Assessment of Pb (II) Removal from Aqueous Solutions by Ascorbic Acid-stabilized Zero-valent Iron Nanoparticles Using Response Surface Methodology (RSM)

Abstract

The growing pollution of water resources and the limited availability of water supplies have led to a growing interest by researchers to develop novel methods of water remediation and reuse. One such method is the use of ascorbic acid-stabilized zero-valent iron nanoparticles (AAS-ZVIN) for the removal of lead (Pb) from aqueous solutions. Using zero-valent iron nanoparticles stabilized with acid ascorbic under aerobic conditions, the present study was conducted to assess the efficiency of Pb removal from aqueous solutions and its optimization by the response surface methodology (RSM). For this purpose, use was made of the central composite design and the response surface methodology with the four input variables of ASS- ZVIN dose (0.5, 1, and 2 g L-1), pH (2, 5, and 7), contact time (5, 20, and 60 min), and initial Pb concentration (5, 10, and 20 mg L-1) to determine the optimal conditions for the process. Numerical optimization revealed that the optimum conditions for Pb removal (97.93%) included an ASS-ZVIN dose of 2 g L-1, an initial Pb (II) concentration of 25 mg L-1, a contact time of 60 min, and an initial solution pH of 7. The results also imply that not only does ASS-ZVIN offer a good potential for the remediation of water bodies contaminated with Pb, given its high reactivity for Pb removal, but that  the RSM optimization process can be successfully employed for the optimization of the process in question.