Seznam abstraktů 2024: POSTEROVÁ SEKCE B

The main aim of the presented research was to synthesize Ti3C2Tx nanosheets with proper structure, flake size and high capacitance by means of a top-down synthesis approach utilising a large-size Ti3AlC2 (MAX) phase precursor (100 m) for further electroconductive functionalisation of cellulose fabric. Thus, the synthesis parameters were changed, i.e., time, temperature and concentrations of selected etchants, preparing eight stable aqueous dispersions of Ti3C2TX nanosheets plus reference Ti3C2TX (from small-size 40 m MAX precursor). As-synthesised products were characterised using various analytical techniques such as Scanning Electron Microscopy (SEM), X-ray powder Diffraction (XRD) and Dynamic Light Scattering (DLS). In addition, prepared Ti3C2Tx nanosheets were applied to cellulose fabric by an optimised dip-coating procedure, and fabrics' surface morphologies, as well as electrical resistances, were inspected. The obtained SEM and XRD results showed successful preparation of the Ti3C2TX nanosheets, wherein the synthesis parameters influenced their size and morphology. Ti3C2TX applied to cellulose fabric exhibited high electrical conductivity, revealing effective cellulose fabric’ functionalisation and, therefore, indicating the potential use of Ti3C2TX in wearable electronic applications.
Acknowledgements: The results leading to this work were funded by the Slovenian Research and Innovation Agency (ARIS) in the frame of research project no. J2-50087 and a research core program group for Textile Chemistry and Advanced Textile Materials P2-0118 within the Young Researchers Programme.

The incorporation of electroconductive compounds onto the textiles' surfaces leads to the fabrication of flexible electronic textiles (e-textiles) for numerous application fields, i.e., sport, medical, protective, fashion, military, etc. Their long-term functionality during daily usage depends on the sufficient durability of applied electroconductive compounds against washing, which can be significantly improved by the employment of protective layers. Thus, this study investigated the efficacy of different coatings for the protection of Ti3C2Tx MXene nanosheets dip-coated onto cotton fabric against laundering, without essentially influencing the electroconductive properties of MXene-coated fabric. Two Mxene-functionalised samples were protected with three different compounds, i.e., modified acrylate resin (MAR), waterborne polyurethane resin (WPR) and biantennary oligoglycine peptide (tectomer - 2 tailed, T) utilising spray-coating, dip-coating and impregnation procedures, respectively. MXene-functionalised/protected samples were washed up to 20 washing cycles and characterised by the determination of their electrical resistance, mass loss, water contact angle, optical properties and changes in surface morphologies. Based on these results, WPR provided the most suitable protection of MXenes on cotton fabric, followed by MAR, balancing high conductivity with long-term stability. Tectomer is not recommended for MXene protection, due to its low durable performance against harsh washing conditions.
Acknowledgements: The results leading to this work were funded by the Slovenian Research and Innovation Agency (ARIS) in the frame of research project no. J2-50087 and a research core program group for Textile Chemistry and Advanced Textile Materials P2-0118 within the Young Researchers Programme.

Composite materials were produced using polylactic acid (PLA) reinforced with lignocellulosic nanofibers (LCNF) dispersed in polyethylene glycol (PEG). To evaluate the effect of LCNF sources on composite properties, suspensions were made from different pulps, including those containing cellulose exclusively, others with cellulose and hemicellulose, and those with cellulose, hemicellulose, and lignin. Each pulp underwent mechanical and enzymatic pretreatments, and homogenization was performed under a pressure of 700 bar. The resulting LCNF suspensions were mixed with PEG and processed in a mixer at 190°C with PLA. Films were produced through compression molding, with a constant PLA/PEG ratio of 80/20, while LCNF amounts varied. The most favorable outcomes were observed for nanofibers consisting of a blend of cellulose and hemicellulose, with 2.5% (w/w). In this case, the materials' tensile strength and Young's modulus increased by 26% and 102%, respectively, compared to the PLA/PEG matrix. This effect was less noticeable for the other composites. We found that the zeta potential modulus of the suspensions of LCNF containing cellulose and hemicellulose decreased from -57.7 to -12 mV in the presence of PEG, while those that only contained cellulose remained unchanged. It is suggested that PEG binds to the surfaces of hemicellulose. Furthermore, FTIR analysis revealed changes in the carbonyl peaks of PLA and the hydroxyl peaks of LCNF and PEG, indicating the formation of hydrogen bonding interactions. Therefore, the improved mechanical properties of these composites can be attributed to a decrease in the tendency of nanofibers to agglomerate due to a reduced number of available hydroxyl groups on the nanofibers. When the concentration of LCNF was increased to 3.75% (w/w), micrometer-sized fibers were observed in the SEM images, which affected the mechanical properties of the composites. These findings provide important insights for selecting suitable lignocellulosic nanoparticles, paving the way for innovative material solutions.

