Decomposition of various endocrine-disrupting chemicals at boron-doped diamond electrode

Abstract

Anodic decomposition of endocrine disrupting chemicals (EDCs) namely, 17β-estradiol (E2) and Bisphenol A (BPA) at boron-doped diamond (BDD) has been studied with a working solution volume of 250 ml under galvanostatic mode. Cyclic voltammetric experiments were performed to examine the redox response of E2 and BPA as a function of cycle number. Kinetic analysis suggests that electro-oxidation reaction of EDCs undergo the control of applied current density ( I appl). The mineralization behavior of EDCs was investigated at BDD anode monitoring the total organic carbon (TOC) value at three different I appl. Electrolysis at high anodic potential causes complex oxidation of EDCs that lead to form the final sole product as CO 2. From these TOC results, the mineralization current efficiency was evaluated and discussed. In order to examine the effect of electrolyte variables on EDCs, BPA compound was taken and undergone the supporting medium and pH variation experiments. Considering global oxidation process, the effect of supporting medium (Na 2SO 4, NaNO 3, and NaCl) has been discussed in terms of electro-generated inorganic oxidants such as S 2O 8 2−, H 2O 2 and ClO −. The better performance of BDD anode was proved on a comparative study with Pt and glassy carbon under similar experimental conditions. A possible reaction mechanism for BPA degradation involving three main aromatic intermediates, identified by GC–MS analysis, was proposed.