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Transformation Of Iopamidol During Chlorination, Friedrich Wendel, Christian Eversloh, Edward Machek, Stephen Duirk, Michael Plewa, Susan Richardson, Thomas Ternes
Transformation Of Iopamidol During Chlorination, Friedrich Wendel, Christian Eversloh, Edward Machek, Stephen Duirk, Michael Plewa, Susan Richardson, Thomas Ternes
Stephen E. Duirk
The transformation of the iodinated X-ray contrast media (ICM) iopamidol, iopromide, iohexol, iomeprol, and diatrizoate was examined in purified water over the pH range from 6.5 to 8.5 in the presence of sodium hypochlorite, monochloramine, and chlorine dioxide. In the presence of aqueous chlorine, only iopamidol was transformed. All other ICM did not show significant reactivity, regardless of the oxidant used. Chlorination of iopamidol followed a second order reaction, with an observed rate constant of up to 0.87 M–1 s–1 (±0.021 M–1 s–1) at pH 8.5. The hypochlorite anion was identified to be the reactive chlorine species. Iodine was released …
Comparison Of Anion Exchange Resins And Aluminum-Based Coagulants For Natural Organic Matter (Nom) Removal And Disinfection By-Product (Dbp) Formation, Elizabeth Crafton, Dayang Wu, Stephen Duirk
Comparison Of Anion Exchange Resins And Aluminum-Based Coagulants For Natural Organic Matter (Nom) Removal And Disinfection By-Product (Dbp) Formation, Elizabeth Crafton, Dayang Wu, Stephen Duirk
Stephen E. Duirk
Anion exchange resins (AERs) were compared with aluminum-based coagulants for reducing disinfection by-product (DBP) precursor concentrations from a source water collected in northeast Ohio, USA. Three AERs (IRA-910, IRA-958, and MIEX) were evaluated to determine which resin would remove the most natural organic matter (NOM) and moieties responsible for DBP formation. All the AERs were found to be highly proficient at NOM removal specifically the moieties that absorb UV254 (i.e., chromophores) over 75 min of contact time; however, MIEX removed NOM at a faster rate than IRA-910 and IRA-958 resins. Enhanced coagulation was effective at removing approximately 35% of the …