Avaliação do desempenho do eletrodo de diamante dopado com boro na degradação eletroquímica de diferentes corantes têxteis: efeito do material eletrocatalítico e reatores

Abstract

The efficiency of the advanced electrochemical oxidative process (POAE's) in the treatment of synthetic textile effluent was the object of this study, through the electrochemical performance of the boron-doped diamond (BDD) electrode, Ru0.3Ti0.7O2 and Pt, investigating the electrochemical oxidation of the dyes Acid Violet 7 (AV7) and Disperse Yellow 3 (DY3). Different experimental variables were applied, such as electric current density (15, 30, e 60 mA cm-2 – AV7; 40 and 60 mA cm-2 – DY3), pH, support electrolytes (Na2SO4 – AV7; Na2SO4 e NaCl – DY3) and different electrochemical reactors with different input-output cylindrical reaction cells (I-O), one in parallel and one perpendicular to the electrodes. To achieve the objectives proposed in this study, color removal, COD, UV-Visible, TOC and HPLC analyzes were performed. With the obtained results, it was investigated the degradation capacity of the textile dyes comparing the electrodes. It was verified that the BDD electrode presented better efficiency, in relation to the other electrodes, for the treatment of the textile effluents. Comparing the electrochemical reactors (parallel and perpendicular), the mass transfer coefficients (Km), 1.86 × 10−5 m s −1 and 2.56 × 10−5m s –1 , respectively, were calculated using the technique acurrent limitation. The degradation results indicated that the most efficient COD removal cell was always achieved in the I-O flow cell in parallel at all current densities. This can be attributed to the possibility of some stagnation in the lateral regions of the electrodes, which favor a longer contact time between the pollutant and the anode.