The performance of Alizarin impregnated bentonite for the displacement of some heavy metals ions from the wet phosphoric acid

The removal of Pb2+, Ni2+, Cd2+, Zn2+, Cu2+, and UO(2)(2+)ions from wet phosphoric acid were employed to gain the purified acid by the low-cost adsorbent that prepared by activation of natural bentonite followed by impregnation with Alizarin. The adsorbent was characterized by X-ray diffraction, scanning electron microscopy - energy dispersive X-ray spectroscopy, and Fourier transforms infrared spectroscopy techniques. The adsorption experiments were applied for the removal of studied metals ions from phosphoric acid. The best conditions for H(3)PO(4)are 5 M/L H(3)PO(4)concentrations (29% P2O5), 150 mg.L(-1)initial concentrations of each metal ions, and 50 mg Alizarin impregnated activated bentonite dose for 60 min contact time at room temperature. Whereas the optimum removal conditions of the studied metals ions from wet phosphoric acid (29% P2O5) were 60 min contact time, 150 mg adsorbent amount, and 50 mL acid volume at room temperature. The adsorption-desorption procedures were repeated by several times, till the desorption efficiencies were reduced from 98.5 to 83.0% for Alizarin impregnated activated bentonite after five successive cycles, it was indicated that the excellent adsorption stability for removal of Pb2+, Ni2+, Cd2+, Zn2+, Cu2+, and UO(2)(2+)on the studied adsorbent.