The ability of adsorbent prepared from by - product of agriculture for the removal of dye was investigated. This study was aimed at the use of citric acid modified Globimetula oreophila to remove copper from aqueous solution. The adsorbent was characterized by Scanning electron microscope (SEM) and Fourier Transform Infrared (FTIR). The parameters investigated are the following: effect of pH, point of zero charge, initial copper concentration, contact time, kinetics and the effect of temperature. The optimum pH of adsorption was 5.2. Adsorption capacity increases gradually with increase in mass of biomass. The adsorption capacity decreased with increase in the initial copper concentration. 93% of the adsorption capacity was achieved in 15 minutes of contact time. The maximum adsorption capacity at equilibrium is 18.5 mg/g. The Dubinin–Radushkevich model was the most appropriate in describing the adsorption process. The Pseudo- second order kinetic model was suitable for explaining the adsorption of copper onto modified Globimetula oreophila. Thermodynamic properties related to the adsorption process were determined to be endothermic for the enthalpy change (36.3 kJmol-1), spontaneous (ΔG = -ve), and there was disorderliness at the adsorbent - adsorbate interface. The adsorption process was physisorption. Citric acid modified Globimetula oreophila is a promising adsorbent for the removal of copper from waste - water.