D. Jovanović

University of Belgrade, Beograd, Central Serbia, Serbia

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Publications (48)51.52 Total impact

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    ABSTRACT: The influence of Ni on the electrochemical performance of Fe containing bentonite-based electrode materials was investigated in the electrochemical oxidation of phenol in acidic solution. Clay originated from Mečji Do, Serbia, was submitted to pillaring. Mixed pillaring solutions containing Al3+ and Fe3+ or Al3+, Fe3+ and Ni2+ were used for this purpose. The XRD, chemical and FTIR analysis and nitrogen physisorption at -196 °C were used for sample characterization. The electrochemical behavior of the pillared clay-based electrodes was tested by cyclic voltammetry. The results confirmed that the pillaring was successful. The presence of Ni in the electrode material enhanced the electrode stability. It is possible that the presence of Ni restricted the electrode fouling caused by the formation of polymeric products during the electrooxidation of phenol.
    Electrochimica Acta 10/2014; 144:92–99. · 4.09 Impact Factor
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    ABSTRACT: In this article partial and complete substitution of cations in the interlayer region of clay with different amounts of hexadecyl trimethylammonium bromide (HDTMABr) was performed. The aim was to investigate the influence of HDTMA/bentonite ratio on phenol electrooxidation. Multisweep cyclic voltammetry was applied to analyze the behavior of clay modified glassy carbon electrode. The influence of phenol concentration was investigated. HDTMA/clay ratio plays key role in phenol oxidation on these electrodes. There is definite amount of surfactant that should be present in bentonite sample in order to achieve good current response and prolonged life of the electrode. The reaction order in respect to phenol was determined to be around 2. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 1124–1128, 2013
    Environmental Progress & Sustainable Energy 12/2013; 32(4). · 0.87 Impact Factor
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    ABSTRACT: Removal of two different dyes: Acid Orange 10 (AO10) and Reactive Black 5 (RB5) from their aqueous solutions using organobentonite as adsorbent was investigated. The experiments were carried out at different temperatures (298, 313, 323, and 333 K) in order to obtain thermodynamic parameters for adsorbate/adsorbent system i.e., activation energy, Gibbs free energy, enthalpy and entropy. The results of thermodynamic studies indicated that the adsorption of both dyes onto organobentonite is an endothermic process, while the values for activation energies (76 kJ mol−1 for AO10 and 51 kJ mol−1 for RB5) indicated that chemisorption occurred.
    Russian Journal of Physical Chemistry 12/2013; 87(13). · 0.49 Impact Factor
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    ABSTRACT: The aim of this study was to obtain enhanced textural properties of macroporous crosslinked copolymer poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) by synthesizing nanocomposites with acid-modified bentonite. Nanocomposites were obtained by introducing various amounts of acid-modified bentonite (BA) into the reaction system. All samples were characterized by attenuated total reflectance infrared spectroscopy, scanning electron microscopy, transmission electron microscopy (TEM), mercury intrusion porosimetry, and low temperature physisorption of nitrogen. The FTIR and TEM analysis confirmed incorporation of BA into the copolymer structure and the successful formation of nanocomposites. TEM images confirmed formation of nanocomposites having both intercalated and exfoliated acid-modified bentonite in copolymer matrix. A significant increase of specific surface area, pore volume, and porosity of the nanocomposites in comparison to the copolymer were obtained. The difference between textural properties of nanocomposites with different amounts of incorporated acid-modified bentonite was less prominent.
    Polymer Bulletin 01/2013; 70(6). · 1.33 Impact Factor
  • Journal of the Serbian Chemical Society 01/2013; · 0.91 Impact Factor
