Insights into the degradation and detoxication mechanisms of aqueous capecitabine in electrochemical oxidation process.

Electrocatalytic oxidation and detoxication of capecitabine (CAP) in aqueous solution were investigated with Ti/SnO-Sb/Ce-PbO anode. The relative contributions of generated free radicals showed an increase in the pseudo zero order tare constants in the following order: OH (9.4%) < SO (24.2%) < O (53.3%). The operating parameters and solution matrixes, i.e. applied current densities, initial CAP concentrations, initial Cl and NO concentrations, influencing the CAP degradation efficiency were evaluated. The kinetic rate constant of 0.1404 min was found within 7 min at current density of 10 mA cm and initial CAP concentration of 20 mg L, while the mineralization efficiency of 59.5%, mineralization current efficiency of 2.06%, detoxication rate to Escherichia coli of 55.5% were achieved at reaction time 90 min. The major degradation pathways of CAP were oxidation, defluorination and bond cleavage, following with the formation of carboxylic acids, NO, NO, NH and F. Electrochemical oxidation process based on Ti/SnO-Sb/Ce-PbO anode is proved to be effective for elimination, mineralization and detoxication of aqueous CAP.