Fenton reaction, which involves hydrogen peroxide and ferrous ion, has been
proposed as an efficient option for effluent treatment. In this work, the
treatment of a pulp bleaching effluent using Fenton-type reactions assisted
by either, 2,3-dihydroxybenzoic acid (2,3-DHBA), 3,4-dihydroxybenzoic acid
(3,4-DHBA) and 1,2-dihydroxybenzene (CAT), were studied. The treatment was
evaluated by the removal of adsorbable organochloride compounds (AOX) and
toxicity. Furthermore, the degradation of 2-chlorophenol and 4-chlorophenol
in aqueous solutions were carried out, separately. Increase in oxidative a
ctivities of Fenton-type reactions mediated by the dihydroxybenzenes (DHBs)
were found. These activities enhancement were related with a higher produc
tion of activated species by Fe/nHBs/H2O2, as indicted by chemiluminesce. T
he large decrease in AOX values and toxicity of the treated bleaching efflu
ent by DHBs at pH 4.0 and 7.0 showed that 2,3-DHBA enhanced the activity of
the Fenton reaction. The use of 3,4-DHBA and CAT resulted in loss of effic
iencies of Fenton reaction to effluent treatment but not to pure chlorophen
ol solutions. At pH 7.0 lower efficiencies than those at pH 4.0 were achiev
ed. (C) 1999 Published by Elsevier Science Ltd on behalf of the IAWQ. All r
ights reserved.