Exploring the potential of Fe (III)-EGTA and Fe (III)-DTPA as the catalysts to enhance UV/Persulfate in the degradation of aqueous sulfamethazine.

The combination of UV and water-soluble Fe (III) complexes is an effective method for generating Fe (II) in situ for activating advanced oxidation processes. This study explored the potential of Fe (III)-diethylenetriaminepentaacetic acid (Fe (III)-DTPA) and Fe (III)-ethylene glycol-bis(2-aminoethylether)-N,N,N',N'-tetraacetic acid (Fe (III)-EGTA) in activating the UV/persulfate (UV/PS) for sulfamethazine removal. The initial screening showed that Fe (III)-EGTA and Fe (III)-DTPA could significantly improve the rate of sulfamethazine removal. The optimum molar ratios of persulfate to Fe (III)-DTPA and Fe (III)-EGTA were 100:1 and 100:2.5. The predicted percentage of sulfamethazine removal under the optimized conditions, obtained using Response Surface Methodology, was ~99% for both catalysts. The pH range of 6 to 8 did not significantly affect the performance of UV/PS in the removal of sulfamethazine. The percentage sulfamethazine removal in the selected water samples ranged from 93.6 to 99.6%, agreeing with the predicted value. The performance of both catalysts in activating UV/PS is comparable to that of the frequently used Fe (III)-EDDS.