Pharmaceutical residues, a group of emerging micro-pollutants, have been globally detected in the aquatic environment since 1990s. As such micro-pollutants are likely to harm human beings and the eco-system, to remove pharmaceuticals from the environment is of great concern. Potassium ferrate (VI) is able to remove a wide range of organic and inorganic pollutants from wastewater. However, the knowledge of treating pharmaceuticals by ferrate (VI) is limited. Therefore, this study aimed to assess the ferrate (VI) performance in the removal of selected pharmaceuticals from water and wastewater and with the following objectives: I) to investigate the removal of selected pharmaceuticals from test solutions and wastewater by ferrate (VI); 2) to assess the influence of solution pH and ferrate (VI) dose towards the treatment; 3) to determine rate constants of ferrate (VI) with selected pharmaceuticals; and 4) to identify oxidation products (OPs) of selected pharmaceuticals during ferrate (VI) treatment. Results revealed that, in test solutions, ferrate (VI) could remove ciprofloxacin (CIP), sulfamethoxazole (SMX), diclofenac (DCF) and carbamazepine (CBl) with a high efficiency (>80%) in optimum conditions, and ferrate (VI) demonstrated considerable apparent second-order rate constants with these four compounds at pH 8 and 9. Moreover, possible OPs of CIP, SMX, DCF and CBl during ferrate (VI) oxidation were identified and their degradation pathways were tentatively proposed. On the other hand, the removal efficiencies of ibuprofen (IBU) and bezafibrate (BlF) by ferrate (VI) were less than 45%, and their rate constants were below 0.5 M-I s - I at pH 8 and 9. No OPs of IBU and BlF were detected during ferrate (VI) oxidation. In the secondary effluent samples from Shieldhall wastewater treatment plant (WWTP) in Glasgow, 15 pharmaceuticals were targeted and eight of them, with concentrations up to 1080 ng/L, were detected. Reduction of naproxen (NPX), lidocaine (LDC) and CBZ in the raw effluent samples was achieved above 40% with 4 mgIL ferrate (VI) at pH 4-8. In the modified effluent samples spiked with 15 target compounds at 10 ug/L, low reduction rates of target compounds were observed (<50%), except for CIP, SMX and erythromycin (ETM). In both test solutions and effluent samples, raising ferrate (VI) dose improved the treatment performance, while the influence of solution pH varied among different pharmaceuticals. For the first time, this study investigated the treatment of BZF by ferrate (VI) and the possible OPs of CIP and DCF during ferrate (VI) oxidation. From this study, it has been demonstrated that ferrate (VI) can efficiently remove pharmaceuticals containing electron-rich moieties (ERMs) and thus is promising in the decontamination of pharmaceutical residues in water and wastewater.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:601454 |
| Date | January 2013 |
| Creators | Zhou, Zhengwei |
| Publisher | Glasgow Caledonian University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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