Journal of the electrochemical society vol:148 issue:9 pages:G487-G493
The solubility of ozone in aqueous solutions expressed as a pseudo-Henry's law coefficient for ozone, *H-O3(T), is measured over a pH range of 1 to 8, and temperature range of 15 to 45 degrees C in the presence of several additives: HCl, HNO3, HAc (Ac is acetate), NaAc, and NaOH. The value of *H-O3(T) was found to be a function of temperature, pH, and nature of the anion. The pseudo-Henry's law coefficient is maximal at low pH and decreases with rising pH of the aqueous solution. The addition of chloride enhances the ozone decay rate and thus decreases the solubility below pH 2 while the addition of acetic acid/acetate results in an increase of *HO3T for pH > 3. The solubility enthalpy DeltaH(sol)(0) for ozone is found to be equal to (-22.38 +/- 0.79) kJ/mol. For applications of ozone in semiconductor cleaning processes, knowledge of the dependence of *H-O3(T) on pH, temperature, gas phase concentration, and additive is important in order to achieve optimized cleaning conditions. (C) 2001 The Electrochemical Society.