This work focuses on the research and development of composite multilayered AC electrospun materials for applications in technical, medical, and bioengineering fields. It investigates the effects of AC electrospinning on the thermal properties and morphology of Polyamide 4,6 (PA 4,6), both in its base pellet form and as nanofibrous materials with and without caffeine as a model drug. The high voltage applied during AC electrospinning can influence the crystallinity and thermal behavior of the material. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were employed to analyze thermal transitions, crystallinity, stability, degradation profiles, and as a tool to properly asses the loading of the model drug. Scanning electron microscopy (SEM) was used to examine fiber morphology and material structure. DSC analysis revealed that, compared to PA 4,6 pellets, the pristine nanofibrous material exhibited a decrease in normalized melting enthalpy and a slight increase in melting temperature, while the caffeine-loaded nanofibrous material showed an increase in normalized melting enthalpy and a decrease in melting temperature. TGA confirmed the proper loading of the model drug with initial weight loss corresponding to the PA 4,6:caffeine ratio of 8:2 in solution. The inflection point decreased for both electrospun materials when compared to the pellets. SEM analysis showed smooth, randomly oriented nanofibers, with a reduction in fiber diameter for the caffeine-loaded sample. This study provides clear insights into the effects of AC electrospinning and the addition of a model drug on the thermal properties and fiber morphology of PA 4,6. This serves as a solid base for the next steps in analyzing the release profiles of biologically active substances from composite/layered AC electrospun nanofibrous materials.
ACKNOWLEDGEMENTS: The study was supported by the Czech Health Research Council, project no. NW24-08-00133 "Nanofibrous sutures functionalized by bioactive compounds", provided by the Ministry of Health of the Czech Republic.
This study was supported by the National Competence Centres II program, project no. TN02000018/015 “Technology for the continuous production of multi-layer nanofibrous composite material using the AC electrospinning”, provided by the Technology agency of the Czech Republic.

In general, one of the challenges of chemical analysis is the processing of environmental or medical samples with significant amounts of water or other polar components and high molecular weight analyses. Such samples must undergo a so-called sorbent pretreatment method before analysis (most often by liquid chromatography) to ensure the necessary concentration, purity and overall quality of the sample for analysis. Sorbents made of a mixture of polymeric micro and nanofibres appear to be very interesting for these pretreatments. Polymer fibre sorbents have been made using the Spun-blown - BIAX technology, which, when optimally set up, allows in the case of some polymers the one-step production of a bulky fibre layer containing a homogeneous mixture of micro- and nanofibres. In the structure thus formed, the microfibers provide mechanical stability and sufficient porosity; on the other hand, the nanofibers provide the necessary specific surface area for binding interactions with the analytes. Specifically, fibre sorbents were prepared from polycaprolactone, polybutylene terephthalate and polyamide 6, which exhibit different functional groups and polarity. The extraction properties of the microfibrous and nanofibrous sorbents were tested as part of the extraction centrifugation filters.
ACKNOWLEDGEMENTS: This research was supported by Czech Science Foundation - GAČR through Project No. 23-05586S and also Czech Technological Foundation - TAČR under Project No. FW06010698.
The research was also realised thanks to Student grant support by Project No. SGS-2024-6429 funded by the Ministry of Education, Youth and Sports (CZE) in 2024.

Due to increasing environmental awareness and the encouragement of sustainable development the new biodegradable materials acceptable for the environment were developed. Natural fibers represent sustainable materials, easily available in nature, with several advantages such as low cost, light weight, renewability, biodegradability and high specific properties, so the development of new polymer materials reinforced with natural fibers are gaining increased attention in both the academic and industrial world. Spanish broom is a wild plant that mostly grows in Mediterranean countries and provides exceptionally strong fibers. Polycarbonate (PC) belongs to group of thermoplastic polymers that contain carbonate groups in their chemical structure. In this study composite materials based on polycarbonate (PC) and Spartium junceum (Sj) fiber extracted from the stem of Spanish broom as reinforcement were investigated, the potential application of such materials is in the automobile industry. PC/Sj composites were prepared by mixing Sj fibers in content of 5, 10, 15, and 20 wt.% in the neat PC in a Brabender mixer. The thermal, mechanical, viscoelastic properties as well as structure and the degree of swelling of the prepared PC/Sj composites were investigated, and the characterization was carried out using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), and FTIR-ATR spectroscopy. The glass transition temperature Tg in PC/Sj composites shifted to lower temperatures compared to the neat PC due to the amorphous structure of lignin. Based on the TGA results the thermal stability of the PC/Sj composites decreased as the Sj fibers content increased. DMA results indicated that with an increase in the content of Sj fibers, Tg shifted to lower temperatures, and the stiffness of PC/Sj composites increased. The FTIR analysis results showed the presence of Sj fibers in PC/Sj composites and the overlap of absorption bands of Sj and PC. The obtained results of mechanical properties show that the Sj fibers increased the tensile strength and reduced the elongation of composites. Examination of swelling determined that PC and Sj fibers, as well as their composites are hydrophobic materials that swell only slightly in distilled water.

