Optimization of Nickel (II) and Cadmium (II) Biosorption on Brewery Sludge Using Response Surface Methodology

Batch biosorption experiments were conducted to find the effect of pH and biosorbent dosage on the metal species sorption using brewery sludge biosorbent. Optimum conditions of pH (X1) and biosorbent dosage (X2) for the biosorption of Nickel (II) [Ni (II)] and Cadmium (II) [Cd (II)] on brewery sludge were determined by response surface methodology using experiments designed as per central composite design (CCD). The optimum conditions for Ni (II) removal was obtained at initial pH of metal solution 5.3 and biosorbent dosage 12.6 g/L. Similarly, optimum conditions for Cd (II) removal was obtained at initial pH of metal solution 6.2 and biosorbent dosage 14.42 g/L. The experimental data were fitted to second order polynomial equation and the analysis of variance (ANOVA) of the polynomial model demonstrates the statistical significance of the model. This study has demonstrated the use of central composite design by determining the optimum conditions for nickel and cadmium biosorption leading to high metal removal efficiency.