Binding Mechanism and Biosorption Characteristics of Fe(III) by Pseudomonas sp. cells

Mahendra Aryal, Maria Liakopoulou-Kyriakides




Pseudomonas sp. biomass was used to remove Fe(III) ions from aqueous solutions. Optimum values including pH, biomass concentration and biomass-Fe(III) contact time were determined at 2.5, 1.0 g/L, and 25 min respectively. The maximum uptake capacity of Pseudomonas sp. biomass for Fe(III) was calculated at 86.206 mg/g using Langmuir isotherm model. The negative values of Gibbs free energy change and enthalpy change confirmed the spontaneous and exothermic nature of Fe(III) biosorption, whereas negative values of entropy change showed the decreased randomness at the solid-solution interface during Fe(III) biosorption. The sorption efficiency of Fe(III) did not affect by the presence of SO42-, Cl-, CO32-, NO3-, Mg2+ and Ca2+ ions from 10 to 200 mg/L, whereas Fe(III) sorption was reduced with increasing the concentrations of Cr(VI), Fe2+, Zn2+, Mn2+, Cd2+, Cu2+ and Ni2+ ions above 20 mg/L. Potentiometric titration and FTIR results confirmed amine and carboxylic groups as the active binding sites for Fe(III) ions. This biomass could be effectively reused up to five cycles, making their application in wastewater detoxification.


Keywords: Pseudomonas sp.; Fe(III); biosorption; desorption; biomass characterization