41. Correlations between photocatalytic activity and chemical structure of Cu-modified TiO2–SiO2 nanoparticle compositesT. Čižmar, Urška Lavrenčič Štangar, Iztok Arčon, 2016, izvirni znanstveni članek Opis: Copper-modified TiO2–SiO2photocatalysts were prepared by sol–gel method based on organic copper,silicon and titanium precursors. Copper concentration varied from 0.1 to 3.0 mol%. A widely appliedmodel reaction of photocatalytic oxidation of terephtalic acid (TPA) in water solution was used in order toevaluate the catalytic activities of elaborated samples. The crystal structures of the titania components ofall tested titania–silica species were studied using XRD analysis. The influence of Cu2+cation incorporationon the crystal structure of titania, as well as the chemical states and the neighbouring structures of coppercations, have been examined by means of Cu K-edge EXAFS and XANES analysis. The experimental datashow that there is a ten times increase in photocatalytic activity when TiO2–SiO2matrix is modified with0.1 mol% of Cu. It can be supposed that an enhancement of photocatalytic activity of low-concentratedcopper-modified titania–silica nanocomposites is probably due to a close attachment of Cu2+cationsto the surfaces of photocatalytically active TiO2nanoparticles. In this case, Cu2+cations may possiblyact as free electron traps reducing the intensity of recombination between opposite free charge carriers(electrons, holes) available at the photocatalyst’s surface.
Ključne besede: Cu-modified TiO2–SiO2photocatalysts, Titanium dioxide, Metal doping, Cu K-edge XANES, EXAFS, Photocatalytic activitya
Objavljeno v RUNG: 17.01.2017; Ogledov: 6277; Prenosov: 0
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42. Reuse of TiO2-based catalyst for solar driven water treatment; thermal and chemical reactivationSubhan Salaeh, Marin Kovacic, Dominik Kosir, Hrvoje Kušić, Urška Lavrenčič Štangar, Dionysios D. Dionysiou, Ana Lončarić Božić, 2017, izvirni znanstveni članek Ključne besede: Solar photocatalysis, TiO2-FeZ, Thermal and chemical reactivation, Ozone, Diclofenac
Objavljeno v RUNG: 03.11.2016; Ogledov: 5885; Prenosov: 0
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43. Hematite-based nanocomposites for light-activated applications: Synergistic role of TiO2 and Au introductionGiorgio Carraro, Chiara Maccato, Alberto Gasparotto, Michael E.A Warwick, Cinzia Sada, Stuart Turner, Antonio Bazzo, Teresa Andreu, Olena Pliekhova, Dorota Korte, Urška Lavrenčič Štangar, Gustaaf Van Tendeloo, Joan Ramón Morante, Davide Barreca, 2017, izvirni znanstveni članek Ključne besede: Fe2O3-TiO2-Au, Plasma enhanced-chemical vapor deposition, Sputtering, Photocatalysis
Objavljeno v RUNG: 10.10.2016; Ogledov: 6182; Prenosov: 0
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44. PREPARATION AND CHARACTERIZATION OF HIGHLY PHOTOACTIVE COATINGS ON GLASS SUPPORTS FOR DEGRADATION OF PHARMACEUTICAL SUBSTANCE PARACETAMOL IN WATERLidija Sinovčić, 2016, magistrsko delo Opis: Pharmaceuticals in aquatic environment are considered as emerging environmental contaminants due to their constant presence, evironmental resistance and toxic effect they could have on aquatic organisms. Studies for Slovenia have shown the presence of pharmaceutical substances in waters to be comparable with published results of pharmaceutical water pollution in Europe. As conventional methods do not reach efficient pharmaceutical removal from water sources, more powerful and effective methods like heterogeneous photocatalysis using TiO2/UV have been implemented. Titanium dioxide coatings in silicate binder were prepared by the sol-gel process and deposited on a glass support with dip-coating technique. The films showed good quality and possibility of multiple use. The characterization of the films was performed with scanning electron microscope (SEM), x-ray diffraction (XRD) and hardness test (Elcometer 501 Pencil Hardness Tester). Effectiveness and quality of prepared TiO2 coatings for photodegradation of pharmaceutical compound paracetamol (PCT) were assessed during photocatalytic treatment and compared to photolysis, a process without presence of a catalyst. Photolysis caused substantial changes in paracetamol concentration between 120 and 180 minutes of irradiation where 92% of degradation was achieved, but with no changes in mineralization. Photocatalytic treatment was much faster and effective where 95% of paracetamol degraded within 90 minutes of UV irradiation and after prolonged irradiation time from 120 to 240 minutes also mineralization of paracetamol solution increased from 59% to 83%. Accordingly, toxicity decreased, but it was still not lower than in the starting PCT solution as it was shown by acute toxicity test on Daphnia magna aquatic organisms. The master thesis represents a step forward in studying photocatalytic removal of paracetamol from water, because to my knowledge all the published investigations on this pharmaceutical up to now include photocatalyst mostly in powder and not in immobilized form, which is more advantageous from application point of view.
