Electrochemical degradation of the Acid Blue 62 dye on a β-PbO2 anode assessed by the response surface methodology

Abstract

The electrochemical degradation of the anthraquinonic dye Acid Blue 62 in a filter-press reactor on a Ti/Pt/ b-PbO 2 anode was investigated using the response surface methodology with the variables: current density, pH, [NaCl], and temperature. The system's modeling was carried out with the charge required for 90% decolorization (Q 90 ) and the chemical oxygen demand removal percentage after a 30 min electrolysis (COD 30 ), with good correlations between predicted and observed values. Best conditions for decolorization were attained in acidic solutions (pH = 4) with medium to high [NaCl] (1.0-2.0 g L -1 ) and lower temperature due to the prevalent oxidant species HOCl and Cl 2 . Optimal conditions for COD 30 removal were attained at high current densities in pH [ 5 solutions with high [NaCl], when the prevalent oxidant species are HOCl and OCl -. The lowest charge per unit volume of the electrolyzed solution necessary for total mineralization was attained at pH 11.

Anodic oxidation of chlorpyrifos in aqueous solution at lead dioxide electrodes

“…Several authors have shown that S 2 O 2À 8 formed at the PbO 2 anode surface participates in the oxidation of the organic matter, in the proximity of the electrode surface and/or in the bulk of the solution [39][40][41][42]. It results an increase in COD removal rate with temperature These results are in agreement with those obtained by other authors [43,44].…”

Effective heterogeneous electro-Fenton process for the degradation of a malodorous compound, indole, using iron loaded alginate beads as a reusable catalyst

“…Electrochemical advanced oxidation processes (EAOPs) such as anodic oxidation (AO) [15][16][17][18], electro-Fenton (EF) and photoelectro-Fenton (PEF) [19][20][21][22][23][24][25][26] have proven to be efficient for removing organic matter. These processes are considered environmentally friendly and they are based on the in situ electrochemical generation of hydroxyl radicals (•OH), which is the second strongest oxidant known after fluorine, with E° (•OH / H 2 O) = 2.8 V vs.SHE (Standard Hydrogen Electrode) [27].…”

Anodic oxidation of salicylic acid on BDD electrode: Variable effects and mechanisms of degradation

“…However, most aromatics in acid and alkaline media treated by anodic oxidation with conventional anodes such as Pt, PbO 2 , doped PbO 2 , doped SnO 2 and IrO 2 , are slowly depolluted due to the generation of difficulty oxidizable carboxylic acids [10,[12][13][14][15]. The recent use of a boron-doped diamond thin film anode has shown that it has much larger O 2 overvoltage than the above anodes, giving a much higher concentration of adsorbed • OH and a quicker oxidation of pollutants.…”