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    ABSTRACT: Phenol and its derivatives are regarded as 'priority pollutants' and p-nitrophenol (p-NP), in particular, is of great interest due to its toxicity and frequent presence in waste waters and fresh waters. Straightforward, inexpensive methods to identify p-NP in water, however, is lacking. In the present study, an electrochemical technique using clay-modified electrodes to measure p-NP was investigated as a potentially promising method to fill that gap. A glassy carbon electrode (GCE) was modified with a thin layer of Na-enriched bentonite and a series of benzyltrimethylammonium (BTMA+)-bentonites (BTMA+-B) in order to confirm these materials as p-NP electrosensitive. A series of organobentonites was synthesized using different BTMA+/bentonite ratios. The materials obtained were characterized using X-ray diffraction, Fourier-transform infrared spectroscopy, and a low-temperature nitrogen adsorptiondesorption method. A monolayer arrangement of BTMA+ within the interlamellar region of beidellite-rich smectite was confirmed. Deterioration of the textural properties was observed with increase of BTMA+ loading. The electro-oxidation of p-NP in an acidic medium on BTMA+-B-modified GCE was investigated. The cyclic voltammetry method with a three-electrode cell was used. The reference electrode was Ag/AgCl in 3 M KCl and a Pt foil was the counter electrode. For each electrochemical measurement, a different BTMA+ loading in BTMA+-B was used as the material for GCE coating and applied as the working electrode. The electrochemical activity of BTMA+-B-based electrodes increased with BTMA+ loading. The results confirmed that the organophylic character of the BTMA+-B-modified surface was the main influence on the electrochemical activity of the BTMA+-B-based GCE; the influence of textural properties was almost negligible. The increased electrode activity toward p-NP was achieved by the adsorption of p-NP on the electrode surface, the process that commonly precedes the electro-oxidation. The present study showed that synthesized materials could potentially be used in an electrochemical test for the presence of p-NP in water solutions.
    Clays and Clay Minerals 01/2012; 60:291. · 1.11 Impact Factor
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    ABSTRACT: The partial and complete substitution of cations in the interlayer region of clay with different amounts of hexadecyl trimethylammonium bromide (HDTMABr) was performed. The aim was to synthesize organo-bentonites to be used as constituents of porous electrodes for the electrooxidation of phenol. Domestic clay from Bogovina was subjected to a common procedure of the production of organo-bentonites. It included the following steps: grinding, sieving, Na-exchange, cation exchange and drying. The samples were characterized by X-ray diffraction (XRD) analysis, while the textural properties were evaluated by nitrogen physisorption. The multisweep cyclic voltammetry was applied to analyze the behavior of the clay modified glassy carbon electrode. The influences of the surfactant loading and pH of the support electrolyte were investigated. Rapid deactivation of electrodes occurred in an acidic environment, while good stability of the investigated electrodes was obtained in alkaline medium.
    Journal of hazardous materials 08/2011; 194:178-84. · 4.33 Impact Factor
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    ABSTRACT: In this study, macroporous composites of poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) i.e. poly(GMA-co-EGDMA) and clay were prepared by radical suspension copolymerization. The composites with either raw (S0) or acid-modified clay (SA) were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric (TG) and textural analysis. The morphological, textural and thermal properties of the composite with raw clay (CP-S0) differed slightly from those of the copolymer (CP), with exception of the thermal stability expressed in the shifting of the initial degradation temperature from 125°C for CP to 210°C for CP-S0. On the other hand, composite with modified clay (CP-SA) was a material with significantly changed morphology, porous structure parameters and a qualitatively different thermal behavior in comparison to CP and CP-S0. CP-SA had mass residue, after heating at 600°C, three times higher than the amount of SA introduced into the reaction system. This indicates a different manner of incorporation of SA, compared to S0, into the composite. Both the obtained composites retained their macroporosity and might be used in all applications that involve macroporous copolymers and, due to the altered thermal properties, their application may be extended.
    Materials Chemistry and Physics 07/2011; 128(1):291-297. · 2.07 Impact Factor
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    ABSTRACT: Technological development brought a number of advantages and conveniences to the modern life, but also brought many problems, environment pollution above all. Although a number of methods for water refining are already developed, there is still a demand to find a more efficient, cheaper and ecologically more acceptable sorbents. Possibility of using bentonite as naturally occurring material for methylene blue (MB) removal from its aqueous solutions was investigated in this paper. Characterization of starting material has been conducted by chemical analysis, XRD, particle size analysis, and N2 physisorption at –196°C. The influence of the acidity of the initial MB solution on bentonite sorption characteristic was examined. Equilibrium sorption isotherms were determined. It was shown that with increase of pH and temperature the amount of sorbed MB increases.
