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

Abstract

► Ethylenediamine- N , N ′-disuccinic acid (EDDS) is a strong complexing agent of iron. ► Fe(III)-EDDS complex is stable in wide range of pH until 9.0. ► Fe(III)-EDDS complex is an efficient source of iron in photo-Fenton like process. ► OH radical formation is observed and measured in different conditions. ► Efficient degradation of organic compounds is achieved in acidic, neutral and alkaline pH. 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 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 OH formation and BPA degradation especially near neutral pH. The effect of H 2 O 2 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.