Dokument-ID Dokumenttyp Autoren/innen Persönliche Herausgeber/innen Haupttitel Abstract Auflage Verlagsort Verlag Herausgeber (Institution) Erscheinungsjahr Titel des übergeordneten Werkes Jahrgang/Band ISBN Veranstaltung Veranstaltungsort Beginndatum der Veranstaltung Enddatum der Veranstaltung Ausgabe/Heft Erste Seite Letzte Seite URN DOI Lizenz Datum der Freischaltung OPUS4-37126 Zeitschriftenartikel Nadejde, C.; Neamtu, M.; Hodoroaba, Vasile-Dan; Schneider, Rudolf; Ababei, G.; Panne, Ulrich Hybrid iron-based core-shell magnetic catalysts for fast degradation of bisphenol A in aqueous systems Three types of hybrid modified magnetite (Fe₃O₄) nanoparticles, functionalized with either chitosan, chitosan/iron (II) oxalate or chitosan/iron (III) citrate, were synthesized by chemical precipitation method. The obtained nanomaterials were characterized by energy dispersive X-ray spectroscopy, X-ray diffraction, Brunauer-Emmett-Teller analysis, scanning and Transmission electron microscopy, Fourier transform infrared spectroscopy and vibrating sample magnetometry. The prepared composites were further tested as magnetic catalysts for the removal of bisphenol A (BPA) in aqueous media. The kinetic Degradation experiments were performed at laboratory scale, while the best operational parameters for all three materials were established: 1.00 g L⁻¹ of catalyst, 10 mmol L⁻¹ H₂O₂, under simulated solar light irradiation. After 15 min of UVA irradiation under the experimental conditions mentioned above, it was possible to decompose up to 99% of the micropollutant over all catalysts. Fe₃O₄/chitosan/iron oxalate catalyst showed the highest and fastest catalytic activity in BPA removal. Catalytic wet peroxide oxidation of non-biodegradable micropollutants on such iron-based hybrid nanoparticles can be a suitable pre-treatment method for wastewater decontamination, as an environment-friendly simplified Approach for water clean-up. Amsterdam Elsevier 2016 Chemical Engineering Journal 302 587 594 10.1016/j.cej.2016.05.090 2016-08-12 OPUS4-33820 Zeitschriftenartikel Nadejde, C.; Neamtu, M.; Hodoroaba, Vasile-Dan; Schneider, Rudolf; Paul, Andrea; Ababei, G.; Panne, Ulrich Green Fenton-like magnetic nanocatalysts: Synthesis, characterization and catalytic application Five iron oxalate core-shell magnetite nanoparticles catalysts are evaluated as magnetic heterogeneous materials. Simple and efficient procedures for the preparation of magnetic iron oxalate coated nanoparticles are presented. The catalysts are fully characterized using various investigation techniques. Additionally, the formation of photo-sensitized oxygen by spin-trapping using electron spin resonance is investigated. The catalytic activity of two model substrates (carbamazepine and bisphenol A) is also evaluated. The effect of operational parameters (catalyst and H2O2 concentration, UVA light) on the degradation performance of the oxidation process is investigated. The obtained reaction rates depend on the nature of the compound and increase with iron oxide shell thickness of the catalyst. Moreover, these materials show a significant activity during two consecutive tests. The optimum experimental parameters are found to be 1.0 g L-1 of catalysts, 10 mM H2O2, under UVA irradiation. More than 99% of both substrates are removed after 30 min of reaction time under the experimental conditions given above. The results obtained show that the catalysts are suitable candidates for the removal of pollutants in wastewaters by means of the Fenton heterogeneous reaction. Amsterdam Elsevier 2015 Applied catalysis / B 176-177 667 677 10.1016/j.apcatb.2015.04.050 2016-02-20 OPUS4-38758 Zeitschriftenartikel Nadejde, C.; Neamtu, M.; Hodoroaba, Vasile-Dan; Schneider, Rudolf; Paul, Andrea; Ababei, G.; Panne, Ulrich Tannic acid- and natural organic matter-coated magnetite as green Fenton-like catalysts for the removal of water pollutants The use of magnetic materials as heterogeneous catalysts has attracted increasing attention in the last years since they proved to be promising candidates for water treatment. In the present study, two types of surface-modified