Removal of low-concentration thiophene by DC corona discharge plasma.

This study focuses on the removal of C4H4S using DC corona discharge plasma. The influences of various factors such as C4H4S concentration (ppm), temperature (°C), O2 concentration (%), and dust concentration (mg/m3) on the conversion of C4H4S were studied. Furthermore, gaseous compositions were determined using Fourier transform infrared (FTIR) spectroscopy. Solid products, which were collected from earth and discharge electrodes, were analyzed using X-ray diffraction (XRD). The results showed that, under the condition of DC corona discharge plasma, C4H4S converted to CO, CO2, S, SO2, and SO42-, and that the conversion rate increased with the increase in specific input energy (SIE). The increase of O2 concentration led to further energy consumption that generated O3, which in turn decreased the conversion rate of C4H4S. The increase in temperature exhibited a positive influence on the conversion of C4H4S when the SIE was less than 268 J/L. However, above this value of SIE, the temperature affected the conversion of C4H4S negatively with the increase in SIE. When dust was introduced, the conversion of C4H4S was significantly improved and the yield of SO2 reduced due to the reaction which took place among C4H4S, SO2 and dust in the electric field. The results showed that the DC corona discharge plasma exhibited considerable potential to remove C4H4S, while dust contributed positively towards the disposal of C4H4S. Graphical abstract In this work, DC corona plasma was used to remove thiophene (C4H4S) from a dust-containing gas stream. The results showed that electron collision, oxidizability of radicals, and existence of O3 were the main causes of C4H4S decomposition. The electron collision effects, contents of radicals, O3, and the conversion rate of C4H4S were enhanced with the increase in SIE (specific input energy). The main products consisted of CO, CO2, SO2, and solid products. The solid products and dust moved to the earth electrode in the electric field.