Effect of chelating agents on Reactive Green 19 decolorization through Fe 0 -activated persulfate oxidation process

The effect of chelating agents on the decolorization of Reactive Green 19 (RG19) through Fe activated persulfate (PS/Fe ) process was investigated. Though other previous studies reported that chelating agent can enhance the degradation of organic contaminant in Fenton-like system, our finding showed that the presence of chelating agents would chelate free Fe and minimize free Fe concentration, which resulted in the retardation of RG19 decolorization. RG19 decolorization decreased to 7%, 21%, and 15% in the presence of sodium citrate, sodium EDTA, and sodium oxalate, compared with control test (without chelating agent, 99%) within 10 min. The degradation efficiencies decreased with increasing chelating agent concentrations because of complex formation with Fe . Higher PS concentration, Fe dosage, and temperature had an obvious enhancement for RG19 decolorization efficiency. Elucidation of RG19 containing sodium EDTA degradation pathways indicated that PS/Fe process could degrade RG19 to carboxylic acids and inorganic salts efficiently. The presence of sodium EDTA had no influence on by-products, and EDTA just played a chelating agent function for chelating Fe ions.