Degradation of phenol in wastewater by electrochemical method

摘要

The research systematically investigated the degradation of organics in the oil wastewater and the simulated wastewater by electrochemical method under different operating conditions.The removal efficiencies for pollutants of COD,NH3-N and phenol were analyzed.The effects of several operating parameters,such as concentration of electrolyte,temperature,current density,initial concentration and the type of the electrode on the electrochemical removal efficiency were discussed with bench scale experiments.The chemical kinetics of the removal of phenol was also investigated.The results obtained from the experiments using RuO2 showed that the removal efficiency of pollutants were significantly higher than that with lrO2.Under the conditions of normal temperature and pressure the phenol removal in the simulated wastewater reached nearly 100％within 70 minutes of treatment time,while 50％of COD and 89.5％of NH3-N were removed when using the oil wastewater.The removal of phenol increased along with the increasing of NaCl concentration.Temperature and current density,but it decreased with the increasing of the initial phenol concentration.The ClO-which is produced during the electrolyzing process can significantly improve the removal efficiency of phenol,it can accelerate the electrode corrosion.The electrolyzing oxidation process of phenol obeyed the first-order kinetics law,the oxidation rate constant has linear relationship with the 0.89th power of current density.The activation energy of the reaction calculated through the Arrhenias equation is 4.68kJ/mol.This vallie is far lower than that of common chemical reaction,so the electrochemical reaction for phenol degradation is more easily to take place.