Biosorption of La^3＋ and Ce^3＋ by Agrobacterium sp.HN1

The Agrobacterium sp.HN1 was isolated from the soil and used to adsorb rare earth ions La3+ and Ce3+.The results showed that the pretreatments of Agrobacterium sp.HN1 did not enhance the adsorption of La3+ and Ce3+.The pH,temperature,time and bacterial age affected the dynamics of adsorption of La3+ and Ce3+.The optimum adsorption conditions for Agrobacterium sp.HN1 were as follows:15 mg/L La3+ of initial concentration,10 mg/L Ce3+,300 mg/L(dry wt.cell) biomass for sorption,6.8 pH,30 oC temperature,150 r/min rotational speed,2 h adsorption time and 28 h bacterial age.The adsorption kinetics of La3+ and Ce3+ for Agrobacterium sp.HN1 followed the pseudo-second order equation.