Potentiality of white-rot fungi in biosorption of nickel and cadmium: Modeling optimization and kinetics study.

The present study aimed to analyze simultaneous biosorption of Cd+2 and Ni+2 by living Phanerochaete chrysosporium as low-cost and eco-friendly biosorbent following optimization by applying a central composite design. The effect of operating parameters such as solution pH (4.0-8.0), temperature (20-40 °C), contact time (3-15 h), initial Cd+2 and Ni+2 concentrations (15-35, 5-25 mg L-1, respectively) was evaluated by response surface methodology (RSM) for optimizing biosorption process. The Cd+2 and Ni+2 ions at 25 and 16 mg L-1 were accumulated in P. chrysosporium with the efficiency of 96.23% and 89.48%, respectively, at pH of 6 and 36 °C after around 9 h under well mixing. The equilibrium data were fitted well with Langmuir isotherm model with maximum biosorption capacity of 71.43 and 46.50 mg g-1 for Cd+2 and Ni+2, respectively. In addition, the pseudo-second order kinetic model could describe the kinetic data adequately. Further, possible interaction pathway among metals and P. chrysosporium functional groups were studied by Fourier transform infrared (FT-IR) spectroscopy. Furthermore, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) techniques were applied for morphology investigation and semi elemental analysis.