In this study, biosorption of Zn(II) from aqueous solutions by Acinetobacter sp. was investigated in batch experiments. Effects of pH, bacterial dosage, initial Zn(II) concentration, contact time and temperature were studied. Optimum biosorption conditions were found to be initial pH of 6, bacterial dosage of 0.5 g/l and initial Zn(II) ion concentration of 100 mg/l at room temperature and contact time of 90 min. The maximum uptake capacity of Acinetobacter sp. for Zn(II) ions was found to be 36 mg/g at optimum conditions. The adjusted R squared for the first-order kinetic model was 0.999. The Langmuir and Freundlich isotherms were also studied and data were better fitted with the Freundlich isotherm. Finally, Acinetobacter sp. adsorption capacity was compared with other biosorbents. This biomass could be used for removal of Zn(II) from wastewater.
