Search

Background: Pesticides are listed among the main environmental stressors directly correlated with severe impacts on ecosystems and human health. Here, the potential of TiO2‐mediated photocatalytic oxidation of the insecticide thiacloprid, in aqueous media, is investigated thoroughly. Results: Degradation was investigated under various operational conditions, including the initial concentration of the pesticide, the type and amount of catalyst, pH and the presence of electron acceptors. The prevalence of TiO2 P25 in comparison to the other titania employed, is obvious both in the case of decomposition and carbon mineralization. Twenty‐seven transformation products generated during the photocatalytic decomposition of thiacloprid under UV‐A irradiation were elucidated by high‐resolution liquid chromatography mass spectrometry analysis, enabling the proposition of potential fragmentation pathways. The initial ecotoxicity of the insecticide determined by measurements of the bioluminescence of marine bacteria Vibrio fischeri was eliminated within 240 min of UV‐A irradiation in the presence of TiO2 P25. A phytotoxicity evaluation based on three eukaryotic plant species led to similar conclusions, resulting in the complete removal of phytotoxicity within 240 min of UV‐A illumination in the presence of TiO2 P25. Conclusions: These findings suggest that TiO2‐mediated photocatalytic oxidation has the potential to efficiently detoxify water containing neonicotinoid pesticides. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Cytarabine (CY) is an anticancer drug which has been identified in wastewater influents, effluents, and surface waters. In the present study, the degradation of CY under simulated solar light (SSL), by photo-Fenton (Fe3+/H2O2/SSL) and photo-Fenton-like processes (Fe3+/S2O82−/SSL and [Fe(C2O4)3]3−/H2O2/SSL), was investigated. The major parameters affecting the applied treatments (e.g., concentration of CY, Fe3+, H2O2, and S2O82−) were optimized and CY's complete removal was achieved within 45 min for all techniques used. Mineralization studies indicated that [Fe(C2O4)3]3−/H2O2/SSL treatment was the most efficient procedure since faster kinetics are achieved and higher mineralization percentage is reached compared to the other techniques used. Furthermore, 12 transformation products (TPs) were identified during the applied processes, by high resolution mass spectrometry, four of which were identified for the first time, indicating that CY molecule undergoes hydroxylation and subsequent oxidation, during the applied processes. Moreover, predictions of acute and chronic ecotoxicity of CY and its TPs on fish, daphnia, and green algae were conducted, using in silico quantitative structure activity relationship (QSAR) calculations. According to these predictions, the TPs generated during the studied treatments may pose a threat to aquatic environment. Finally, the efficiency of CY degradation by photo-Fenton and photo-Fenton-like treatment in real wastewater was evaluated, under the optimized conditions, which resulted in lower degradation rate constants compared to ultrapure water. [ABSTRACT FROM AUTHOR]

A direct method based on immersion solid phase microextraction (DI-SPME) gas chromatography mass-spectrometry (GC-MS) was optimized and validated for the determination of 16 biogenic amines in Polish wines. In the analysis two internal standards were used: 1,7-diaminoheptane and bis-3-aminopropylamine. The method allows for simultaneous extraction and derivatization, providing a simple and fast mode of extraction and enrichment. Different parameters which affect the extraction procedure were studied and optimized including ionic strength (0–25%), fiber materials (PDMS/DVB, PDMS/DVD + OC, Polyacrylate, Carboxen/PDMS and DVB/CAR/PDMS) and timings of the extraction, derivatization and desorption processes. Validation studies confirmed the linearity, sensitivity, precision and accuracy of the method. The method was successfully applied to the analysis of 44 wine samples originating from several regions of Poland and 3 wine samples from other countries. Analysis showed that many of the samples contained all examined biogenic amines. The method, assessed using an Eco-Scale tool with satisfactory results, was found to be green in terms of hazardous chemicals and solvents usage, energy consumption and production of waste. Therefore the proposed method can be safely used in the wine industry for routine analysis of BAs in wine samples with a minimal detrimental impact on human health and the environment. [ABSTRACT FROM AUTHOR]

Photocatalytic oxidation of carboplatin, a platinum antineoplastic drug, has been investigated in aqueous heterogeneous solutions containing TiO 2 photocatalysts. The current study, besides the photocatalytic degradation of the drug, examines the utilization of the photo-reduction process occurring on the surface of the catalyst, leading simultaneously to the photo-deposition and recovery of platinum. TiO 2 photocatalytic process was evaluated for its ability to degrade the molecule of carboplatin and concurrently result in the synthesis of efficient platinum modified TiO 2 catalysts. The degradation kinetic was studied under different operational conditions, such as type of photocatalyst, catalyst loading, initial pH and addition of electron acceptors. Three systems were evaluated namely, TiO 2 P25 under UV-A and TiO 2 Kronos vlp 7000 under UV-A or visible illumination, with respect to their activity for substrate degradation and mineralization and their ability to bind platinum on their surface during photocatalytic oxidation of the drug. The initial degradation rate (r 0 ) decreased in the order TiO 2 P25/UV-A > TiO 2 Kronos vlp 7000/UV-A > TiO 2 Kronos vlp 7000/visible light. For TiO 2 P25/UV-A, the addition of 100 mg L −1  H 2 O 2 increases slightly the initial mineralization rate, while degradation rates gradually decrease as photocatalysis takes place in neutral and alkaline pH. Phytotoxicity measurements, showed that heterogeneous photocatalytic oxidation in the presence of TiO 2 P25 is capable of reducing the phytotoxicity of carboplatin. For TiO 2 P25 and TiO 2 Kronos vlp 7000 under UV-A illumination, photo-reduction and deposition of platinum is fully accomplished within 60 min of oxidation, while for TiO 2 Kronos vlp 7000 in the presence of visible light, the percentage of platinum deposited on the surface of the catalyst reaches 40%. Platinum photo-deposition is feasible, employing TiO 2 P25, even after the catalyst is reused. The synthesized platinum modified TiO 2 P25, demonstrated higher photocatalytic efficiency in comparison to the bare one, leading to 100% degradation of the model pollutant malachite green and 40% DOC reduction, after 30 min of photo-oxidation. [ABSTRACT FROM AUTHOR]