title: Advanced oxidation of iodinated X-ray contrast media in reverse osmosis brines: the influence of quenching.
abstract: Among the main restrictions for the implementation of advanced oxidation processes (AOPs) for removal of micropollutants present in reverse osmosis (RO) brines of secondary effluents account the quenching performed by background organic and inorganic constituents. Natural organic matter (NOM) and soluble microbial products (SMP) are the main effluent organic matter constituents. The inorganic fraction is largely constituted by chlorides and bicarbonate alkalinity with sodium and calcium as main counterions. The quenching influence of these components, separately and their mixture, in the transformation of model compounds by UVA/TiO2 was studied applying synthetic brines solutions mimicking 2-fold concentrated RO secondary effluents brines. The results were validated using fresh RO brines. Diatrizoate (DTZ) and iopromide (IOPr) were used as model compound. They have been found to exhibit relative high resistance to oxidation process and therefore represent good markers for AOPs techniques. Under the conditions applied, oxidization of DTZ in the background of RO brines was strongly affected by quenching effects. The major contribution to quenching resulted from organic matter (≈70%) followed by bicarbonate alkalinity (≈30%). NOM displayed higher quenching than SMP in spite of its relative lower concentration. Multivalent cations, i.e., Ca(+2), were found to decrease effectiveness of the technique due to agglomeration of the catalyst. However this influence was lowered in presence of NOM. Different patterns of transformation were found for each model compound in which a delayed deiodination was observed for iopromide whereas diatrizoate oxidation paralleled deiodination.
authors.affiliation: Faculty of Civil & Environmental Engineering and Grand Water Research Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Sara P
authors.initials: SP
authors.lastname: Azerrad
authors.affiliation: Faculty of Civil & Environmental Engineering and Grand Water Research Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Shirra
authors.initials: S
authors.lastname: Gur-Reznik
authors.affiliation: Faculty of Civil & Environmental Engineering and Grand Water Research Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Lilly
authors.initials: L
authors.lastname: Heller-Grossman
authors.affiliation: Faculty of Civil & Environmental Engineering and Grand Water Research Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel. Electronic address: carlosd@tx.technion.ac.il.
authors.forename: Carlos G
authors.initials: CG
authors.lastname: Dosoretz
mesh_terms: D000468:Alkalies / Q000737:chemistry; D002853:Chromatography, Liquid; D003287:Contrast Media / Q000737:chemistry*; D003973:Diatrizoate / Q000737:chemistry; D054879:Halogenation; D006863:Hydrogen-Ion Concentration; D007472:Iohexol / Q000031:analogs & derivatives / Q000737:chemistry; D007700:Kinetics; D013058:Mass Spectrometry; D009995:Osmosis; D010084:Oxidation-Reduction; D054712:Salinity; D012492:Salts / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D014025:Titanium / Q000737:chemistry; D014466:Ultraviolet Rays; D014865:Waste Disposal, Fluid; D014867:Water / Q000737:chemistry; D014965:X-Rays
chemical_list: D000468:Alkalies; D003287:Contrast Media; D012492:Salts; C017082:brine; D014867:Water; D003973:Diatrizoate; C009495:titanium dioxide; D007472:Iohexol; C038192:iopromide; D014025:Titanium
keywords: Advanced oxidation processes; Brines desalination; Iodinated X-ray contrast media; Radicals quenching; Synthetic brines; Titanium dioxide oxidation