pH-Dependent adsorption of aromatic compounds on graphene oxide: An experimental, molecular dynamics simulation and density functional theory investigation

JOURNAL OF HAZARDOUS MATERIALS

卷:395

Article

Tang, Huan^1,2  Zhang, Shuyan^1,2  Huang, Tinglin^1,2  Cui, Fuyi³  Xing, Baoshan⁴ 

[1] Xian Univ Architecture & Technol, Key Lab Northwest Water Resource Environm & Ecol, MOE, Xian 710055, Peoples R China

[2] Xian Univ Architecture & Technol, Shaanxi Key Lab Environm Engn, Xian 710055, Peoples R China

[3] Chongqing Univ, Coll Environm & Ecol, Chongqing 40045, Peoples R China

[4] Univ Massachusetts, Stockbridge Sch Agr, Amherst, MA 01003 USA

关键词: Graphene oxide;    Aromatic compounds;    pH;    Molecular dynamics simulation;    Density functional theory;   

DOI  :  10.1016/j.jhazmat.2020.122680

来源: Elsevier

【 摘 要 】

This work provides a comprehensive understanding for the pH-dependent adsorption of aromatic compounds (ACs) on graphene oxide (GO). Isothermal and kinetics experiments indicated both adsorption capacity and adsorption rate were suppressed at higher pH, and the mechanisms were revealed by molecular dynamics simulations and density functional theory calculations. More specifically, pi-pi, hydrogen bond, vdWs, and water-mediated steric hindrance interactions were examined to reveal how pH affected the adsorption capacity, and microscopic dynamic adsorption process was captured to reveal how pH affected the adsorption rate. Results showed the reduced adsorption capacity at higher pH was mediated by increased electrostatic repulsion, weakened Tr-TC interaction, and increased water-mediated steric hindrance. The pH-dependent behaviour of GO was responsible for the effect of pH on adsorption rate. Self-aggregation of GO at lower pH helped to capture ACs and created more favourable adsorption sites. Upon the adsorption of ACs on GO, GO/water/AC/water/GO sandwich-like structure formed, which was also mediated by solution pH. Overall, pH affects the adsorption of ACs on GO by regulating driving forces, adsorption process, and the configuration property of GO-AC complex.

【 授权许可】

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