The conversion of methanol to hydrocarbons (MTH) over H-ZSM-5 zeolites offers an alternative route for hydrocarbon production independent of crude oil. The MTH process transforms methanol into a mixture of olefins, paraffins, and alkylaromatics, with the potential to produce hydrocarbon mixtures rich in gasoline-range components (MTG) or short-chain olefins (MTO). However, MTH processes are generally challenged by issues of selectivity and catalyst deactivation or regeneration [1].
In this study, we investigate the impact of Si- and Al-related framework perturbations (defects) within the regular structure of small crystals of microporous and micro-mesoporous H-ZSM-5 on their catalytic activity, selectivity, and lifetime during methanol conversion to hydrocarbons [1-4]. The results highlight the critical role of a highly regular H-ZSM-5 framework in methanol-to-olefin conversion and suggest that the preparation of micro-mesoporous H-ZSM-5 through desilication with alkaline solution followed by acid leaching of electron acceptor sites significantly enhances catalyst lifetime.
ACKNOWLEDGEMENT: This work was supported The Technology agency of the Czech Republic under Project No. FW10010328. The authors acknowledge the assistance provided by the Research Infrastructure NanoEnviCz, supported by the Ministry of Education, Youth, and Sports of the Czech Republic under Project No. LM2023066.
REFERENCES: 1. P. Sazama et al., Microporous and Mesoporous Materials 143 (2011) 87-96; 2. P. Sazama et al., Angewandte Chemie - International Edition 52 (2013) 2038-2041; 3. J. Brus et al., Angewandte Chemie - International Edition, 54 (2015) 541-545; 4. J. Pastvova et al., ACS Catalysis 7 (2017) 5781-5795.

The soda-lime glass is recognized as one of the best recyclable materials. However, surface contamination of glass waste or bulk impurities in the glass matrix can significantly alter glass properties limiting its direct reuse in the glass industry. As an alternative utilization strategy, the incorporation of waste glass as a partial replacement for sand or binder in concrete-based materials for sustainable construction applications has shown promise. Nevertheless, impurities in glass that may affect the alkalinity of concrete or calcium-silicate-hydrate formation must be carefully considered. For example, when the glass waste is in the form of shards or small fragments (particles), the potential diffusion of metal ions into the environment (e.g., through reaction with rainwater) becomes an important issue.
In this work, we perform wet chemistry treatment on the recycled glass particles obtained from the commercial source. The resulting changes in glass particle properties were analyzed using microscopic and spectroscopic techniques. In particular, changes in the concentrations of Mg, Al, Ca and Na near the particle surfaces were detected, indicating potential to elements release to the environment via leaching. The observed results can be helpful in the explanation of processes at interfacial transition zones in waste glass containing concrete-based materials. The work was supported by the Czech Science Foundation project no 23-05500S.

