Removal Of Uranium(Vi) From Aqueous Solution By Mg(Oh)(2)-Coated Nanoscale Zero-Valent Iron: Reactivity And Mechanism

Nanoscale zero-valent iron (nZVI) is considered to be an effective material for removing U(VI), but its application in in-situ remediation is limited due to its easy oxidation and agglomeration. In order to solve this problem, nZVI@Mg(OH)(2) was synthesized by modified liquid phase reduction method and used to remove U(VI) from aqueous solution. The effects of pH, contact time, dosage and initial concentration on the removal of U(VI) by nZVI@Mg(OH)(2) were studied by batch experiments. The results showed that nZVI@Mg(OH)(2) presented better removal efficiency than nZVI, the removal ratio and amount reached 97.8 % and 122.3 mg/g respectively at 0.4 g/L dosage with 50 mg/L U(VI) solution. Various techniques were implemented to characterize nZVI@Mg(OH)(2). The results indicated that Mg(OH)(2) was successfully coated on the nZVI surface, thus turned rough, aggregation and oxidation of Fe degrees particles was minimized, then the removal performance of U(VI) increased. Mechanisms were also explored by a comparative study of the phase, morphology, and surface valence state of composite before and after reaction, indicating that nZVI@Mg(OH)(2) remove U(VI) mainly through reduction and adsorption. The results of column experiments and sedimentation experiments showed that the suspension stability and mobility of nZVI have been improved after coating. It can be seen that nZVI@Mg(OH)(2) has certain potential for in-situ remediation of U(VI).