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 (Na2SiO3) was used as the electrolyte in an electrolysis catalyzed ozone (ECO-Na2SiO3) system. More importantly, the pseudo-first-order rate constants (0.112 min(-1)) for DMAC degradation in ECO-Na2SiO3 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)-O-center dot) played a dominant role for the degradation of DMAC, and O-2(center dot-) and H2O2 were also contained in ECO-Na2SiO3 system. The contributions of contained oxidative reactions in ECO-Na2SiO3 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.

Automated summary

In this study, a system using dissolved silicate as the electrolyte in iron-based electrochemical techniques showed clear effluent and prevented iron sludge generation, with a higher rate of DMAC degradation compared to other systems. An inhibition film on the iron electrode surface played a key role in preventing excess corrosion and catalyzing ozone decomposition. Hydroxyl radical was identified as the dominant factor in DMAC degradation in the ECO-Na2SiO3 system.