Degradation of polyacrylamide in oil wastewater by electrocatalytic oxidation

Electrocatalytic oxidation of polyacrylamide (PAM) at Ti/PbO2 anode was studied in a three-electrode cell without any diaphragm but with a sandwich bath by galvanostatic electrolysis. Turbidimetry was used to determine the concentration of PAM. The change of degradation ratio with current density. and reaction temperature was studied through single factor experiment in order to determine the optimal conditions. The optimal conditions of PAM degradation by electrocatalytic oxidation were: current density was 200 mA.cm-(2), and reaction temperature was 60 degrees C. Under these conditions, the degradation ratio of PAM reached 88% after 3.0 h electrolysis. The total dissolved salts (TDS) and different ions affected on the degradation ratio of PAM by changing the size of PAM molecule and the viscosity of solution. The results of experiments showed that the degradation ratio increased firstly then decreased with the increasing of ion concentration. When TDS was 3000 mg.L-1, the degradation ratio reached the highest level. The high valence cation promoted the degradation of PAM. Cl- and HCO3- promoted the degradation of PAM because of the direct and indirect electrocatalytic oxidation and hydrolysis in alkaline solution respectively.