Feasibility of using carbon fiber, graphite, and their modified versions by PbO2 as electrodes in electrochemical oxidation of phenolic wastewater

Abstract

Human development and the great growth in the industry led to the deterioration of water quality as a result of the introduction of many pollutants into the environment and the arrival of a large number of contaminants into the water. There are many techniques used to treat these pollutants, but in this research, electrochemical oxidation processes have been proposed to remove phenol of different initial concentrations (30 and 150 ppm) from wastewater. The oxidation processes were carried out at 35 °C and by using different electrodes of carbon fiber and graphite and their modified versions by depositing PbO2 on their surface. The results indicated that the phenol removal enhanced when the modified electrodes were used in all oxidation processes, and the performance of the electro-Fenton oxidation process is better than the direct and indirect oxidation processes. It was observed that both current density and ferrous ion concentration had a positive effect on the amount of phenol removed using the electro-Fenton oxidation process for both modified electrodes, as the highest values of phenol removal were recorded using 8 mA/cm2 current density and 0.4 mM of ferrous ion concentration. The obtained energetic parameters also showed that the values of the specific power consumption increased, while the current efficiency decreased with the increasing of the applied current, which was accompanied by an apparent increase in the voltage of the cells due to the formation of intermediate compounds that led to an increase in the resistance values of the electrolytes.