This investigation delves into the augmentation of urea-furfural resin attributes via the incorporation of bentonite nano-clay at levels of 0.5%, 1%, and 2%, alongside nano-graphene oxide at concentrations of 0.05%, 0.15%, and 0.25% for the fabrication of oriented strand boards (OSB). Critical parameters of the resin, including density, solid content, viscosity, and gelation time, were meticulously evaluated. Advanced analytical techniques such as Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), and X-ray Diffraction (XRD) were employed to scrutinize the interaction of nano-clay and its dispersion within the resin matrix. The shear strength of the resin adhesive was notably enhanced, rising from 1.7 MPa in the control specimen to 2.7 MPa in samples containing 0.5% nano-clay and reaching 2.92 MPa in samples augmented with 0.05% nano-graphene oxide.
Subsequently, the physical and mechanical properties of poplar strand boards fortified with nano-clay and nano-graphene oxide were thoroughly assessed. The outcomes revealed a substantial increase in bending strength, from 55 MPa in the control boards to 83 MPa in boards synthesized with resin incorporating 0.5% nano-clay, and further to 89 MPa in boards containing 0.05% nano-graphene oxide. Furthermore, the internal bond strength exhibited significant improvement, escalating from 0.33 MPa in the control samples to 0.45 MPa in boards with 0.5% nano-clay, and advancing to 0.52 MPa in boards with 0.15% nano-graphene oxide. Viscosity measurements demonstrated an increase from 95 seconds in the control boards to 145 seconds in boards with resin infused with 0.5% nano-clay and to 152 seconds in boards containing 0.05% nano-graphene oxide. The gelation time decreased from 180 seconds for the control boards to 147 seconds for boards with 0.5% nano-clay, and to 160 seconds for boards with 0.05% nano-graphene oxide. Moreover, thickness swelling was reduced from 11.2% in control boards to 6.57% in boards with 2% nano-clay and to 9.17% in boards with 0.25% nano-graphene oxide.
In light of these findings, it is evident that urea-furfural resin, enhanced with 0.5% nano-clay and 0.05% nano-graphene oxide, stands as a superior alternative to urea-formaldehyde resin for OSB production. This improved resin formulation is also highly recommended for applications in the particleboard and fiberboard industries.

With the development of polymer nanocomposites and their application in various industries, it was necessary to be able to adapt the nanocomposites themselves to the design specifications. Thus, machining operations are required to fabricate the composite into its final form. Unlike metals, machining of these materials is more demanding discipline due to the inhomogeneous structure, poor thermal conductivity and the possible occurrence of delamination. These properties particularly affect tool wear, which has an impact on the quality of the machining process and the resulting quality (roughness) of the machined surface.

In this research we investigated the effect of humidity and temperature on the self-cleaning performance of water based TiO2 coatings applied on the surface of hardened cement pastes. P25 titanium dioxide was used for the preparation of stable water suspensions. The suspensions were sprayed on the surface of hardened pastes made of Portland cement. The self-cleaning performance of such treated surfaces was tested using discoloration of rhodamine B applied on the surface under the investigation. The self-cleaning performance under UV irradiation was tested in environmental chambre at the temperatures 10, 20 and 30°C and relative humidity 20, 40, 60 and 80 %RH. The results showed the best performance of the TiO2 coating at temperature 20°C, and 80 %RH.
ACKNOWLEDGEMENTS: This research was supported by the Czech Science Foundation (project 24-10949S), while the infrastructure has been utilized in the frame of project No. CZ.02.01.01/00/22_008/0004631 Materials and technologies for sustainable development within the Jan Amos Komensky Operational Program financed by the European Union and from the state budget of the Czech Republic. Authors also thank to project SP2024/025 (VSB - Technical University of Ostrava).

Heteroatom-doped nanocarbons (HNCs) are attracting attention as electrocatalysts for electric double-layer capacitors and fuel cells. HNCs synthesis has mainly been carried out by adding a heteroatom source during the synthesis and chemical modification of nanocarbons, however the uncontrollable amount and position of doping has been a problem. It is not easy to synthesize hetero-π-conjugated compounds with partial structures of HNCs, and the precise synthesis of HNCs has not progressed. On the other hand, corannulene derivatives are an important class of materials for liquid crystals, molecular tweezers, single-chirality carbon nanotubes. However, corannulene analogues having heteroatoms incorporated into corannulene skeletons have not yet been studied in detail, even though doping of heteroatoms in polycyclic aromatic hydrocarbons is highly important in order to realize new functions by modulating the physical properties and molecular structures of these species. Very recently, corannulene analogues having one nitrogen atom have synthesized, and their bowl-shaped structure and C60 binding behaviour have been revealed. Herein, we report the scalable synthesis of the BN-embedded corannulenes (BN-Cors) in four steps from commercially available compounds. In addition, we report the late-stage diversification of BN-Cors via coupling reactions to provide a variety of arylated derivatives, exhibiting strong blue fluorescence. An organic light-emitting diode (OLED) employing one of the derivatives as an emitter exhibited a high external quantum efficiency and long operational lifetime, indicating the significant potential for the development of efficient and stable OLED materials. The synthetic details, crystal structures, and physical properties of these compounds will be reported in this presentation.

