Development of a new homogenous photo-Fenton process using Fe(III)-EDDS complexes

We report for the first time the use of Fe(III)-EDDS (EDDS: ethylenediamine-N,N'-disuccinic acid) complex as an iron source in a homogeneous photo-Fenton system. The performance of this system was followed through the formation of the center dot OH and the degradation of 2,2-bis-(4-hydroxyphenyl)propane (BPA). It was observed that Fe(III)-EDDS can enhance the efficiency of both center dot OH formation and BPA degradation especially near neutral pH. The effect of H2O2 concentration, Fe(III)-EDDS concentration, pH value and oxygen concentration on the BPA degradation during this photo-Fenton system was investigated. It was observed that O-2 is an important parameter affecting the efficiency of this process not only due to its reactivity with BPA but also because of its effect on the iron species present in solution. Comparison with iron complexes of oxalate, citrate and EDTA have demonstrated that Fe(III)-EDDS is a very efficient iron source for this photo-Fenton process. This work also demonstrates that Fe(III)-EDDS plays a positive role in the photo-Fenton system, especially at higher pHs, and makes this system an encouraging method for the treatment of organic pollutants in the natural environment. (C) 2012 Elsevier B.V. All rights reserved.