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- ItemContinuous Sustainable Production of Biobased Multicomponent Enhanced Resin for SLA 3D Printing(American Chemical Society, 2025-04-28) Jašek, Vojtěch; Bartoš, Otakar; Lavrinčíková, Veronika; Fučík, Jan; Figalla, Silvestr; Kameníková, Eliška; Přikryl, RadekThis work focuses on biobased reactive diluents' synthesis, continuing with optimized oil-based resin precursor production. Our approach introduces vanillin methacrylate (VanMMA), cinnamyl methacrylate (CinMMA), and vanillyl dimethacrylate (VanDiMMA) synthesis using methacrylic anhydride. The introduced approach involves an innovative and available catalyst, potassium acetate, which possesses much suitable potential compared with the usually used 4-dimethylaminopyridine (DMAP). Moreover, we separated the formed secondary product, methacrylic acid (MA), and used it to modify rapeseed oil to prepare a curable thermoset. All synthesized products were structurally verified via complex cross-analysis (NMR, ESI-MS, and FTIR). The reactive systems were mixed to form a multicomponent mixture appropriate for stereolithography (SLA) and 3D printing. It was found that VanDiMMA exhibited comparable diluting properties to the commercially available and used compound, isobornyl methacrylate (IBOMA), while achieving better mechanical, thermo-mechanical, and thermal properties than IBOMA. VanDiMMA-containing SLA resin reached a tensile strength of 12.7 +/- 0.3 MPa, a flexural strength of 16.8 +/- 0.4 MPa, a storage modulus of 570 MPa at 30 degrees C, a glass-transition temperature of 83.7 degrees C, and the heat-resistant index of 169.5 degrees C.
- ItemApplication of QuEChERS extraction and LC-MS/MS for determination of pharmaceuticals in sewage sludges sampled across the Czech Republic(Springer Nature, 2024-11-09) Landová, Pavlína; Mravcová, Ludmila; Poláková, Šárka; Kosubová, PetraThe use of pharmaceuticals entails a significant risk of environmental contamination. Wastewater treatment plants (WWTPs) are considered to be the main contributors to contamination as they ineffectively eliminate these compounds from wastewater. Simultaneously, they produce solid waste, sludge, which often contains a variety of retained pollutants, including pharmaceuticals. Since sewage sludge is frequently applied to agricultural soil due to its rich nutrient content, pollutants are introduced into the environment in this way. Only a few studies have been carried out on the topic of the analysis of pharmaceuticals in sludge. Therefore, information on the occurrence of pharmaceuticals in sludge is limited. The present study employed quick, easy, cheap, effective, rugged and safe (QuEChERS) extraction and liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS) analysis to establish a simple and reliable procedure for determining 16 pharmaceuticals (antibiotics, anticonvulsants, antidepressants and -blockers) in sewage sludge. The method has been thoroughly validated, and parameters such as linear range, accuracy, precision, matrix effects and detection and quantification limits were assessed. Our method achieved low limits of quantification (0.5–9.0 µg kg1) and satisfactory recoveries (51–101%). Forty sludge samples from different WWTPs across the Czech Republic were analysed. Fourteen compounds were detected and quantified in most samples, with antidepressants having the highest detection frequency and overall content. Sertraline, with a mean concentration of 521.0 µg kg1, was notably prevalent alongside its metabolite norsertraline (mean concentration 204.9 µg kg1). The antibiotic azithromycin was also found at higher levels (mean concentration 185.1 µg kg1).
