Substâncias húmicas aquáticas: fracionamento molecular e caracterização de rearranjos internos após complexação com íons metálicos

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Data

2001-06-01

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Editor

Sociedade Brasileira de Química

Resumo

The aquatic humic substances (AHS) investigated in this study were conventionally isolated from Rio Negro waters - Amazonas State/Brazil by means of the collector XAD 8. A special five-stage tangential-flow ultrafiltration device was used for analytical fractionation of AHS. The fractionation patterns (6 fractions each) showed that metal traces remaining in AHS after their XAD 8 isolation have different size distributions. For instance, the major percentage of traces of Ni, Cu, Zn, Cd and Pb (determined using ICP-AES) was preferably complexed by molecules with relatively high molecular size (30-100 kDa) and the following complexation order was characterized: F2 >> F1 = F4 = F5 > F3 > F6. Moreover, the species formed between AHS and metals prepared by spiking, showed distribution patterns changing as a function of the complexation time (ageing process), indicating a slow transformation process and an inner rearrangements in the binding sites within the AHS molecules.

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Palavras-chave

aquatic humic substances, fractionation, metal ions

Como citar

Química Nova. Sociedade Brasileira de Química, v. 24, n. 3, p. 339-344, 2001.