Electrical and optical properties of zinc oxide, in particular the relatively wide direct band gap of ~3.3 eV predetermines ZnO as a photocatalytic material at room temperature. ZnO itself is non-toxic and the hydrothermal growth method we use to prepare its nanostructures is environmentally friendly. These facts contribute to the attractiveness of this material. Recently, we have focused on studying the influence of doping or of plasma surface treatment on the photocatalytic efficiency of ZnO. However, the main disadvantages are the high recombination rate of charge carriers and the poor use of visible light. The solution is the use of ZnO as part of nanocomposites. In the past, ZnO-detonation nanodiamons (DND) composites were studied. The disadvantage of DND is the formation of clusters of different sizes, therefore we focused our attention on the use of HPHT nanodiamonds (NDs). We modified the surface of commercial HPHT NDs by oxidation in order to increase the concentration of hydroxyl-, carbonyl- and carboxyl- functional groups. The resulting ZnO-HPHT NDs composites were synthesized using a dehydration-condensation process between oxygen-containing functional groups on the NDs surface and hydroxyl groups on the ZnO surface.
The prepared nanocomposites were characterized by SEM, AFM, FTIR and PL and tested by photocatalytic dye degradation.
This work was supported by the Slovak Research and Development Agency under the Contract no. DS-FR-22-0035 and Ministry of Education, Youth and Sports of Czech Republic (MEYS) Danube project 8X23025, and the Mobility project CAS-SAS-2022-08 (SAV-23-13) and by the Slovak Scientific Grant Agency (VEGA: 2/0132/23).

While all traditional photovoltaic materials are covalent compounds with coordination number 4, currently the most progressive materials - hybrid halide perovskites - have coordination number 6 and are ionic. We believe that this can be the key to success, especially in terms of surface electronic properties, which are essential for polycrystalline semiconductors. This motivates us to explore completely new materials - cubic lithium thiospinels - and compare them with the former. Li thiospinels are prepared from stoichiometrically mixed precursors in the form of pellet in nitrogen filled glove-box. This tablet serves as a target in Pulsed Laser Deposition (PLD) and a special chamber is constructed that avoids air exposure of the precursor tablet during the loading. Thin films of lithium thiospinels are deposited on glass substrates and they are characterized by X-ray diffraction and optically by Photothermal Deflection Spectroscopy for accurate determination o absorption edge. Results are compared with properties of hybrid halide perovskites.
ACKNOWLEDGEMENTS: The work was supported by Czech Science Foundation grant no. 23-06285S

The development of solar-blind ultraviolet photodetectors represents a significant challenge in the field of electronic devices. For deep-UV optoelectronics (wavelength less than 280 nm), the active material’s bandgap has to be greater than 4.4 eV, leading to the development of ultrawide bandgap semiconductors such as AlxGa1−xN, hBN, Ga2O3, and diamond. While exceptional properties are typically assigned to single-crystalline materials, their high cost and limited availability necessitate alternative solutions. Polycrystalline materials offer a cost-effective solution with tailorable opto-electronic properties and customizable technological processes.
This study focuses on the fabrication of a heterojunction-based UV-sensitive photodetector utilizing highly-textured or polycrystalline n-type Ga2O3 and polycrystalline p-type diamond. Due to the limited research on the technological procedures for this material combination, we investigate two distinct approaches: i) diamond growth on Ga2O3 films and ii) Ga2O3 growth on diamond films. The prepared individual films and heterostructures were characterized by Raman, SEM, TEM, I-V, and optical measurements.
Preliminary results validate the proof-of-concept and demonstrate the viability of both approaches with great potential for continued optimization. Our findings suggest that the next generation of deep-UV solar-blind photodetectors based on polycrystalline Ga2O3/diamond heterojunctions may outperform the current mainstream technologies.
ACKNOWLEDGEMENTS: M.V. acknowledges support from the project IM-2023-87 funded by the Slovak Academy of Sciences via the programme IMPULZ 2023. F.G. acknowledges the funding from International Visegrad Fund (project # 22320095) and Slovak Research and Development Agency (project # APVV-20-0220).

Recently, doped carbon has gained much attention in the fields of electrochemistry and energy storage. However, there is not a universal method to prepare well-defined doped carbon nanostructures. In this work, we report a simple way to obtain nitrogen and phosphorus-doped carbonized polypyrrole nanotubes (NP-cNTs) as a catalyst for ORR and HER reactions, as well as a materials for supercapacitor. First, polypyrrole nanotubes were synthesized and then carbonized under an inert atmosphere to obtain NP-cNTs. The successful synthesis and chemical composition, of the desired structures was confirmed by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy SEM-EDX. The amorphous nature of the obtained materials was confirmed by XRD analysis. The chemical composition was further investigated by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Subsequently, the electrochemical activity was investigated using model reactions of HER and ORR. Both reactions showed enhanced catalytic properties of the NP-cNTs compared to undoped material. Furthermore, the prepared materials demonstrated potential for energy storage applications.
ACKNOWLEDGEMENT: This work was supported by the GACR under project 22-25734S.

