pH dependence of persulfate activation by EDTA/Fe(III) for degradation of trichloroethylene.

The ability of free ferrous ion activated persulfate (S(2)O(8)(2-)) to generate sulfate radicals (SO(4)(-)) for the oxidation of trichloroethylene (TCE) is limited by the scavenging of SO(4)(-) with excess Fe(2+) and a quick conversion of Fe(2+) to Fe(3+). This study investigated the applicability of ethylene-diamine-tetra-acetic acid (EDTA) chelated Fe(3+) in activating persulfate for the destruction of TCE in aqueous phase under pH 3, 7 and 10. Fe(3+) and EDTA alone did not appreciably degrade persulfate.