In-situ investigation of dye pollutant adsorption performance on graphitic carbon nitride surface: ATR spectroscopy experiment and MD simulation insight

• Published in: Journal of hazardous materials 2021-09, Vol.418, p.126297-126297, Article 126297
• Main Authors: Li, Jun, Xiong, Yan, Wan, Haiqin, Chen, Jie, Fang, Shenwen, Song, Xiaoqing, Li, Rui, Duan, Ming, Hu, Ruiqi
• Format: Article
• Language: English
• Subjects: Attenuated total reflection spectroscopy (ATRS); G-C3N4 surface; In-situ adsorption investigation; Molecular dynamics simulation (MDS); Organic dye pollutants
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2021.126297

The adsorption performances on graphitic carbon nitride (g-C3N4) surface were investigated for organic dye pollutants by both experimental and calculation methods. For experimental investigation, adsorption thermodynamics and kinetics results were in-situ obtained and evaluated. With ΔGMB+=−31.78MO-. With linear and exponential modeling, g-C3N4 showed only adsorption process for MB+ but both diffusion and adsorption processes for MO-. For simulation insight, all MB+ molecules but only parts of MO- molecules were inclined to orient in parallel position at g-C3N4 surface after optimization during low concentration. And both MB+ and MO- molecules were inclined to orient in perpendicular position at g-C3N4 surface after optimization during high concentration. Combined with experimental and calculation results, a molecular-orientation and force-dominance mechanism adsorption model are proposed to explain the surface interaction processes between dyes and g-C3N4. Electrostatic interaction and π-π stacking interaction were revealed to dominate for MB+ adsorption, and π-π stacking interaction and van der Waals force were revealed to dominate for MO- adsorption. This work obtained ‘localized’ interfacial information and elucidated in-situ intermolecular interactions at g-C3N4 interface, which can provide fundamental basis for operation removal of organic dye pollutants by g-C3N4. [Display omitted] •Dye pollutant adsorption on g-C3N4 surface were investigated by ATRS experiment and MD simulation.•ATRS experiment obtained thermodynamics result of superior adsorption spontaneity for MB+ >MO-.•MD simulation obtained parallel and perpendicular adsorption configurations on g-C3N4 surface.•Interaction process is explained by molecular-orientation and force-dominance mechanism model.•This work obtained interfacial information and intermolecular interaction at g-C3N4 interface.