The Use of Nonthermal Plasmas in Environmental Applications

Nonthermal plasmas are widely used environmental applications covering a broad and diverse range of topics, which have been studied extensively in laboratory, bench-scale investigations, particularly during the past two decades. However, only a few research breakthroughs were successfully translated into economically viable technologies for large-scale industrial applications. Those include ozonizers using dielectric barrier discharges and electrostatic precipitators using corona discharges. In this chapter, we describe the current status of ozonizers and electrostatic precipitators. We also try to identify some of the bottlenecks that prevent other nonthermal plasma-based environmental technologies from becoming widely applicable. As an example, we look at the use of nonthermal plasmas for the treatment of gaseous and (to a lesser extent) liquid waste streams, with an emphasis on waste streams containing volatile organic compounds (VOCs). Bottlenecks preventing or slowing down the rapid and efficient translation of successful bench-scale studies to widely used industrial technologies include the identification, quantification, and control of byproducts produced in the plasma chemical reactions and establishing carbon closure (i.e., the accounting of the ultimate fate of each initial carbon atom that is exposed to the plasma).