KINETICS OF THE PERACETIC-ACID DECOMPOSITION .2. PH EFFECT AND ALKALINE-HYDROLYSIS

The effect of pH on the decomposition of peracetic acid in an aqueous solution was studied. It was found that three potential reactions, nam ely i) the spontaneous decomposition, ii) the hydrolysis and iii) the transition metal catalysed decomposition, are responsible for the cons umption of peracetic acid. The spontaneous decomposition reaches its m aximum at pH 8.2, while both the hydrolysis and metal ion catalysed de composition increase as the pH increases. At pH 10.5 and higher, the h ydrolysis becomes dominant when the metal ion catalysed decomposition is minimized by the addition of DTMPA. The kinetics of the peracetic a cid hydrolysis was developed, which can very well predict the developm ent of peracetic acid and hydrogen peroxide during the decomposition r eaction.