A novel multifunctional cell coupled by electrodialysis and electrocatalysis for seawater desalination, wastewater decontamination and H2O2 production

Abstract

There is an increasing demand for wastewater decontamination and seawater desalination in coastal areas due to severe water crisis and environmental pollution. Herein, a versatile process coupled by electrocatalysis and electrodialysis was established to achieve wastewater decontamination, seawater desalination and H2O2 production. The coupled process not only realized about 70% desalination of seawater, 90% removal of 200 mg/L ampicillin (AMP) and 3.2 g/L H2O2 production at 4 V, but also showed the ability to effectively remove various contaminants including rhodamine B, urea, nitrobenzene and quinoline. The coupled process represented a great processing capacity for 100–300 mg/L AMP and seawater with 15–45 g/L NaCl. The mechanism exploration indicated the electrodialysis and electrocatalysis worked synergistically. The electrodialysis could generate an internal potential of 0.5 V to promote the electrocatalysis, and provide Cl− and Na+ as the electrolytes for electrocatalysis. Furthermore, the chlorine evolution reaction through electrocatalysis improved efficiency of electron transfer, resulting in a higher AMP removal and H2O2 production. Radical scavenging experiments and chemical analysis indicated that •OH and reactive chlorine species (RCS) accounted for 70% and 30% for AMP removal in anode chamber. Increasing reactants (H+ and O2) could significantly improve H2O2 production in cathode chamber. The coupled process also exhibited satisfactory effectiveness to real wastewater/seawater with 100% removal of AMP and 75% desalination of seawater, accompanying with 6 g/L H2O2 production. This study provides a promising multifunctional water treatment strategy for decontamination, desalination and simultaneous production of H2O2.