    01/2011;
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    ABSTRACT: Ni/SiO2 materials with identical composition (SiO2/Ni = 1.0) have been synthesized by precipitation of Ni(NO3)2 · 6H2O solution with Na2CO3 solution on the silica gel, obtained at three different pH values. The present investigation was undertaken in an endeavor to study the effects of the silica gel support type and the reduction temperature on the formation and dispersion of the metallic nickel phase in the reduced Ni/SiO2 precursors of the vegetable oil hydrogenation catalyst. The physicochemical characterization of the unreduced and reduced precursors has been accomplished appropriately by powder X-ray diffraction, infrared spectroscopy, temperature programmed reduction and H2-chemisorption techniques. It can be stated that the texture peculiarities of the silica gels used as supports influence on the crystalline state and distribution of the deposited Ni-containing phases during the preparation of the precursors, on the reduction temperature of the investigated solids as well as on the bulk size and surface dispersion of the arising metallic nickel particles. It was shown that two types of Ni2+-species are formed during the synthesis procedure, namely basic nickel carbonate-like and Ni-phyllosilicate with different extent of presence, location and strength of interaction. The different location of these species is supposed to result in various strength of Ni-O and Ni-O-Si interaction, thus determining the overall reducibility of the precursors. It was specified that the Ni2+-species are strongly bonded to the surface of the silica gel obtained at neutral pH value and weakly bonded to the surface of those prepared in acidic and alkaline conditions. It was established that the precursor, derivates from the silica gel obtained at alkaline conditions, demonstrates both significant reduction of the Ni2+ ions at 430°C and finely dispersed metallic nickel particles on its surface. High dispersion of the metallic nickel might be the crucial reason for achieving of high activity in the vegetable oil hydrogenation.
    Russian Journal of Physical Chemistry 01/2011; 85(13):2392-2398. · 0.49 Impact Factor
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    ABSTRACT: Bentonite was modified by the exchange of inorganic cations with hexadecyl trimethylammonium, dodecyl trimethylammonium or tetramethylammonium cation. The obtained materials were characterized by physisorption of nitrogen and X-ray diffraction analysis. Multisweep cyclic voltammetry was applied to analyze phenol response on different organo bentonite-based electrodes. The aim of the investigation was to determine the influence of the type of modifying agent on the electrochemical performance of the investigated electrodes. All electrodes exhibited similar electrochemical behavior but with different intensities of the electrochemical response and Tafel slopes. The difference in Tafel slopes reflected different level of involvement of pores in the phenol electrooxidation.
    Applied Clay Science - APPL CLAY SCI. 01/2011; 53(2):331-335.
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    ABSTRACT: In order to enhance nickel effectiveness for methanol oxidation reaction, zeolite type 13X was used as a support for nickel nanodispersion. Nickel modified samples were characterized by XRD, SEM and nitrogen adsorption-desorption measurements. The incorporation of nickel into zeolite cavities led to the partial destruction of the zeolite framework. Modified zeolite was used as the electrode material for methanol oxidation in a deaerated 0.1 M NaOH aqueous solution. It showed similar electrochemical behavior to that of polycrystalline nickel. The destruction of zeolite structure probably enabled aluminum from the framework to stabilize α-Ni(OH)2. Mixture of β- and γ-NiOOH was obtained at the 13XNi100 electrode after cycling in alkaline solution. It was concluded from the electrochemical measurements that β-NiOOH was preferable oxide form for methanol oxidation.
    Fuel and Energy Abstracts 01/2011; 36(21):13343-13351.
