Document Type : Original Article
Department of Chemical Engineering, College of Engineering, University of Baghdad
Chemical Engineering Department, College of Engineering, University of Baghdad, Baghdad. Iraq
Marshes Research Center-University of Thi-Qar
Phenolic wastewater was treated electrochemically by various cells consist different arrangements of carbon fiber and graphite electrodes by direct, indirect, and Fenton electrochemical oxidation processes. The oxidation process carried at 35 °C for 180 minutes and at 8 mA/cm2 current density. One gram of NaCl per liter of electrolyte and 0.4 mM of ferrous ion concentration were used as a catalyst in the indirect and Fenton electrochemical oxidation process, respectively. The results indicated that the effectiveness of graphite-graphite cells in removing phenol via direct and indirect electrochemical removal was the highest of the other cells. In contrast, the cell of a graphite anode and a carbon fiber cathode was the most efficient in removing phenol using the electro-Fenton process. This significant increase in the removal via the electro-Fenton process using carbon fiber as a cathode was due to the large surface area of the cathode, which improves the hydrogen peroxide production rate. The results of the kinetics study of phenol removal by different oxidation processes and by using other cells in the arrangement of the electrodes indicated that the phenol removal reactions followed the first-order kinetics. The extensive study of the reaction rate constant values showed that the electro-Fenton process in a cell of graphite (as an anode) and carbon fiber (as a cathode) cell was faster than the other electro-oxidation processes and cells. Specific power consumption (SPC) was also investigated and showed that the better arrangement is using graphite as an anode that gives the lowest SPC.