Insights into the Synthesis, types and application of iron Nanoparticles: The overlooked significance of environmental effects

Abstract

The application of iron-based nanoparticles in environmental remediation. • Typical core–shell structure of bare iron nanoparticles with Fe 0 as core. • Superior properties of different modified iron nanoparticles. • The pathway of removing pollutants by iron nanoparticles through adsorption, redox and coprecipitation. • The environmental effects caused by the application of iron nanoparticles. • Risk assessment and green-sustainable development of iron nanoparticles in ecosystems. Two decades ago, iron nanoparticles have been widely studied in environmental protection due to their particular characters. Compared with traditional absorbents, iron nanoparticles not only have higher specific surface area, but also can oxidize and reduce multiple pollutants. Iron nanoparticles have been employed for the remediation of organic and inorganic pollutants in polluted water, soil and sediments. With in-depth research, various modified iron nanoparticles have been prepared to further overcome the original defects of aggregation or oxidation, and improve the reaction efficiency. Based on the properties of iron-based nanoparticles, this review summarizes different synthesis methods of iron nanoparticles and the removal mechanism of various pollutants. We also systematically classified the unstable and stable iron nanoparticles. At present, stable iron nanoparticles are possible to overcome the aggregation and retention of bare iron nanoparticles so as to achieve higher efficiency for the removal of pollutants. The application of iron nanoparticles in environmental remediation has significant effect on the environmental pH value, the pollutant morphology and the toxicity to microorganisms. Subsequently, some suggestions and conclusions are put forward for the application of iron nanoparticles.