Efficiency of methylene blue in water purification using atmospheric plasma jet under varying conditions

Globally 2.5 billion people are unable to access clean water. Advanced oxidation processes (AOP’s), an accepted method of water purification, use hydroxide radicals (OH) to break down pollutants, but many AOP’s employ harsh chemicals and are expensive. Low temperature, atmospheric pressure plasma (LTAPP) presents novel methods of creating AOP’s to purify water. LTAPP provides a cheaper, greener method of purification because it can create plasma from ambient air and does not use chemical consumables such as ozone, hydrogen peroxide, or chlorine that need constant renewal. Thus the only cost associated with LTAPP purification is the cost of electricity to generate the plasma. The research presented studied the effects of different voltages, pulse widths, frequencies, and stand-off distances (SOD, distance from the edge of the plasma tube to the surface of the water) on water purification. Methylene blue dye (a known pollutant) in water was run at a set of standard conditions and tests were then run at conditions above and below standard conditions. The results of this research are presented in this work as an examination of total carbon content and a comparison of reduced methylene blue concentration and spectrometer measurements as a function of different plasma jet parameters.