Insights into trivalent chromium biosorption onto protonated brown algae Pelvetia canaliculata: Distribution of chromium ionic species on the binding sites

• Tipo: Artigo em Revista Científica Internacional
• Data: 2012

Autores

Vítor J. P. Vilar (Autor) FEUP; José A.B. Valle (Autor) Outra; Amit Bhatnagar (Autor) Outra; João C. Santos (Autor) Outra; Selene M. A. Guelli U. de Souza (Autor) Outra; Antônio Augusto U. de Souza (Autor) Outra; Cidália M. S. Botelho (Autor) FEUP; Rui A. R. Boaventura (Autor) FEUP

Revista

Título: Chemical Engineering Journal

Vol. 200

Páginas: 140-148

ISSN: 1385-8947

Editora: Elsevier

Indexação

ISI Web of Knowledge - 24 Citações

ISI Web of Science

Scopus - 32 Citações

INSPEC

Classificação Científica

FOS: Ciências da engenharia e tecnologias > Engenharia do ambiente

CORDIS: Ciências Tecnológicas > Engenharia > Engenharia química

Projetos Associados

LA 20 - Projeto Estratégico-LA 20 - 2011-2012

Outras Informações

ID Authenticus: P-002-6X6

DOI: 10.1016/j.cej.2012.06.023

Abstract (EN): In the present study, biosorption of trivalent chromium by protonated brown algae, Pelvetia canaliculata, was studied in batch system. FTIR analyses provided information about the possible binding groups present in the algae, as carboxylic, hydroxyl and sulfonate groups. Potentiometric acid-base titrations showed a heterogeneous distribution of two major binding groups, carboxyl and hydroxyl ones, following the Quasi-Gaussian affinity constant distribution suggested by Sips, which allowed to estimate the maximum amount of acidic functional groups (2.26 +/- 0.02 mmol g(-1)) and proton binding parameters (pK'(H) = 3.18 +/- 0.01; m(H) = 0.78 +/- 0.03) for an ionic strength of 0.2 M. The trivalent chromium removal was found to increase with pH and the maximum chromium uptake was observed at pH 4.0 (similar to 0.6 mmol/g), corresponding to 1.34 meq/g, since at that pH, 25.8% of total chromium is in the Cr3+ form and 72.7% as CrOH2+. An equilibrium model incorporating the hydrolysis reactions that chromium undergoes in the aqueous phase was able to predict the chromium biosorption at different pH values and chromium concentrations, enabling the prediction of the distribution of chromium ionic species on the binding sites. A mass transfer model provided a good representation of the chromium biosorption kinetics, resulting in intraparticle homogeneous diffusion coefficients of 4.6 x 10(-7) cm(2)/s for Cr3+ and 1.8 x 10(-8) cm(2)/s for CrOH2+. The distribution of chromium ionic species in the solution and on the binding sites was also predicted by the kinetic model.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 9