Atmospheric pressure plasma for decontamination of chem/bio warfare agents

Abstract

Summary form only given. The Atmospheric Pressure Plasma Jet (APPJ) is a unique, a capacitively-coupled RF, nonthermal, uniform discharge operating at atmospheric pressure with a high flow of He/O/sub 2/ feedgas. The APPJ generates highly reactive atomic and metastable species of oxygen and directs them on to a contaminated surface at high velocity. This may provide a much needed method of decontamination of CBW agents which, unlike traditional decon methods, is dry and nondestructive to sensitive equipment. The reactive effluent of the APPJ at 175/spl deg/C has been shown to kill Bacillus globigii spores, a surrogate for Anthrax, with a D value (time to reduce viability by a factor of 10) of 4.5 sec at a standoff distance of 0.5 cm. This is 10 times faster than hot gas at the same temperature and requires 80% less energy input to achieve the same level of kill. This D value is also an order of magnitude better than achieved by other nonthermal plasma discharges, and unlike these other discharges, the APPJ provides a downstream process which can be applied to all accessible surfaces with no need for the contaminated object to fit within a chamber. Through active cooling of the electrodes we have also achieved a D value of 15 sec at an effluent temperature of just 75/spl deg/C, making the decontamination of personnel a definite possibility. The APPJ has also been shown to oxidize surrogates of the CW agents Mustard and VX, and a collaborative effort is now proceeding with the actual agents at the Edgewood Chem/Bio Center (ECBC, formerly ERDEC). Efforts are now being directed towards reducing the consumption of He and increasing the working stand-off distance.