The desorption of Ni2+ from three oil palm fruit fibre adsorbents (UOPF, 0.5MOPF and 1.0MOPF) using five desorbing solutions showed a desorption efficiency following the trend, 0.1M HCl > 0.1MH2SO4 > 0.1MHNO3 > 0.1MNaOH >hot deionized H2O. The Elovich desorption constant, β values for the 0.1MHCl desorbent were: 6.45 X10-1, 5.57 x 10-1 and 4.34 x 10-1g. mg-.min-1 for UOPF,0.5MOPF and 1.0MOPF adsorbents respectively. The surface residence time  values for the 0.1MHCl desorbent were; 32.3, 28.6 and 26.8 seconds for UOPF, 0.5MOPF and 1.0MOPF adsorbents respectively. Kinetic modeling analysis of the Elovich and pseudo-first order desorption equations, indicates that the latter model described the desorption of Ni2+ better.

Keywords: Nickel, desorption, modeling, kinetics, Elovich, oil palm.