Smart Design of Self-Assembled Mesoporous α-FeOOH Nanoparticles: High-Surface-Area Sorbent for Hg2+ from Wastewater

Self-assembled mesoporous alpha-FeOOH nano-particles with high surface area and controlled structure have been synthesized through a simple and environmentally friendly method. The formation mechanism of self-assembled mesoporous structures, as well as the effect of pH on the structure of the materials, is carefully discussed. The self-assembled mesoporous alpha-FeOOH nanoparticles have been characterized by small-angle X-ray scattering (SAXS) analysis, powder X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), N-2 sorption, and X-ray photoelectron spectroscopic (XPS) studies. N-2 sorption analysis revealed high surface areas (74-152 m(2) g(-1)) and narrow pore size distributions (2.5 nm) for different samples. The XPS analysis revealed that the materials contain a large amount of surface Fe-OH groups which are the active suite for Hg2+ adsorption. The adsorption process has been discussed using Langmuir and Freundlich models. These self-assembled mesoporous alpha-FeOOH nanoparticles can act as a very efficient and reusable adsorbent for Hg2+ from polluted water.