Porous silica (SiO 2 ) ceramic with a wood-like structure was prepared by wet impregnation tetrae... more Porous silica (SiO 2 ) ceramic with a wood-like structure was prepared by wet impregnation tetraethyl orthosilicate (TEOS) into biological template that was derived from linden wood (tilia amurensis). After repeated pressure impregnation the subsequent annealing in air ...
Nanometric Bi2O3 powder was successfully synthesized by applying the method based on self-propaga... more Nanometric Bi2O3 powder was successfully synthesized by applying the method based on self-propagating room temperature reaction (SPRT) between bismuth nitrates and sodium hydroxide. X-ray powder diffraction (XRPD) and Rietveld's structure refinement method were applied to characterize prepared powder. It revealed that synthesized material is a single phase monoclinic α-Bi2O3 (space group P21/c with cell parameters a = 5.84605(4)Å, b = 8.16339(6) Å, c = 7.50788(6) Å and β = 112.9883(8)). Powder particles were of nanometric size (about 50 nm). Raman spectral studies conformed that the obtained powder is single phase α-Bi2O3. Specific surface area of obtained powder was measured by Brunauer–Emmet–Teller (BET) method.
The kinetics and mechanism of the hydrogen oxidation reaction were studied in 0.5 mol dm −3 HClO ... more The kinetics and mechanism of the hydrogen oxidation reaction were studied in 0.5 mol dm −3 HClO 4 solution on an electrode based on titanium oxide with Magneli phase structure-supported platinum electrocatalyst applied on rotation Au disk electrode. Pt catalyst was prepared by impregnation method from 2-propanol solution of Pt(NH 3 ) 2 (NO 2 ) 2 and sub-stoichiometric titanium oxide powder. Substiochiometric titanium oxide support was characterized by X-ray diffraction and BET techniques. The synthesized catalyst was analyzed by TEM technique. Based on Tafel-Heyrovsky-Volmer mechanism the corresponding kinetic equations were derived to describe the hydrogen oxidation current-potential behavior on RDE over the entire potential region. The polarization RDE curves were fitted with derived polarization equations according to proposed model. The fitting shows that the HOR on Pt proceeds most likely via the Tafel-Volmer (TV) pathway in the lower potential region, while the Heyrovsky-Volmer (HV) pathway is operative in the higher potential region. It is pointed out that Tafel equation that has been frequently used for the kinetics analysis in the HOR, can not reproduce the polarization curves measured with high mass-transport rates. Polarization measurements on RDE revealed that the Pt catalyst deposited on titanium suboxide support showed equal specific activity for the HOR compared to conventional carbon-supported Pt fuel cell catalyst.
Porous silica (SiO 2 ) ceramic with a wood-like structure was prepared by wet impregnation tetrae... more Porous silica (SiO 2 ) ceramic with a wood-like structure was prepared by wet impregnation tetraethyl orthosilicate (TEOS) into biological template that was derived from linden wood (tilia amurensis). After repeated pressure impregnation the subsequent annealing in air atmosphere at 800 C resulted in burn out of the template and consolidation of the oxide layers. The products exhibit structures corresponding to negative replication of biological templates. X-ray diffraction (XRD), scanning electron microscopy (SEM), infra red (IR), and Brunauer Emmett Teller (BET) measurements were employed to characterize the phases and crystal structure of biomorphic ceramics. It was found that the bio-organic structure was converted into oxide ceramics (SiO 2 ). At low temperature (800 C), pore radius varied between 2 and 10 nm indicating that the samples were mostly mesoporous. Samples treated at higher temperature (1300 C) lost the mesoporous character; however, they were still porous having the microstructural features of the biological perform.
ABSTRACT Ruthenium oxide/titanium oxide, with a Ru:Ti atomic ratio of 7:3 was synthesized by modi... more ABSTRACT Ruthenium oxide/titanium oxide, with a Ru:Ti atomic ratio of 7:3 was synthesized by modified sol–gel procedure and used as a support for platinum nanocatalyst for oxygen reduction reaction. The synthesized materials were characterized in terms of morphology, particle size distribution, chemical and phase composition by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), high angle annular dark filed scanning transmission electron microscopy (HAADF, STEM) and electron energy loss spectroscopy (EELS). XPS spectra revealed that Ru atoms were in mainly in Ru(4+) oxidation state, the Ti atoms in Ti(4+) oxidation state, whereas the Pt-atoms were in metallic state. TEM analysis proved that platinum nanoparticles nucleated at both oxide species and homogeneous distribution was observed. The average platinum nanoparticle size was 3.05 nm.