Addressing the urgent need for sustainable energy sources, this study investigates the intricate relationship between Rhodium (Rh5) nanoclusters and TiO2 rutile (110) surfaces, aiming to advance photocatalytic water splitting for green hydrogen production. Motivated by the imperative to transition from conventional fossil fuels, the study employs density functional theory (DFT) with DFT-D3 and HSE06 hybrid functional to analyse the geometrical stabilities and electronic structures of Rh5 nanoclusters on TiO2 rutile (110). TiO2, a prominent photocatalyst, faces challenges such as limited visible light absorption, leading researchers to explore noble metals like Rh as cocatalysts. Our results show that bipyramidal Rh5 nanoclusters exhibit enhanced stability and charge transfer when adsorbed on TiO2 rutile (110) compared to trapezoidal configurations. The most stable adsorption induces oxidation of the nanocluster, altering the electronic structure of TiO2. Extending the analysis to defective TiO2 surfaces, the study explores the impact of Rh5 nanoclusters on oxygen vacancy formation, revealing stabilisation of TiO2 and increased oxygen vacancy formation energy. This theoretical exploration contributes insights into the potential of Rh5 nanoclusters as efficient cocatalysts for TiO2 -based photocatalytic systems, laying the foundation for experimental validations and the rational design of highly efficient photocatalysts for sustainable hydrogen production. The observed effects on electronic structures and oxygen vacancy formation emphasize the complex interactions between Rh5 nanoclusters and TiO2 surface, guiding future research in the quest for clean energy alternatives.

Allyl isothiocyanate (AITC) has been recognized for its potent antibacterial and antioxidant properties, positioning it as a promising agent for food preservation. However, its practical application in the food industry is significantly hindered by its high volatility and strong, unpleasant odor. To address these limitations, we utilized the multifunctional attributes of chitosan, a polysaccharide derived from chitin, to stabilize and enhance the efficacy of AITC. The abundance of amino and hydroxyl groups in chitosan chain facilitates strong interactions with AITC, thus achieving high encapsulation efficiency. Additionally, the inherent antibacterial properties of chitosan synergizes with AITC, potentially reducing the required dose for effective microbial inhibition. In this study, AITC-loaded chitosan nanoparticles (AITC-CSNPs) were synthesized using a two-step emulsion-ionic gelation method. Comprehensive characterization of the nanoparticles was performed using Dynamic Light Scattering (DLS) to determine their hydrodynamic size, zeta potential, and polydispersity index, while Scanning Electron Microscopy (SEM) provided detailed insights into their morphology and distribution. Afterwards, the antibacterial properties of AITC-CSNPs were evaluated on prevalent food-borne pathogens through the agar well diffusion assay. The findings indicated that the as-synthesized AITC-CSNPs possessed a sperical shape with nanosize and demonstrated satisfactory antibacterial effects, thereby presenting a viable method for extending the shelf life of perishable food products.
ACKNOWLEDGEMENTS: This study was supported by the VUT Specific Research Project CEITEC VUT-J-24-8615, Brno University of Technology

The escalating global energy demand has significantly contributed to the rise in greenhouse gas emissions, an issue urgently addressed at the 27^th Conference of the Parties, which called for immediate and collective action towards sustainable energy and decarbonization technologies. Given that the fertilizer industry heavily relies on the energy-intensive Haber-Bosch process, which is a major source of CO2 emissions, the future of food security depends on developing sustainable alternatives for ammonia production, a critical fertilizer feedstock. In this work, we present an alternative pathway for ammonia synthesis through electrocatalytic nitrate reduction, utilizing nitrates commonly found in wastewater streams. Our approach focuses on the strategic integration of Single Atom Catalysts (SACs), achieved by coupling single metal atoms with functionalized graphenes. Specifically, we synthesize Cu(I)/Cu(II) mixed-valent species stabilized on N-doped graphene acid. The functionalities on the graphene lattice not only enhance the coordination of metal atoms but also facilitate the reduction of Cu(II) to Cu(I). When applied in electrocatalytic nitrate reduction to ammonia, the Cu(I) sites serve as nucleophilic centers, coordinating H+ and converting it to H*ads, while Cu(II) sites coordinate with nitrates. The subsequent reduction of nitrates by H*ads leads to ammonia formation. This process not only offers a sustainable route for ammonia electrosynthesis but also valorizes wastewater contaminants, reducing the environmental and health risks associated with high nitrate levels.

