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 SO₄^2-, 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.