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    Improvements in the Production of Isosorbide Monomethacrylate Using a Biobased Catalyst and Liquid-Liquid Extraction Isolation for Modifications of Oil-Based Resins
    (AMER CHEMICAL SOC, 2024-05-30) Jašek, Vojtěch; Fučík, Jan; Melčová, Veronika; Přikryl, Radek; Figalla, Silvestr
    The improved production of a polar curable monomer, isosorbide monomethacrylate (MISD), with methacrylic anhydride (MAAH) as an acyl donor, was performed. A sustainable and cheap catalyst, potassium acetate (CH3COOK), was used for a solvent-free synthesis, requiring only the equimolar amount of reagents (no excess). The production included the quantitative separation of the secondary product, methacrylic acid (MAA), preventing the reaction batch from the purification process (neutralization of MAA), and gaining a usable reagent. The synthesis resulted in a sufficient yield of MISD (61.8%) obtained by the liquid-liquid extraction process (LLE), which is a significant improvement in the process, avoiding the flash chromatography step in the isolation of MISD. The purity of synthesized and isolated MISD via the LLE was confirmed by H-1 NMR, MS, and FTIR analyses. The thermal analyses, namely, DSC and TGA, were used to characterize the curability and thermal stability of MISD. The activation energy of MISD's curing was calculated (E-a = 94.6 kJ/mol) along with the heat-resistant index (T-s = 136.8). The polar character of isosorbide monomethacrylate was investigated in a mixture with epoxidized acrylated soybean oil (EASO). It was found that MISD is entirely soluble in EASO and can modify the rheological behavior and surface energy of EASO-based resins. The apparent viscosity of EASO at 30 degrees C (eta(app) = 3413 mPas) decreased with the 50% content of MISD significantly (eta(app) = 500 mPas), and the free surface energy value of EASO (gamma(S) = 42.2 mJ/m(2)) also increased with the 50% content of MISD (gamma(S) = 48.7 mJ/m(2)). The produced MISD can be successfully used as a diluent and the polarity modifier of curable oil-bas
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    Hydrodynamic cavitation-enhanced activation of sodium percarbonate for estrogen removal
    (IWA Publishing, 2023-12-01) Odehnalová, Klára; Přibilová, Petra; Maršálková, Eliška; Zezulka, Štěpán; Pochylý, František; Rudolf, Pavel; Maršálek, Blahoslav
    The present paper investigated the potential of hydrodynamic cavitation (HC) as an effective tool for activating sodium percarbonate (SPC). The method's efficiency was demonstrated by effectively removing estrogens, which are pollutants that have adverse impacts on aquatic ecosystems. The effects of the SPC concentration, temperature of solution, and cavitation time were evaluated. After SPC/HC treatment, the removal of estrogens was monitored by LC-MS/MS. Already after 4 s of treatment and 24 h of reaction time, more than 97% of estrogens (initial concentration of 300 ng/L) were removed. The effect of post-treatment time is not considered in several papers, even though it seems to be crucial and is discussed here. The results were supported by the values of degradation rate constants, which fit the pseudo-first-order kinetic model. We also verified that HC alone was not effective for estrogen removal under the selected conditions. The sustainability of the SPC/HC system was evaluated based on electric energy per order calculation. The combination of SPC and HC is a promising approach for rapidly degrading micropollutants such as estrogenic compounds without the need for additional technological steps, such as pH or temperature adjustment.
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    The Role of Biochar Co-Pyrolyzed with Sawdust and Zeolite on Soil Microbiological and Physicochemical Attributes, Crop Agronomic, and Ecophysiological Performance
    (Springer Nature, 2023-09-14) Mustafa, Adnan; Holátko, Jiří; Hammerschmiedt, Tereza; Kučerík, Jiří; Kintl, Antonín; Baltazár, Tivadar; Malíček, Ondřej; Brtnický, Martin
    The overuse of synthetic fertilizers has been associated with negative environmental consequences. The use of biochar in this regard has been recommended as a win-win strategy. However, our understanding on the comparative influences of biochar prepared from various feedstocks mixed with other bulking agents on soil health and crop performance remained limited. Therefore, in the present study, three types of biochar produced from sewage sludge, food, and agricultural waste were analyzed and compared for their effects on soil enzymes (dehydrogenase, DHA; & beta;-glucosidase, GLU; phosphatase, PHOS; urease, URE; N-acetyl-& beta;-D-glucosaminidase, NAG; and arylsulphatase, ARS), soil basal, as well as substrate-induced respirations and plant growth and physiology characters. The results revealed that food waste-derived biochar co-pyrolyzed with zeolite and/or sawdust was more effective in improving soil physicochemical properties and carbon and phosphorous cycling enzyme (DHA, GLU, and PHOS) activities in addition to soil basal respiration. While the influence of wastewater sewage sludge-derived biochar was more pronounced on urease, N-acetyl-& beta;-D-glucosaminidase, and arylsulphatase enzymes as well as plant biomass accumulation and physiological attributes. Moreover, agricultural waste-derived biochar was found to be effective in enhancing substrate-induced respirations. This study thus concluded that biochar derived from various feedstocks has the tendency to improve soil health and plant growth attributes which further depend on the type of modification prior to pyrolysis.
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    Density of bulk trap states of hybrid lead halide perovskite single crystals: temperature modulated space-charge-limited-currents
    (Springer Nature, 2019-03-04) Pospíšil, Jan; Zmeškal, Oldřich; Nešpůrek, Stanislav; Krajčovič, Jozef; Weiter, Martin; Kovalenko, Alexander
    Temperature-modulated space-charge-limited-current spectroscopy (TMSCLC) is applied to quantitatively evaluate the density of trap states in the band-gap with high energy resolution of semiconducting hybrid lead halide perovskite single crystals. Interestingly multicomponent deep trap states were observed in the pure perovskite crystals, which assumingly caused by the formation of nanodomains due to the presence of the mobile species in the perovskites.
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    Impact of various oxidation processes used for removal of sulfamethoxazole on the quality of treated wastewater
    (KeAi Communications Co., Ltd., 2023-04-17) Tulková, Tereza; Fučík, Jan; Kozáková, Zdenka; Procházková, Petra; Krčma, František; Zlámalová Gargošová, Helena; Mravcová, Ludmila; Sovová, Kateřina
    The objective of this research is to describe the impact of different advanced oxidation processes used for the removal of sulfamethoxazole on wastewater quality. Ozone, UV, a combination of ozone and UV, and plasma discharge were employed. Concentrations of sulfamethoxazole were analysed by LC-MS/MS. Chemical and microbiological analyses and ecotoxicological tests were conducted to investigate the quality of treated wastewater. The results of this study show that the most effective technique for the removal of sulfamethoxazole is O3, followed by plasma discharge, O3 + UV and, finally, UV. A significant effect of tested advanced oxidation processes on the chemical composition of wastewater was not observed; however, the number of microorganisms was reduced. In the case of ecotoxicological tests with Lemna minor and crustacean Daphnia magna, a significant negative effect was only observed when plasma was applied.