Selective biosorption of lanthanide (La, Eu) ions by Mycobacterium smegmatis
Résumé
The ability of Mycobacterium smegmatis to adsorb lanthanide (lanthanum (La), europium (Eu)) cations from aqueous solutions was studied. Adsorption isotherms of lanthanum ions showed that the adsorption capacity was higher for wet biomass than for dry biomasses (37 degrees C and 70 degrees C). The biosorption capacity on cells dried at 70 degrees C is reduced. Potentiometric titrations revealed the existence of at least two types of acidic functions in the cell wall, with strong and weak affinity. The weak acidic groups became inaccessible at a drying temperature of 70 degrees C. Lanthanum and europium adsorption by Mycobacterium smegmatis obeyed the Freundlich and Langmuir isotherm relations. Eu3+ was preferentially adsorbed with respect to the lanthanum cations. The extended Langmuir equation enabled a preliminary theoretical approach of the multicomponent adsorption phenomenon.