Adsorption of Ni(II) by Exi gu o b a c t eri u m sp. 27 and Polyaniline Nanoparticles

The present study was carried out to investigate three different adsorbents; dry cells of the bacterium Exiguobacterium sp. 27, polyaniline and a mixture of both in different ratios for removal of Ni(II) from aqueous solution. The results showed that the adsorption of Ni(II) using dry cells of Exiguobacterium sp. 27 was very fast and the equilibrium time was 15 min, while the equilibrium time for polyaniline was 120 min. Finally, for a mixture of dry cells of Exiguobacterium sp. 27 and polyaniline, the equilibrium time was 40 min. Adsorption isotherm and kinetics were studied. The reaction of Exiguobacterium sp. 27 when exposed to Ni(II) solution was found to be pseudo-second order reaction and the reaction obeyed the Langmuir equation. Whereas, the reaction of polyaniline with Ni(II) solution was pseudo-second order reaction and the reaction obeyed Freundlich equation. The experimental studies showed that mixture of Exiguobacterium sp. 27 and PANI had better metal uptake than both Exiguobacterium sp. 27 and PANI individually. This work provided an evidence for the possible application of nanoparticles of bacterial cells and/or polyaniline for Ni(II) biosorption from solution for a safe and clean environment.