Dispersion of zerovalent iron nanoparticles onto bentonites and use of these catalysts for orange II decolourisation

Nano zerovalent iron (Fe0) was reported as an effective material for azo dye removal, however, similar to other nano-materials, ultra-fine powder has a strong tendency to agglomerate into larger particles, resulting in an adverse effect on both effective surface area and catalyst performance. Here we report the preparation of nano sized Fe0 particles dispersed onto the surface of natural bentonites and their ability to decolourize orange II (OII). X-ray diffraction was used to study the sample phases while scanning electron microscopy and transmission electron microscopy were used to study the morphological changes. Spherical individual Fe0 particles were observed after dispersion onto bentonites, and these samples were used for OII decolourization over a wide pH range. Higher reactivity was attributed to the good dispersion of Fe0 particles on clay mineral surface. This study has great significance in providing novel modified clay based catalysts for the decolourization of azo dye contaminants from wastewater.

► Fe0 particles on clay bring higher efficiency toward azo dye decolourization.
► Fe0 mainly exists as individual spherical shaped particles on clay surface.
► High efficiency can be attributed to the good dispersion of Fe0 particles.
► These Fe0 modified clay samples have wide working pH range.