Pb(II) removal from aqueous solution by polyacrylic acid stabilized zero-valent iron nanoparticles: process optimization using response surface methodology

Optimization and modeling of Pb(II) removal using polyacrylic acid stabilized zero-valent iron nanoparticles (PAA-ZVINs) from aqueous solution was performed. Central composite design (CCD) as the most applicable method in response surface methodology (RSM) was employed for optimization of Pb(II) removal. ZVINs were synthesized using the borohydride reduction method in the presence of PAA as a stabilizer and characterized via scanning electron microscopy (SEM) and X-ray diffraction (XRD). The independent variables for CCD optimization of Pb(II) removal were initial solution pH, ZVINs concentration (g/L), and initial concentration of Pb(II) (mg/L). Results showed a significant correlation between predicted values obtained from second-order polynomial model and experimental values (R-2 = 93.19 and adj-R-2 = 87.07). Maximum removal of Pb(II) (90.09 %) was observed at the optimal conditions of ZVINs concentration of 3 g/L, initial Pb(II) concentration of 10 mg/L, and initial solution pH of 5.