Efficient decomposition of gaseous formaldehyde by surface dielectric barrier discharge with different dielectric materials

Abstract In recent years, research on atmospheric-pressure low-temperature plasma technology has made significant progress and demonstrated great potential in the field of environmental remediation. Numerous studies have shown that low-temperature plasma technology has significant advantages for eliminating volatile organic compounds (VOCs). However, the direct treatment of formaldehyde gas must be improved. Therefore, this study investigated the degradation of formaldehyde in the gas phase, using air as the working gas, following the principles of economic and environmental protection. Furthermore, the degradation effect of surface dielectric barrier discharge (SDBD) plasma on formaldehyde in the gas phase was investigated. This study examined the characteristics of a surface air plasma under sinusoidal power supply excitation. The effects of the dielectric plate material, discharge area, and voltage on the discharge characteristics were also discussed. The results showed that the discharge voltage and temperature increase of the alumina ceramic dielectric board were the lowest at the same power, and the concentration of excited-state reactive species generated was relatively high. For the detection of neutral gas components under different voltages, it was found that the discharge gradually transformed from ozone mode to nitrogen oxide mode with increasing voltage. In the experiment on formaldehyde degradation in the gas phase, it was found that the degradation rate in the direct degradation mode was positively correlated with the discharge power and negatively correlated with the initial concentration and gas flow rate, with the highest degradation rate of 96.57%. In cyclic degradation mode, the treatment reached the national safety standard within 5 min.