Removal of Iopromide and Its Intermediates from Ozone-Treated Water Using Granular Activated Carbon

The potential of granular activated carbon (GAC) to remove iopromide and its intermediates from ozone- treated river water was evaluated. Mass spectrum analysis showed that ozone treatment lead to partial removal of iopromide (m/z 791.8) with generation of various intermediates. GAC demonstrated a lower iopromide adsorption (1.60 mu g/g) in the presence of natural organic matter (NOM) compared to NOM-free water (12.54 mu g/g), indicating the inhibitory effect of NOM on iopromide adsorption. Ozone treatment of the influent reduced the inhibitory effect of NOM by altering its composition and inducing polarity shift. GAC post- treatment resulted in improved removal of residual iopromide and its intermediates from the ozone- treated influent. Application of such combined treatment of ozonation followed by GAC adsorption can be an effective strategy for the removal of iopromide and its intermediates from contaminated water streams.