In-situ construction of abundant active centers on hierarchically porous carbon electrode toward high-performance phosphate electrosorption: Synergistic effect of electric field and capture sites

Abstract

Phosphate removal is crucial for eutrophication control and water quality improvement. Electro-assisted adsorption, an eco-friendly electrosorption process, exhibited a promising potential for wastewater treatment. However, there are few works focused on phosphate electrosorption, and reported electrodes cannot attach satisfactory removal capacities and rates. Herein, electro-assisted adsorption of phosphate via in-situ construction of La active centers on hierarchically porous carbon (LaPC) has been originally demonstrated. The resulted LaPC composite not only possessed a hierarchically porous structure with uniformly dispersed La active sites, but also provided good conductivity for interfacial electron transfer. The LaPC electrode achieved an ultrahigh phosphate electrosorption capability of 462.01 mg g−1 at 1 V, outperforming most existing electrodes. The superior phosphate removal performance originates from abundant active centers formed by the coupling of electric field and capture sites. Besides, the stability and selectivity toward phosphate capture were maintained well even under comprehensive conditions. Moreover, a series of kinetics and isotherms models were employed to validate the electrosorption process. This work demonstrates a deep understanding and promotes a new level of phosphate electrosorption.

Keywords

• Electro-assisted adsorption
• Electrosorption
• Phosphate removal
• Active centers
• MOF-derived carbon