Nano zerovalent iron (Fe 0 ) 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 Fe 0 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 Fe 0 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 Fe 0 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.