Perrhenate (ReO) removal from aqueous solutions by mono-, bi-, and tri-metallic iron nanoparticles; A Comparative study

Maamoun, I.; Tokunaga, Kohei   ; Falyouna, O.*; Eljamal, O.*; Tanaka, Kazuya  

Recently, the rapid development of nuclear power technologies and the continuous energy demand around the world exhibited massive amounts of contaminated water with radionuclides. The exposure to TcVII-contaminated water can be harmful to human health, causing toxic effects and organs damage when ingested. Therefore, TcO removal from aqueous solutions can be challenging, in terms of fast and efficient immobilization. Correspondingly, perrhenate (ReO) was considered as perrhenate (TcO) surrogate to ease the radioactivity-related complications, owing to the physiochemical similarities between Tc and rhenium (Re). In this study, nickel (Ni) andzirconium (Zr) were considered in the preparation of bi- and tri-metallic Fe0 nanoparticles, as they both showed the highest ReO removal performance comparing with other metals. The effect of reaction conditions on ReO removal was investigated, including mass ratio of iron to the doped metal, material dosage, and initial pH. Results showed enhanced ReO removal rate when using bi-metallic Ni-Fe0 (mass ratio 2.5) and Zr/Fe0 (mass ratio 20) comparing with Fe0. The difference in ReO removal using mono-, bi-, and tri-metallic was not clear at high material dosage, such as 2.0 and 1.0 g/L. Nevertheless, comparing lower dosage (0.5 g/L)of bi- and tri-metallic to 1.0 g/L mono-metallic Fe0 dosage exhibited a clear superiority of tri-metallic Zr-Ni/Fe0 to other materials; where 0.5 g/L of the material could efficiently achieve around 98% ReO removal within just 10 min reaction time (1.8 times higher than 1.0 g/L Fe0). The significant enhancement in ReO removal rate by tri-metallic Fe0 nanoparticles can be attributed to the induced rate of electron transfer from iron core through the mixed Zr-Nideposits on Fe0 surface.