An indirect electrochemical method, which is very efficient for the degrada
tion of organic pollutants in water, is described. The method, named electr
o-fenton, is based on electrocatalytical generation of Fenton's reagent to
produce hydroxyl radicals, which are very active toward organic compounds.
An industrial pollutant p-nitrophenol (PNP), was chosen for this study and
was eventually mineralized. The major intermediary degradation products suc
h as hydroquinone, benzoquinone, 4-nitro-catechol, 1,2,4-trihydroxybenzene
and 3,4,5-trihydroxy-nitrobenzene were unequivocally identified by HPLC and
GC-MS methods. The rate constants of the hydroxylation reactions were dete
rmined. The mineralization of the initial pollutant and the intermediates f
ormed during electro-Fenton treatment was followed by total organic carbon
(TOC) analyses. Dependence of mineralization on the amount of electrical en
ergy consumed is shown by the relative decrease of TOC values. A mineraliza
tion reaction mechanism is proposed.