Degradation and Mineralization of Metformin by Electro-Oxidation on Ti/DSA (Ta2O5-Ir2O5) Anode and Combined Electro-Oxidation and Electro-Coagulation on Stainless Steel (SS) Anode

We conducted electro-oxidation, and combined electro-oxidation and electro-coagulation batch experiments on synthetic wastewater containing an anti-diabetic drug metformin hydrochloride (MET-HCl). Degradation and mineralization were studied on Ti/DSA (Ta2O5-Ir2O5) and stainless steel (SS) anodes. Electrochemical behavior was observed by cyclic voltammetry techniques. The effect of applied current density was evaluated at 50 ppm concentration of supporting electrolyte sodium sulphate (Na2SO4). Electro-oxidation on Ti/DSA anode resulted in maximum degradation of 94.88% at the corresponding specific charge (Q) of 2.1 Ah/L, current density of 0.93 mA/cm2 and Na2SO4 concentration of 100 ppm. Similarly, maximum mineralization obtained was 70.64% at corresponding specific charge (Q) of 2.1 Ah/L, current density of 0.93 mA/cm2 and Na2SO4 concentration of 50 ppm. Energy consumption was 2081.56 kWh/kgTOC. Further, under identical conditions, combined electro-oxidation and electro-coagulation on SS anode resulted in maximum degradation of 99.48% at corresponding specific charge (Q) of 2.1 Ah/L, current density of 0.93 mA/cm2 and Na2SO4 concentration of 100 ppm. Similarly, maximum mineralization obtained was 99.04% at corresponding specific charge (Q) of 2.1 Ah/L, current density of 0.93 mA/cm2, and Na2SO4 concentration 75 ppm. Energy consumption was 870.98 kWh/kgTOC.