Advances in design and synthesis of stabilized zero-valent iron nanoparticles for groundwater remediation

Surface modified Zerovalent iron (ZVI) nanoparticles are one of the most sought-after materials for groundwater remediation. In the area of water research, modified ZVI nanoparticles gain popularity because of their high efficiency in deactivating hazardous contaminants (both organic and inorganic), prolonged stability, recyclability, enhanced surface area and environmental friendliness. A significant progress in modifying ZVI nanoparticles using various techniques have been made in recent years [1], [2]. So far, Control Release Materials (CRMs) and Permeable Reactive Barriers (PRBs) are mostly preferred techniques for application of these modified ZVI nanoparticles in groundwater. This review updates the recent techniques such as surface modification by conjugation, in-situ fabrication, electrospinning etc. developed for producing ZVI nanoparticles modified with metallic and polymeric materials and their applicability in groundwater remediation. Lab scale studies simulating the ground conditions, real field studies and various challenges such as transport of ZVI nanoparticles towards groundwater are discussed. Most importantly, improved reactivity of ZVI nanoparticles resulted in > 95% degradation of groundwater pollutants in contaminated sites. The scope and outlook of modified ZVI nanoparticles in contaminated sites and lands are also explored. This article further emphasizes on future research that requires to be carried out with stabilised ZVI nanoparticles acquired from efficient techniques of modifying ZVI nanoparticles on larger scale for in situ remediation of contaminated groundwater.