Title
Iodinated contrast media oxidation by nonthermal plasma: The role of iodine as a tracer
Date Issued
01 January 2011
Access level
metadata only access
Resource Type
journal article
Author(s)
Technion-Israel Institute of Technology
Publisher(s)
Elsevier Ltd
Abstract
The oxidation of trace pharmaceutical compounds in wastewater desalination streams by nonthermal plasma (NTP) was evaluated. Brines from a two stage-RO pilot plant process as well as two sources of tertiary effluents, ultrafiltrated secondary effluents and membrane biological reactor effluents, were comparatively tested with ultra-pure water. The non-ionic and ionic iodinated contrast media (ICM) compounds, iopromide (IOPr) and diatrizoate (DTZ), respectively, were used as model compounds. The neurostabilizer drug carbamazepine (CBZ) was used for reference purposes. Based on deiodination profiles, two distinct patterns of initial oxidation could be established for the ICM. The time profile of deiodination and transformation paralleled for DTZ, indicating that transformation of the aromatic ring is the main initial pattern of transformation. For IOPr, a considerable lag phase of deiodination was observed, suggesting that oxidation of the alkyl chains rather than ring oxidation is the main pattern of initial transformation. Although transformation rate of IOPr was higher compared to DTZ, the rate and degree of deiodination was higher for DTZ than IOPr. Both ICM displayed a markedly lower susceptibility to NTP oxidation compared to CBZ. However, the kinetics of IOPr transformation seems to be less affected by the water matrixes, compared to DTZ and CBZ. Whereas NTP mediated oxidation of ICM followed first-order kinetics, a better fit to Harris model was found for CBZ. As a result of the NTP oxidation, treated brines and effluents displayed a substantial increase in biodegradability (measured as BOD).To conclude, NTP displayed a high potential for treating reluctant pharmaceuticals active compounds such as ICM, even at the background of relatively high DOC concentrations, as can be found in treated effluents and desalination brines, and with no need for chemical additives. © 2011 Elsevier Ltd.
Start page
5047
End page
5057
Volume
45
Issue
16
Language
English
OCDE Knowledge area
Química
Subjects
Scopus EID
2-s2.0-80052271338
PubMed ID
Source
Water Research
ISSN of the container
00431354
Sponsor(s)
The fate of the background DOC during NTP treatment, i.e., mineralization, is presented in . The rate of DOC mineralization was in the order of 25% for the tertiary effluents and approx. 15% and 10% for the RO Fig. 4 1 and RO 2 brines, respectively. Compared to mineralization, a high SUVA reduction was observed: 80 ± 0.2%, 61 ± 6% and 48 ± 9% for tertiary effluents, RO 1 and RO 2 brines, respectively, depicting a considerable reduction of the total dissolved organic carbon aromaticity ( Jarusutthirak et al., 2002 ); Gerrity et al. (2010) and Westerhoff et al. (2009) reported that the reduction in UVA 254 exceeded the DOC removal. Since SUVA is the ratio of UVA at a wavelength of 254 nm to DOC, this observation is supported by the results presented here as well. UVA 254 indicates favorable oxidation of unsaturated carbon bonds ( Westerhoff et al., 2009 ). Moreover, a very high reduction in 280 nm wavelength absorption; 90 ± 10%, 73 ± 5% and 59 ± 3% for tertiary effluents, RO 1 and RO 2 brines, respectively, was also observed. This most probably implies that transformation of the proteinic and phenolic DOC groups took place.
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