SCIENTIFIC PUBLICATIONS :
Figueira, M.M., Volesky, B. Azarian, K, & Ciminelli, V.S.T. 2000.
Biosorption column performance with a metal mixture. Envir. Sci. Technol.
34(20); 4320-4326.
Figueira, M.M.F., Volesky, B. and Ciminelli, V.S.T. 2000. Biosorption
of metals in brown seaweed biomass. Wat. Res. 34: 196-204.
Figueira, M.M.F., Volesky, B., Azarian, K. and Ciminelli, V.S.T. 1999.
Multimetal biosorption in a column using Sargassum biomass,
Biohydrometallurgy and the Environment Toward the Mining of the 21st
Century. Internat. Biohydrometallurgy Symposium Proceedings: Ballester, A. and
Amils, R., eds. Elsevier Sciences, Amsterdam, The Netherlands, 503-512.
Figueira, M.M., Volesky, B and Mathieu, J.H. Instrumental analysis
study of iron species biosorption by Sargassum biomass. Environ.
Sci. Technol. 33 (11), 1840-1846.
Nauter, G.C.C., Figueira, M.M., Linardi, V.R. 1998. Degradation of cyano-metal
complexes and nitrites by an Escherichia coli strain. Rev.
Microbiol., 29.
Figueira, M.M., Volesky, B. Ciminelli, V.S.T. 1997. Assessment of
interference in biosorption of a heavy metals. Biotechnol. Bioeng.
54(4):344-350.
Figueira, M.M., Ciminelli, V.S.T., Andrade, M.C., Linardi, V.R.
1996. Cyanide degradation by an Escherichia coli strain. Can. J.
Microbiol. 42(5):519-523.
Andrade, M.C., Figueira, M.M., Linardi, V.R. 1995. Utilization of
ammonia, generated from abiotic cyanide degradation, by Rhodotorula rubra. World
J. Microbiol. Biotechnol., 11(3):343-345.
Figueira, M.M. 1992. Biotechnological alternatives for wastewater
treatment. In IBRAM - Instituto Brasileiro de Mineracao. Mining
and environment. Brasilia: IBRAM [Portuguese, colaborative book].
Figueira, M.M., Yang, J., Volesky, B., Camargos, E.R.S. 1995.
Interference of Fe on Cd adsorption by Sargassum biomass. In Jerez,
C.A.,Vargas, T., Toledo, H., Wiertz, J.V. (ed) Biohydrometallurgical Processes.
Santiago: Universidad de Chile, v.II, p. 187-194.
Figueira, M.M., Ciminelli, V.S.T., Linardi, V.R. 1995 Bacterial degradation of
metal cyanides. In Jerez, C.A., Vargas, T., Toledo, H., Wiertz, J.V. (ed).
Biohydrometallurgical Processes. Santiago: Universidad de Chile, v.II,
p. 333-340.
Gomes, N.C.M., Camargos, E.R.S, Dias, J.C.T., Figueira, M.M., Linardi,
V.R. Metals and cyanide removal by Aspergillus niger
in cyanide-containing solutions of gold mining effluents. In Jerez, C.A.,
Vargas, T., Toledo, H., Wiertz, J.V. (ed) Biohydrometallurgical Processes.
Santiago: Universidad de Chile, v.II, p. 401-406.
Linardi, V.R., Andrade, C.M.M.C., Figueira, M.M., Andrade, M.C., Souza,
A.A.V. 1993. Characterization of the amylolytic system of Candida
strains. Folia Microbiol. 38(4): 281-284.
Figueira, M.M., Linardi, V.R., Ciminelli, V.S.T. 1992. Bacterial degradation of
cyanide. In Ciminelli, V.S.T., Salum, M.J.G. (ed). Gold Extraction:
fundamentals, practice and environment. Belo Horizonte: ABMT, p.
132-151.
PhD Thesis ABSTRACT :
The objective of this thesis was to determine the mechanisms
of heavy metal biosorption by brown seaweeds using mathematical modeling and
instrumental analysis. Two different models, ion exchange and multicomponent
Langmuir, were applied to the experimental equilibrium sorption data in order to
evaluate the performance of different biomass types on the sorption of Cd, Cu
and Zn. The tested seaweeds were Ecklonia, Durvillaea, Homosira and
Laminaria. It was found that ion exchange is the main mechanism involved in
the biosorption of these metals. When comparing these results with those
obtained for Sargassum, it was found that the best sorbent was that
produced with Sargassum biomass.
In order to understand the molecular aspects of the ion exchange, the system
Sargassum-iron species was studied in depth by using different instrumental
analysis. The XPS and FTIR analyses of the biomass exposed to ferrous or ferric
iron solutions showed that, while Fe(III) was sorbed by the material only as
Fe(III) ions, Fe(II) was present in the biomass as both ferric and ferrous ions.
This result suggested that the biomass material may play a role in the oxidation
of ferrous iron. Moreover, FTIR analyses revealed the participation of carboxyl
groups of the biomass in the uptake of both states of the Fe ion, whereby
sulfate groups were also involved in the uptake of ferric iron. The observation
of biomass samples with TEM and its analysis with EDS showed that most of the Fe
was present in the cell wall.
A new processing of the biomass was developed in order to achieve higher
affinity of the Sargassum biomass towards Cu, Cd and Zn. The best
performance was observed when the biomass was acid-washed and then treated with
K solution, when compared with Mg, Ca and Na treatment. Affinity constants were
calculated for each of those metals from equilibrium biosorption experiments and
the affinity sequence obtained was Cu > Ca @
Cd > Zn> Na @ K.
Finally, the biosorption performance was evaluate in plug-through column
experiments. Multi-metal solutions were fed to a column containing the biomass
previously treated with K solution. Breakthrough curves were obtained by
collecting samples at each hour and analyzing them for their heavy metal
content. In a three-metal solution system, smooth overshoot of Cd and a strong
overshoot of Zn were observed when Cu was present in solution. This fact can be
explained by the lower affinity of those heavy metals towards the biomass, as
compared to Cu. This represent a chromatographic effect where Cu exchanges first
with Zn, and then Cd, in the biomass sites, leading to a concentration of those
metals in the effluent higher than that of the feed solution.
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