Carriers for nano zerovalent iron (nZVI): synthesis, application and efficiency

Nanoparticles refer to very small size elements less than 100 nm. These particles have a large surface area to volume ratio with enhanced reactivity. One nanomaterial very interesting for remediation activities is nano zero valent iron (nZVI) estimated to be 10 to 1000 times more reactive than granular ZVI, thereby creating a greater reductive capacity per gram. Thus smaller amounts of iron would be needed to treat a contaminated plume at a faster rate, which would further reduce costs. nZVI also has the potential to treat recalcitrant pollutants such as chlorinated organic compounds, nitrates and hexavalent chromium. But the high reactivity of nZVI alone is not enough to make it an effective remediation agent, the nano iron particles should also be able to form stable dispersions and migrate to contaminated plumes. These expected additional properties are seen to be missing as the nZVI quickly agglomerates and oxidizes once released into the environment. This study looks at the challenges associated with the use of nZVI and the different transporters or carriers that have sought to overcome these shortfalls. Further attention is focused on how these nZVI particles are synthesized on carriers and the results obtained when used to treat pollutants.