Degradation of organic pollutants in waters by a water-insoluble iron(III) Schiff base complex

Abstract

To degrade organic pollutants in water with hydrogen peroxide (H2O2) under visible light (λ≥420nm), a novel water-insoluble iron Schiff base complex, iron(III)-bis-salicylaldehyde-o-aminophenol (Fe-SAP), was prepared and characterized using NMR, MS, IR, and UV–Vis spectroscopy. Rhodamine B (RhB) and salicylic acid were used as probes to characterize the photocatalytic system. High catalytic activity of Fe-SAP was observed over a wide range of pH values from 3 to 9. Scavenging studies of reactive oxygen species (ROS) and ESR experiments indicate that the primary ROS from photocatalytic conversion of H2O2 is 1O2, rather than OH. To date, there have been few reports on the generation of 1O2 by iron organic complexes for the oxidative decomposition of organics. The catalyst stability and reusability are good, most likely because the water-insoluble Fe-SAP is able to reduce the damage to its organic ligands by OH. Given these favorable characteristics, Fe-SAP exhibits excellent potential for practical application in removing refractory organic pollutants and pollutants of emerging concern from water and wastewater.