Kinetics of the Oxidation of Phenols and Phenolic Endocrine Disruptors during Water Treatment with Ferrate (Fe(VI))

摘要

The ability of ferrate (Fe(VI)) to oxidize phenolic endocrine-disrupting chemicals (EDCs) and phenols during water treatment was examined by determining the apparent second-order rate constants (k_(app)) for the reaction of Fe(VI) with selected environmentally relevant phenolic EDCs (17alpha-ethinylestradiol,beta-estradiol,and bisphenol A) and 10 substituted phenols at pH values ranging from 6 to 11.The three selected groups of EDCs showed appreciable reactivity with Fe(VI) (k_(app) at pH 7 ranged from 6.4 X 10~2 to 7.7 X 10~2 M~(-1) s~(-1)).The k_(app) for the substituted phenols studied at pH 7 ranged from 6.6 to 3.6 X 10~3 M~(-1) s~(-1),indicating that many other potential phenolic EDCs can be oxidized by Fe(VI) during water treatment.The Hammett-type correlations were determined for the reaction between HFeO_4~- and the undissociated (log(k) = 2.24-2.27sigma~+) and dissociated phenol (log(k) = 4.33-3.60sigma~+).A comparison of the Hammett correlation obtained forthe reaction between HFeO_4~- and dissociated phenol with those obtained from other drinking water oxidants revealed that HFeO_4~- is a relatively mild oxidant of phenolic compounds.The effectiveness of Fe(VI) for the oxidative removal of phenolic EDCs was also confirmed in both natural water and wastewater.