magnetite (Fe3O4) nanoparticles, coated with non-hazardous naturally occurring agents—either tannic acid (TA) or dissolved natural organic matter—were evaluated as magnetic heterogeneous catalysts. Chemical synthesis (co-precipitation) was chosen to yield the nanocatalysts due to its well-established simplicity and efficiency. Subsequently, the properties of the final products were fully assessed by various characterization techniques. The catalytic activity in heterogeneous oxidation of aqueous solutions containing a model pollutant, Bisphenol A (BPA), was comparatively studied. The effect of operational parameters (catalyst loading, H2O2 dosage, and UV light irradiation) on the Degradation performance of the oxidation process was investigated. The optimum experimental parameters were found to be 1.0 g/L of catalysts and 10 mM H2O2, under UV irradiation. The highest mineralization rates were observed for Fe3O4-TA catalyst. More than 80 % of BPA was removed after 30 min of reaction time under the specified experimental conditions. The obtained results showed that the two catalysts studied here are suitable candidates for the removal of pollutants in wastewaters by means of heterogeneous reaction using a green sustainable treatment method. Springer 2015 Journal of Nanoparticle Research 17 12 476 (1) 476 (10) 10.1007/s11051-015-3290-0 2016-12-21 OPUS4-38760 Zeitschriftenartikel Nadejde, C.; Neamtu, M.; Schneider, Rudolf; Hodoroaba, Vasile-Dan; Ababei, G.; Panne, Ulrich Catalytical degradation of relevant pollutants from waters using magnetic nanocatalysts The catalytic efficiency of two magnetically responsive nanocatalysts was evaluated for the Degradation of Reactive Black 5 (RB5) and Reactive Yellow 84 (RY84) azo dyes using hydrogen peroxide as oxidant undervery mild conditions (atmospheric pressure, room temperature). In order to obtain the nanocatalysts, thesurface of magnetite (Fe3O4) nanoparticles, prepared by a co-precipitation method, was further modified with ferrous oxalate, a highly sensitive non-hazardous reducing agent. The sensitized nanomaterials were characterized by X-ray diffraction, scanning and transmission electron microscopy, energy-dispersive X-ray spectroscopy and vibrating sample magnetometry, and used in the catalytic wet hydrogen peroxideoxidation (CWHPO) of RB5 and RY84, in laboratory-scale experiments. The effect of important variables such as catalyst dosage, H2O2 concentration, and contact time was studied in the dye Degradation kinetics. The results showed that it was possible to remove up to 99.7% dye in the presence of 20 mM H2O2 after 240 min of oxidation for a catalyst concentration of 10 g L−1at 25◦C and initial pH value of 9.0.CWHPO of reactive dyes using sensitized magnetic nanocatalysts can be a suitable pre-treatment methodfor complete decolorization of effluents from textile dyeing and finishing processes, once the Optimum operating conditions are established. Elsevier B.V. 2015 Applied Surface Science 352 10th International Conference On Physics Of Advanced Materials (ICPAM-10) Iasi, Romania 22.09.2014 28.09.2014 42 48 10.1016/j.apsusc.2015.01.036 2016-12-21 OPUS4-44829 Zeitschriftenartikel Neamtu, Mariana; Nadejde, C.; Hodoroaba, Vasile-Dan; Schneider, Rudolf; Verestiuc, L.; Panne, Ulrich Functionalized magnetic nanoparticles: Synthesis, characterization, catalytic application and assessment of toxicity Cost-effective water cleaning approaches using improved Treatment technologies, for instance based on catalytic processes with high activity catalysts, are urgently needed. The aim of our study was to synthesize efficient Fenton-like photo-catalysts for rapid degradation of persistent organic micropollutants in aqueous medium. Iron-based nanomaterials were chemically synthesized through simple procedures by immobilization of either iron(II) oxalate (FeO) or iron(III) citrate (FeC) on magnetite (M) nanoparticles stabilized with polyethylene glycol (PEG). Various investigation techniques were performed in order to characterize the freshly prepared catalysts. By applying advanced oxidation processes, the effect of catalyst dosage, hydrogen