Modeling of Electrochemical Treatment of Phenol and Prediction of Specific Energy Consumption

Phenol belongs to the recalcitrant pollutants to conventional physical chemical and biological treatments. These compounds are released in the surface water by a considerable number of industries، constituting an environmental hazard. On the other hand، the advanced oxidation processes (AOPs) have been defined as effective processes for treatment of wastewater containing toxic and persistent organic pollutants. In this work، a mathematical model is developed to quantify the variation of chemical oxygen demand (COD) as a function of time during electrochemical oxidation of phenol for a batch system. Depending on applied current density (iappl) with respect to limiting current density (ilim)، which decreased during treatment، different operating regimes were identified. In particular، for high organic concentrations or low current densities (iappl ilim)، COD decreased linearly over time، indicating a kinetically controlled process. Conversely، for low organic concentrations or high current densities، electrolysis was under mass-transport control and COD removal followed an exponential trend. Model parameters were: current density، initial phenol concentration and electrode area. The present purpose is to use the model as a design tool for the prediction of specific energy consumption for the elimination of a given organic loading (kg COD h-1). The results showed that the increase of density and applied potential caused increase of specific energy consumption of initial phenol concentration decrease in energy consumed. In the mathematical model validation، the model results were compared with experimental results published in the literature. The good agreement between experimental and model predicted data was obtained in all the examined conditions by accounting root mean square error (RMSE) between 0. 013-1. 22 and R2>0. 91.