In this study, adsorption of important pollutant cations on the surface of graphitic carbon nitride (g-C₃N₄) was investigated by density functional theory. The calculations indicated that N₆ cavity surrounded by triazine units is the most probable adsorption site on this surface. The structural optimizations also predicted a planar surface for Cr³⁺, and Ni²⁺/g-C₃N₄ systems while the structure of the surface for other systems indicated a considerable distortion with strong dependency on the cation size. Also, g-C₃N₄ surface exhibited the high adsorption energies for Cr³⁺, As³⁺, and Sb³⁺ ions in the gas phase. However, formation energies of the metal-aquo complexes of these cations indicated that only adsorption of Sb³⁺, As³⁺, Pb²⁺, Hg²⁺ and Cd²⁺ cations from the aqueous solution is favorable in a thermodynamic point of view, in such a way that efficiency of adsorption obeys a Sb³⁺ > As³⁺ > Pb²⁺ > Hg²⁺ > Cd²⁺ trend. Moreover, time-dependent density functional calculations indicated “metal to ligand charge transfer” vertical excitations for Cr³⁺/g-C₃N₄ structure, and “ligand to metal charge transfer excitations” for Hg²⁺/g-C₃N₄, Cd²⁺/g-C₃N₄, As³⁺/g-C₃N₄, and Sb³⁺/g-C₃N₄ systems, which indicates the potential of these systems for future use in variety fields of nanotechnology and catalysis.

在这项研究中，采用密度泛函理论研究了重要污染物阳离子在石墨氮化碳（gC ₃ N ₄）表面的吸附。计算表明，被三嗪单元包围的N ₆腔是该表面上最可能的吸附位点。结构优化还预测了Cr ³⁺和Ni ²⁺ / gC ₃ N ₄系统的平面，而其他系统的表面结构则显示出相当大的变形，与阳离子尺寸密切相关。另外，gC ₃ N ₄表面对Cr ³⁺，As具有高吸附能。气相中的³⁺和Sb ³⁺离子。然而，这些阳离子的金属-水配合物的形成能表明，从热力学观点来看，仅从水溶液中吸附Sb ³⁺，As ³⁺，Pb 2 ⁺，Hg ²⁺和Cd ²⁺阳离子是有利的。 ，从而使吸附效率服从Sb ³⁺  > As ³⁺  > Pb ²⁺  > Hg ²⁺  > Cd ²⁺趋势。此外，随时间变化的密度泛函计算表明，Cr ³⁺ / gC ₃ N的“金属到配体电荷转移”垂直激发Hg ²⁺ / gC ₃ N ₄，Cd ²⁺ / gC ₃ N ₄，As ³⁺ / gC ₃ N ₄和Sb ³⁺ / gC ₃ N ₄系统具有“ _4”结构和“配体至金属的电荷转移激发” ，表明这些系统在纳米技术和催化的各种领域中的未来使用潜力。