Biosorption of lead and cadmium from aqueous solutions by proteins extracted from E. coli cells

he potential use of bacterial-based protein extracts for heavy metal removal from aqueous solution was investigated. The proteins-based biosorbent were extracted from wild-typeE. colistrain MG16755 using sonication. The metal ions adsorption efficiency was determined in batch mode. The maximum metal ions adsorption capacity was achieved after 24 hours at 37표C and pH=6. Fourier-transform infrared spectroscopy (FTIR) analysis demonstrated that the protein extract is capable of interacting with heavy metal ions through its functional groups (O-H / N-H, C=O, and C-O / P-O). The equilibrium data aligned well with the Langmuir model, indicating that the protein extract's maximum adsorption capacities (푄푚푎푥) for Pb (II) and Cd (II) were 204 mg/g and 164 mg/g, respectively.The Dubinin-Radushkevich (DRK) isotherm model estimated the mean free energy to be 0.7 kJ/mol for both Pb (II) and Cd (II), indicating that the adsorption process is primarily physical in nature. Additionally, the adsorption of Pb (II) and Cd (II) followed pseudo-second-order kinetics most closely. The findings of this study provide fundamental recommendations for the optimal utilization of EPS from E. coliin bioremediation for wastewater treatment.