Constructing physical and chemical synergistic effect of graphene aerogels regenerated from spent graphite anode of lithium ion batteries achieves high efficient adsorption of lead in wastewater

Abstract

The treatment and disposal of lead in wastewater is deeply troubled in industry due to the limitations of physical adsorption and exclusivity of chemical adsorption methods. Herein, an unique graphene aerogel (GA) structure, rich in active functional groups such as sulfur, carboxyl and hydroxyl, etc., is designed and synthesized from the waste graphite anode of lithium ion batteries in our work. Through the physical adsorption of the porous structure of graphene itself, combined with the chemical adsorption of special functional groups, the synergistic effect can achieve high efficiency absorption of lead in wastewater, reaching the maximum of 152.70 mg/g. The best conditions for the adsorption of lead-containing wastewater are using 50 mg of GAs for adsorbing at 30 °C for 1 h when the initial concentration is 50 mg/L. The adsorption process conforms to the Langmuir isothermal adsorption model, the adsorption dynamics conform to the quasi-secondary kinetic equation, and the adsorption activation energy is 47.29 kJ/mol, confirming that the adsorption is controlled by the chemical reaction. Owing to the superiority of waste recycling, our research provides a novel idea for the combined physical adsorption and chemical adsorption of heavy metals in wastewater.