ABSTRACT The main objective of this work was to find optimal production parameters for the prepar... more ABSTRACT The main objective of this work was to find optimal production parameters for the preparation of activated hemp fibers (ACh) with good adsorption properties toward pesticides. In order to examine the role of manufacturing parameters on ACh surface characteristics, activation process of carbonized hemp fibers was investigated by temperature programmed reaction and evolved gaseous products of activation were monitored by mass spectrometry. ACh samples were characterized by BET surface area, scanning electron microscopy and temperature-programmed desorption. KOH activation induces the reduction of oxygen groups existing on the carbonized hemp fiber surface and the formation of the more stable, predominantly anhydride groups, while porosity development correlates with both H2 and CO, evolved during the activation, and increases with carbonization and activation temperature. Finally, the highest efficiency in pesticides removal was achieved by carbonization of waste hemp fibers and activation at 900 °C with KOH/carbonized material ratio of 2/1. High efficiency in pesticides removal indicates that activated hemp fibers could be successfully used as a sorbent in water purification.
ABSTRACT In water distribution systems (WDS) of developing countries, data about assets and consu... more ABSTRACT In water distribution systems (WDS) of developing countries, data about assets and consumption have great uncertainty. That uncertainty propagates to the performance indicators (PIs), leading to possible incorrect management decisions. To reduce the PI's uncertainty, it is necessary to analyze and reduce errors of each input variable. This paper presents methodology, based on a set of activities, to reduce the uncertainty of water balance components and Infrastructure Leakage Index. The method is tested on the WDS of Požarevac (Serbia) city. The example demonstrates how execution of activities reduced the indicator's uncertainty, although the overall indicator's value wasn’t continuously improving.
Journal of Radioanalytical and Nuclear Chemistry, 2014
Ordered mesoporous carbon (OMC) was used as an adsorbent for the removal of pertechnetate (TcO 4 ... more Ordered mesoporous carbon (OMC) was used as an adsorbent for the removal of pertechnetate (TcO 4 -) anion. The maximum uptake (93 %) of TcO 4 was obtained after 60 min of contact. The adsorption of TcO 4 is almost pH-independent in very wide pH region (from 4.0 to 10.0). Maximum K d of 6.6 9 10 3 cm 3 g -1 was found at pH 2.0. TcO 4 interacts with carboxylic functional groups present at the surface of the OMC by displacing the OHions with TcO 4 via ion exchange mechanism.
Porous silica (SiO 2 ) ceramic with a wood-like structure was prepared by wet impregnation tetrae... more Porous silica (SiO 2 ) ceramic with a wood-like structure was prepared by wet impregnation tetraethyl orthosilicate (TEOS) into biological template that was derived from linden wood (tilia amurensis). After repeated pressure impregnation the subsequent annealing in air ...
Nanometric Bi2O3 powder was successfully synthesized by applying the method based on self-propaga... more Nanometric Bi2O3 powder was successfully synthesized by applying the method based on self-propagating room temperature reaction (SPRT) between bismuth nitrates and sodium hydroxide. X-ray powder diffraction (XRPD) and Rietveld's structure refinement method were applied to characterize prepared powder. It revealed that synthesized material is a single phase monoclinic α-Bi2O3 (space group P21/c with cell parameters a = 5.84605(4)Å, b = 8.16339(6) Å, c = 7.50788(6) Å and β = 112.9883(8)). Powder particles were of nanometric size (about 50 nm). Raman spectral studies conformed that the obtained powder is single phase α-Bi2O3. Specific surface area of obtained powder was measured by Brunauer–Emmet–Teller (BET) method.
The kinetics and mechanism of the hydrogen oxidation reaction were studied in 0.5 mol dm −3 HClO ... more The kinetics and mechanism of the hydrogen oxidation reaction were studied in 0.5 mol dm −3 HClO 4 solution on an electrode based on titanium oxide with Magneli phase structure-supported platinum electrocatalyst applied on rotation Au disk electrode. Pt catalyst was prepared by impregnation method from 2-propanol solution of Pt(NH 3 ) 2 (NO 2 ) 2 and sub-stoichiometric titanium oxide powder. Substiochiometric titanium oxide support was characterized by X-ray diffraction and BET techniques. The synthesized catalyst was analyzed by TEM technique. Based on Tafel-Heyrovsky-Volmer mechanism the corresponding kinetic equations were derived to describe the hydrogen oxidation current-potential behavior on RDE over the entire potential region. The polarization RDE curves were fitted with derived polarization equations according to proposed model. The fitting shows that the HOR on Pt proceeds most likely via the Tafel-Volmer (TV) pathway in the lower potential region, while the Heyrovsky-Volmer (HV) pathway is operative in the higher potential region. It is pointed out that Tafel equation that has been frequently used for the kinetics analysis in the HOR, can not reproduce the polarization curves measured with high mass-transport rates. Polarization measurements on RDE revealed that the Pt catalyst deposited on titanium suboxide support showed equal specific activity for the HOR compared to conventional carbon-supported Pt fuel cell catalyst.
