Response surface methodology approach for optimization of biosorption process for removal of Cr(VI),Ni(II)and Zn(II)ions by immobilized bacterial biomass sp.Bacillus brevis

摘要

In this study,the Box-Behnken design matrix and response surface methodology(RSM)have been applied to design the experiments to evaluate the interactive effects of three most important operating variables:pH(2.0-6.0),temperature(25-40 C)and initial concentration of metal ions(10.0-60.0 mg/L)on biosorption of Cr(VI),Ni(II)and Zn(II)ions with immobilized bacterial strain Bacillus brevis.The total 17 experiments were conducted in the present study towards the construction of a quadratic model.Independent variables have significant value 0.0001 which indicates the importance of these variables in the biosorption process.Values of"Prob > F"less than 0.0500 indicate that model terms are significant for the biosorption of Cr(VI),Ni(II)and Zn(II)ions.The regression equation coefficients were calculated and the data fitted to a second-order polynomial equation for removal of Cr(VI),Ni(II)and Zn(II)ions with immobilized bacterial strains B.brevis.