Jr. Feng et al., ELECTROCATALYSIS OF ANODIC OXYGEN-TRANSFER REACTIONS - THE ELECTROCHEMICAL INCINERATION OF BENZOQUINONE, Journal of the Electrochemical Society, 142(11), 1995, pp. 3626-3632
The electrochemical performance of several anode materials is compared
for the electrochemical incineration of p-benzoquinone in acetate buf
fer media (pH 5). The chemical oxygen demand (GOD) estimated for benzo
quinone by titration with standard permanganate solution can be decrea
sed to virtually zero by electrolysis at electrodes comprised of Fe(II
I)-doped beta-PbO2 films on Ti substrates. Carbon dioxide is a product
of the electrochemical process; however, the possibility of other vol
atile products cannot be dismissed. Addition of solid benzoyuinone to
acetate media is followed by slow formation of a brownish black color
that is concluded to result from one or more humic compounds produced
by condensation of benzoquinone; however, it cannot be concluded wheth
er the condensation reaction is a necessary prerequisite to successful
electrochemical incineration of benzoquinone. Optimal operating condi
tions suggested for electrochemical incineration of benzoquinone in ac
etate buffer include heating of the anode (e.g., 60 degrees C) to incr
ease the rate of anodic discharge of H2O and, thereby, decrease the an
odic overpotential. Evidence also is presented that the rate of electr
ochemical incineration is enhanced slightly by the addition of a trace
s of Fe(III) with reduction of dioxggen (O-2) to hydrogen peroxide (H2
O2) at a cooled stainless steel cathode (e.g., 15 degrees C) in an und
ivided cell.