Effect of external magnetic field on mass transport of reactive species in the reaction between nano zero valent iron and selenate anions in a simulated flue gas desulfurization wastewater

Abstract

The mechanism involved in the reaction of regulated ions with nano Zero-Valent Iron (ZVI) in the presence of an applied weak magnetic field (WMF) was investigated. The WMF effect on mass transport of reacting ions and morphology and composition of the oxide layer in nano ZVI was elucidated using Electron Energy Loss Spectroscopy (EELS). The magnetic gradient force produced by ferromagnetic ZVI particles had a greater influence on the rate of selenate diffusion in solution than the Lorentz force due to the externally applied weak magnetic field. Moreover, the magnetic gradient force was suggested to suppress ZVI corrosion reactions. Despite changes in the iron oxide layer under the WMF influence, the rate of selenate reduction has not been significantly affected over short term lasting several hours. Most crucially, WMF had a negligible effect on the rate of mass transport of selenate anions, as compared to the dominant effect of forced convection.