Action mechanism of montmorillonite/Fe₃O₄/ humic acid composite on U(Ⅵ)

Abstract

The montmorillonite/Fe3O4/humic acid composite (MFH) was prepared by hydrothermal method. The effects of pH value, MFH dosage, adsorption time, initial concentration of U (Ⅵ) and temperature on the adsorption of U(Ⅵ)by MFH were investigated. The experiment shows that the dosage of MFH has the greatest influence on the adsorption of U(Ⅵ) within the selected test conditions; when the initial concentration of U(Ⅵ) is 5 mg·L-1, the pH value is 6, and the dosage of MFH is 0.3 g·L-1, and the temperature is 30 ℃, the removal of U(Ⅵ) by MFH reaches the adsorption equilibrium after 30 min, and the adsorption rate reaches 97.7%. The adsorption of U(Ⅵ) by MFH conforms to the quasi-second-order kinetic model and Langmuir model; the removal mechanism of MFH to U(Ⅵ) is complexation and reduction. The adsorption-desorption tests show that the adsorption rate of U(Ⅵ) by MFH composites is still as high as 90% after 5 cycles. The test shows that MFH has a good removal efficiency and efficient reusability for U(Ⅵ).

Keywords

• montmorillonite/fe₃o₄/humic acid composite material
• u(ⅵ)
• adsorbent
• adsorption
• reduction
• complexation