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- Antoniou, Maria G., et al.
(författare)
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Required ozone doses for removing pharmaceuticals from wastewater effluents
- 2013
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Ingår i: Science of the Total Environment. - Amsterdam : Elsevier BV. - 1879-1026 .- 0048-9697. ; 456, s. 42-49
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the this study was to investigate the ozone dosage required to remove active pharmaceutical ingredients (APIs) from biologically treated wastewater of varying quality, originated from different raw wastewater and wastewater treatment processes. Secondary effluents from six Swedish wastewater treatment plants (WWTP) were spiked with 42 APIs (nominal concentration 1 mu g/L) and treated with different O-3 doses (0.5-12.0 mg/L ozone) in bench-scale experiments. In order to compare the sensitivity of APIs in each matrix, the specific dose of ozone required to achieve reduction by one decade of each investigated API (DDO3) was determined for each effluent by fitting a first order equation to the remaining concentration of API at each applied ozone dose. Ozone dose requirements were found to vary significantly between effluents depending on their matrix characteristics. The specific ozone dose was then normalized to the dissolved organic carbon (DOC) of each effluent. The DDO3/DOC ratios were comparable for each API between the effluents. 15 of the 42 investigated APIs could be classified as easily degradable (DDO3/DOC <= 0.7), while 19 were moderately degradable (0.7 < DDO3/DOC <= 1.4), and 8 were recalcitrant towards O-3-treatment (DDO3/DOC > 1.4). Furthermore, we predict that a reasonable estimate of the ozone dose required to remove any of the investigated APIs may be attained by multiplying the experimental average DDO3/DOC obtained with the actual DOC of any effluent. (C) 2013 Elsevier B.V. All rights reserved.
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| 2. |
- Antoniou, Maria G., et al.
(författare)
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Variability in required ozone doses for removing pharmaceuticals from wastewater effluents
- 2013
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Ingår i: Proceedings of the 13th International Conference on Environmental Science and Technology. - : Global Nest, Secretariat. - 9789607475510
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Konferensbidrag (refereegranskat)abstract
- Aim of study. The aim of the present study was to investigate the ozone dosage required to remove active pharmaceutical ingredients (APIs) from biologically treated wastewater of varying quality originating from different wastewater treatment processes. Methods. Secondary effluents from six Swedish wastewater treatment plants (VWVTP) were spiked with 42 APIs (nominal concentration 1pg/L) and treated with different 03 doses (0.5-12.0 mg/L ozone) in bench-scale experiments (Antoniou et al, 2012). Concentrations of APIs were measured by SPE extraction using OASIS HLB cartridges followed by quantification using LC-MS-MS (Grabic et al, 2012).. Results. For each wastewater effluent a profile of sensitivity of each API to a range of ozone doses were generated as shown in Figure 1.
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| 3. |
- Westerström, Rasmus, et al.
(författare)
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Oxidation and reduction of Pd(100) and aerosol-deposited Pd nanoparticles
- 2011
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Ingår i: Physical Review B - Condensed Matter and Materials Physics. - 2469-9950 .- 2469-9969 .- 1098-0121. ; 83:11
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Tidskriftsartikel (refereegranskat)abstract
- Using in situ high-pressure x-ray photoelectron spectroscopy, we have followed the oxidation and the reduction of Pd model catalysts in oxygen and CO pressures in the millibar range. The study includes a Pd(100) single crystal as well as SiOx-supported Pd nanoparticles of 15 or 35 nm diameter, respectively. We demonstrate that nanoparticles also form ultrathin surface oxides prior to the onset of the bulk PdO. The Pd nanoparticles are observed to bulk oxidize at sample temperatures 40 degrees lower than the single-crystal surface. In the Pd 3d(5/2) and the O 1s spectrum, we identify a component corresponding to undercoordinated atoms at the surface of the PdO oxide. The experimentally observed PdO core-level shift is supported by density functional theory calculations. In a CO atmosphere, the Pd 3d(5/2) component corresponding to undercoordinated PdO atoms is shifted by + 0.55 eV with respect to PdO bulk, demonstrating that CO molecules preferably adsorb at these sites. CO coordinated to Pd atoms in the metallic and the oxidized phases can also be distinguished in the C 1s spectrum. The initial reduction by CO is similar for the single-crystal and the nanoparticle samples, but after the complete removal of the oxide we detect a significant deviation between the two systems, namely that the nanoparticles incorporate carbon to form a Pd carbide. Our results indicate that CO can dissociate on the nanoparticle samples, whereas no such behavior is observed for the Pd(100) single crystal. These results demonstrate the similarities, as well as the important differences, between the single crystals used as model systems for catalysis and nm-sized particles on oxide supports.
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