Simultaneously enhanced degradation of N, N-dimethylacetamide and reduced formation of iron sludge by an efficient electrolysis catalyzed ozone process in the presence of dissolved silicate.

The generation of sludge is the main issue in iron-based electrochemical techniques. Interestingly, in this study, the effluent was totally limpid and iron sludge did not generate when dissolved silicate (NaSiO) was used as the electrolyte in an electrolysis catalyzed ozone (ECO-NaSiO) system. More importantly, the pseudo-first-order rate constants (0.112 min) for DMAC degradation in ECO-NaSiO process was much higher than those of ECO systems using other electrolytes. An inhibition film formed on the iron electrode surface was identified to inhibit excess corrosion of iron electrodes and efficiently catalyze decomposition of ozone simultaneously. It was confirmed that hydroxyl radical (OH) played a dominant role for the degradation of DMAC, and O and HO were also contained in ECO-NaSiO system. The contributions of contained oxidative reactions in ECO-NaSiO system were quantitatively evaluated. Finally, the degradation pathway of DMAC was proposed. This work provides an effective way for protecting electrode from corrosion in electrochemical process.