Water Purification by Plasmas: Which Reactors are Most Energy Efficient?

Decomposition of toxic organic compounds is a major environmental problem. Increasingly, research is being conducted to use plasmas to decompose these wastes in water, as it is simple, effective and does not require the addition of other chemical agents. Different groups have used varied reactor designs. This study calculates and compares relative energy yields of about 27 major types of plasma reactors. The results reveal dramatic differences in the energy yields, up to five orders of magnitude. The most efficient are pulse powered reactors, in which plasma is formed in gas phase and the waste solution sprayed into it. Factors that account for this improved energy yield are discussed. This study will help narrow down efficient reactors for further studies, development and commercial uses.