Pokročilé keramické materiály


Recent Submissions

Now showing 1 - 5 of 48
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    Combination NIPS/TIPS Synthesis of -Fe2O3 and /-Fe2O3 Doped PVDF Composite for Efficient Piezocatalytic Degradation of Rhodamine B
    (MDPI, 2023-10-02) Magomedova, Asiyat; Rabadanova, Alina; Shuaibov, Abdulatip; Selimov, Daud; Sobola, Dinara; Rabadanov, Kamil; Giraev, Kamal M.; Orudzhev, Farid
    Highly porous membranes based on polyvinylidene fluoride (PVDF) with the addition of nanoscale particles of non-magnetic and magnetic iron oxides were synthesized using a combined method of non-solvent induced phase separation (NIPS) and thermo-induced phase separation (TIPS) based on the technique developed by Dr. Blade. The obtained membranes were characterized using SEM, EDS, XRD, IR, diffuse reflectance spectroscopy, and fluorescent microscopy. It was shown that the membranes possessed a high fraction of electroactive phase, which increased up to a maximum of 96% with the addition of 2 wt% of alpha-Fe2O3 and alpha/gamma-Fe2O3 nanoparticles. It was demonstrated that doping PVDF with nanoparticles contributed to the reduction of pore size in the membrane. All membranes exhibited piezocatalytic activity in the degradation of Rhodamine B. The degree of degradation increased from 69% when using pure PVDF membrane to 90% when using the composite membrane. The nature of the additive did not affect the piezocatalytic activity. It was determined that the main reactive species responsible for the degradation of Rhodamine B were (OH)-O-center dot and O-center dot(2)-. It was also shown that under piezocatalytic conditions, composite membranes generated a piezopotential of approximately 2.5 V.
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    Analysis of processing efficiency, surface, and bulk chemistry, and nanomechanical properties of the Monel® alloy 400 after ultrashort pulsed laser ablation
    (IOP Publishing Ltd, 2024-01-01) Ronoh, Kipkurui; Novotný, Jan; Mrňa, Libor; Knápek, Alexandr; Sobola, Dinara
    Monel (R) alloy 400 has excellent corrosion resistance and finds applications in marine industries. The processing of marine components requires high processing efficiency and a quality finish. Hence, this research aims to investigate the effects of the laser processing parameters such as laser fluence, scanning velocity, hatching distance, and the scanning pass on the ablation rates and efficiency, chemistry, and nanomechanical properties of the Monel (R) alloy 400 after pulsed picosecond (ps) laser ablation. From the experimental findings, the ablation depth increases as the laser fluence increases while decreasing as the scanning velocity increases. Surface roughness was noted to increase as the laser fluence increased. The findings demonstrated that the ablation rate increases as laser fluence increases while ablation efficiency decreases. Energy dispersive x-ray spectroscopy (EDX) showed that the elemental composition of laser-ablated zones is almost similar to that of the polished sample. X-ray spectroscopy (XPS) shows that the outer layer on the surface of Monel (R) alloy 400 is composed of NiO and CuO. The hardness and Young's modulus of the laser-processed alloy were found to be less than those of the bulk material. This study can be used to establish optimal processing parameters for the ultrafast ps laser processing of materials to achieve high ablation efficiency with a high-quality surface finish for industrial applications.
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    Oxygen Vacancies and Surface Wettability: Key Factors in Activating and Enhancing the Solar Photocatalytic Activity of ZnO Tetrapods
    (MDPI, 2023-11-15) Orudzhev, Farid; Muslimov, Arsen; Selimov, Daud; Gulakhmedov, Rashid; Lavrikov, Alexankder; Kanevsky, Vladimir; Gasimov, R.D.; Krasnova, Valeryia; Sobola, Dinara
    This paper reports on the high photocatalytic activity of ZnO tetrapods (ZnO-Ts) using visible/solar light and hydrodynamic water flow. It was shown that surface oxygen defects are a key factor in the photocatalytic activity of the ZnO-Ts. The ability to control the surface wettability of the ZnO-Ts and the associated concentration of surface defects was demonstrated. It was demonstrated that the photocatalytic activity during the MB decomposition process under direct and simulated sunlight is essentially identical. This presents excellent prospects for utilizing the material in solar photocatalysis.
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    Carboxymethyl starch as a reducing and capping agent in the hydrothermal synthesis of selenium nanostructures for use with three-dimensional-printed hydrogel carriers
    (ROYAL SOC, 2023-10-11) Vishakha, Vishakha; Abdellatif, Abdelmohsen Moustafa; Michalička, Jan; White, Paul B.; Lepcio, Petr; Tinoco Navarro, Lizeth Katherine; Jančář, Josef
    The hydrothermal method is a cost-effective and eco-friendly route for preparing various nanomaterials. It can use a capping agent, such as a polysaccharide, to govern and define the nanoparticle morphology. Elemental selenium nanostructures (spheres and rods) were synthesized and stabilized using a tailor-made carboxymethyl starch (CMS, degree of substitution = 0.3) under hydrothermal conditions. CMS is particularly convenient because it acts simultaneously as the capping and reducing agent, as verified by several analytical techniques, while the reaction relies entirely on green solvents. Furthermore, the effect of sodium selenite concentration, reaction time and temperature on the nanoparticle size, morphology, microstructure and chemical composition was investigated to identify the ideal synthesis conditions. A pilot experiment demonstrated the feasibility of implementing the synthesized nanoparticles into vat photopolymerization three-dimensional-printed hydrogel carriers based on 2-hydroxyethyl methacrylate (HEMA). When submersed into the water, the subsequent particle release was confirmed by dynamic light scattering (DLS), promising great potential for use in bio-three-dimensional printing and other biomedical applications.
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    Loading of Silver (I) Ion in L-Cysteine-Functionalized Silica Gel Material for Aquatic Purification
    (MDPI, 2023-10-30) Al-Anber, Mohamed A.; Al Ja´afreh, Malak; Al-Momani, Idrees F.; Hijazi, Ahmed, K.; Sobola, Dinara; Sagadevan, Suresh; Al Bayaydah, Salsabeel
    The L-cysteine-functionalized silica (SG-Cys(-)Na(+)) matrix was effectively loaded with silver (I) ions using the batch sorption technique. Optimal Ag(I) loading into SG-Cys(-)Na(+) reached 98% at pHi = 6, 80 rpm, 1 mg L-1, and a temperature of 55 degree celsius. The Langmuir isotherm was found to be suitable for Ag(I) binding onto SG-Cys-Na+ active sites, forming a homogeneous monolayer (R-2 = 0.999), as confirmed by FTIR spectroscopy. XRD analysis indicated matrix stability and the absence of Ag2O and Ag(0) phases, observed from diffraction peaks. The pseudo-second-order model (R-2 > 0.999) suggested chemisorption-controlled adsorption, involving chemical bonding between silver ions and SG-Cys(-)Na(+) surface. Thermodynamic parameters were calculated, indicating higher initial concentrations leading to increased equilibrium constants, negative Delta G values, positive Delta S values, and negative Delta H. This study aimed to explore silver ion saturation on silica surfaces and the underlying association mechanisms. The capability to capture and load silver (I) ions onto functionalized silica gel materials holds promise for environmental and water purification applications.