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

XII Iberian Meeting of Electrochemistry & XVI Meeting of the Portuguese Electrochemical Society PA 03
Influence of hydrodynamic conditions on the anodic
degradation of phenol on BDD
S. Sobreira, L. Ciríaco, M.J. Pacheco, A. Lopes
UMTP and Department of Chemistry, University of Beira Interior, 6201-001 Covilhã, Portugal
analopes@ubi.pt
The anodic oxidation of effluents containing organic pollutants is an alternative that has
received great attention in the last years due to its interesting characteristics, since it is a
clean process, can operate at low temperature and, in most cases, without adding any
reagent and without sludge formation. Recently, an important development in these
processes took place with the use of boron-doped diamond (BDD) as anode material for
the oxidation of all kind of organic pollutants [1].
The objective of this work was to study the influence of hydrodynamic conditions on the
mass transfer process during the anodic oxidation of a model compound, phenol, using
BDD as anode material.
The electrochemical assays were performed in galvanostatic mode, at an imposed
current density of 100 A m -2 . Two sets of electrochemical assays were run, using two
different experimental set-ups: an electrochemical cell, with a BDD anode of 17.5 cm 2
area, working in batch mode, at several stirring rates, and a DiaCel 196PVDF, with two
monopol BDD electrodes, with 70 cm 2 area, working in batch with re-circulation mode,
at several different flow rates. Degradation of phenol was followed by Chemical Oxygen
Demand (COD) determinations, Total Organic Carbon (TOC) tests and UV-VIS
spectrophotometry measurements. The experimental results have demonstrated that an
increase in the stirring rate or in the recirculation flow rate leads to an increase in the
COD, TOC and absorbance removal rates.
The obtained results have shown that the turbulence near the electrode surface is a
very important parameter and its control can be used to increase the degradation rate,
with equal energy consumption, thus decreasing energetic costs for the anodic oxidation
of organic pollutants.
Acknowledgments: The financial support of Fundação para a Ciência e a Tecnologia, F CT,
PDCT/AMB/59392/2004, and Adamant Technologies are gratefully acknowledged.
References
[1] Panizza M.; Cerisola G. Electrochim. Acta, 2005, 51, 191.
September, 811, 2010. ISEL - Lisbon 58