Application of calcium peroxide activated with Fe(II)-EDDS complex in trichloroethylene degradation

CaO2 activated with Fe(II)-EDDS removed TCE efficiently at near neutral pH.EDDS prevented soluble iron from precipitation by forming complex.The dominant free radicals was HO. while O2− promoted HO generation.Cl−, HCO3− and humic acid inhibited CP/Fe(II)-EDDS performance on different levels.

This study was conducted to assess the application of calcium peroxide (CP) activated with Fe(II) chelated by (S,S)-ethylenediamine-N,N′-disuccinic acid (EDDS) to enhance trichloroethylene (TCE) degradation in aqueous solution. It was indicated that EDDS prevented soluble iron from precipitation, and the optimum molar ratio of Fe(II)/EDDS to accelerate TCE degradation was 1/1. The influences of initial TCE, CP and Fe(II)-EDDS concentration were also investigated. The combination of CP and Fe(II)-EDDS complex rendered the efficient degradation of TCE at near neutral pH range. Chemical probe and scavenger tests identified that TCE degradation mainly owed to the oxidation of HO while O2− promoted HO generation. Cl−, HCO3− and humic acid were found to inhibit CP/Fe(II)-EDDS performance on different levels. In conclusion, the application of CP activated with Fe(II)-EDDS complex is a promising technology in chemical remediation of groundwater, while further research in practical implementation is needed.