Decomposition of P-Xylene by microwave plasma generated at atmospheric pressure

This is an experimental study on effectively decomposing volatile organic waste by atmospheric-pressure microwave plasma. P-Xylene (PX) was used as a sample agent in the experiment because it is the main volatile organic compound (VOC) exhaust waste produced in many chemical industries and difficult to eliminate completely. We developed a microwave plasma apparatus which was designed for research on characteristic of atmospheric plasma and material treatment. The microwave plasma could be easily generated and be stably existing at the microwave frequency of 2.45GHz, and the power of 2-2.5 kW in the air. 2-4 lpm nitrogen as the carrier gas conducted p-Xylene into the air plasma zone to react. The GC analysis presented that the microwave plasma could eliminate p-Xylene efficiently at the destruction rate over 98%. And optical emission spectroscopy was also studied for research of reaction process. NO₂, the main by-product which was produced by recombination of N2 and O₂ at a high temperature, could be eliminated completely by passing the Exhaust gas into the alkaline solution. Due to its high efficiency, microwave plasma could be an advantageous option in VOC decomposing in PX industry.