Biosorption of iron (II) by Lactobacillus fermentum from aqueous solutions

Abstract

The biomass of Lactobacillus fermentum was used as biosorbent for the biosorption of iron (II) ions from aqueous solutions. Batch biosorption experiments were carried out with varying initial concentrations of Fe(II) ions, biosorbent dose, pH and time intervals. From the inductive coupled plasma optical emission spectroscopy (ICP-OES) result, the maximum biosorption capacity per gram of the biosorbent was found to be 7.25 mg for Fe(II) ions at a biomass concentration of 1 g/L at pH 4.5, contact time of 24 hrs, and an initial Fe(II) ion concentration of 100 mg/L. The equilibrium data was found to fit better with the Freundlich isotherm and pseudo second order kinetic model. The surface morphology and elemental composition of the biomass was characterized by using a scanning electron microscope (SEM) equipped with EDX, which confirmed that the iron was biosorbed, evident as bulky particles on the surface of the biomass, and as a peak for Fe in the EDX spectrum. Fourier transform infrared spectroscopy (FTIR) indicated that hydroxyl, amino and carboxyl functional groups are mainly involved in the biosorption of iron ions. Point zero charge of the biosorbent was found to be 3.0. X-ray diffraction (XRD) analysis revealed the amorphous nature of the biomass. The biomass of Lb. fermentum can be used as an efficacious and inexpensive biosorbent for the removal of Fe (II) ions from contaminated water resources.