Catalytic ozonation with silicate-based microfiltration membrane for the removal of iopamidol in aqueous solution

A novel flat microfiltration membrane was prepared by the compression method with cement and sucrose as a pore-forming agent for catalytic ozonation of iopamidol (IPM). The microfiltration membrane was characterized by SEM, EDS, FT-IR, XRD and XPS spectra. The results showed that various metal oxides and alkaline hydration products which are rich in hydroxyl groups existed in the structure of the membrane. The degradation and mineralization of IPM were improved by the membrane catalyzed ozonation process than that of the sole ozonation process. The effects of the ozone concentration, solution pH, inorganic ions and natural organic matter (NOM) on the catalytic performance were investigated. The results indicated that hydroxyl radicals (center dot OH) played an important role during IPM degradation. The intermediate degradation products of IPM were detected by the UPLC-QTOF/MS, and the results showed that the degradation mechanism included amide hydrolysis, amino oxidation and dehydrogenation.