Preparation of MnO2 modified magnetic graphitic carbon nitride composite and its adsorption toward Pb(II) in waste water

Based on graphitic carbon nitride (CN) nanosheets, a novel MnO2 modified magnetic graphitic carbon nitride composite (MMCN) was prepared via magnetization and in-situ deposition of MnO2. Then, an array of characterizations and experiments were conducted to explore the physical and chemical properties of the synthesized MMCN material. The adsorption behavior and removal mechanism of the MMCN were also discussed intensively. The best pH value of Pb(II) of MMCN was 6. The maximum adsorption capacity of MMCN was as high as 187.6 mg/g, which was much higher than that of MCN and original CN, and removal percentage of Pb(II) was about 99%. The adsorption kinetics and isotherms were in accordance with the pseudo-second-order model and Langmuir model, respectively. The chemical adsorption of Pb(II) indicated that MMCN was a successful modified sorbent and pretty efficient to remove Pb(II) in an aqueous medium owing to the complexation and ion exchange of ample amino and hydroxyl groups. Moreover, MMCN could be separated easily from the aqueous medium under an external field after reaction with its magnetic performance.