peroxide concentration and UV-A light exposure were examined for Bisphenol A (BPA) conversion, at laboratory scale, in mild conditions. The obtained results revealed that BPA degradation was rapidly enhanced in the presence of low-concentration H2O2, as well as under UV-A light, and is highly dependent on the surface characteristics of the catalyst. Complete photo-degradation of BPA was achieved over the M/PEG/FeO catalyst in less than 15 minutes. Based on the catalytic performance, a hierarchy of the tested catalysts was established: M/PEG/FeO > M/PEG/FeC > M/PEG. The results of cytotoxicity assay using MCF-7 cells indicated that the aqueous samples after treatment are less cytotoxic. London Springer Nature 2018 Scientific Reports 8 Article 6278, 1 11 urn:nbn:de:kobv:b43-448297 10.1038/s41598-018-24721-4 https://creativecommons.org/licenses/by/4.0/deed.de 2018-05-04 OPUS4-44555 Zeitschriftenartikel Rambu, A. P.; Nadejde, C.; Schneider, Rudolf; Neamtu, M. Thin films containing oxalate-capped iron oxide nanomaterials deposited on glass substrate for fast Fenton degradation of some micropollutants The main goal of the study was to evaluate the catalytic activity of two hybrid nanocatalysts consisting in Fe3O4 nanoparticles modified with either chitosan (CS) or polyethylene glycol (PEG)/ferrous oxalate (FO), and further deposited on solid substrate as thin films. X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and scanning electron microscopy (SEM) were employed for the structural and morphological characterizations of the heterogeneous catalysts. The Degradation kinetic studies of two reactive azo dye (Reactive Black 5 (RB5) and Reactive Yellow 84 (RY84)) as well as Bisphenol A (BPA) solutions were carried out using Fenton-like oxidation, in the presence of different concentrations of H2O2, at initial near-neutral pH and room temperature. The results indicated that a low amount of catalytic material (0.15 g/L), deposited as thin film, was able to efficiently trigger dye degradation in solution in the presence of 6.5mmol/LH2O2 for RB5 and of only 1.6mmol/LH2O2 in the case of BPA and RY84. In the presence of complex matrices such asWWTP waters, the removal of BPAwas low (only 24% for effluent samples). Our findings recommend the studied immobilized nanocatalysts as promising economical tools for the pretreatment of wastewaters using advanced oxidation processes (AOPs). Heidelberg Springer 2018 Environmental Science and Pollution Research 25 7 6802 6813 10.1007/s11356-017-1022-y 2018-03-23 OPUS4-45267 Zeitschriftenartikel Neamtu, M.; Nadejde, C.; Hodoroaba, Vasile-Dan; Schneider, Rudolf; Panne, Ulrich Singlet oxygen generation potential of porphyrin-sensitized magnetite nanoparticles: Synthesis, characterization and photocatalytic application Singlet oxygen generation potential of two novel free-base-porphyrin photocatalysts was investigated. The freebase-porphyrin-sensitized Fe3O4 magnetic nanoparticles (MNPs) were tested for the degradation of the model pollutant Bisphenol A (BPA) in aqueous solution, for the first time. MNPs with either cubic or spherical shape were synthesized using the sonochemical approach, followed by sensitizing with photoactive 4,4′,4′′,4′′′- (Porphine-5,10,15,20-tetrayl)tetrakis(benzoic acid) (TCPP). The resulted photocatalysts were characterized in detail by scanning and transmission electron microscopy, Brunauer-Emmett-Teller analysis, spectral techniques and vibrating sample magnetometry. The electron spin resonance experiments have confirmed the high activity of the photocatalysts through the efficient formation of singlet oxygen in solution. The optimum operational parameters for BPA degradation were established as follows: 1.0 μmol L−1 BPA, 1.0 g L−1 of photocatalyst, 100 μmol L−1 H2O2, under UVA irradiation. In these conditions, the results for both photocatalysts revealed that after only 10 min of reaction, over 64% and ca. 90% of BPA have been removed from solution in the absence and presence of H2O2, respectively. Whereas after 60 minutes of treatment, only 24% of BPA in real wastewater effluent samples were removed under UVA irradiation