Fabrication of the Al2O3 aerogels by in situ water formation method for the highly efficient removal of uranium(VI)

Al2O3 aerogels have been synthesized by in situ water formation method using different agents including phenylenediamine, aniline, thiourea and urea for in-situ water formation. Then, various of techniques were implemented to analyze the structure of these as-prepared Al2O3 aerogels. The results showed that the Al2O3-Th possessed the uniform porous morphology, which might provide the large specific surface area and a large number of active sites to dislodge U(VI) species. Additionally, the adsorption properties of the as-prepared Al2O3 aerogels to U(VI) from solution were investigated. It could be concluded that the removal of U(VI) on Al2O3 aerogels were independent on ionic strength and strongly reliant on the initial pH. The adsorption isotherms of Al2O3-Th to U(VI) could be imitated using the Langmuir model and the maximum adsorption capacities in simulated seawater and aqueous solution were 270.9 and 634.0 mg/g, respectively, which showed that the adsorption property of Al2O3-Th was much better than that of other reported Al2O3-based adsorbents. In addition, the adsorption efficiency of Al2O3-Th reached 70% within 5 min and the equilibrium of U(VI) adsorption was achieved within 100 min (C0 = 10 mg/L). Meanwhile, the adsorption efficiency of Al2O3-Th to U (VI) maintained quite good and the value still reached about 93% after five consecutive cycles. These results indicated that the Al2O3 aerogels would be applied as potential materials for wastewater treatment.