- ItemThe Effect of Biochar Particle Size on the Leaching of Organic Molecules and Macro- and Microelements(MDPI, 2024-10-11) Bačovská, Šárka; Mravcová, Ludmila; Pořízka, Jaromír; Kubíková, Leona; Kalina, MichalBiochar is a carbon-rich material that has recently received attention due to its increasing agronomical potential. The agricultural utilization of biochar relates to its potential to act in the soil as a soil conditioner; nevertheless, complex information on the direct dependence of biochar’s physical properties (texture, particle size) and corresponding leaching and availability of organic molecules (e.g., the polycyclic and heterocyclic organic compounds) and inorganic mineral salts (based on micro- and macroelements) is still inconsistent. Multi-elemental analysis by using inductively coupled plasma atomic emission spectroscopy (ICP-OES) was used to assess the information on the contents and availability of macro- and microelements in studied commercial biochar samples. The results showed a statistically significant indirect relation between an increase in the size fraction of biochar and the content of aqueous-extractable K and Na and the direct relation with the aqueous-extractable Ca, Mg, and P. Compared to the macroelements, the detected contents of aqueous-extractable microelements were almost three orders lower, and the dependence on fraction size was not consistent or statistically significant. In addition, gas chromatography (GC) coupled with mass spectroscopy (MS) was further used to reveal the concentrations of available polycyclic aromatic and heterocyclic compounds in biochar samples. The detected concentrations of these types of organic compounds were far below the certified limits, and a statistically significant indirect correlation with particle size was also observed for all the studied biochar samples. The proposed methodological concept could provide the necessary insights into the description of biochar mineral content and its connection to biochar texture, the physicochemical properties, and the potential of biochar to release nutrients into the soil. These findings could help in the further assessment of biochar as a soil conditioner in modern agriculture.
- ItemPhotocurable Oil-Based Thermosets Containing Modifiers from Renewable Sources for Coating Applications(AMER CHEMICAL SOC, 2024-10-28) Jašek, Vojtěch; Fučík, Jan; Bartoš, Otakar; Figalla, Silvestr; Přikryl, RadekCoating materials involving nature-inspired compounds or renewable sources have recently attracted vast attention. This article presents the synthesis of modified rapeseed oil (MRO) as a precursor possessing high biobased carbon content suitable for cured thermosets formation. Two reactive diluents based on renewable sources, methacrylated methyl 3-hydroxybutyrate (M3HBMMA) and ethyl 3-hydroxybutyrate (E3HBMMA), were successfully synthesized. Lastly, isosorbide monomethacrylate (MISD) was suggested and produced as a polarity modifier miscible with modified curable oil systems capable of increasing the thermoset surface energy. All synthesized compounds were structurally analyzed via NMR, ESI-MS, and FTIR. The characterized reactive substances were coated on paper, stainless steel, and beech wood to investigate their suitability for forming thin layers. The paper dip coating verified the reactive diluting properties of M3HBMMA, resulting in the average formed coating deviation decrease (87.5% for undiluted MRO and 28.0% for 50 wt % M3HBMMA containing MRO). Also, the additional cured thermoset weight decreased from 350 to 69 wt % for the same systems. The standardized bend test applied on the coated stainless steel specimens revealed the thermoset's flexibility and adhesion increase from a 12 +/- 2 degrees bending angle of 100% pure MRO to a 121 +/- 2 degrees bending angle measured for 40 wt % E3HBMMA containing the MRO-based thermoset. The coated beech wood samples underwent the standardized cross-hatch test investigating the substrate's coating quality. The 100% MRO reached a level 1 rating (second worst), while the system with 40 wt % of MISD obtained a level 5 rating (the best).
- ItemPoly(lactide) Upcycling Approach through Transesterification for Stereolithography 3D Printing(AMER CHEMICAL SOC, 2024-10-02) Figalla, Silvestr; Jašek, Vojtěch; Fučík, Jan; Menčík, Přemysl; Přikryl, RadekThe legislature determines the recycled and waste contents in fabrication processes to ensure more sustainable production. PLA's mechanical recycling and reuse are limited due to the performance decrease caused by thermal or hydrolytic instability. Our concept introduces an upcycling route involving PLA depolymerization using propylene glycol as a reactant, followed by the methacrylation, assuring the liquid systems' curability provided by radical polymerization. PLA-containing curable systems were studied from a rheological and thermomechanical viewpoint. The viscosity levels varied from 33 to 3911 mPas at 30 degrees C, giving a wide capability potential. The best system reached 2240 MPa storage modulus, 164.1 degrees C glass-transition temperature, and 145.6 degrees C heat-resistant index, competitive values to commercial systems. The printability was verified for all of the systems. Eventually, our concept led to SLA resin production containing PLA waste content up to 51 wt %.