Résumé:
A tight control of acidity is needed for performing oxidation–reduction reactions of organic
compounds dissolved in liquid media, since the relevant reactions often involve the occurrence of protons;
the matching kinetics are therefore acidity dependent. This feature holds for plasma treatments of aqueous
wastes which are intended to abate the concentration in organic pollutants. Exposure of aqueous solutions
to a gliding arc plasma in humid air induces acid and oxidising reactions in the condensed phase. Acid
effect results from the occurrence of NO species formed in the plasma and leads to the formation in
water of nitrous and nitric acids, which are responsible for a steep pH fall. Using selected buffers allows
accurate controlling of the acidity, which is necessary for most of the plasma-chemical or plasma-biochemical
reactions.
