Uranium ions adsorption from acid leach liquor using acid cured phosphate rock: kinetic, equilibrium, and thermodynamic studies

The adsorption of uranium from acid leach liquor was studied in batch experiments using acid cured phosphate rock (ACPR). Different factors affecting the adsorption process such as pH, contact time, L/S ratio, initial uranium concentration, and temperatures were investigated to optimize the operation conditions for the composite. The kinetic, equilibrium and thermodynamic characteristics of U (VI) adsorption using acid cured phosphate rock have been determined. Batch sorption experiments are performed to evaluate the optimum conditions at pH 4, L/S ratio (0.2) for 60 min. contact time at room temperature. The maximum sorption capacity from Langmuir reaches to 125 mg/g at room temperature. The kinetics data are well described by the pseudo-second-order kinetic model at 500 mg/L uranium concentration. The evaluation of thermodynamic parameters (Delta G(o), Delta H-o and Delta S-o) indicated that the adsorption process is spontaneous in nature, exothermic and randomness. Uranium (VI) can be desorbed from the loaded acid cured phosphate rock using 0.5M H2SO4 solution. Finally, the optimized factors have been carried out for uranium (VI) adsorption from Hammamat sediments leach liquor.