Recycling lithium-ion battery graphite: Synthesis of adsorbent materials for highly efficient removal of dye and metal ions from wastewater

The fate of residual graphite derived from hydrometallurgical treatment of spent Lithium-ion batteries remains uncertain. This study dwells on the aim of identifying the potentialities of recycling residual graphite for wastewater treatment. Graphite was recovered hydrometallurgically, and new adsorption materials: graphite oxide (GO) and graphene oxide (GrO) were synthesized from the residual graphite using the chemical oxidization method. Synthesized materials showed higher interlayer spacings (GO = 0.81 nm, GrO = 0.78 nm) than the commercially available similar materials. Adsorption studies revealed higher adsorption capacities for both dye (>550 mg/g in all cases) and metal ions (highest ∼93 mg/g for Ni2+ and lowest ∼68 mg/g for Zn2+). GrO showed superior results than GO due to its high surface area and porosity despite GO having more functional groups. Moreover, produced materials showed about 97 % removal of dye and about 94 % removal of contaminated metals which are higher performance than existing commercial or similar materials. These findings highlight the promising recycling capabilities of waste graphite and suggest its potential as a substitute for natural graphite.