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    ABSTRACT: Sandwich-like composites based on clays and textiles are extensively applied in various fields, including civil engineering and environmental protection. In this paper, the synthesis of a new type of composite with embedded bentonite particles within a non-woven polyester matrix is presented. The synthesized com-posite has improved mechanical properties compared to the corresponding non--woven matrix. Although more than two-times thinner, the synthesized composite showed mechanical properties similar to those of a commercial composite chosen for comparison. Sorption test results confirmed that the contribution of the textile component to the sorption of aqueous Cu(II) ions by the composite was negligible. The sorption of aqueous Cu(II) ions on the synthesized composite was best-fitted using the Langmuir model. The presented study confirmed that the loss of bentonite particles from the composite can be eliminated using the suggested synthesis method.
    Journal of the Serbian Chemical Society 01/2011; 11:1411. · 0.91 Impact Factor
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    ABSTRACT: Bentonite was pillared with Al, Al-Cu, Al-Fe or Al-Co poly(hydroxo metal) cations for electrochemical oxidation of phenol in acidic solution. Multisweep cyclic voltammetry was applied to analyze the behavior of the bentonite modified glassy carbon electrode. The influence of pillaring on the electrocatalytic properties was investigated. Reactivation of the electrodes after prolonged phenol oxidation was performed by cathodisation at -2 V.
    Applied Clay Science 06/2010; 49:84-89. · 2.34 Impact Factor
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    ABSTRACT: Partial substitution of the interlayer cations of a local bentonite (Bogovina) by hexadecyl trimethylammonium ions (HDTMA) was performed to prepare adsorbents able to simultaneously adsorb toxic metal cations and organic pollutants.Acid Orange10 adsorption increased with increasing HDTMA addition, while the adsorption of Pb2+ decreased with increasing organophilicity. The adsorption of the dye and Pb2+ and their mixture onto Na-rich bentonite and HDTMA-bentonites, regardless of adsorbents' organophilicity, obeyed the pseudo-second-order kinetics model.
    Applied Clay Science 01/2010; 47:452-456. · 2.34 Impact Factor
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    ABSTRACT: The influence of aluminosilicate support on the catalyst efficiency was investigated. Three different aluminosilicate materials containing cobalt (II) ion as active specie for phenol or nitrite oxidation were obtained. The first sample was zeolite 13X impregnated with Co by impregnation/thermal degradation procedure using Co-acetylacetonate. Bentonite was pillared with Al3+/Co2+ mixture to obtain the second sample. For the third one Co was introduced into Al-pillared bentonite by ion-exchange using Co(NO3)2*6H2O. Reactions of either phenol or nitrite oxidation were used as test reactions for the investigation of the influence of the type of aluminosilicate support on the catalytic activity of Co.
    Applied Clay Science - APPL CLAY SCI. 01/2010; 48(1):179-184.
  • European Psychiatry 01/2010; 25:1718-1718. · 3.29 Impact Factor
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    ABSTRACT: The aim of this study was to investigate the influence of different components of interpenetrating polymer networks (IPNs) on their behavior in dual curing automotive applications. Dual curing is one of possible ways to obtain fast curing, scratch resistant coatings for use in OEM and car refinish applications. Dual curing systems, upon hardening, represent interpenetrating networks (IPNs) [1]. IPN's were obtained using novel acrylate-terminated hyperbranched polyester with high functionality and compared to classical 2-pack polyurethane clear coat.In our previous manuscript [1] we investigated the influence of the acrylated hyperbranched polyester (HBP(A)) content in dual curing systems. In this article we studied the influence of the reactive diluent on dual curing compositions. To this end, we have chosen IPN with 50/50 weigth ratio of polyurethane (PU) and polyacrylic (PA) component. In order to determine more clearly the role of the HBP(A) in one IPN HBP(A) was changed with hexane diol diacrylate (HDDA), keeping the same ratio with EHA.The IPNs were characterized by dynamic-mechanical analysis (DMA), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The mechanical properties of the IPNs were also investigated. The IPN with HDDA as reactive diluent, had the best performance. IPN with HBP(A) had the highest glass transition temperature Tg and the highest crosslink density, but it did not have the highest hardness.
    Progress in Organic Coatings - PROG ORG COATING. 01/2010; 68(4):293-298.

Publication Stats

83 Citations
51.52 Total Impact Points

Institutions

  • 2000–2013
    • University of Belgrade
      • • Department of Catalysis and Chemical Engineering
      • • Institute for Chemistry, Technology and Metallurgy
      Beograd, Central Serbia, Serbia
  • 2008–2009
    • Institute of Chemistry, Technology and Metallurgy
      Beograd, Central Serbia, Serbia