The adsorption of 6 polychlorinated biphenyl (PCB) congeners by one pristine graphene (GN), and two functionalized graphene nanomaterials (graphene oxide (GO), and sulfonated graphene (SG)) was investigated in the environmentally relevant pg-mu g L-1 concentration range. Influence of solution pH and temperature on planarity effect of PCBs adsorption on GO and SG was subsequently assessed. GN exhibited stronger adsorption capacities than GO and SG, mainly due to the higher contribution of surface adsorption. Obvious planarity effect displayed in the adsorption of PCBs congeners on the three graphene nanomaterials at low aqueous concentrations (0.01-10 ng L-1) whereas gradually diminished with the increase of aqueous concentration. Interestingly, functionalized graphene illustrated greater planarity effect than pristine GN, especially at the lower concentrations. Compared with neutral condition, acidic or alkaline conditions notably led to the attenuation of the planarity effect on GO through preferable dispersion of GO particles in solution. However, solution pH exhibited minimal or negligible impact on the planarity effect on SG. Low temperature promoted the planarity effect of PCBs adsorption on both functionalized graphene, and the promotion degree on SG was obviously lower than that on GO, while warming resulted in the suppression on the planarity effect.