Acceleration of the bisphenols oxidation in the Fe(III)/peracetic acid system with salicylic acid

The paper presents the use of a chelating agent − salicylic acid (SAc) for the modification of ferric ions-peracetic acid based advanced oxidation process. Process conditions such as the concentration of oxidant (5 mM), activator (0.5 mM), chelating agent (1 mM) and initial pH (4) were optimized. The addition of salicylic acid reduces the time needed for complete oxidation of bisphenols (BPs) ([BPs]0 = 1 µM) form 90 to 10 min. The chelating agent increases the pH range from 4 to 6 at which PAA activation with iron ions can be used. The Fe(III)-SAc-PAA process is highly efficient at pH 6, which has been proven in the oxidation of organic micropollutants in wastewater. Experiments with radical scavengers and electron paramagnetic resonance (EPR) proved the dominant share of HO radicals in the Fe(III)-PAA system. In the Fe(III)-SAc-PAA system, Fe(IV) species play a key role in the degradation of organic micropollutants.