Showing papers by "Peter Baláž published in 2015"
15 Sep 2015
TL;DR: Significant increase of the adsorption ability of the eggshell biomaterial toward cadmium was observed upon milling, as is evidenced by the value of maximum monolayer advertisersorption capacity of 329mgg(-1), which is markedly higher than in the case of most "green" sorbents.
Abstract: Significant increase of the adsorption ability of the eggshell biomaterial toward cadmium was observed upon milling, as is evidenced by the value of maximum monolayer adsorption capacity of 329mgg(-1), which is markedly higher than in the case of most "green" sorbents The main driving force of the adsorption was proven to be the presence of aragonite phase as a consequence of phase transformation from calcite occurring during milling Cadmium is adsorbed in a non-reversible way, as documented by different techniques (desorption tests, XRD and EDX measurements) The optimum pH for cadmium adsorption was 7 The adsorption process was accompanied by the increase of the value of specific surface area The course of adsorption has been described by Langmuir, Freundlich and Dubinin-Radushkevich isotherms The adsorption kinetics was evaluated using three models, among which the best correlation coefficients and the best normalized standard deviation values were achieved for the pseudo-second order model and the intraparticle diffusion model, respectively
63 citations
TL;DR: In this paper, a theoretical model of the continuum medium was used to calculate frequencies of the confined optical phonons in ZnS, and the mode at 345 cm −1 was assigned as LO type phonon confined in ZNS nanocrystal.
51 citations
TL;DR: In this paper, nanosuspensions of three arsenic sulfide (As4S4) compounds, commercial synthetic arsenic(II) sulfide, and natural realgar and pararealgar minerals were prepared.
Abstract: In this paper, nanosuspensions of three arsenic sulfide (As4S4) compounds, commercial synthetic arsenic(II) sulfide, and natural realgar and pararealgar minerals were prepared. Nanosuspensions were obtained by ultrafine wet milling in a circulation mill. The zeta potential and particle size distribution were measured for stability estimation. Structural changes were studied using Raman and Fourier transform infrared spectroscopic methods and positron annihilation lifetime method. The morphology of the prepared nanoparticles was determined using scanning and transmission electron microscopy. The anticancer effects were tested using flow cytometry and western blotting analysis. The average particle size in the individual samples varied from 137 to 153 nm. The effects of milling were associated with the formation of arsenic sulfide crystalline nanoparticles and the fragmentation of the corresponding free-volume entities. Consequently, an increase in the arsenic dissolution was observed. The anti-cancer effects of the nanosuspensions were verified on the human cancer H460 cell line, in which case DNA damage and greater numbers of apoptotic cells were observed.
49 citations
TL;DR: The stability of the arsenic sulfide nanosuspension prepared by wet milling in a circulation mill in the environment of copolymer Poloxamer 407 was studied and the best stability was achieved when stored at 4°C and in the dark.
40 citations
TL;DR: In this paper, the first one-step mechanochemical synthesis from elemental arsenic and indium by high-energy milling up to 90 min was presented. But, most of the InAs showed defects, defect-free ones were found as well.
8 citations
TL;DR: In this article, the authors compared the reactivity of three different species of FCS, i.e., polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), and perfluorooctanoic acid (PFOA), and found that PVdF exhibited the highest reactivity, followed by PTFE and PFOA.
Abstract: Interfacial reactions at the surface of SnO2 nanoparticles adjacent to the fluorocarbon solids (FCS) under mechanical stressing were compared in an attempt to their modification by introducing fluorine and carbon. Emphasis was laid on the comparison of the reactivity of 3 different species of FCS, i.e., polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), and perfluorooctanoic acid (PFOA). PVdF exhibited the highest reactivity, followed by PTFE and PFOA, as confirmed by Raman, FT-IR, XPS, and 19F MAS NMR spectra. The preferential reactivity could be explained in terms of the electrophilicity of FCS toward the nucleophilic oxygen in SnO2, since the decomposition of FCS is catalyzed by the coexisting SnO2. PFOA behaved in a different manner, due to its carboxylic groups. At the same time, carbon nanospecies were introduced as a decomposed product of FCS. This results in the formation of SnO2:F/C nanocomposite. Fluorine introduced to SnO2 survived even after heating up to 600 °C either in air or in Ar. This indicates the thermal stability of the present partially fluorinated SnO2 nanoparticles.
4 citations
01 Jan 2015
TL;DR: In this article, two samples of CdS/TiO2 composites have been prepared by single-step solid-state mechanochemical route, and the results of the synthesized composite materials by means of XRD, DRS, PL, SEM, and EDX showed that the particles were attached to titania.
Abstract: Two samples of CdS/TiO2 composites have been prepared by single-step solid-state mechanochemical route. Sample 1 was prepared in a ball mill by mixing commercial TiO2 Degussa P25 with CdS mechanochemically synthesized in advance (cubic hawleyite phase). Sample 2 has been obtained by the mechanochemical synthesis from cadmium acetate and sodium sulphide in the presence of TiO2 Degussa P25. Characterization of the synthesized composite materials by means of XRD, DRS, PL, SEM, and EDX showed that the CdS particles were attached to titania. XRD analysis proved that the rutile TiO2 phase is prevailing in Sample 1, unlike the case of Sample 2, which contained mainly anatase TiO2 phase. UV-vis diffuse reflectance spectroscopy was applied in order to evaluate the band gaps of the synthesized samples. Obtained values of the band gap for the composite CdS/TiO2 samples are lying below the band gap value interval of pure anatase TiO2 phase (3.2 eV) and that of pure CdS (2.42 eV) enabling visible light illumination. The photocatalytic oxidation of ethylene (model air contaminant) was studied both under the effect of UVand under visible light irradiation. It was established that the mechanochemically synthesized CdS/TiO2 shows a higher photocatalytic activity in the oxidation of ethylene under visible light irradiation in comparison with pure titania due to the effect of the CdS component.
1 citations