Biosorption of La3+and Ce3+ 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°C 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.