Response surface methodology for cadmium biosorption on Pseudomonas aeruginosa

Abstract

In this research the effects of various physicochemical factors on Cd2+ biosorption such as initial metal concentration, pH and contact exposure time were studied. This study has shown a Cd2+ biosorption, equilibrium time of about 5 min for Pseudomonas aeruginosa and the adsorption equilibrium data were well described by Langmuir equation. The maximum capacity for biosorption has been extrapolated to 0.56 mmol.g−1 for P. aeruginosa. The thermodynamic properties ΔG0, ΔH0, and ΔS0 of Cd2+ for biosorption were analyzed by the equilibrium constant value obtained from experimented data at different temperatures. The results show that biosorption of Cd2+ by P. aeruginosa are endothermic and spontaneous with ΔH value of 36.35 J.mol−1. By response surface methodology, the quadratic model has adequately described the experimental data based on the adjusted determination coefficient (R2 = 0.98). The optimum conditions for maximum uptake onto the biosorbent were established at 0.5 g.l−1 biosorbent concentration, pH 6 for the aqueous solution, and a temperature of 30 °C.