CIDEPINT   05376
CENTRO DE INVESTIGACIONES EN TECNOLOGIA DE PINTURAS
Unidad Ejecutora - UE
artículos
Título:
Biosorption of chromium(III) by two brown algae Macrocystis pyrifera and Undaria pinnatifida: Equilibrium and kinetic study
Autor/es:
JOSEFINA PLAZA CAZON LEONARDO BENı´TEZ EDGARDO DONATI MARISA VIERA
Revista:
ENGINEERING IN LIFE SCIENCES
Editorial:
WILEY-V C H VERLAG GMBH
Referencias:
Lugar: Weinheim; Año: 2012 vol. 12 p. 95 - 103
ISSN:
1618-0240
Resumen:
Two brown algae, Macrocystis pyrifera and Undaria pinnatifida, were employed to remove Cr(III) from aqueous solutions. Both seaweeds were characterized in terms of alginate yields. The alginate contents were 20 and 30% of the dry weight for M. pyrifera and U. pinnatifida, respectively. Kinetics experiments were carried out at different initial pH values. Cr(III) biosorption was affected by the solution pH. The highest metal uptake was found at pH 4 for both biosorbents. Different models were applied to elucidate the rate-controlling mechanism: pseudo-firstorder, pseudo-second-order, external mass transfer and intra-particle diffusion. The application of Langmuir, Freundlich and Dubinin?Radushkevich models to the equilibrium data showed a better fitting to the first model. The maximum Cr(III) sorption capacity (qm) and the affinity coefficient (b) were very similar for both biosorbents: 0.77 mmol/g and 1.20 L/mmol for M. pyrifera and 0.74 mmol/g and 1.06 L/mmol for U. pinnatifida. The free energy of the sorption process was estimated using the Dubinin?Radushkevich isotherm. The values indicate that the processes are chemical sorptions. To evaluate the significance of the ion-exchange mechanism, the light metals (Ca21, Na1, Mg21 and K1) and pH were measured during the experiments.