AQUEOUS S(IV) OXIDATION .3. CATALYTIC EFFECT OF SOOT PARTICLES

The paper reports on studies of S(IV) oxidation in aqueous media containing suspensions of soot particles from domestic coal burning and activated carbon RB-1. The results show that the reaction rate depends upon dissolved iron leached from soot particles. At a low initial pH (less-than-or-equal-to 4), Fe(III) species are responsible for the high oxidation rate, whereas at a higher initial pH (5.2 - 5.5), Fe(II), which is primarily present in soot suspensions, acts as a catalyst. These homogeneous reactions dominate the catalytic effect of the coal soot surface. It is shown that the mechanism of S(IV) oxidation catalysed by activated carbon is quite different.