Optimization studies on Biosorption of Copper (II) by Crab Shell Using Response Surface Methodology(RSM)

In the present work, crab shell was used as the biosorbent to remove copper from aqueous
solution. Batch experiments were performed at different initial copper concentration of copper
solutions (1-40 g/l), initial pH (2-9), temperature (20-400C), and biosorbent dosages (2-10 g/l).
The maximum removal of copper using crab shell occurred at a pH of 3 and at a temperature of
400C using an optimum biosorbent dosage of 5 g/l. A mathematical model was proposed to identify
the effects of the individual interactions of these variables on the biosorption of copper. The
results have been modeled using response surface methodology using a Box-Behnken design. The
response surface method was developed using three levels (-1, 0, +1) with the above mentioned
four factors. The second order quadratic regression model fitted the experimental data with Prob >
F to be < 0.0001. The experimental values were found to be in good agreement with the predicted
values, with a satisfactory correlation coefficient of R2 = 0.9999.