Synthesis of novel surface-modified hematite nanoparticles for lead ions removal from aqueous solution

Abstract

Abstract In this study, novel surface-modified hematite nanoparticles (α-Fe2O3 NPs) were synthesized by hydrothermal method at 250 °C using iron (III) chloride hexahydrate (FeCl3.6H2O) and oleic acid (C₁₈H₃₄O₂) as raw materials for removal of lead ions (Pb2+) from aqueous solution. This adsorbent was characterized by X-Ray Diffraction (XRD), Fourier Transform Infra-Red (FT-IR), Scanning Electron Microscope (SEM), Transmission Electron Microscopy (TEM) and Brunauer-Emmett-Teller (BET). According to the results, the average diameter and length of the synthesized α-Fe2O3 nanorod were 30–60 nm and 400–700 nm, respectively, when its specific surface are a was 31.29 m2 g−1. Furthermore, in batch experiments, the lead ions adsorption onto the α-Fe2O3 NPs was found to be dependent on pH, adsorbent weight, cation concentration and contact time. Thus, the optimum condition to uptake Pb2+ on α-Fe2O3 NPs was obtained, and the mechanism adsorption of lead ions onto the nano-crystals well fitted the Ho model as linear pseudo-second order kinetics. In contrast, analysis of equilibrium data revealed that the Langmuir isotherm model was suitable to describe Pb2+ adsorption onto α-Fe2O3 NPs, and the maximum uptake capacity was estimated to be 111 mg g−1 at 25 ± 1 °C. Therefore, it can be concluded that the synthesized novel surface-modified α-Fe2O3 NPs is an environment-friendly and a promising adsorbent for the removal of lead ions as heavy metal from aqueous solutions.