Thermodynamic and Kinetic Aspects on the Biosorption of Cadmium by Low Cost Materials: A Review

Pablo Lodeiro; Roberto Herrero; Manuel E. Sastre de Vicente

doi:10.1071/EN06043

RESEARCH FRONT

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Thermodynamic and Kinetic Aspects on the Biosorption of Cadmium by Low Cost Materials: A Review

Pablo Lodeiro ^A , Roberto Herrero ^A and Manuel E. Sastre de Vicente ^A ^B

+ Author Affiliations

- Author Affiliations

^A Departamento de Química Física e Enxeñería Química I, University of A Coruña, Alejandro de la Sota 1, A Coruña 15008, Spain.

^B Corresponding author. Email: eman@udc.es

Pablo Lodeiro is a graduate in Chemistry from the University of A Coruña (1999). He is now in the last year of his Ph.D., working in the Department of Physical Chemistry and Chemical Engineering at the University of A CoruÃ±a. His research is centered in the field of biosorption and he has coauthored 11 papers in international journals.

Roberto Herrero is a lecturer of Physical Chemistry at the University of A Coruña in Spain. Dr. Herrero obtained his degree in Chemistry at the University of Santiago de Compostela in Spain and his Ph.D. in Physical Chemistry at the University of A CoruÃ±a in 1994. His scientific interests have moved from ionic interactions in solutions to bioelectrochemistry and, nowadays, his research interest is the biosorption of different pollutants on low-cost materials. Roberto Herrero is author of about 40 papers in international journals.

Manuel Sastre de Vicente was born in A Coruña in 1959 and is Full Professor of Physical Chemistry and Head of the Department of Physical Chemistry and Chemical Engineering at the University of A Coruña in Spain. He obtained his Ph.D. in Physical Chemistry at the University of Santiago de Compostela in 1986. He has carried out research in electrochemistry, about the redox behaviour of molecules with biological significance, in the field of salt effects in chemistry and more recently he has been involved in the study of the sorbent properties of biomass. He has published about 100 journal articles, chapters and two books on these topics.

Environmental Chemistry 3(6) 400-418 https://doi.org/10.1071/EN06043
Submitted: 1 August 2006 Accepted: 8 November 2006 Published: 13 December 2006

Environmental Context. The toxicity of cadmium in waters can be decreased by using a wide variety of low-cost biomaterials. A number of such investigations are reviewed here and the models used to describe the process of biosorption discussed. Fundamental investigations that probe the thermodynamics and kinetics of the biosorption process are essential for a strong understanding of all biosorption processes. Areas that still need addressing are highlighted, in particular with regard to cadmium biosorption, some models for which are ready to be tested in pilot plants.

Abstract. Cadmium is internationally recognized as an important pollutant in the environment, and different methods for its removal from wastewaters (chemical precipitation being the most commonly used) have been reported in the literature. Those methods are in most cases oriented to situations with high concentrations of the pollutant. Thus, alternative removal and recovery methods are being considered for removing very low concentrations of cadmium. These methods are all based on biosorption, the passive adsorption and sequestration of metals by several natural materials of biological origin. In this review we have considered the biosorption of cadmium onto biomaterials from a physicochemical, thermodynamic, and kinetic perspective. The thermodynamic perspective is based on the characterization of the interactions of the binding sites of the biosorbents with cadmium species in aqueous solution. Traditionally, this approach has been quantified using different kinds of isotherms. In addition, the description is completed by taking into account electrostatic effects, and the influence of pH and ionic strength, which are associated with the negative charge developed, in most cases, by the biomaterial. The other point of view in this review is the kinetic one, which is necessary for a full physicochemical description of the sorbate–biosorbent system. Consequently, an updated description of the various approaches commonly employed in kinetic studies in biosorption has been carried out.

Keywords. : acid–base properties — biosorption — cadmium — isotherms — kinetics

References

Thermodynamic and Kinetic Aspects on the Biosorption of Cadmium by Low Cost Materials: A Review

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