Enhancing reactivity of zerovalent iron toward U(VI) by weak magnetic field

The influence of weak magnetic field (WMF) on the process of U(VI) removing by zero valent iron (ZVI) was explored and the main mechanism was investigated. The weak magnetic field could obviously promote the U(VI) sequestration under the condition of different initial pH (pH_ini). The first-order kinetic rate constants of U(VI) removal by ZVI with WMF at pH 3.0-7.0 were about 0.7 to 11.2 fold greater than those without WMF. The removal capacity of zero-valent iron toward U(VI) was 1.7 g·g^-1 with WMF at initial pH 4.0 and Fe 0.5 g·L^-1, being of 0.3-fold higher than that without WMF. The weak magnetic field could promote the corrosion of the zero-valent iron, thereby increasing its removal of U(VI), which could be verified by SEM, [Fe²⁺] and pH variation. The main mechanism of U(VI) removal by zero valent iron was adsorption together with reduction. The application of WMF did not change the mechanisms but accelerated its adsorption and reduction toward U(VI). As a chemical-, energy-free and environmental-friendly method, improving the reactivity of ZVI by WMF superimposition was novel and promising in the prospect of U(VI) sequestration from water.