Electrochemical decrease of sulfide in sewage by pulsed power supply

• Pulsed electrochemical process achieved higher total removal rate than direct current power.
• Pulsed electrochemical process effectively decrease sulfur deposition and inhibit anodic passivation.
• Cathodic scaling is effectively controlled by pulsed electrochemical process.
• Sulfide of 97.8% was decreased at pH 7–8, cell voltage of 7 V, duty cycle of 60%, pulse frequency at 1000 Hz.

Pulsed electrochemical process was explored to remove sulfide in municipal sewage, which successfully achieved higher removal rate of 93.2% compared with 73.2% by direct current (DC) power supply. The sulfur content on the electrode was 0.21% by pulsed electrochemical process compared with that of 1.05% on anode by DC electrochemical process, indicating that pulsed electrochemical process can inhibit anodic passivation resulting from sulfur deposition compared with DC electrochemical process. Besides, the electrode scaling can also be effectively controlled during pulsed electrochemical process. Moreover, the process optimization was investigated for pulsed electrochemical treatment, which obtained the highest removal rate of 97.8% at pH 7–8, cell voltage of 7 V, duty cycle of 60%, pulse frequency at 1000 Hz and electrode spacing of 2.5–3.0 cm. These results indicate that pulsed electrochemical process is a promising method of efficient and sustainable electrochemical sulfide removal from sewage.