Adsorption and Recovery of Amidoxime Modified Nano-Fe3O4-Aspergillus niger for U(VI) from Low Concentration Uranium Solution

摘要

The Aspergillus niger magnetic bioadsorbent ANFAN (amidoxime modified Nano-Fe3O4-Aspergillus niger, ANFAN) was prepared by amine oximation reaction with Aspergillus niger and nano-Fe3O4. The effects of initial pH value, adsorption time, adsorbent dosage, initial uranium concentration and coexisting ions on the adsorption of ANFAN for uranyl ion were studied in detail. The results showed that under the optimum adsorption conditions, the maximum adsorption efficiency of ANFAN for U(VI) solution amounted to 92.35%, and the maximum biosorption capacity could reach 23.38 mg/g. The kinetic data followed the pseudo-second-order model which indicated that the adsorption for uranium was mainly chemical activity on the surface of ANFAN. The adsorption equilibrium data fitted the Langmuir isotherm model well, which indicated that the adsorption of ANFAN for uranium was a single layer of chemical adsorption. Adsorption thermodynamics studies indicated that adsorption of ANFAN for uranium was a viable, spontaneous and endothermic process. The study provided a novel magnetic biosorbent with high adsorption capacity and a new method of adsorption for low concentrations of uranium.