Comparative Effect of UV, UV/H2O2 and UV/H2O2/Fe on Terbuthylazine Degradation in Natural and Ultrapure Water

Abstract

Different advanced oxidation processes (AOPs) (ultraviolet radiation, hydrogen peroxide photolysis and photo-Fenton) were applied to test the degradation of terbuthylazine in three types of water: (a) ultrapure water, (b) surface water from the Gaditana area (Los Hurones reservoir, Cádiz, Spain) and (c) groundwater from the Tempul spring in Jerez de la Frontera (Cádiz, Spain). The experiments were carried out on a laboratory scale, using two different types of reactors, batch and semi-continuous. In batch reactors, the most efficient process for the experiments carried out with both ultrapure water and underground groundwater was ultraviolet radiation, whereas for surface water from the Gaditana area, the process that obtained the best results was the photolysis of hydrogen peroxide with 2.5 mg L−1 of H2O2. In semi-continuous reactors, the most efficient process was the photolysis of hydrogen peroxide with 2.5 mg L−1 of H2O2 for all the matrices studied. In both types of reactors, terbuthylazine degradation percentages higher than 90% were achieved; the main difference was in the reaction time, which varied from minutes in the batch reactor to seconds in the semi-continuous reactor. In all the applied AOPs, N-terbutyl-6-hydroxy-N′ethyl-1,3,5-triazine-2,4-diamine (TBA-212) was generated as a reaction intermediate.

Kinetics and mechanism of dissolved organic phosphorus (DOP) digestion by the UV/O3 process

“…Among them, advanced oxidation techniques that combine light with oxidants or catalysts are gaining significant interest, and the hydroxyl radicals or other radicals they excite can digest compounds more efficiently 17 . Different combinations of AOPs, such as UV/O 3 , UV/H 2 O 2 , 18‐20 UV/Fe 2+ /H 2 O 2 , 21 ultrasonic/photocatalytic oxidation, 22 and light/acoustic/electric‐assisted Fenton reaction processes, 23 can produce hydroxyl radicals more efficiently and thus more significantly improve the oxidation efficiency of pollutants 24 …”