Thorium ions recovery using activated carbon modified with triphenyl phosphine oxide: kinetic and equilibrium studies

Activated carbon (AC) modified with triphenyl phosphine oxide (TPPO) was tested for thorium(IV) adsorption. Different factors affecting the adsorption process such as pH, contact time, modified AC dose, initial thorium concentration, triphenyl phosphine oxide (TPPO) concentration and temperature were investigated to optimize Th(IV) adsorption operating conditions. Kinetic and equilibrium studies of the adsorption process have been studied. The obtained most favorable conditions for Th(IV) adsorption were: pH 3.6, 40 min contact time, 0.5 g modified AC dose, 0.02 M TPPO in toluene and 400 mg/L of thorium concentration at room temperature. The maximum sorption capacity according to Langmuir isotherm reached 71.94 mg/g for modified AC. Adsorption kinetics obeys pseudo-second order kinetic model. Thorium(IV) was efficiently desorbed from the loaded composite using 0.5 M H2SO4 solution. The optimized factors have been carried out to recover thorium(IV) from Abu Rusheid leach liquor, south Eastern Desert, Egypt.