Transport and retention behavior of Graphene Oxide (GO) is influenced by the physical and chemical properties of porous media under subsurface environmental conditions. Fixed-bed column studies using quartz sand and biochar (BC) in different configurations were conducted as a function of ionic strength and flowrate. Colloid filtration theory (CFT) was employed to develop mathematical models based on the one-dimensional convection-dispersion equation using experimental GO breakthrough curves (BTCs) and retention profiles (RPs) obtained from the experimental data. GO transport and retention behavior was modeled using BC and BC-nZVI (BC surface modified with nanoscale zero-valent iron) as filter media to understand the effect of media properties. It was demonstrated that the model can describe measured BTCs and RPs of GO in the sand, BC, and BC-nZVI. The inverse modeling approach was implemented to determine the attachment coefficient (Ka) and maximum solid-phase retention capacity (Smax) using GO BTCs for different experimental conditions. Higher Ka in BC at 10 mM IS indicated the influence of straining which agrees with the depth-dependent retention kinetics. Furthermore, pronounced GO aggregation at higher IS supports the higher Ka values at 10 mM compared to 0.1 mM. In contrast, higher Ka values were predicted in BC-nZVI at lower ionic strength (0.1 mM) primarily due to the attachment of GO onto nZVI where nZVI in BC pores was also favorable for the straining process. This study revealed that CFT including the attachment, straining, and blocking process can effectively describe the GO transport in BC and surface-modified BC-nZVI under subsurface environmental conditions.