Deiodination of iopamidol by zero valent iron (ZVI) enhances formation of iodinated disinfection by-products during chloramination

Electrochemical dehalogenation of disinfection by-products and iodine-containing contrast media: A review

“…Reductive dehalogenation (referred to in the case of ICMs as deiodination) induced via external EC polarization of a working electrode or promoted by zero-valent metals and metal-based catalysts has shown promise in the treatment of ICMs [13,[40][41][42]. The susceptibility of ICMs to reductive degradation was demonstrated by Zwiener et al [12] who examined the EC reduction of iomeprol on nickel cathode.…”

“…The reaction rates were strongly affected by pH and hydrodynamic conditions which indicated the presence of mass transfer limitations. The ZVI-driven reduction of iopamidol in the presence of monochloramine was studied in Dong et al [41]. The contact times were as long as 60 h although the removal of iopamidol was most notable within the initial 10 h of reaction time.…”

Disinfection byproduct formation during drinking water treatment and distribution: A review of unintended effects of engineering agents and materials

“…Given that unlined cast iron pipes are widely used in many drinking water distribution systems, reactions between chloramphenicol antibiotics and ZVI may contribute to the formation of DCAM. Iis considered as the main iodine source accounting for the formation of toxic I-DBPs during disinfection, while iodinated X-ray contrast media and iodate can also serve as the iodine sources of I-DBPs in the presence of ZVI (Xia et al, 2017;Dong et al, 2018). Iopamidol or iodate is subjected to the deiodination or reduction by ZVI to yield I -, which enhances the formation of I-DBPs during subsequent chlor(am)ination (Xia et al, 2017;Dong et al, 2018).…”

Iodinated disinfection byproducts: Formation and concerns

“…Iopamidol deiodination, and hence, iodo-DBP formation, also can also occur under Ferrate (Fe(VI)) oxidation [37] and in the presence of zerovalent iron [38]. In the case of Fe 0 , the reaction was enhanced in acidic conditions and in the presence of specific anions (SO 4 -2 and Cl-) and monochloramine [38].…”