Electrochemical and photoelectrochemical treatment of 1-aminonaphthalene-3,6-disulphonic acid

1-Aminonaphthalene-3,6-disulphonic acid (ANDS) is one of the components in the wastewater produced during the synthesis of H-acid used in production of various dyes. Electrochemical oxidation of this wastewater can be an interesting alternative to other treatment methods, especially if it is combined with photochemical oxidation. Cyclic and differential pulse voltammetry was used in the determination of the kinetic parameters of the process. EIS method was used in the investigation of the adsorption at a platinum electrode. The first step of the ANDS electrooxidation proceeds in at least one step and is irreversible. The substrate is adsorbed at an electrode with the maximum coverage of its surface at the potential of 0.25 V. At the potential of 0.6 V the substrate is desorbed from the surface. An increase in pH causes the reaction of the first step to proceed easier but does not change its rate. Electrochemical oxidation of the substrate causes a decrease in TOC and COD by 18 and 36%, respectively. Results of the ANDS electrochemical oxidation can be improved by combining this method with photochemical oxidation. This yields a decrease in TOC and COD by 40.0 and 58.3%, respectively.