Highly crystalline lithium chloride-intercalated graphitic carbon nitride hollow nanotubes for effective lead removal

TLDR: LiCl-intercalated graphitic carbon nitride (LiClCN-4 h) was fabricated through well-controlled molten salt synthesis as discussed by the authors, and the as-prepared materials presented hollow tube morphology with tetragonal geometric configurations.

Abstract: The functional groups and intercalated ions in the structure of graphitic carbon nitrides can be tailored to attain excellent physiochemical properties for environmental remediation. In this work, a highly crystallized lithium chloride-intercalated graphitic carbon nitride (LiCl-CN) material was fabricated through well-controlled molten salt synthesis. The as-prepared materials presented hollow tube morphology with tetragonal geometric configurations. Batch adsorption experiments showed that the LiCl-intercalated graphitic carbon nitride (LiCl-CN-4 h) exhibited excellent lead cation (Pb(II)) adsorption capacity (172.41 mg g−1) at pH 5.5. Thermodynamic parameters revealed the endothermic and spontaneous nature of Pb(II) adsorption on LiCl-CN-4 h, and the kinetics results demonstrated that chemisorption dominated the adsorption process. X-ray diffraction analysis indicated that the intercalation of Cl and Li can lead to a larger interlayer spacing between carbon nitride layers. An X-ray photoelectron spectroscopy and X-ray absorption spectroscopy investigation further elucidated the chemical binding sites of Cl–Pb in the lattice of LiCl-CN, indicating the intercalation of Cl− ions contributed to the large improvement of Pb(II) adsorption capacity in g-C3N4 materials. The experimental results demonstrate that this is a facile and environmentally friendly strategy for synthesizing highly crystalline LiCl-CN with hollow tube morphology, and that the material showed promise for efficient Pb(II) removal in environmental remediation applications.