Study On Plasma Oxidation Of Adsorbed VOCs At Atmospheric Pressure And Room Temperature

The indoor air pollutants, such as formaldehyde and benzene, have been attracted more andmore attentions in recent years. In this paper, a novel method, combining adsorption with plasma,was proposed to remove VOCs from indoor air. Using this method, the gaseous VOCs wasadsorbed on adsorbents, and then the adsorbed VOCs were oxidized in DBD plasma atatmospheric pressure and room temperature.At the condition of room temperature, 100 ppm formaldehyde, 1.5ï¼…water, 22.4 kV of V_pand 50Hz of frequency, the adsorbing performance ofγ-Al₂O₃, HZSM-5, NaY and CeO2 forformaldehyde was investigated. The results indicate that CeO₂ has the best capacity to adsorbformaldehyde and gives the highest selectivity to the CO₂ in the plasma oxidation reaction.Using CeO₂ as an adsorbent, it has been found that by the "adsorption-plasma" methods, theselectivities of CO₂ were 95ï¼…(for 1-stage case) and 99ï¼…(for 2-stage case), respectively. While atthe same condition, using a common plasma method, it were 20ï¼…(for 2-stage case) and 56ï¼…(for1-stage case), respectively.By the "adsorption-plasma" method, benzene has been oxidized as well as formaldehyde overdifferent adsorbents. It is shown that this method can be used in a wide area.In addition, the energy cost of "adsorption-plasma" method and the regeneration ability of theadsorbents have been studied. The energy cost in this method is lower than the common plasmamethod, especially for the low concentration of VOCs. The adsorbents have been well regeneratedin the plasma and keep high stability.It demonstrates that this method is a promising approach to removing VOCs pollutants fromindoor air.