1. Nickel-decorated ZnO nanoparticles for effective solar reduction of hexavalent chromium and removal of selected pharmaceuticalsMiha Ravbar, Ksenija Maver, Tilen Knaflič, Iztok Arčon, Nataša Novak Tušar, Urška Lavrenčič Štangar, Andraž Šuligoj, 2025, original scientific article Abstract: The efficient visible light driven photocatalytic reduction of hexavalent chromium, Cr(VI) was demonstrated using ZnO nanoparticles (NPs) decorated with oxo-clusters of transition metals. The ZnO NPs were synthesized by a facile one-pot solvothermal synthesis followed by a fast microwave-assisted (MW) grafting of transition metals on the surface of NPs. Nickel was found to be the most active transition metal for photocatalytic activity as demonstrated by reduction of Cr(VI) to Cr(III). The optimally grafted samples contained 0.5 wt% Ni and increased photocatalytic activity by almost one-fold. The oxo-clusters did not enter the lattice of ZnO but rather resided on the surface and their efficient bonding to the ZnO surface was proved by Raman, TEM and X-Ray absorption techniques. Influence of MW power was studied and shown that excessive power load leads to formation of elongated structures of ZnO which decreases the photocatalytic activity. It was demonstrated by measuring fluorescent radical products that electrons, efficiently transferred via oxygen, were the main active species in combination with the unchanged oxidation power of holes and • OH in the grafted samples. The applicability of the materials was tested in immobilized plug flow photoreactor system degrading five pharmaceuticals simultaneously where their long-term use was shown. Keywords: Zinc oxide, Pharmaceuticals, Grafting, Cr(VI), Zn XANES, Zn EXAFS Published in RUNG: 24.10.2024; Views: 322; Downloads: 3 Full text (4,49 MB) This document has many files! More... |
2. Reduced TiO2 nanotube arrays for photoelectrochemical degradation of pharmaceuticalManel Machreki, Takwa Chouki, Georgi Tyuliev, Dušan Žigon, Bunsho Ohtani, Alexandre Loukanov, Plamen Stefanov, Saim Emin, 2022, published scientific conference contribution abstract Keywords: TiO2, nanotube arrays, photoelectrochemical degradation, pharmaceuticals Published in RUNG: 10.02.2023; Views: 1905; Downloads: 0 This document has many files! More... |
3. Development of a simple method for the extraction of pharmaceuticals from fishTopić Jelena, Klančar Anita, Trontelj Jurij, Roškar Robert, 2016, published scientific conference contribution abstract Abstract: Pharmaceuticals are considered as emerging pollutants of particular concern due to their continuous release into the environment and the potential impact on aquatic organisms. The selection of the target compounds for evaluation in fish tissue was based on physico-chemical properties, bioaccumulation potential and the results of the screening of pharmaceuticals in the effluent of WWTP Sevnica in March 2015. We chose tramadol, risperidone, desipramine, carbamazepine, irbesartan, naproxen, valsartan, atorvastatin, triclosan, simvastatin and diclofenac. The method was developed on muscle tissue and is based on the tissue homogenization with stainless steel beads, followed by extraction with acetonitrile, centrifugation and sample clean-up with solid-phase extraction (SPE). The instrumental analysis was performed with LC-MS/MS. The best and the most reproducible recoveries were observed for the samples that were diluted to 25 mL with 50 mM phosphate buffer pH 7. The method was validated and the linearity range was established, which was in the range of 0.1 – 1000 ng/g, depending of the compound. The recoveries for the target pharmaceuticals were in the range of 24.0 – 108.5 %, with good reproducibility as the relative RSD values for all compounds were below 7.5 %. LOQ values for the compounds were in the 0.1 – 50 ng/g range. We applied the method to the fish tissue samples from the river Sava and from the aquaculture establishment. We chose muscle, liver, skin and kidney tissue samples. The results showed presence of tramadol and carbamazepine in some tissue, but the concentrations were below the LOQ. Keywords: pharmaceuticals, fish, SPE, LC-MS/MS Published in RUNG: 16.11.2016; Views: 6684; Downloads: 0 This document has many files! More... |
4. PREPARATION AND CHARACTERIZATION OF HIGHLY PHOTOACTIVE COATINGS ON GLASS SUPPORTS FOR DEGRADATION OF PHARMACEUTICAL SUBSTANCE PARACETAMOL IN WATERLidija Sinovčić, 2016, master's thesis Abstract: 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. Keywords: Pharmaceuticals, paracetamol, titanium dioxide, photocatalytic degradation, Daphnia magna. Published in RUNG: 14.09.2016; Views: 7920; Downloads: 303 Full text (2,50 MB) |