Anodic mineralization of organic substrates in chloride-containing aqueousmedia

The electrochemical incineration of glucose in alkaline media, in the prese nce of sodium chloride, has been investigated. The process has been followe d through the dependence of chemical oxygen demand (COD) and total organic carbon content, on electrolysis duration, t. The influence of current densi ty, sodium chloride concentration, temperature, sodium hydroxide concentrat ion on the rate of COD abatement has been followed. The rate of the inciner ation was found to increase with increasing the current density and pH and decreasing the solution temperature. With increasing the chloride concentra tion up to a given critical value, the mineralization rate increases. Furth er increase causes a decrease of efficiency of the process of interest. The critical value of the mediator concentration has been found to be lower at higher pH. On the basis of this preliminary screening, an attempt of optim ization of the mediated electrochemical incineration as a function of curre nt density and chloride concentration has been carried out, basing the anal ysis on the Simplex algorithm. Two different response functions have been c hosen: the glucose oxidation rate and a weighed combination of electrolysis time and energy consumption. On the basis of the obtained results, an expl anation of the mediating role of chloride ions has been proposed. (C) 2000 Elsevier Science Ltd. All rights reserved.