Statistical Modelling and Optimisation of the Biosorption of Cd(II) and Pb(II) onto Dead Biomass of Pseudomonas Aeruginosa

Abstract

Abstract Dead biomass of micro-organisms can be used as biosorbents for the mitigation of heavy metal pollution in the aqueous environment. The aim of this study was to statistically model and optimise the sorption of Cd(II) and Pb(II) by dead biomass of Pseudomonas aeruginosa and to study the interactions between operating conditions. Statistically significant models were obtained for Cd(II) and Pb(II) sorption. The standard deviation for the Cd(II) and Pb(II) models were 0.86 and 1.54 while the coefficient of determination (R2) were 0.9978 and 0.9928 respectively. For both models, the adjusted R2 was in good agreement with the predicted R2 as the difference was less than 0.2. Numerical optimisation revealed that optimum Cd(II) removal of 88.6 % can be achieved at 1.172 ppm initial metal concentration, pH of 8.85, temperature of 43.72 °C, agitation time of 125.96 minutes and dead cell mass of 114.8 mg. Also, an optimum Pb(II) removal of 100 % can be achieved at 1.936 ppm initial metal concentration, pH of 6.88, temperature of 37.24 °C, agitation time of 130.57 minutes and dead cell mass of 122.85 mg. The study has revealed that at careful selected operational parameters, dead biomass of Pseudomonas aeruginosa can be valorised for the removal of heavy metals in aqueous media.