Gliding arc discharge (GAD) assisted catalytic degradation of bisphenol A in solution with ferrous ions

Abstract

The degradation of an endocrine disruptor (ED), the bisphenol A (BPA), was studied using Gliding ArcDischarge (GAD). This kind of discharge generates a non-thermal plasma at atmospheric pressure andquasi-ambient temperature. The resulting plasma is the source of several chemical reactions that leadto the hydroxyl radical formation. Hydroxyl radicals,•OH, are very powerful and non-selective oxidizingagents (E◦•OH/H2O2.8 V vs. normal hydrogen electrode) able to degrade compounds resistant to conventionaltreatment. GAD belongs to the group of advanced oxidation processes (AOPs).Under different working gases such as air, argon, oxygen/argon mixture (20/80, v/v), a BPA aqueoussolution (120 M) was submitted to GAD. The evolution of BPA concentration was followed by high per-formance liquid chromatography (HPLC) method. The global oxidation of the organic matter was followedby chemical oxygen demand (COD) measurement. The mineralization was determined from the totalorganic carbon (TOC). The GAD treatment of the aqueous solution is accompanied by a massive produc-tion of hydrogen peroxide. The addition of Fe (II) to the reaction allows a better elimination of the organicmatter through the production of additional•OH radicals, issued from the decomposition of hydrogenperoxide according to Fenton reaction.The optimized system – GAD with oxygen/argon (20/80) as working gas, in presence of Fe (II) – wasvery efficient for BPA treatment: the compound disappeared after 30 min, the abatement of the COD wastotal after 120 min and the TOC diminished by 70%.