Ključne besede: Pharmaceuticals, paracetamol, titanium dioxide, photocatalytic degradation, Daphnia magna.
Objavljeno v RUNG: 14.09.2016; Ogledov: 8067; Prenosov: 303
 Celotno besedilo (2,50 MB) |
45. Novel two-step vapor-phase synthesis of UV – Vis light active Fe2O3/WO3 nanocomposites for phenol degradationDavide Barreca, Giorgio Carraro, Alberto Gasparotto, Chiara Maccato, Cinzia Sada, Elza Bontempi, Mariangela Brisotto, Olena Pliekhova, Urška Lavrenčič Štangar, 2016, izvirni znanstveni članek Opis: Supported Fe2O3/WO3 nanocomposites were
fabricated by an original vapor phase approach, involving
the chemical vapor deposition (CVD) of Fe2O3 on Ti sheets
and the subsequent radio frequency (RF)-sputtering of WO3.
Particular attention was dedicated to the control of the W/Fe
ratio, in order to tailor the composition of the resulting
materials. The target systems were analyzed by the joint use
of complementary techniques, that is, X-ray diffraction
(XRD), field emission-scanning electron microscopy
(FE-SEM), atomic force microscopy (AFM), energy
dispersive X-ray spectroscopy (EDXS), X-ray photoelectron
spectroscopy (XPS), secondary ion mass spectrometry
(SIMS), and optical absorption spectroscopy. The results
showed the uniform decoration of α-Fe2O3 (hematite)
globular particles by tiny WO3
aggregates, whose content
could be controlled by modulations of the sole sputtering time. The photocatalytic degradation of phenol in the liquid phase
was selected as a test reaction for a preliminary investigation
of the system behavior in wastewater treatment applications.
The system activity under both UVand Vis light illumination
may open doors for further material optimization in view of
real-world end-uses.
Ključne besede: Fe2O3, WO3, Nanocomposites, Chemical vapor deposition, Sputtering, Photocatalysis
Objavljeno v RUNG: 03.08.2016; Ogledov: 6682; Prenosov: 0
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46. Solar-driven photocatalytic treatment of diclofenac using immobilized TiO2-based zeolite compositesMarin Kovacic, Subhan Salaeh, Hrvoje Kušić, Andraz Suligoj, Marko Kete, Mattia Fanetti, Urška Lavrenčič Štangar, Dionysios D. Dionysiou, Ana Lončarić Božić, 2016, izvirni znanstveni članek Opis: The study is aimed at evaluating the potential of
immobilized TiO2-based zeolite composite for solar-driven
photocatalytic water treatment. In that purpose, TiO2-iron-exchanged
zeolite (FeZ) composite was prepared using commercial
Aeroxide TiO2 P25 and iron-exchanged zeolite of ZSM5
type, FeZ. The activity of TiO2-FeZ, immobilized on glass
support, was evaluated under solar irradiation for removal of
diclofenac (DCF) in water. TiO2-FeZ immobilized in a form
of thin film was characterized for its morphology, structure,
and composition using scanning electron microscopy/energydispersive
x-ray spectroscopy (SEM/EDX). Diffuse reflectance
spectroscopy (DRS) was used to determine potential
changes in band gaps of prepared TiO2-FeZ in comparison
to pure TiO2. The influence of pH, concentration of hydrogen
peroxide, FeZ wt% within the composite, and photocatalyst
dosage on DCF removal and conversion efficiency by solar/
TiO2-FeZ/H2O2 process was investigated. TiO2-FeZ demonstrated
higher photocatalytic activity than pure TiO2 under
solar irradiation in acidic conditions and presence of H2O2.
