Optimization of the removal of chromium and lead by Penicillium chrysogenum using 2k factorial experiments

Abstract

AbstractThis study aims to prepare a low‐cost, environmentally friendly, and alternative, biosorbent to remove chromium Cr (III) and lead Pb (II) from polluted water and to find out the highest removal efficiencies using 2k factorial experiments. The Cr (III) and Pb (II) tolerant fungal strain identified as Penicillium chrysogenum was isolated from ceramic industrial sludge. The impact of process variables on biosorption of Cr (III) and Pb (II) by P. chrysogenum was first evaluated with the Taguchi screening design. Factors and levels were determined to optimize Cr (III) and Pb (II) removal efficiency. According to this, five factors; initial concentration, pH, biosorbent dose, temperature, and inactivation methods were determined for both metals, each factor defined as a fixed factor with two levels. Optimization of the parameters affecting the removal process was determined by the Taguchi method and the signal‐to‐noise (S/N) ratios are calculated. The maximum removal efficiency (99.92%) was observed at pH 7, biosorbent 1 mg L–1, inactivation with autoclaving, and at 20°C with an initial metal concentration of 50 mg L–1 Cr (III). On the other hand, the maximum removal efficiency (98.99%) was observed at pH 4, biosorbent 5 mg L–1, inactivation with autoclaving, and at 20°C with an initial metal concentration of 50 mg L–1 Pb (II). Furthermore, metal ions removal by P. chrysogenum was also confirmed by scanning electron microscopy (SEM) combined with an energy dispersive X‐ray spectrometer (EDS). The presence of functional groups on fungal cells of metal binding was investigated by Fourier transform infrared (FT‐IR).