In the present paper, two different types of materials were used for strontium elimination from an aqueous environment. Bentonite (B) and ladle furnace slag (FS) were modified by iron oxide (FexOy) nano/micro-particles (NPs) with magnetic properties by microwave procedure. Sorption properties, stability and influence of magnetically modified bentonite (MB) and ladle furnace slag (MFS) modification by FexOy NPs were tested. Although the sorption properties of both magnetically modified adsorbents (MB and MFS) were slightly lower than the sorption properties of original B and FS, the Sr elimination from solutions was still effective. The maximum sorption capacity was determined as follows: 24.2 mg/g for B, 20.6 mg/g for MB, 50 mg/g for FS and 35 mg/g for MFS, respectively. The release of FexOy NPs during the sorption experiments was monitored as well. The determined concentration of Fe in solutions after sorption experiments was lower than 0.01 mg/l. The presence of FexOy NPs on the MB and MFS surface after sorption experiments was confirmed by scanning electron microscopy. The MB and MFS were magnetically active and were removed from the solution after sorption using a magnet. The experimental results demonstrated that the FexOy NPs were not released into aqueous solutions during the sorption. Therefore, MB and MFS are stable and promising sorbents for pollutant elimination.

An inkjet printing method was used to fabricate a flexible gas sensor. This fabrication method is characterized by low material consumption, fast design to the fabrication process, and low fabrication cost. Thanks to these properties is this technology still more popular in the fabrication of electronic circuits and devices.
Gas sensors are devices that are generally used to detec the presence, or in a more complex solutions, to measure the concentration of the various gases. The used fabrication technology or material determines sensor properties like sensitivity, selectivity, repeatability, and stability for the application in the general or industrial environment.
In this research, we present the design preparation, fabrication, and characterization of the inkjet printed gas sensor. The structures are based on silver nanoparticle ink and dielectric ink. The structures are printed on a flexible substrate and are sintered with intense pulsed light and UV light, respectively. The printed sensors consist of an Interdigital electrode (IDE) structure, dielectric separation layer, and heater pattern. The IDE structure is printed on the dielectric layer which separates the heating and sensing structures. As a sensing layer, polyaniline is dropcasted on the top of the IDE sensor structures. The inkjet printed sensor was characterized in a term of response to the humidity and testing gas.

Electrospun fibrous membranes are used for the filtration of pollutants from air and water, but continued use can lead to pollutant accumulation and a decrease in effectiveness. To address this issue, we developed polyvinylidene fluoride (PVDF) fibrous membranes modified with photocatalytic graphitic carbon nitride (g-C3N4) particles using three methods: blending, thermal, and chemical. Their photocatalytic efficiency was investigated using phenol as a model pollutant compound under visible light irradiation. The membranes prepared via chemical activation exhibited the highest activity (kapp of 21.7×10-4 min-1) compared to those prepared by the thermal method (kapp of 5.41×10-4 min-1) and blending method (kapp of 2.51×10-4 min-1).
For full membrane characterization, a new non-destructive method was developed to determine the area density differences of g-C3N4 among the methods. The membranes were exposed to LED irradiation (λ = 365 nm) to obtain the photoluminescent emission of the g-C3N4 particles, which was captured by a spectrometer for analysis and compared to a calibration sample with a known area density of g-C3N4. Despite the highest g-C3N4 area density (1.7098 ± 0.0404 mg·cm-2) for the blend method, the photocatalytic activity was the lowest due to particle encapsulation in the polymer fibre. Although, chemical method led to low particle concentration (0.3321 ± 0.0736 mg·cm-2), the covalent bonds between PVDF and g-C3N4 on the fibre surface allow the formation of oxidative species on their surface leading to the highest photocatalytic activity.
ACKNOWLEDGEMENT: This work was supported by the European Union under the REFRESH project number CZ.10.03.01/00/22_003/0000048 and NCK polymery TN7503813.

In this research, we tested the performance of the self-cleaning coatings based on exfoliated g-C3N4 applied on the surface of sandstone. Research activities include: i) preparation of exfoliated g-C3N4, ii) preparation of exfoliated g-C3N4 water suspensions, iii) application of the suspensions on the surface of the sandstone samples, and iv) testing of the self-cleaning performance. Exfoliated g-C3N4 was prepared by thermal exfoliation of bulk g-C3N4 prepared by thermal polycondensation of melamine. Water suspensions of g-C3N4 (XX and XX g/l) were prepared and applied on the surface of the sandstone samples using the spraying technique. Such prepared samples were subjected to the self-cleaning performance test based on the discolouration of rhodamine B under VIS irradiation and constant humidity and temperature. Changes in the the a* coordinate in CIE L*a*b* colour space were used to quantitatively monitor the discolouration of the tested samples.
ACKNOWLEDGEMENTS: This research was supported by the Czech Science Foundation (project 24-10949S) and VSB-Technical University of Ostrava under the project SP2024/025.

