Preparation and Pb (II) adsorption in aqueous of 2D/2D g‐C3N4/MnO2 composite

A novel g‐C 3 N 4 /MnO 2 composite was prepared by in situ deposition of MnO 2 on graphitic carbon nitride (g‐C 3 N 4 ) nanosheets, and its adsorption properties were evaluated for removal of Pb (II) in aqueous. Fourier transform‐infrared, spectrometer scanning electron microscopy and transmission electron microscopy characterization showed the g‐C 3 N 4 /MnO 2 composite had a two‐dimensional/two‐dimensional (2D/2D) structure with ample active sites. The Brunauer–Emmett–Teller specific surface area of g‐C 3 N 4 /MnO 2 composites (234.9 m 2 /g) was 13.5 times larger than that of g‐C 3 N 4 (17.37 m 2 /g), providing better conditions for adsorption. The adsorption kinetic data were better fitted with the pseudo‐second‐order model. The Langmuir model was more suitable for describing the experimental equilibrium data of g‐C 3 N 4 /MnO 2 , and the maximum adsorption capacity was 204.1 mg/g for Pb (II). The adsorption of g‐C 3 N 4 /MnO 2 composite for Pb (II) was an endothermic and spontaneous process, and reached adsorption equilibrium rapidly within initial 150 min. This composite was an excellent adsorbent because of its higher adsorption capacity and facile preparation progress.