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Diclofenac removal by simulated solar assisted photocatalysis using TiO2-based zeolite catalyst; mechanisms, pathways and environmental aspects
Dionysios D. Dionysiou, Urška Lavrenčič Štangar, Sandra Babich, Hrvoje Kušić, Martina Biosic, Daria Juretic Perisic, Subhan Salaeh, Ana Lončarić Božić, 2016, original scientific article

Abstract: 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.
Found in: osebi
Keywords: Solar photocatalysis, TiO2-FeZ catalyst, Diclofenac, Degradation pathway, Biodegradability, Toxicity
Published: 21.07.2016; Views: 4384; Downloads: 0
.pdf Fulltext (2,10 MB)

Comparative analysis of UV-C/H2O2 and UV-A/TiO2 processes for the degradation of diclofenac in water
Urška Lavrenčič Štangar, Hrvoje Kušić, Marin Kovacic, Daria Juretic Perisic, Vedrana Marin, Ana Lončarić Božić, 2016, original scientific article

Abstract: 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.
Found in: osebi
Keywords: Diclofenac, Photooxidation, Photocatalysis, Biodegradability, Toxicity
Published: 21.07.2016; Views: 3913; Downloads: 0
.pdf Fulltext (496,03 KB)

Solar-driven photocatalytic treatment of diclofenac using immobilized TiO2-based zeolite composites
Urška Lavrenčič Štangar, Mattia Fanetti, Marko Kete, Andraz Suligoj, Hrvoje Kušić, Subhan Salaeh, Marin Kovacic, Dionysios D. Dionysiou, Ana Lončarić Božić, 2016, original scientific article

Abstract: 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.
Found in: osebi
Keywords: Photocatalysis, Thin films, TiO2-FeZ, Solar irradiation, Diclofenac, Water Treatment
Published: 22.07.2016; Views: 4942; Downloads: 0
.pdf Fulltext (2,88 MB)

Photocatalytic sol-gel/P25 TiO [sub] 2 coatings for water treatment
Lev Matoh, Boštjan Žener, Marin Kovačić, Hrvoje Kušić, Iztok Arčon, Meta Levstek, Urška Lavrenčič Štangar, 2022, original scientific article

Abstract: The effect of different water matrices on the photocatalytic degradation of dissolved pharmaceuticals was explored. The focus was on the degradation efficiencies in wastewater effluent from a bioreactor and water effluent from a central wastewater treatment plant and comparing the results with degradation in deionized H2O. The compounds tested included: oxytetracycline, marbofloxacin, ibuprofen, diclofenac, phenytoin, ciprofloxacin, sulfamethoxazole. For the experiments performed in this study, a compact packed-bed photocatalytic reactor was used in which the hybrid TiO2 photocatalyst (sol-gel/P25) was deposited on ~3 mm glass beads. As expected, the reactions proceed more slowly in wastewater than in deionized water, yet it is shown that removal of the compounds from the water is still possible even when other organic molecules are present. Total organic carbon measurements have shown that complete mineralization takes place albeit at slower rates than the initial degradation of parent compounds. The results show that an acidic pH can increase the reaction rates and the adsorption on the photocatalyst surface. Analyses of the degradation intermediates were performed using tandem liquid chromatography triple-quadrupole mass spectrometry system. Additionally, X-ray absorption spectroscopy was applied to get insight into the local structure of the photocatalyst before and after use. Understanding the effects that different wastewater compositions have on photocatalytic reactions will help to refine the potential applications of the technology.
Found in: osebi
Keywords: titanium dioxide, sol-gel processes, functionla applications, water treatment
Published: 30.09.2022; Views: 169; Downloads: 0
.pdf Fulltext (8,11 MB)

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