For the past few decades, wastewater treatment has become one of the largest worldwide concerns, particularly regarding pharmaceutical contaminants due to an increase in their consumption rate. Graphitic carbon nitride (g-C3N4) is a popular choice in wastewater treatment due to its low-cost preparation method, physiochemical stability and non-toxicity. It has large surface area, porous structure, and photocatalytic activity in visible range. By incorporating g-C3N4 into PA6 nanofibers (“fabric”), our goal was to create a robust and photocatalytically active surface. We employed atmospheric pressure plasma (dielectric coplanar surface barrier discharge) to modify the fabric. We have treated the fabric in ambient air, oxygen, and nitrogen plasma at various times. All the chemical and structural changes were analyzed by SEM, EDX, XRD and XPS. We have used wastewater model with diclofenac, a non-steroidal anti-inflammatory medicine that is used as an analgesic and is taken in around 940 tons annually worldwide. We have also tested real wastewater effluent.
ACKNOWLEDGEMENTS: Authors wish to acknowledge the Czech Science Foundation for supporting financially the research, project No. 23-06843S. This research was also supported by projects LM2023039 and LM2023051 funded by the Ministry of Education, Youth and Sports of the Czech Republic.

Nanoparticles are increasingly becoming part of microalgal biotechnologies. Certain types of nanoparticles are suggested as stimulators for lipid synthesis in microalgal biofuel production. The variety of responses from microalgal cultures depends on many factors, such as the type of nanoparticles, their size, concentration, origin, the duration of contact with microorganisms, the age of the culture, and the cultivation conditions. Another determining factor in the relationship between microorganisms and the presence of nanoparticles in their growth environment is the type of microorganisms. Eukaryotic organisms, such as microalgae, respond differently to nanoparticles than prokaryotic organisms, such as cyanobacteria. A study was conducted to determine the differences in the effects of PVP-stabilized silver nanoparticles on the microalga Porphyridium cruentum and the cyanobacterium Arthrospira platensis. Silver nanoparticles at concentrations ranging from 0.05 mg/L to 5 mg/L were added to the mineral medium from the first day of the cultivation cycle. The microorganism cultures were cultivated under autotrophic conditions. Biochemical tests were performed on the collected biomass. The cyanobacterium Arthrospira platensis reacted to AgNP-PVP by reducing biomass content and showing an insignificant change in structural compounds. Reduced antioxidant levels evidenced stress in cyanobacterial culture. For Porphyridium cruentum, biomass content increased, while lipid and carbohydrate content decreased. Higher malondialdehyde levels indicated stress in microalgal culture. The variety of responses from microalgae and cyanobacteria cultures to silver nanoparticles supports the idea that diverse mechanisms are involved in maintaining viability, which creates the possibility of remodeling biosynthetic activity depending on the intended purpose.
This work was supported by a grant of Ministry of Education and Research of Republic of Moldova, project number 020101.

Ag modified Bi0.5Na0.5TiO3 particles with different concentrations of 0.0, 1%, 3%, and 5% has been synthesised via sol-gel route to explore its catalytic activity. All samples were characterized by X-ray diffraction, Raman, SEM and UV- absorbance spectroscopy. XRD verified that all compositions had a monoclinic phase structure with a Cc space group. To further confirm the phase purity of the samples, the FullPROF program was used for the Rietveld refinement. Raman spectra also confirmed the structure by matching vibrational modes. The particle size ranged from 300 to 400 nm using energy dispersive x-ray spectra (EDX) and scanning electron microscopy (SEM) for morphological and elemental analysis. The optical bandgap for all synthesized particles was determined using UV-vis absorbance spectra, and it was found to be between 3.65-2.63 eV. The best piezo-photocatalytic activity for sample x=0.01 evaluated for rhodamine B dye was around 82%, when subjected to mechanical disturbances and UV light for 80 minutes. In contrast, degradation was approximately 52.4% and 22.7% for photo- and piezocatalysis, respectively. Using the first order rate kinetics equation, kinetics study and rate constant values were determined. Systematic trapping experiments and stability tests were conducted on the catalysts, revealing that the primary active species are superoxide and hydroxyl radicals. A decrease of around 9% in degradation capacity after three cycles was seen as a result of catalyst loss. Less recombination rate, more oxygen vacancies, high degradation yield, high absorption capacity, and optimal bandgap values over the other compositions are found to be responsible for the degradation improvement. Consequently, a unique, effective piezo-photocatalyst for the treatment of organic dyes may be found in a 1% Ag doped BNT sample.