Optimization of process variables by dried Bacillus cereus for biosorption of nickel(II) using response surface method

The biosorption of nickel(II) by dried cells of Bacillus cereus, isolated from the sediment from an SBR reactor, was studied by response surface methodology (RSM). In this study, RSM based on central composite rotatable design was used to analyze the combined and individual effects of operating parameters (biomass dose,initial concentration of nickel(II), and pH) on the nickel adsorption capacity by dried B. cereus at an ambient temperature. A quadratic polynomial equation was obtained which could predict the amount of adsorbed nickel(II) by dried B. cereus. The analysis of variance showed that the effects of pH and biomass dose both had a significant influence on the removal of nickel(II), but the effect of pH was the most significant. The maximum adsorption amount of nickel(II) was found at a pH of 4, biomass concentration of 2.0gL(-1), and initial nickel(II) ion concentration of 150mgL(-1). Under this condition, the maximum adsorption amount of nickel(II) and the maximum adsorption rate were 20.79mgg(-1) and 41.44%, respectively. This study indicated that RSM was an effective method for optimizing the biosorption process. Dried B. cereus as an eco-friendly biosorbent showed a remarkable performance on the removal of nickel(II).