Electrochemical degradation of sodium dodecylbenzene sulfonate on boron doped diamond and lead dioxide anodes

In view to carry out a global treatment of used emulsions like that contained in effluents from metallurgic industries, the surfactant behaviour should be known. This paper reports a study of the electrochemical degradation of sodium dodecylben- zenesulfonate (SDBS), a quite common surfactant, encountered in effluents from metal industries. Electrochemical oxidation of solutions containing SDBS at initial concentrations of 25 and 250 ppm was performed in an electrolytic flow cell without separator. A comparison of the performance of PbO2 and BDD used as anodes in the same electrolysis cell are presented. Today PbO2 is a material commercially available, while BDD, not yet accessible at large scale is presented as a good candidate for electrochemical treatment of waste waters polluted by organics. Electrolyses monitored by Total Organic Carbon (TOC), Chemical Oxygen Demand (COD) and Liquid Chromatography (HPLC) measurements, have shown that BDD is more efficient than PbO2 for the same oper- ating conditions. The study, focused on the BDD electrode in neutral or acidic media, under different current densities, have shown that SDBS is cut into small carboxylic acids (maleic, oxalic and formic acids), and that the aliphatic chain is attacked before the aromatic ring.