Electrosorption of Lead Ions by Nitrogen-Doped Graphene Aerogels via One-Pot Hydrothermal Route

We present an efficient Pb2+ electrosorption by nitrogen-doped graphene aerogels (NGAs) prepared by one-pot hydrothermal synthesis of nitrogen-doped graphene hydrogels (NGHs) followed by freeze-drying treatment. Pb2+ can be effectively removed by the as-prepared NGAs at an applied negative potential, and the removal mechanisms include (1) electrostatic attraction derived from external electric field, (2) electrostatic attraction caused by intrinsic charges on NGAs and Pb2+, (3) large specific surface area (SBET) of NGAs, and (4) coordination between doped nitrogen atoms and Pb2+. More importantly, after a simple and convenient electrodesorption treatment, the NGAs exhibit promising performance in recyclable electrosorption, and the removal ratio (%R) of Pb2+ decreases only similar to 5% after successive 100 cycles, which is significantly superior to conducting polymer and conducting polymer/reduced graphene oxide (rGO) composites-based electrosorption.