adsorption equilibrium and kinetics of lead ion onto synthetic ferrihydrites

batch experiments were conducted to study the adsorption behaviors of lead ion (pb2+) onto ferrihydrites prepared using three different procedures which were characterized  by textural analysis (bet). the adsorption removal of pb2+ by the three ferrihydrites (called fh-1, fh-2 and fh-3, respectively) were compared, and fh-3 shows fast adsorption kinetics as well as high adsorption capacities, the adsorption properties of the three ferrihydrites for lead ion depend on the ph value and the optimal ph for pb2+ adsorption of fh-3 is 6.0. the maximum adsorption capacity of lead ion on fh-3 is 13.75 mg/g and the adsorption isotherms followed langmuir isotherm model better than the freundlich isotherm model. the adsorption kinetic data could be described well by pseudo-second-order kinetic equation.