Porous silica (SiO 2 ) ceramic with a wood-like structure was prepared by wet impregnation tetrae... more Porous silica (SiO 2 ) ceramic with a wood-like structure was prepared by wet impregnation tetraethyl orthosilicate (TEOS) into biological template that was derived from linden wood (tilia amurensis). After repeated pressure impregnation the subsequent annealing in air atmosphere at 800 C resulted in burn out of the template and consolidation of the oxide layers. The products exhibit structures corresponding to negative replication of biological templates. X-ray diffraction (XRD), scanning electron microscopy (SEM), infra red (IR), and Brunauer Emmett Teller (BET) measurements were employed to characterize the phases and crystal structure of biomorphic ceramics. It was found that the bio-organic structure was converted into oxide ceramics (SiO 2 ). At low temperature (800 C), pore radius varied between 2 and 10 nm indicating that the samples were mostly mesoporous. Samples treated at higher temperature (1300 C) lost the mesoporous character; however, they were still porous having the microstructural features of the biological perform.
ABSTRACT Ruthenium oxide/titanium oxide, with a Ru:Ti atomic ratio of 7:3 was synthesized by modi... more ABSTRACT Ruthenium oxide/titanium oxide, with a Ru:Ti atomic ratio of 7:3 was synthesized by modified sol–gel procedure and used as a support for platinum nanocatalyst for oxygen reduction reaction. The synthesized materials were characterized in terms of morphology, particle size distribution, chemical and phase composition by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), high angle annular dark filed scanning transmission electron microscopy (HAADF, STEM) and electron energy loss spectroscopy (EELS). XPS spectra revealed that Ru atoms were in mainly in Ru(4+) oxidation state, the Ti atoms in Ti(4+) oxidation state, whereas the Pt-atoms were in metallic state. TEM analysis proved that platinum nanoparticles nucleated at both oxide species and homogeneous distribution was observed. The average platinum nanoparticle size was 3.05 nm.
ABSTRACT The main objective of this work was to find optimal production parameters for the prepar... more ABSTRACT The main objective of this work was to find optimal production parameters for the preparation of activated hemp fibers (ACh) with good adsorption properties toward pesticides. In order to examine the role of manufacturing parameters on ACh surface characteristics, activation process of carbonized hemp fibers was investigated by temperature programmed reaction and evolved gaseous products of activation were monitored by mass spectrometry. ACh samples were characterized by BET surface area, scanning electron microscopy and temperature-programmed desorption. KOH activation induces the reduction of oxygen groups existing on the carbonized hemp fiber surface and the formation of the more stable, predominantly anhydride groups, while porosity development correlates with both H2 and CO, evolved during the activation, and increases with carbonization and activation temperature. Finally, the highest efficiency in pesticides removal was achieved by carbonization of waste hemp fibers and activation at 900 °C with KOH/carbonized material ratio of 2/1. High efficiency in pesticides removal indicates that activated hemp fibers could be successfully used as a sorbent in water purification.
ABSTRACT In water distribution systems (WDS) of developing countries, data about assets and consu... more ABSTRACT In water distribution systems (WDS) of developing countries, data about assets and consumption have great uncertainty. That uncertainty propagates to the performance indicators (PIs), leading to possible incorrect management decisions. To reduce the PI's uncertainty, it is necessary to analyze and reduce errors of each input variable. This paper presents methodology, based on a set of activities, to reduce the uncertainty of water balance components and Infrastructure Leakage Index. The method is tested on the WDS of Požarevac (Serbia) city. The example demonstrates how execution of activities reduced the indicator's uncertainty, although the overall indicator's value wasn’t continuously improving.
Journal of Radioanalytical and Nuclear Chemistry, 2014
Ordered mesoporous carbon (OMC) was used as an adsorbent for the removal of pertechnetate (TcO 4 ... more Ordered mesoporous carbon (OMC) was used as an adsorbent for the removal of pertechnetate (TcO 4 -) anion. The maximum uptake (93 %) of TcO 4 was obtained after 60 min of contact. The adsorption of TcO 4 is almost pH-independent in very wide pH region (from 4.0 to 10.0). Maximum K d of 6.6 9 10 3 cm 3 g -1 was found at pH 2.0. TcO 4 interacts with carboxylic functional groups present at the surface of the OMC by displacing the OHions with TcO 4 via ion exchange mechanism.
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Papers by Biljana Babic