XII Iberian Meeting of Electrochemistry XVI Meeting of the ...

XII Iberian Meeting of Electrochemistry & XVI Meeting of the Portuguese Electrochemical Society K N 05
Electrochemical degradation of organic pollutants:
optimization of the experimental conditions
Ana Lopes
UMTP and Department of Chemistry, University of Beira Interior, 6201-001 Covilhã, Portugal
analopes@ubi.pt
Biological degradation is the cheapest process for removal of organic pollutants from
wastewaters. However, some compounds have low biodegradability or give origin to
biotic products that persist in the receiving waters. When conventional biological
treatments fail, a tertiary process, like chemical or electrochemical coagulation,
adsorption or membrane filtration, is usually performed, with the disadvantage of sludge
formation. Other alternatives, such as chemical oxidation with strong oxidants and
advanced oxidation processes, besides being quite expensive, still present operational
problems.
Anodic oxidation techniques have also shown to be very efficient in the degradation of
organic persistent pollutants. The use of these processes in wastewaters treatment has
been intensively investigated in the last two decades [1,2]. The materials that can be
used as electrodes are numerous and some of them are extraordinary promising. In
particular, boron doped diamond (BDD) anodes have received great attention in the last
years, due to their unique characteristics of mechanical and electrochemical stability,
wide potential window for oxygen evolution and ability to produce radical species
capable of oxidation of most of the organic pollutants [2-7].
Although anodic oxidation with BDD electrodes can be very effective, energetic costs
are a drawback in the application of these techniques at industrial scale. This way, the
optimization of experimental parameters and hydrodynamic conditions, in order to
reduce maintenance costs, are a requirement for the implementation of these processes.
In this study, the influence of pollutant type and concentration, electrolyte concentration,
initial pH, applied current density, operation mode, stirring speed and recirculation flow
rate in the organic load removal are evaluated.
Acknowledgments: The financial support of Fundação para a Ciência e a Tecnologia, F CT,
PDCT/AMB/59392/2004, PDCT/AMB/59388/2004, PTDC/CTM/64856/2006 and PTDC/AAC-
AMB/103112/2008 and Adamant Technologies are gratefully acknowledged.
References
[1] Juttner, K., Galla, U., Schmieder, H., Electrochim. Acta, 2000, 45, 2575.
[2] Martínez-Huitle, C.A., Ferro, S., Chem. Soc. Rev., 2006, 35, 1324.
[3] Morão, A., Lopes, A., Pessoa de Amorim, M.T.,.Gonçalves, I., Electrochim. Acta, 2004, 49,
1587.
[4] Panizza, M., Cerisola, G., Electrochim. Acta, 2005, 51, 191.
[5] Pacheco, M.J., Morão, A., Lopes, A., Ciríaco L. , Gonçalves, I., Electrochim. Acta, 2007,
53, 629.
[6] Ciríaco, L., Anjo, C., Correia, J., Pacheco, M. J., Lopes, A., Electrochim. Acta, 2009, 54, 1464.
[7] Santos, V., Diogo, J., Pacheco, M.J.A., Ciríaco, L., Morão, A., Lopes, A., Chemosphere , 2010,
79, 637.
September, 811, 2010. ISEL - Lisbon 22