Adsorption of cobalt(III) by graphene and activated carbon

Graphene and activated carbon were tested as absorbents for the adsorption of cobalt(III) complexes. The SEM and TEM images showed that graphene disperses more evenly and had more uniform spacing of layers than activated carbon. However, the FTIR analysis showed that activated carbon had more characteristic functional groups than graphene. These property differences led to different cobalt(III) adsorption efficiencies. Graphene showed higher adsorption efficiency than activated carbon under identical experimental conditions. For both adsorbents, the adsorption efficiency increased with the increasing mechanical mixing intensity, solution temperature, and absorbent concentration, and decreased with solution pH. Under the conditions tested herein, the adsorption efficiency using graphene could reach more than 95 %.