title: Degradation of Iodinated Contrast Media in Aquatic Environment by Means of UV, UV/TiO2Process, and by Activated Sludge.
abstract: Iodinated contrast media (ICM), which are used for radiological visualization of human tissue and cardiovascular system, are poorly biodegradable; hence, new methods of their removal are sought. In this study, the effectiveness of selected X-ray ICM removal by means of UV and UV/TiO2pretreatment processes from synthetic hospital wastewater was demonstrated. The following compounds were investigated: iodipamide, iohexol, and diatrizoate. The experiments were as follows: (i) estimated susceptibility of the ICM to decay by UV radiation in different aquatic matrices, (ii) determined an optimal retention time of hospital wastewater in the UV reactor, (iii) determined optimum TiO2concentration to improve the effectiveness of the UV pretreatment, and (iv) investigated removal of ICM by combination of the photochemical and biological treatment methods. The quantum yields of selected ICM decay in deionized water (pH = 7.0) were established as 0.006, 0.004, and 0.029 for iohexol, diatrizoate, and iodipamide, respectively. Furthermore, the experiments revealed that diatrizoate and iohexol removal in the UV/TiO2process is more efficient than in UV process alone. For diatrizoate, the removal efficiency equaled to 40 and 30 %, respectively, and for iohexol, the efficiency was 38 and 27 %, respectively. No significant increase in iodipamide removal in UV and UV/TiO2processes was observed (29 and 28 %, respectively). However, highest removal efficiency was demonstrated in synthetic hospital wastewater with the combined photochemical and biological treatment method. The removal of diatrizoate and iohexol increased to at least 90 %, and for iodipamide, to at least 50 %.
authors.affiliation: Environmental Biotechnology Department, The Silesian University of Technology, Akademicka 2, 44-100 Gliwice, Poland ; Centre for Biotechnology, The Silesian University of Technology, Krzywoustego 8, 44-100 Gliwice, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Borowska
authors.affiliation: Environmental Biotechnology Department, The Silesian University of Technology, Akademicka 2, 44-100 Gliwice, Poland ; Centre for Biotechnology, The Silesian University of Technology, Krzywoustego 8, 44-100 Gliwice, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Felis
authors.affiliation: Environmental Biotechnology Department, The Silesian University of Technology, Akademicka 2, 44-100 Gliwice, Poland.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Żabczyński
keywords: Iodinated contrast media; Membrane bioreactors; Photolysis; UV/TiO2 process