Ključne besede: Photocatalysis, Thin films, TiO2-FeZ, Solar irradiation, Diclofenac, Water Treatment
Objavljeno v RUNG: 22.07.2016; Ogledov: 7142; Prenosov: 0
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47. Efficient mineralization of aqueous organic pollutants by photocatalytic ozonationUrška Lavrenčič Štangar, Marko Kete, predavanje na tuji univerzi Opis: Photocatalytic ozonation process using TiO2 photocatalyst (O3/TiO2/UV – PH-OZ) conducted in acidic water environment often leads to synergistic effect in terms of decomposition and mineralization of aqueous organic contaminants, which makes the process suitable for waste water treatment or pretreatment of drinking water. [1,2] The synergism is among other factors (pH, O3 dose, T,…) greatly influenced by photocatalyst physicochemical properties and pollutant type. In the first part of the study, five different commercial TiO2 photocatalysts (P25, PC500, PC100, PC10 and JRC-TiO-6) were used in O2/TiO2/UV, O3/TiO2 and O3/TiO2/UV advanced oxidation systems for degradation of two pollutants (dichloroacetic acid - DCAA and thiacloprid – neonicotinoid pesticide), simultaneously present in water solution. [3] Results of PH-OZ (O3/TiO2/UV) experiments showed that in contrast to DCAA which adsorbs on TiO2 surface, synergistic effect is much more expressed in the case of thiacloprid which doesn’t adsorb. The influence of BET surface area of the photocatalyst and its dispersivity will be discussed.
In the second part of this study, selected catalysts were immobilized on a proper support to avoid post-filtration step in the process of greywater treatment. A good adhesion of a catalyst on various supports was successfully achieved by immobilization of commercial TiO2 powders (P25, P90, PC500) with the help of a sol-gel silica-titania binder [4]. For the purpose of simulated greywater treatment, special compact reactor was designed and developed, utilizing Al2O3 porous reticulated monolith foams as TiO2 carriers and UVA-lamps inside (Fig. 1). [5] With degradation of LAS+PBIS and Reactive blue 19 (RB 19) as representatives of surfactants and textile dyes respectively, commonly found in household greywater, and phenol as trace contaminant, an evaluation of PH-OZ and photocatalytic oxidation has been performed (an example in Fig. 2). Synergistic effect of PH-OZ was generally much more expressed in mineralization reactions, showing TOC half lives of less than one hour for the mixture of pollutants in compact reactor. [5] Due to its superior cleaning capacity, PH-OZ process employing efficient photocatalysts is suitable for treating wastewaters also with higher loading of organic pollutants.
1. U. Černigoj, U.Lavrenčič Štangar, J. Jirkovsky, J. Hazard. Mater. (2010) 177:399–406.
2. U. Černigoj, U.Lavrenčič Štangar, P. Trebše, Appl. Catal. B Environ. (2007) 75:229–238.
3. M. Kete, U. Černigoj, U. Lavrenčič Štangar: Photocatalytic ozonation – study of reaction parameters and mechanism, article under submission
4. M. Kete, E. Pavlica, F. Fresno, G. Bratina, U. Lavrenčič Štangar, Environ. Sci. Pollut. Res. (2014) 21:11238–11249.
5. M. Kete: Towards efficient removal of contaminants in water from household appliances by TiO2-photocatalysis: design, optimization and performance studies of the photoreactor with immobilized catalysts, Doctoral dissertation (2015), University of Nova Gorica, Nova Gorica.
Ključne besede: photocatalysis, ozonation, TiO2, dichloroacetic acid, thiacloprid, mechanisms, LAS+PBIS, Reactive blue 19, phenol
Objavljeno v RUNG: 21.07.2016; Ogledov: 7868; Prenosov: 0
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48. Comparative analysis of UV-C/H2O2 and UV-A/TiO2 processes for the degradation of diclofenac in waterDaria Juretic Perisic, Marin Kovacic, Hrvoje Kušić, Urška Lavrenčič Štangar, Vedrana Marin, Ana Lončarić Božić, 2016, izvirni znanstveni članek Opis: The study investigates the treatment of diclofenac (DCF), a pharmaceutical
included in the first watch list of the European Water Framework Directive
as a new potential priority substance in water. Since the conventional wastewater
treatment technologies do not efficiently remove DCF, advanced treatment technologies
capable of its complete removal or destruction of its biological activity,
need to be evaluated and eventually employed. For that purpose, typical representatives
of photooxidative and photocatalytic advanced oxidation processes were
applied. The effectiveness of UV-C/H2O2 and UV-A/TiO2 were compared regarding
DCF conversion and mineralization kinetics, water quality parameters for
assessing biodegradability and toxicity. In spite of similar biodegradability profiles,
the obtained results indicate different DCF degradation pathways, which are
reflected in different profiles of toxicity towards Vibrio fischeri. The observed DCF
conversion and mineralization kinetics revealed the benefits of UV-C/H2O2 process.
