Performance test of negative ion plasma as air purifier to degrade volatile organic compounds (case study for ethanol and toluene)

Abstract

Volatile organic compounds (VOCs) are pollutants that can reduce indoor air quality and the leading cause of respiratory disorders such as Acute Respiratory Infections (ARI) and Sick Building Syndrome (SBS). Because of that, the indoor air must be cleaned by degrading VOCs. One of the non-thermal plasma applications to degrade VOCs is negative ion plasma or Negative Air Ion (NAI), i.e., ionized air becomes negatively charged. Superoxide is one of the most widely produced NAI and can be a degrading agent for VOCs in the air. The ability of plasma negative ions in degrading VOCs was further investigated using case studies in 1500 ppm ethanol and 600 ppm toluene. The research was conducted by injecting ethanol and toluene gas into the prototype, equipped with a negative ion plasma generator that produces a DC voltage of 5.6 kV. The measured negative ion density in the prototype is 8 x 106 – 1.2 x 107 ion/m3. The Removal efficiency of ethanol reached 99.94% during a contact time of 4 hours with a final concentration of 0.97 ppm, while that of toluene reached 99.77% during a contact time of 5 hours with a final concentration of 1.33 ppm. Fan blowing speed can increase the performance of negative ion plasma, where the fan speed of 1600 RPM at a voltage of 12VDC gives the best results in this study.