U. Jans et J. Hoigne, ACTIVATED CARBON AND CARBON-BLACK CATALYZED TRANSFORMATION OF AQUEOUSOZONE INTO OH-RADICALS, Ozone: science & engineering, 20(1), 1998, pp. 67-90
In an ozone-containing water a suspension of a few milligrams per lite
r of activated carbon (AQ or carbon black (CB) initiates a radical-typ
e chain reaction that then proceeds in the aqueous phase and accelerat
es the transformation of O-3 into secondary radicals, such as hydroxyl
radicals (degrees OH). This results in an Advanced Oxidation Process
(AOP) that is similar to an O-3-based AOP involving application of H2O
2 or UV-irradiation. We have studied these phenomena by observing the
effect of suspensions of AC and CB on the rate of transformation of O-
3 in lakewater and in well-characterized solutions. In addition, the s
toichiometric yield factor of the AC-catalyzed conversion of O-3 into
degrees OH has been shown to be comparable to that which is achieved b
y a slower process in the absence of AC. This comparison has been base
d on the measured depletion of an O-3-resistant organic degrees OH pro
be that was added as a trace reference compound and that competed with
a kinetic excess of solutes that controlled the lifetime of degrees O
H. The AC-catalyzed transformation of O-3 into degrees OH for creating
an O-3-based AOP may be of practical interest to water utilities as a
n alternative to extended reaction times, to hydrogen peroxide additio
n, or to UV-catalyzed transformation of O-3. We propose the name ''Car
bozone Process'' for this new type of AOP.