Abstract

CUIZANO, Norma A. et al. Relevance of the PH on the adsorption of metallic ions by brown seaweeds. Rev. Soc. Quím. Perú [online]. 2010, vol.76, n.2, pp.123-130. ISSN 1810-634X.

The effect of the pH on the biosorption process of heavy metals is evaluated by considering the chemistry of the metal ions by means of batch experiments at room temperature. The adsorption of the metal ions of lead, zinc, copper, cadmium and gold were evaluated on the brown seaweeds Bory and Bory. The results show a strong pH effect on the aqueous chemistry of the metal ions dominated by aquo and hydroxo complexes. This aqueous chemistry is conditioned by the own acidity of the cation.   The preference of both algae towards the Pb (II) ion was experimentally confirmed. The affinity of the algae towards the studied metal ions followed the trend: Pb>Cd>Zn Cu. The AuCl ion showed a slow kinetics in the formation of chloro and hydroxyl complexes. These complexes strongly depended on the pH. This suggests a unique mechanism by ligands exchange rather than the well-known ionic exchange that was observed for the studied divalent cations.

Keywords : biosorption; pH; heavy metals; brown seaweed; chemical speciation.

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