However, lower toxicity favored the application of photocatalytic over photooxidative
treatment for DCF removal.
Ključne besede: Diclofenac, Photooxidation, Photocatalysis, Biodegradability, Toxicity
Objavljeno v RUNG: 21.07.2016; Ogledov: 5924; Prenosov: 0
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49. Diclofenac removal by simulated solar assisted photocatalysis using TiO2-based zeolite catalyst; mechanisms, pathways and environmental aspectsSubhan Salaeh, Daria Juretic Perisic, Martina Biosic, Hrvoje Kušić, Sandra Babich, Urška Lavrenčič Štangar, Dionysios D. Dionysiou, Ana Lončarić Božić, 2016, izvirni znanstveni članek Opis: The study explores the potential of immobilized TiO2-based zeolite composite photocatalyst (TiO2-FeZ)
made of commercial AEROXIDE TiO2 P25 and iron-exchanged zeolite of ZSM5 type (FeZ), for solar assisted
treatment of diclofenac (DCF), pharmaceutical included in the ‘‘watch list” during last prioritization in
water legislation by EU.
In this study the efficiency of applied photocatalytic treatment, solar/TiO2-FeZ/H2O2, of DCF water
solution was evaluated on basis of DCF removal and conversion kinetics, as well as the changes of
common parameters for assessing water quality. Hence, the changes in the removal and mineralization
of overall organic content, biodegradability, toxicity to Vibrio fischeri, dechlorination of DCF and
its formed by-products, were monitored during the treatment. The obtained data were correlated with
the evolution of DCF by-products, identified and monitored during the treatment by HPLC/MSMS
analysis. In order to estimate the influence of water matrix, all experiments were performed in the
presence of chloride or sulphate as counter ions. The obtained data revealed that degradation
mechanism of DCF by applied treatment process using immobilized TiO2-FeZ includes the adsorption
onto photocatalyst surface and consequent degradation. The contribution of homogeneous Fenton
reaction due to leached iron ions was found to be negligible. The adsorption and degradation pathway of DCF were influenced by the type of counter ions, which was reflected in the observed changes of
water quality parameters.
Ključne besede: Solar photocatalysis, TiO2-FeZ catalyst, Diclofenac, Degradation pathway, Biodegradability, Toxicity
Objavljeno v RUNG: 21.07.2016; Ogledov: 6755; Prenosov: 0
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50. Photocatalytic Activity of Zirconium- and Manganese- Codoped Titania in Aqueous Media: The Role of the Metal Dopant and its Incorporation SiteO. L. Pliekhov, Iztok Arčon, Nataša Novak Tušar, Urška Lavrenčič Štangar, 2016, izvirni znanstveni članek Opis: The development of efficient TiO2-based photocatalysts for
water treatment is mainly performed by doping with transition
metals or by establishing junctions between different phases,
metal–semiconductor or semiconductor–semiconductor. We
present, for the first time, the synthesis of Zr- and Mn-modified
TiO2 by a redesigned sol–gel technique that allows the formation
of heterometallic bridges on the TiO2 surface. Cations of
the doping metals are located in the pores of mesoporous
anatase and attached to the crystalline TiO2 walls. The presence
of the Zr enhances the photoactivity of the TiO2 catalyst.
However, the introduction of Mn decreases the photocatalytic
efficiency in a nonadditive manner. The inhibition effect was
assigned to the side reaction between hydroxyl radicals and
Mn ions. The fact that Mn effectively scavenges the hydroxyl
radicals and, consequently, inhibits the whole oxidation process
is direct proof that hydroxyl radicals are the main reactive
species in the photocatalytic oxidative processes on TiO2 surfaces
in aqueous media and the process of COH generation is the
rate-determining step, which was confirmed using a method
based on the decolorization of a commercial dye Bezaktiv Blau
in a reaction with Fenton’s reagent as a source of hydroxyl radicals.
Ključne besede: doping, manganese, oxidation, X-ray absorption spectroscopy, zirconium
Objavljeno v RUNG: 21.07.2016; Ogledov: 5046; Prenosov: 0
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