Decorating of ultra small and recyclable nanoscale zero-valent iron on NH2-SiO2 for enhanced high-performance removal of water pollutants

The synthesis of nanoscale zero-valent iron (NZVI) with dimensions ranging from 20 to 100 nm has received tremendous attention in the control of environmental pollutants. However, due to strong magnetic attraction and van der Waals forces of NZVI, creating well-dispersed and stable NZVI particles with subnanometre size while avoiding their aggregation and retaining surface activity is a challenge. Here, for the first time, a novel Fe-0@NH2-SiO2 nanocomposite was prepared by making SiO2 amino-functionalization in a simple process of hydrolysis polymerization, grafting Fe3+ on NH2-SiO2 nanospheres, and reduction by sodium borohydrid. It was found that the surface of NH2-SiO2 nanospheres (around 200 nm) was uniformly decorated by plentiful of well-defined Fe-0 nanoparticles with a diameter of <10 nm. The as-synthesized NZVI particles exhibited some unique features, such as ultra small size and excellent dispersibility, which significantly enhanced their reactivity in the removal of pollutants from water. Compared with the unsupported NZVI, these supported Fe-0 nanoparticles showed a remarkable reduction activity in the application for the removal of water pollutants, and could be recycled easily with the aid of NaBH4. (C) 2018 Elsevier B.V. All rights reserved.