Structural characterisation of the coloured organic matter from an eucalyptus pleached Kraft pulp mill effluent

XAD-8 and XAD-4 resins in tandem were used to isolate and fractionate the coloured organic matter from an eucalyptus bleached Kraft pulp mill effluent which is discharged into river Vouga (Portugal) near the lagoon that exists in its terminal part. The composition of the isolated organic matter was investigated by FTIR and CPMAS-C-13-NMR and compared to that of humic matter isolated before from the same river at a non-polluted site and a site very contaminated with the effluent of a sulphite pulp mill. The results put into evidence that the organic matter from both kinds of effluent is more aromatic and contains more lignin derived structural units than the humic matter from the unpolluted site. However, the organic matter from the sulphite pulp mill effluent is more soluble due to its content of sulphonic functional groups.