Efficient removal of Congo red with graphene aerogel derived from recycled anode of lithium-ion battery

Abstract

The anode active material graphite in the waste lithium-ion battery was prepared into graphene oxide, which was used for preparation of graphene aerogel through hydrothermal reduction. Taking Congo red as the model dye contaminant, the effects of graphene aerogel input, initial concentration of pollutants, initial pH, temperature and adsorption time on the adsorption of Congo red were studied. The kinetics thermodynamics of adsorption process was analyzed. The experimental results showed that the adsorption rate was up to 99% under optimal condition. The adsorption process of Congo red by graphene aerogel was in accordance with the Freundlich isotherm adsorption model. The adsorption process was multi-molecular layer adsorption, and the quasi-second-order kinetic equation indicated that the adsorption could be chemical adsorption. The maximum adsorption capacity was 53.91 mg g−1, and the adsorption activation energy was 72.49 kJ mol−1. Our results show that the strategy of using the recycled anode material for dye removal may have high environmental and economic benefits.