In this study, graphitic carbon nitride (gCN) enriched with carboxylic and hydroxyl groups was synthesized via thermal condensation, followed by acid and hydrogen peroxide treatment. This 'Oxygen' enriched gCN, denoted as gCN-OH, was characterized using FT-IR, SEM, XRD, and TGA analysis. U(VI) adsorption efficiency of gCN-OH was evaluated via batch experiments. The kinetic study showed adsorption equilibrium was reached within 80 min. The equilibrium adsorption capacity from isotherm experiments was 254.1 mg g-1. Temperature-dependent studies indicated the adsorption process is endothermic and spontaneous. U(VI) could be desorbed from loaded gCN-OH using 0.01 M HNO3 and gCN-OH can be reused multiple times.