Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

PP-II-14where TOC 0 is the initial TOC (mgC·L –1 ), t is time (min) and k is the first order kineticconstant (min –1 ). Results of the experimental fitting with PolyMath ® v5.0 for k lead to acorrelation coefficient r 2 >0.985 in all individual runs as it is shown in table 1.From table 1, overlapping of experimental results is observed in the experimental runswhere only sulphate concentration was modified. These experimental results can be describedas it is shown in table 1 (k I ) and one value of the kinetic parameter independent of theelectrolyte concentration has been obtained. Kinetic parameters for high current density(60 mA·cm –2 ) were later lumped together, as summarized in table 1 (k II ) showing thenegligible influence of the initial lignosulphonate concentration at high current densities.ConclusionsKinetic results summarized in table 1 show that the concentration of sodium sulphatesupporting electrolyte between 2.5 and 5 g·L –1 at each level of initial TOC and applied currentdensity does not show any influence on the kinetic parameter and therefore this influence canbe neglected in the studied range of variables. At high current density (60 mA·cm –2 ) there isnot an influence of the initial TOC in the kinetic parameter (k·10 3 = 4.42±0.12 min –1 ); at lowcurrent density (30 mA·cm –2 ) kinetics is faster at low initial TOC (at 150 mgC·L –1 , k·10 3 =3.78±0.17 min –1 ) when compared to high initial TOC (at 450 mgC·L –1 , k·10 3 = 2.98±0.13min –1 ). Previous studies with phenol oxidation in sulphate media gave higher values of thefirst order kinetic constant (k·10 3 = 11.94±0.62 min –1 ) operating at low current density (2).AcknowledgmentsThis research is financially supported by the Spanish Ministry of Science and Technology(Project CONSOLIDER CTM2006-00317).References1. Rodrigo, M.A.; Michaud, P.A.; Duo, I.; Panizza, M.; Cerisola, G.; Comninellis, C. Oxidation of4-Chlorophenol at Boron-Doped Diamond Electrode for Wastewater Treatment. Journal of theElectrochemical Society 2001, 148 (5), D60-64.2. Sierra, L.; Rodríguez, N.; Urtiaga, A.M.; Ortiz, I. Electrochemical degradation of industrial wastewaters byanodic oxidation using a boron-doped diamond electrode. Viability study, 10 th Mediterranean Congress,Barcelona, SPAIN, 2005.298