Željko Radovanović
University of Belgrade
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Featured researches published by Željko Radovanović.
Carbohydrate Polymers | 2018
Aleksandra R. Nesic; Milan Gordić; Sladjana Z. Davidović; Željko Radovanović; Jovan M. Nedeljković; Irina Smirnova; Pavel Gurikov
Environmental-friendly pectin-TiO2 nanocomposite aerogels were prepared via sol-gel process and subsequent drying under supercritical conditions. The first step includes dissolution of pectin in water, addition of proper amount of TiO2 colloid and crosslinking reaction induced in the presence of tert-butanol and zinc ions. Then, the gels are subjected to the solvent exchange and supercritical CO2 drying. The influence of TiO2 nanoparticles on the textural, mechanical, thermal and antibacterial properties of aerogels was investigated. Results indicate that in the presence of TiO2 nanoparticles (NPs) mechanical, thermal and antimicrobial properties of pectin-based aerogels are improved in comparison to the control pectin aerogels. It should be emphasized that the thermal conductivity of pectin-based aerogels (0.022-0.025 W m-1 K-1) is lower than the thermal conductivity of air. Generally, the results propose that the pectin-TiO2 nanocomposite aerogels, as bio-based material, might have potential application for the storage of temperature-sensitive food.
Fibers and Polymers | 2018
Darka Marković; Stoja Milovanovic; Željko Radovanović; Irena Zizovic; Zoran Šaponjić; Maja Radetić
This study discusses a novel approach for fabrication of floating photocatalyst which can be efficiently exploited for photodegradation of dyes in aqueous solutions. A fabrication of the floating photocatalyst consisted of two steps: transformation of the poly(ε-caprolactone) beads (PCLb) into poly(ε-caprolactone) foam (PCLf) with porous structure in supercritical carbon-dioxide and subsequent loading of PCLf with TiO2 nanoparticles (NPs). Morphological characterization of the PCLf before and after TiO2 NPs loading was carried out by FESEM. The presence of titanium on the surface and inside the PCLf was detected by EDX. Photocatalytical activity of the floating photocatalyst was investigated in aqueous solution of textile dyes C.I. Acid Orange 7 (AO7) and C.I. Basic Yellow 28 (BY28) which were exposed to lamp that simulates the sun light. In addition to sustainable floatability for a long period of time, developed floating photocatalyst exhibited high rate of photodegradation since the complete discoloration of AO7 and BY28 solutions and photocatalysts alone occurred after 300 and 180 min of illumination, respectively. Its photocatalytic activity was preserved after three repeated photodegradation cycles with unchanged chemical structure that was confirmed by FTIR analysis.
Cellulose | 2018
Darka Marković; Matea Korica; Mirjana Kostic; Željko Radovanović; Zoran Šaponjić; Miodrag Mitrić; Maja Radetić
In situ synthesis of Cu/Cu2O nanoparticles on the cotton fabric discussed in this study relies on adsorption of Cu2+-ions by carboxylate groups generated through the TEMPO-mediated oxidation of cellulose and their subsequent reduction by sodium borohydride. In order to establish the influence of aldehyde and carboxylate groups on the nanoparticles formation, the duration of TEMPO-mediated oxidation was varied. Chemical changes induced by TEMPO-mediated oxidation were evaluated by titrimetric determination of the amounts of aldehyde and carboxylic groups in cotton and FTIR spectroscopy. The presence of Cu/Cu2O nanoparticles on the cotton fabric was confirmed by FE-SEM, AAS and XRD analyses. Antimicrobial activity of synthesized nanoparticles was tested against Gram-negative bacteria E. coli, Gram-positive bacteria S. aureus and fungi C. albicans. The extension of TEMPO oxidation time led to an increase of carboxylate group content and consequently, formation of larger amounts of Cu/Cu2O nanoparticles. All fabricated textile nanocomposites provided excellent antibacterial and acceptable antifungal activity. They also ensured a controlled release of Cu2+-ions in physiological solution which is an imperative for infection prevention.
Carbohydrate Polymers | 2018
Darka Marković; Christopher Deeks; Tim Nunney; Željko Radovanović; Marija Radoičić; Zoran V. Saponjic; Maja Radetić
The fabrication of antimicrobial textile nanocomposite by in situ synthesis of Cu-based nanoparticles on cotton fabrics modified with different polycarboxylic acids was discussed in this study. In order to evaluate the influence of carboxyl group content on Cu2+-ions adsorption, their subsequent reduction with sodium borohydride and formation of Cu-based nanoparticles, cotton fabrics were modified with succinic, citric and 1,2,3,4-butanetetracarboxylic acids. It was shown that the larger the number of carboxyl groups in applied acid, the larger the content of free carboxyl groups on the fibers and consequently, the larger the Cu2+-ions uptake and total amounts of Cu-based nanoparticles. On the basis of the XPS and XRD measurements, it was suggested that synthesized nanoparticles were mixture of Cu2O and CuO. Fabricated nanocomposites provided maximum reduction of Gram-negative bacterium E. coli and Gram-positive bacterium S. aureus and controlled release of Cu2+-ions in physiological saline solution which are necessary prerequisites for infection prevention.
Applied Surface Science | 2014
Željko Radovanović; Bojan Jokić; Djordje Veljović; Suzana Dimitrijević; Vesna Kojić; Rada Petrović; Djordje Janackovic
Journal of The Taiwan Institute of Chemical Engineers | 2014
Marija Pavlović; Aneta V. Buntić; Katarina Mihajlovski; Slavica Šiler-Marinković; Dušan G. Antonović; Željko Radovanović; Suzana Dimitrijević-Branković
Ceramics International | 2017
Abdusalam Drah; Nataša Z. Tomić; Zorica Veličić; Aleksandar D. Marinković; Željko Radovanović; Zlate Veličković; Radmila Jančić-Heinemann
Journal of The Serbian Chemical Society | 2018
Negovan Ivankovic; Dušan Rajić; Radovan Karkalić; Dušan Janković; Željko Radovanović; Stevan Stupar; Darko Janković
Journal of The Serbian Chemical Society | 2018
Darka Marković; Stoja Milovanovic; Marija Radoičić; Željko Radovanović; Irena Zizovic; Zoran Šaponjić; Maja Radetić
Journal of Polymer Research | 2018
Nataša Z. Tomić; Aleksandar D. Marinković; Željko Radovanović; Kata Trifković; Milena Marinović-Cincović; Radmila Jančić Heinemann