Honeycomb-like cork activated carbon modified with carbon dots for high-efficient adsorption of Pb(Ⅱ) and rhodamine B

Adsorption is the most promising method for wastewater purification, but it is limited by the low adsorption efficiency and single adsorption performance of the present adsorbents. Herein, a novel multifunctional adsorbent ([email protected]) for high-efficient adsorption of heavy metal ions and dyes was synthesized using cork activated carbon (CAC) and branched polyethylenimine (BPEI)-modified carbon dots (CDs). CAC is an excellent carrier for CDs-BPEI and can provide strong driving force for the adsorption of contaminants, while CDs-BPEI with numerous amino groups can improve the adsorption capacity and selectivity of the adsorbent for metal ions. The obtained [email protected] had unique honeycomb structure, ultrathin carbon nanosheet wall layer (∼200 nm), well hierarchical porous structure, high specific surface area (1088.97 m2/g). In addition, it contained abundant amino and oxygen-containing groups. The unique structure and surface chemistry of [email protected] contributed to its ultra-high adsorption efficiency for Pb(Ⅱ) (231.48 mg/g, 10 min) and RhB (1734.55 mg/g, 180 min). It is worth mentioning that the adsorption capacity of [email protected] for Pb(Ⅱ) increased by more than 200% compared with that of CAC. Moreover, the resorption efficiency of [email protected] for Pb(Ⅱ) and RhB can reach approximately 82% and 70%, respectively, after five consecutive adsorption-desorption cycles. The high adsorption efficiency, excellent recyclability, and good stability make the [email protected] an ideal adsorbent for wastewater treatment.