in the absence of H2O2, showing the high complexity of real wastewater. Moreover, both photocatalysts were successfully used for BPA removal in three consecutive runs, without significant loss of catalytic features. Amsterdam, NL Elsevier B.V. 2018 Applied Catalysis B: Environmental 232 553 561 10.1016/j.apcatb.2018.03.079 2018-06-25 OPUS4-35382 Zeitschriftenartikel Neamtu, M.; Macaev, F.; Boldescu, V.; Hodoroaba, Vasile-Dan; Nadejde, C.; Schneider, Rudolf; Paul, Andrea; Ababei, G.; Panne, Ulrich Removal of pollutants by the new Fenton-like highly active catalysts containing an imidazolium salt and a Schiff base Two iron-based molten salts comprising an imidazolium and Schiff base were evaluated as catalysts for removal of carbamazepine (CBZ) from water. The catalysts were fully characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDX), nuclear magnetic resonance spectroscopy (NMR), electrospray ionisation-mass spectrometry (ESI-MS), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and nitrogen adsorption-desorption isotherms (BET). Additionally, the formation of photo-sensitized oxygen was investigated by spin-trapping using electron spin resonance (ESR). The catalytic activity in heterogeneous oxidation of the micropollutant (CBZ) was also evaluated. The effects of catalyst loading, pH, H2O2 dosage and UV light on the oxidation of the selected compound were investigated. After 15 min of UVA irradiation in the presence of 200 μM H2O2, CBZ was completely removed over both catalysts. Amsterdam Elsevier B.V. 2016 Applied Catalysis B: Environmental 183 335 342 10.1016/j.apcatb.2015.10.032 2016-03-15 OPUS4-50636 Zeitschriftenartikel Neamtu, M.; Nadejde, C.; Brinza, L.; Dragos, O.; Gherghel, D.; Paul, Andrea Iron phthalocyanine-sensitized magnetic catalysts for BPA photodegradation The catalytic behavior of iron phthalocyanine (FePc)-sensitized magnetic nanocatalysts was evaluated for their application in the oxidative treatment of Bisphenol A (BPA) under mild environmental conditions. Two types of FePc (Fe(II)Pc and Fe(III)Pc), which are highly photosensitive compounds, were immobilized on the surface of functionalized magnetite. The nanomaterials were characterized by high resolution transmission electron microscopy (HR-TEM), X-ray difraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analyses (TGA). The generation of singlet Oxygen by nanomaterials was also investigated. In the presence of UVA light exposure (365nm) and 15mM H2O2, the M@Fe(III)Pc photocatalyst gave the best results; for a catalyst concentration of 2.0gL −1, around 60% BPA was removed after 120min of reaction. These experimental conditions were further tested under natural solar light exposure, for which also M@Fe(III)Pc exhibited enhanced oxidative catalytic activity, being able to remove 83% of BPA in solution. The water samples were less cytotoxic after treatment, this being confrmed by the MCF-7 cell viability assay. 2020 Scientific Reports 10 1 5376 urn:nbn:de:kobv:b43-506368 10.1038/s41598-020-61980-6 https://creativecommons.org/licenses/by/4.0/deed.de 2020-04-08 OPUS4-48316 Zeitschriftenartikel Neamtu, Mariana; Nadejde, C.; Hodoroaba, Vasile-Dan; Schneider, Rudolf; Ababei, G.; Panne, Ulrich Photocatalysis of γ-cyclodextrin-functionalised Fe3O4 nanoparticles for degrading Bisphenol A in polluted waters The efficiency, relatively low cost and eco-friendly nature of hydrogen peroxide-assisted photocatalysis treatment procedures are significant advantages over conventional techniques for wastewater remediation. Herein, we evaluate the behaviour of g-cyclodextrin (g-CD) immobilised on either bare or chitosan (CS)-functionalised Fe3O4 nanoparticles, for photodegrading Bisphenol A (BPA) in ultrapure water and in real wastewater samples. The BPA removal efficiencies with Fe3O4/g-CD and Fe3O4/CS/g-CD were compared with those of Fe3O4/b-CD, and were monitored under UVA irradiation at near-neutral pH. The addition of H2O2 at low concentrations (15 mmol L-1) significantly increased BPA photodegradation in the presence of each nanocomposite. The highest catalytic activity was shown by both Fe3O4/g-CD and