Oxidation of Phenolic Endocrine Disrupting Chemicals by Potassium Permanganate in Synthetic and Real Waters

• Published in: Environmental science & technology Vol. 46; no. 3; pp. 1774 - 1781
• Main Authors: Jiang, Jin, Pang, Su-Yan, Ma, Jun, Liu, Huiling
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 07.02.2012
• Subjects: Benzothiazoles; Chemicals; Chlorine; Comparative analysis; Endocrine Disruptors - chemistry; Indicators and Reagents; Kinetics; Oxidation; Oxidation-Reduction; Phenols - chemistry; Potassium; Potassium Permanganate - chemistry; Spectrum Analysis - methods; Sulfonic Acids; Waste Disposal, Fluid - methods; Water Pollutants, Chemical - chemistry; Water Purification - methods
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es2035587

In this study, five selected environmentally relevant phenolic endocrine disrupting chemicals (EDCs), estrone, 17β-estradiol, estriol, 17α-ethinylestradiol, and 4-n-nonylphenol, were shown to exhibit similarly appreciable reactivity toward potassium permanganate [Mn(VII)] with a second-order rate constant at near neutral pH comparable to those of ferrate(VI) and chlorine but much lower than that of ozone. In comparison with these oxidants, however, Mn(VII) was much more effective for the oxidative removal of these EDCs in real waters, mainly due to the relatively high stability of Mn(VII) therein. Mn(VII) concentrations at low micromolar range were determined by an ABTS [2,2-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid diammonium] spectrophotometric method based on the stoichiometric reaction of Mn(VII) with ABTS [MnVII + 5ABTS → MnII + 5ABTS•+] forming a stable green radical cation (ABTS•+). Identification of oxidation products suggested the initial attack of Mn(VII) at the hydroxyl group in the aromatic ring of EDCs, leading to a series of quinone-like and ring-opening products. The background matrices of real waters as well as selected model ligands including phosphate, pyrophosphate, NTA, and humic acid were found to accelerate the oxidation dynamics of these EDCs by Mn(VII). This was explained by the effect of in situ formed dissolved Mn(III), which could readily oxidize these EDCs but would disproportionate spontaneously without stabilizing agents.