Pulsed Discharge Plasma over a Water Surface Induces Decoloration of Dyes

Abstract

It was well known that plasma can be defined as a partially ionized gas composed of ions, electrons and neutral species. Recently, plasma-water interaction has attracted growing interest as it may provide experimental chemists with a quite unique reaction medium. In this work, decoloration of dyes in water as a reaction media and the effects of various parameters with pulsed high-voltage discharge plasma are studied. Such as plasma applied under hydrothermal conditions generates high-energy electrons, ions, and radicals, which in turn may generate new reaction fields, leading to effective organic compounds oxidation for both homogeneous and heterogeneous reactions. Here, we utilize pulse discharge plasma over water surface to study the decoloration of Orange G, Orange II, Congo Red, and Naphthol Blue Black. They were directly fed as starting materials without additives. The experiments were conducted under argon atmospheric at 313 K using a batch type reactor. The products were directly analyzed by UV-Vis (ultra violet-visible) spectrophotometer V-550. The decoloration rate increased with increasing peak pulse voltage and pulse numbers, presumably due to the increased electric field energy. Based on these results, the present system may be promising.