In this work, uranium adsorption from Egyptian phosphoric acid onto chemical modified Olive Stones has been
studied by two methods (H3PO4 and ZnCl2) at 800ºC was used to carbonized. The relevant factors affecting uranium
adsorption onto our Olive Stones Activated Carbon adsorbent were studied. These factors involved phosphoric acid
concentration, the contact time, adsorbent weight, initial uranium concentration and the temperature were investigated.
The theoretical capacity of Olive Stones Activated Carbon adsorbent is about (47.8, 46.08) mg/g for O.S-H3PO4, O.SZnCl2 respectively. The optimum adsorption conditions were choiced in two methods and P2O5 ineffective by these
conditions. The sorption process of uranium U(VI) follow Langmuir isotherm model with pseudo-second order
mechanism and exothermic nature and spontaneous process according to studying (enthalpy change, entropy change and
Gibbs free energy change). More Than 80 % of the loaded uranium amount on the Olive Stones Activated Carbon
adsorbent has been eluted using 0.1 M HNO3 as an efficient eluent.