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The manuscript describes the key aspects of Zn-Al mixed oxides prepared by different methods (the so-called urea method and co-precipitation methods using either NaOH/Na2CO3 alkaline solution or solution of NaOH) affording high conversion and selectivity values in aldol condensation of furfural with acetone. The structure, composition and acid-base properties of Zn-Al mixed oxides were described by using of TGA, XRD, N2-adsorption, TPD-NH3/CO2 and in-situ diffuse reflectance spectroscopy and correlated with the catalytic performance of a series of Zn-Al mixed-oxides catalysts. Along with the impact of specific surface area and basicity on the furfural conversion, the conversion of furfural also increased with the increasing value of the edge of UV-vis spectrum of Zn-Al mixed oxide reflecting ZnO-Al2O3 interaction. We have introduced a simple method based on diffuse reflectance spectroscopy with a potential to predict furfural conversion over Zn-Al mixed oxides in aldol condensation of furfural with acetone.

Manuscript focuses on the role of N-doping on photocatalytic behaviour of N-La/TiO2 materials in decomposition of methanol-water solution. N-La/TiO2 materials were prepared with approximately the same amounts of La (0.14-0.16 wt%) and different amounts of N (0.33-0.97 at. % of surface nitrogen). Addition of small amount of surface nitrogen significantly increased the amount of hydrogen produced for N-La/TiO2 photocatalysts in contrast to TiO2 and La/TiO2. The chemical composition (XRF, AAS, XPS), structural (XRD, Raman, XPS, TEM), textural (N-2-adsorption) and optical properties (DRS) were studied. N-La/TiO2 materials showed approximately the same specific surface area and crystallite size, with values ranging for La/TiO2 and N/TiO2 photocatalysts. For studied N-La/TiO2 photocatalysts, the photocatalytic activity increased with the increasing amount of surface nitrogen (interstitial positions, XPS), and subsequently with increasing amount of oxygen vacancies (Raman spectroscopy) and decreasing amount of surface oxygen species (surface lattice O species and hydroxyl groups evidenced by XPS). Práce je zaměřena na roli N dopingu na fotokatalytické chování N-La/TiO2 materiálů při roykladu vodného roytoku metanolu. Přídavek malého množství povrchového dusíku významně ovlivnil množství produkovaného vodíku během fotokatalytického rozkladu.

The influence of He atmosphere and gate width in laser-induced breakdown spectroscopy (LIBS) determination of fluorine concentration was investigated in detail. The measurements were realized on two double pulse LIBS devices featuring different parameters. Calibration curves, describing the relationship between the fluorine concentration and the corresponding intensity of the LIBS signal, were constructed for both LIBS devices, with and without He flow, respectively. Detection limits achieved were in the range 1.18-0.47 wt.%. The best LOD value was obtained in He atmosphere. The LIBS measurement of fluorine content is influenced by different gate widths and the atmosphere in the working chamber. The proposed method was successfully applied to the determination of fluorine concentration in glass ionomer cements.

The composition of the surface layer of 13 low-cost jewelry samples with a high Cd content was analyzed using an energy-dispersive X-ray fluorescence spectrometer (ED XRF). The analyzed jewels were obtained in cooperation with the Czech Environmental Inspectorate. The jewels were leached in two types of artificial sweat (acidic and alkaline) for 7 days. Twenty microliters of the resulting solution was subsequently placed on a paper carrier and analyzed by an LIBS (Laser-Induced Breakdown Spectrometry) spectrometer after drying. The Cd content in the jewelry surface layer detected by using ED XRF ranged from 13.4% to 44.6% (weight per weight—w/w). The samples were subsequently leached in artificial alkaline, and the acidic sweat and leachates were analyzed using laser-induced breakdown spectrometry (LIBS). The amount of released Cd into alkaline sweat ranged from 24.0 to 370 µg Cd per week, respectively 3.23–61.7 µg/cm2/week. The amount of released Cd into acidic sweat ranged from 16.4 to 1517 µg Cd per week, respectively 3.53–253 µg/cm2/week. The limit of Cd for dermal exposure is not unequivocally determined in the countries of the EU (European Union) or in the U.S. Based on the US EPA (United States Environmental Protection Agency) approach used to establish the reference dose (RfD) for Cd contained in food and information about the bioavailability of Cd after dermal exposure, we assessed our own value of dermal RfD. The value was compared with the theoretical amount of Cd, which can be absorbed into the organism from jewelry in contact with the skin. The calculation was based on the amount of Cd that was released into acidic and alkaline sweat. The highest amount of Cd was released into acidic sweat, which represents 0.1% of dermal RfD and into alkaline sweat, 0.5% of dermal RfD. These results indicate that the analyzed jewelry contains Cd over the limit for composition of jewelry available within the territory of the EU. The determined amount of Cd in analyzed jewelry does not, however, pose a threat in terms of non-carcinogenic toxic effects.