016 - English
Voltammetric behavior of potassium salt of 2,4-dinitrobenzofuroxan (KDNBF) has been\nfirstly studied using hanging mercury drop electrode (HMDE) and silver solid amalgam\nelectrode (AgSAE). Cyclic voltammetry was applied for the measurements of dependences on\npH and scan rate required for the elucidation of the ongoing electrode reactions and\ndifferential pulse voltammetry served for the development of sensitive method for KDNBF\ndetermination.
Keywords:
Potassium salt of 2,4-dinitrobenofuroxan; Hanging mercury drop electrode; voltammetry
Available at various institutes of the ASCR
Voltammetric Behavior of Explosive Potassium Salt of 2,4-Dinitrobenzofuroxan\non Electrodes with Mercury Surface
Voltammetric behavior of potassium salt of 2,4-dinitrobenzofuroxan (KDNBF) has been\nfirstly studied using hanging mercury drop electrode (HMDE) and silver solid amalgam\nelectrode (AgSAE). Cyclic ...
Effect of substrate hydrophobicity on the electrocatalytic behaviour of phthalocyanine
Klusáčková, Monika; Janda, Pavel; Tarábková, Hana
2016 - English
In this work, the electrocatalytic activity of pyridinoporphyrazine mediator deposited on two substrates with different hydrophobicity has been presented. We focused on hydrophobic highly oriented pyrolytic graphite (HOPG) as well as hydrophilic annealed gold electrode (Au111). The immobilization of mediator has been carried out spontaneous adsorption from aqueous solution on electrode surfaces. The different hydrophobicity surface resulted in change the electrocatalytic activities of mediator to hydrogen in aqueous solution. For this purpose, electrochemical, in situ spectroelectrochemical, and ex situ microscopically characterizations have been performed. The detailed comparison of surface morphology, surface coverage, surface roughness parameters, thickness of deposited layers of mediator, and pH solution has been studied.
Keywords:
atomic force microscopy; cyclic voltammetry; electrocatalysis
Available at various institutes of the ASCR
Effect of substrate hydrophobicity on the electrocatalytic behaviour of phthalocyanine
In this work, the electrocatalytic activity of pyridinoporphyrazine mediator deposited on two substrates with different hydrophobicity has been presented. We focused on hydrophobic highly oriented ...
Electrochemical Methods for Determination of Three Tumor Biomarkers for Neuroblastoma: Homovanillic Acid, Vanillylmandelic Acid, and 5-Hydroxyindoleacetic Acid
Makrlíková, A.; Ktena, A.; Fischer, J.; Navrátil, Tomáš; Vyskočil, V.
2016 - English
Tumor biomarkers – homovanillic acid, vanillylmandelic acid, and 5-hydroxyindoleacetic acid – have been determined at a screen-printed carbon electrode in small volume samples. For all measurements, Britton-Robinson buffer (0.04 moll−1, pH 3.0) was used as an optimum medium for all three analytes. Dependences of the peak current on the concentration were linear for all compounds, with the limits of quantification 0.8 μmol∙l–1 for homovanillic acid, 0.2 μmol∙l–1 for vanillylmandelic acid, and 0.2 μmol∙l–1 for 5-hydroxyindoleacetic acid. Depending on the results of the measurements, the future experiments should be performed in human urine.
Keywords:
Screen-printed carbon electrodes; Differential pulse voltammetry; Homovanillic acid
Available at various institutes of the ASCR
Electrochemical Methods for Determination of Three Tumor Biomarkers for Neuroblastoma: Homovanillic Acid, Vanillylmandelic Acid, and 5-Hydroxyindoleacetic Acid
Tumor biomarkers – homovanillic acid, vanillylmandelic acid, and 5-hydroxyindoleacetic acid – have been determined at a screen-printed carbon electrode in small volume samples. For all measurements, ...
Mercury and its Future in the Czech Republic
Navrátil, Tomáš; Vytopilová, M.; Vlčková, Š.; Mrázová, K.; Zakharov, S.; Honsová, Š.; Pelclová, D.
2016 - English
Toxicity of mercury has been discussed for many years by specialists as well as by laymen. Legislative tools connected with measures and conditions concerning the trade, manufacture, use and interim storage of mercury, mercury compounds, mixtures, mercury-added products and the management of mercury waste are currently being prepared. Some suggestions and prepared measurements are mentioned and discussed in this contribution. Of course, it is necessary to differentiate among various forms of it, i.e., metallic form, vapors, amalgams, soluble and insoluble inorganic and organic compounds.
Keywords:
mercury; toxicity odf mercury; Homovanillic acid; Ministry of Environment of the Czech Republic
Available at various institutes of the ASCR
Mercury and its Future in the Czech Republic
Toxicity of mercury has been discussed for many years by specialists as well as by laymen. Legislative tools connected with measures and conditions concerning the trade, manufacture, use and interim ...
Oxidation Mechanism of Rhamnetin, a Bioflavonoid Compound
Ramešová, Šárka; Sokolová, Romana; Degano, I.
2016 - English
The natural flavonoid rhamnetin (2-(3,4-dihydroxyfenyl)-3,5-dihydroxy-7-methoxychromen-4-one) is important bioactive compound. Rhamnetin was studied in aqueous solution by electrochemical methods. The oxidation mechanism proceeds in sequential steps, which correspond to the hydroxyl oxidation of groups in the three aromatic rings. The study is based on in situ spectroelectrochemistry and identification of products by HPLC-DAD and HPLC–ESI MS/MS.
Keywords:
flavonoids; electrochemistry; oxidation mechanism
Available at various institutes of the ASCR
Oxidation Mechanism of Rhamnetin, a Bioflavonoid Compound
The natural flavonoid rhamnetin (2-(3,4-dihydroxyfenyl)-3,5-dihydroxy-7-methoxychromen-4-one) is important bioactive compound. Rhamnetin was studied in aqueous solution by electrochemical methods. The ...
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