Investigation of Some Factors Affecting the Stability of Zero Valent Iron Nanoparticles in Aqueous Environments

Document Type : Research Paper



Considering the high potential of zero-valent iron nanoparticles (NZVI) for removal of contaminants from surface and groundwater, it essential to investigate the factors affecting their stability in aquatic environments. Throughout the present study, the effects of surface coating and background solution characteristics including nanoparticle concentration, ionic strength, and electrolyte type and dissolved organic matter content on the stability of NZVI in aqueous suspensions were investigated. A number of four two-way factorial experiments, based on completely randomized design of three replications, were conducted to explore the effects of surface coating and each of four background solution characteristics on the stability of NZVI suspension. Initially, bare NZVI (B-NZVI) and Carboxymethyl cellulose coated NZVI (CMC-NZVI) were synthesized and characterized. Thereafter NZVI suspensions were prepared in distilled water and at different levels of the selected characteristics. The hydrodynamic diameter and zeta potential were then assessed in each of the prepared suspensions. Results indicated CMC-NZVI suspensions were more stable than B-NZVI in all tested solutions. Increase in nanoparticle concentration, ionic strength and cation valence of background solution, increased hydrodynamic diameter and while decreasing zeta potential of NZVI which lead to more aggregation of NZNI and less stability of the suspension. On the contrary, increase in dissolved organic matter content resulted in more stability of NZNI suspension. Results also revealed that there are significant interactions between nanoparticle type and solution characteristics; as B-NZVI is more affected by change in solution chemistry than CMC-NZVI. 


Main Subjects

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