Potential of red algae Gracilaria for biosorption of cadmium: Isotherm and response surface methodology study

The objective of the present work was to investigate the removal of cadmium by red algae Gracilaria as biomass. The effects of independent variable on biosorption of cadmium ion on the red algae Gracilaria as biomass were evaluated. The experimental data were analyzed via two custom isotherm models, i.e., Langmuir and Freundlich. The design of the experimental was developed for evaluate cooperating effects of pH, contact time, temperature, biomass dosage and initial metal concentration. The Box-Behnken model in response surface modeling was used for the optimization of the experimental data in Minitab software. The five parameters were fitted into second order polynomial equation and a mathematical function was developed. Statistical significance of coefficients in the second order polynomial equation are evaluated by t-test and p-value. The modified equation can be used for prediction of biosorption in any conditions.