▎ 摘　　要

Understanding the transport behavior of N-doped graphene (NG) in porous media is critical to assess its environmental impact. In this work, sand column experiments were conducted to compare the transport and retention of NG and graphene oxide (GO) and to investigate the effects of temperature (4 and 25 degrees C), solution ionic strength (1 and 5 mM) and sand grain size (0.3-0.4 and 0.5-0.6 mm) on the transport and retention of NG in saturated porous media. The retention of NG in the column was larger than GO. The transport of NG was sensitive to solution ionic strength, and it was more mobile under lower ionic strength. The transport of NG increased with the increasing of sand grain size, and the results can be expounded by the colloid filtration theory. The transport of NG was larger at the lower temperature tested because of the reduction of repulsively electrostatic forces between sand and NG as temperature increased. Advection-dispersion equation was applied to simulate the transport and retention of GO and NG in saturated porous media and model simulations fitted the experimental data very well. Findings of this study are of great importance for exploring the transport and fate of NG in the natural environment.