Oxidative exfoliation of spent cathode carbon: A two-in-one strategy for its decontamination and high-valued application

Abstract

Spent cathode carbon (SCC) from aluminum electrolysis is a potential graphite resource. However, full use of the SCC remains a challenge, since it contains many hazardous substances (e.g., fluoride salts, cyanides), encapsulated within the thick carbon layers and thus posing serious environmental concerns. This work presents a chemical oxidative exfoliation route to achieve the recycling of SCC and the decontaminated SCC with high-valued graphene oxide (GO)-like carbon structures (SCC-GO) is applied as an excellent adsorbent for organic pollutants. Specifically, after the oxidative exfoliation, the embedded hazardous constituents are fully exposed, facilitating their subsequent removal by aqueous leaching. Moreover, benefiting from the enhanced specific surface areas along with abundant O-containing functional groups, the as-produced SCC-GO, shows an adsorption capacity as high as 347 mg·g−1 when considering methylene blue as a pollutant model, which exceeds most of the recently reported carbon-based adsorbents. Our study provides a feasible solution for the efficient recycling of hazardous carbonaceous wastes.