Comparison of the Sorption Kinetics of Lead(II) and Zinc(II) on Titanium Phosphate Ion-Exchanger

The treatment of heavy metal-contaminated wastewater is an important action to reduce the negative impacts of industrial wastes on water bodies. This work focuses on the application of a low-cost titanium (IV) phosphate sorbent of TiO(OH)H(2)PO(4)·2H(2)O chemical composition toward lead and zinc ions depending on their concentration and the temperature of the solution. The kinetic studies showed that the values of the rate of intraparticle diffusion and the effective diffusion coefficients for Zn(2+) were considerably higher than those for Pb(2+). To explain the difference between the sorption kinetics rates for Pb(2+) and Zn(2+), the effective radius and dehydration degree of the adsorbed ions were calculated. The sorbent capability of the lead and zinc ion removal and its excellent efficiency in the presence of a high concentration of calcium ions were demonstrated using simulated mine water. Due to the fast kinetics and the high exchange capacity of titanium phosphate toward divalent ions, this sorbent can be considered as a promising material for the concentration and immobilization of heavy metals into the phosphate matrix.