Fe3O4/CS/g-CD nanocomposites (,60 and 27%BPA removal in ultrapure water and real wastewater effluent, respectively). Our findings reveal the superior performance of g-CD-functionalised Fe3O4 relative to that of Fe3O4/b-CD. The use of CD-based nanocomposites as photocatalytic materials could be an attractive option in the pre- or post-treatment stage of wastewaters by advanced oxidation processes before or after biological treatment. Clayton South CSIRO Publishing CSIRO 2019 Environmental Chemistry 16 2 125 136 10.1071/EN18181 2019-06-26 OPUS4-40072 Zeitschriftenartikel Neamtu, Mariana; Nadejde, C.; Hodoroaba, Vasile-Dan; Schneider, Rudolf; Paul, Andrea; Ababei, G.; Panne, Ulrich Green Fenton-like magnetic nanocatalysts: Synthesis, characterization and catalytic application Five iron oxalate core-shell magnetite nanoparticles catalysts are evaluated as magnetic heterogeneous materials. Simple and efficient procedures for the preparation of magnetic iron oxalate coated nanoparticles are presented. The catalysts are fully characterized using various investigation techniques. Additionally, the formation of photo-sensitized oxygen by spin-trapping using electron spin resonance is investigated. The catalytic activity of two model substrates (carbamazepine and bisphenol A) is also evaluated. The effect of operational parameters (catalyst and H2O2 concentration, UVA light) on the degradation performance of the oxidation process is investigated. The obtained reaction rates depend on the nature of the compound and increase with iron oxide shell thickness of the catalyst. Moreover, these materials show a significant activity during two consecutive tests. The optimum experimental parameters are found to be 1.0 g L−1 of catalysts, 10 mM H2O2, under UVA irradiation. More than 99% of both substrates are removed after 30 min of reaction time under the experimental conditions given above. The results obtained show that the catalysts are suitable candidates for the removal of pollutants in wastewaters by means of the Fenton heterogeneous reaction. Elsevier 2015 Applied Catalysis B: Environmental 176-177 667 677 10.1016/j.apcatb.2015.04.050 2017-05-04 OPUS4-40074 Beitrag zu einem Tagungsband Nadejde, C.; Neamtu, Mariana; Hodoroaba, Vasile-Dan; Schneider, Rudolf; Paul, Andrea; Ababei, G.; Panne, Ulrich Green Fenton-like catalysts for the removal of water pollutants Two types of surface modified magnetite (Fe3O4) nanoparticles, coated with either tannic acid (TA) or dissolved natural organic matter (NOM), were evaluated as magnetic heterogeneous catalysts. Simple and efficient procedures for the synthesis of the magnetic catalysts were employed, their properties being fully assessed by various characterization techniques. The catalytic activity in heterogeneous oxidation of aqueous solutions containing Bisphenol A (BPA) over the catalysts was comparatively studied. The optimum experimental parameters were: 1g/L of catalysts, 10 mM H2O2, under UV irradiation. The highest mineralization rates were observed for Fe3O4-TA catalyst. More than 80% of BPA were removed after 30 minutes of reaction time under the specified experimental conditions. The results showed that the obtained catalysts are suitable candidates for the removal of pollutants in wastewaters by means of heterogeneous reaction CRC Press, Taylor&Francis Group 2015 Materials for Energy, Efficiency and Sustainability 2 978-1- 4987-4733-2 TechConnect World Innovation Conference Nanotech 2015 Washington, DC, Maryland, USA 14.06.2015 17.06.2015 87 90 2017-05-05 OPUS4-40082 Beitrag zu einem Tagungsband Nadejde, C.; Neamtu, Mariana; Hodoroaba, Vasile-Dan; Schneider, Rudolf; Ababei, G.; Panne, Ulrich Characterization and application of Green Fenton-like catalysts for the removal of water pollutants Three types of magnetite-chitosan/iron oxalate/iron citrate nanoparticles (NP) were evaluated as magnetic heterogeneous catalysts for water treatment. Proteomass 2015 PTIM 2015 Book of Proceedings 978-989-99361-6-4 PTIM 2015, 1st International Caparica Conference on Pollutant Toxic Ions and Molecules Caparica, Portugal 02.112015 04.11.2015 186 187 2017-05-08