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

Abstract

Al 2 O 3 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 Al 2 O 3 aerogels. The results showed that the Al 2 O 3 –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 Al 2 O 3 aerogels to U(VI) from solution were investigated. It could be concluded that the removal of U(VI) on Al 2 O 3 aerogels were independent on ionic strength and strongly reliant on the initial pH. The adsorption isotherms of Al 2 O 3 –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 Al 2 O 3 –Th was much better than that of other reported Al 2 O 3 -based adsorbents. In addition, the adsorption efficiency of Al 2 O 3 –Th reached 70% within 5 min and the equilibrium of U(VI) adsorption was achieved within 100 min ( C 0 = 10 mg/L). Meanwhile, the adsorption efficiency of Al 2 O 3 –Th to U(VI) maintained quite good and the value still reached about 93% after five consecutive cycles. These results indicated that the Al 2 O 3 aerogels would be applied as potential materials for wastewater treatment. • A novel in situ water formation method was used to prepare Al 2 O 3 aerogels. • The Al 2 O 3 aerogels could be used to efficiently capture U(VI). • The maximum capacity of the Al 2 O 3 –Th reached 634.0 mg/g. • The removal efficiency of Al 2 O 3 –Th remained about 93% after five cycles. • The adsorption of U(VI) on Al 2 O 3 –Th achieved WHO targets.