Influential biosorption of lead from aquatic solution using Escherichia coli/carbon nanofibers

The study was conducted for the biosorption of Pb(II) from aquatic solution treated with Escherichia coli (E. coli) waste biomass immobilized with carbon nanofibers. Physicochemical characteristic studies were conducted by applying FTIR, SEM, and XRD. The study for biosorption of Pb(II) were optimized by different experimental parameters, contact pH 2–7, temperature 20–60 °C, contact time 10–50 min, amount of E. coli/carbon nanofibers(CNFs) composite biosorbent 4–16 g/L, and initial Pb(II) solution 1–20 mg/L. The factorial statistical design was also selected to evaluate parameters performance and define the relationships among factors and optimum response. Based on the equilibrium study, high regression correlation coefficient value (R² = 0.995) was obtained for the non-linear Langmuir model and was best fitted for biosorption of Pb(II) by E. coli/ CNFs composite with a sorption capacity of 166.3 mg g⁻¹. Experimental data for the kinetic model was best fitted with a pseudo-second-order model with a high correlation coefficient, R² = 0.996. The binding mechanism of Pb(II) to the composite was characterized by some physicochemical attractions such as the electrostatic force of interaction, metal ion chelation, and ion exchange. The study revealed that E. coli/CNFs composite was an effective biosorbent to remove Pb(II) ions from aquatic solution.