Identification and characterization of Leucobacter sp. N-4 for Ni (II) biosorption by response surface methodology

Abstract

In the present study, batch experiments were carried out to characterize and optimize the removal process of Ni (II) by a nickel tolerant strain Leucobacter sp. N-4, which was isolated from the soil samples. The effects of operating parameters with respect to initial solution pH (3.0–6.5), initial nickel concentration (50–100 mg/L) and biomass dosage (1–10 g/L) on Ni (II) biosorption were investigated by response surface methodology (RSM). The maximal Ni (II) removal efficiency (nearly 99%) was achieved under the following conditions: pH 4.75, biomass dosage 5.38 g/L and initial Ni (II) concentration 53.6 mg/L. The adsorption-equilibrium data fitted well with both Langmuir and Freundlich isotherms. The monolayer adsorption capacity of biomass obtained from Langmuir isotherm was about 19.6 mg/g. Infrared spectrometer (IR) results showed that chemical functional groups (e.g. –NH 2, –OH and COO–M) of the biomass should be the active binding sites for Ni (II) biosorption from aqueous solutions.