Nano-zero-valent Fe/Ni particles loaded on collagen fibers immobilized by bayberry tannin as an effective reductant for uranyl in aqueous solutions

Abstract In this study, nano-zero-valent Fe/Ni particles (NZFNP) loaded on collagen fibers through the immobilization of bayberry tannin was prepared and used for uranium adsorption-reduction from aqueous solution. The effects of environmental conditions for uranium removal onto NZFNP were studied in detail. The as-prepared adsorbent was characterized by TEM, SEM, EDS, FT-IR to investigated the adsorption-reduction mechanism of uranium on NZFNP. The results indicated that the major removal reaction of uranium should be recognized as a process of adsorption and reduction, and the U(VI) was adsorbed onto NZFNP firstly under the effect of electrostatic interaction. Then the Fe0 in the inner layer of the metal sphere lost electrons to generate Fe(II) as a new reductant, and U(VI) could be reduced by the Fe(II) generated on the surface of sample at the interface between adsorbent and aqueous. In particular, a higher uranium reduction ratio of 70.6% have been obtained due to the introduction of Ni0, where a battery is formed between Fe0 and Ni0, thereby forming a continuous electron flow and an increase in Fe0 activity. Thus, the NZFNP is promising for the rapid and effective removal of uranium from waste water.