Oxidation of contaminants of emerging concern by combination of peracetic acid with iron ions and various types of light radiation – Optimization, kinetics, removal efficiency and mechanism investigation

Abstract

The aim of this work was to check the effectiveness of PAA activated by fluorescent light low intensive radiation, UV radiation (254 or 366 nm), simulated solar light and also in PAA-iron (Fe2+ or Fe3+) ions in the degradation of selected contaminants of emerging concern (CECs). The kinetics of the degradation process of benzophenone (BPH), 4-n-octylphenol (4OP), 4-n-nonylphenol (4NP), 3-(4-methylbenzylidene) camphor (MBC), endosulfan I (ESI), endosulfan II (ESII), oxybenzone (OXB), bisphenol A (BPA), diethylstilbestrol (DSB) and estrone (E1) in such systems have been studied. Using chemometric technique design of experiments (DoE) the following composition of PAA-H2O2 equilibrated mixture was selected as optimal: CPAA = 10.5 mgL-1, CH2O2 = 20 mgL-1 and pH = 6. The most effective appeared to be PAA-Fe(III) oxidizing system. High degradation efficiency, above 90 %, was observed for all tested compounds in the presence of Fe (III) ions as an activator. Using the EPR technique, the radical nature of the processes under study was proved. The influence of a matrix (raw and purified wastewater) on the degradation rate has been checked. Insight into the process done with Density Functional Theory (DFT) showed that ∙OH addition and H abstraction are the main mechanisms initiating analytes degradation.