Mechanism of Biosorption of Nickel Ions from Polluted Effluent by Bacillus sp. Strain MGL-75

The aim of this work was to investigate Bacillus sp. strain MGL-75 as biosorbent, for the fixation of Ni ion in batch reactor. Pollution of the environment by toxic metals is a major environmental concern. In a first step, biosorption kinetics and isotherms have been performed at pH 7. The equilibrium time was about 5 min and the adsorption equilibrium data were well described by the Langmuir`s equation. The point of zero net proton charge (PZNPC) was found close to pH 5.7. Using the single extrapolation method, three kinds of acidic functional groups with three intrinsic pka were determined at 4.4, 6.9 and 11.2. The maximum capacity has been extrapolated to 0/52 mmol/g. Finally the effect of autoclave, 2, 4 Dinitrophenol (DNF) and Na-Azid (NaN3), and the effect of pH values, were studied. These results indicated that the Bacillus sp. strain MGL-75 is an excellent candidate for use in reactor to remove Nickel ions from polluted aqueous effluents