Degradation of Aqueous Rhodamine B With Gaseous Streamer Corona Plasma

Abstract

Gaseous streamer corona plasma was used to treat the wastewater containing rhodamine B (RhB). Three kinds of discharge modes, including dc discharge, pulsed discharge, and dc/pulse bias discharge, were investigated. Both of RhB degradation rate and energy efficiency were studied under experimental conditions of different peak voltages, repetitive frequencies, H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> concentrations, and initial pH, respectively. The results showed that the pulsed discharge had the fastest degradation rate while having an energy efficiency similar to that of dc/pulse bias discharge. The best efficiency of dc/pulse bias discharge was achieved at moderate voltage (17 kV) and low repetitive frequency (100 Hz). Additional H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> was found to accelerate the degradation reaction as well as decreasing initial pH. The Fourier transform infrared spectroscopy (FTIR) results showed that the products of degradation could be N, N-dimethylacetamide because of two strong peaks at 1656 and 1384 m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> .