In this study, we report the application of pulsed electrochemistry to enhanced water decontamination by electrochemical oxidation. By applying square current waveforms, the alternating pulse-on/off operation results in periodic oscillation of anode potential, which is favourable for periodic renewal of electrical double layer (EDL) and alternant condition for oxidation of organic pollutant. Under mass-transfer dominance at current density of 20 mA cm-2, the rate constant for phenol oxidation under pulsed-current mode (PC, k=1.48 h-1) is 52.5% higher than that under direct-current mode (DC, k=0.97 h-1), accounting for 57.1% decrease in energy consumption. In comparison with DC, PC does not change the pathway of phenol oxidation, but is more selective for less accumulation of characteristic intermediates and efficient mineralization. The duty ratio and pulse period are shown to have significant impact to removal of chemical oxygen demand (COD), current efficiency and energy consumption. The non-steady diffusion models based on Fick’s second law illustrate that the transient local phenol concentration at anode surface and limiting current density under PC condition are approximately 2.8 times of that under DC, which provides a theoretical verification for the EDL-renewal mechanism of pulsed electrochemistry. This study suggests a simple, reliable and economic route to enhance the performance of electrochemical oxidation, which can also be generalized to other kinds of electro-process for water purification.

Application of pulsed electrochemistry to enhanced water decontamination

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.