Biosorption of iron by heavy-metal tolerant <i>Micrococcus</i> sp.

Abstract

The presence of metal ions in aqueous solutions represents, nowadays a major environmental problem. The present study investigates the potential adsorption capacity of Micrococcus sp. for the removal of iron (III) ions from aqueous solution. The adsorbent was characterized using FTIR analysis, in order to reveal the presence of functional groups. Batch adsorption experiments were carried out to evaluate the effect of process parameters such as pH, contact time, initial iron concentration, temperature and adsorbent dosage on removal capacity. The optimum removal of iron (III) ions was obtained at pH 6 with 94.2%, adsorbent dose of 0.5g with 92.5% and equilibrium time of 30 min with 88.6%. Kinetic data were successfully described with pseudo-first order, pseudo-second order and elovich models. The results show that the biosorption process of Fe (III) followed pseudo second order with R²= 0.999. The equilibrium data was further tested using Langmuir, Freundlich and Temkin models, and was found to follow the Langmuir isotherm (R²= 0.978).Thermodynamic parameters such as ∆Go, ∆Ho and ∆So were evaluated and it has been found that the biosorption process was feasible, spontaneous and exothermic in nature.

Keywords: Bacteria, Biosorption, Iron, Isotherm, Kinetic