Pilot scale investigation of DBD-Plasma photocatalysis for industrial application in livestock building air: Elimination of chemical pollutants and odors

Abstract

Photocatalysis and Plasma are widely considered as efficient and eco-friendly methods for the air treatment at domestic and industrial scales. In fact, the respective application of titanium dioxide (TiO2) and Dielectric-Barrier-Discharge(DBD) drew increasing attention in the last decades for their, flexible, non-selective and high efficiencies for the mineralization and the degradation of large selection of molecules. Nevertheless, the application of these techniques in separate conditions might generate undesired by-products that might hinder their treatment efficiencies. In this study, the effect of combining photocatalysis and Dielectric-Barrier-Discharge (DBD)techniques was investigated for the treatment of livestock building air at laboratory and industrial scale.. of Experiments were conducted in separate (i.e., Photocatalysis or plasma) and combined (i.e., Photocatalysis and plasma) systems to assess the degradation efficiency of two molecules, namely (NH3) and Propionaldehyde (ProPA) under various operating conditions. Studies onducted on laboratory scale showed a interesting level of treatment when applying either photocatalysis or plasma, with degradation yields reaching 29 and 36% for NH3 and 37 and 42% for ProPA, respectively. These degradation efficiencies were further enhanced when combining the processes, thus reaching 72 and 83% for NH3and ProPA, respectively. Moreover, investigations conducted on the generation of ozone during photocatalysis / Plasma treatment showed a decrease in the O3 concentration when compared to separate Plasma treatment. The photocatalytic degradation of ozone under UV radiation and in presence of TiO2 led to Low concentrations of ozone were detected at joint processas a consequence ofits catalytic decomposition under UV-light into HO2°, OH°,O2°-radicals at high humid conditions. The synergetic effect during the pollutant degradation was explained by the association of discharge plasma, presence of O3, UV-light and TiO2..Additionally,The implementation of the photocatalytic-plasma discharge reactor was performed to treat livestock sector air effluent loaded with ammonia.The effect of airflow and relative himidity were assessed. Results showed a significant NH3 removal efficiency in real conditions where it varied between59 and 75% for a flowrate of 2 m2/h and a relative humidity of 100%. Additonnlay, chemical and olfactometric studies were conducted to assess the performance of cimined sytem with real efflluent of livestock building air.