Preparation of a Phosphate-Modified Flower-Like α-FeOOH Composite and Its Application for Aqueous U(VI) Removal
Goethite is a stable and widespread mineral in soil, which affects the transportation and immobilization of heavy metals in soil. Here, the three-dimensional flower-like goethite (TDFLG) was synthesized by refluxing precipitation method. The modified three-dimensional flower-like goethite (MTDFLG) was prepared by NaH2PO4 with dipping method. The obtained samples were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis, N2 adsorption–desorption (BET), and X-ray diffraction (XRD). SEM images showed that the modification of phosphate had no major changes on the morphology of the original sample and the morphology of MTDFLG after adsorbed U(VI) had clearly change. For the goethite and modified goethite, the BET-specific surface area was 229.96 and 203.17 m2/g, respectively. Moreover, the effects of adsorption time, sorbent dose, solution pH, and initial uranium concentration on the uranium adsorption behaviors were investigated using the two materials as adsorbent for the treatment of uranium-containing wastewater. The results showed that MTDFLG had better adsorption capacity than TDFLG on uranium. The increase in uranium removal on MTDFLG was due to the formation of ternary surface complexes (≡FePO4UO2). TDFLG and MTDFLG followed the pseudo-second-order kinetic model and the Langmuir adsorption isotherm model, which indicated that uranium adsorption on TDFLG or MTDFLG is mainly based on chemisorption, and the maximum adsorption capacity of two adsorbents is 48.24 and 112.36 mg/g, respectively.
KeywordsUranium α-FeOOH Phosphate Sorption Mechanism
This paper is supported by the double first class construct program of USC (2017SYL05), Hunan Provincial Innovation Foundation For Postgraduate (CX2016B454), and Scientific Research Fund of Hunan Provincial Education Department (15C1196).
- Li, H., Li, W., Zhang, Y. J., Wang, T. S., Wang, B., Xu, W., Jiang, L., Song, W. G., Shu, C. Y., & Wang, C. R. (2011). Chrysanthemum-like α-FeOOH microspheres produced by a simple green method and their outstanding ability in heavy metal ion removal. Journal of Materials Chemistry, 21(22), 7878–7881.CrossRefGoogle Scholar
- Liu, F., Jie, X. L., He, J. Z., Zhou, D. H., Xu, F. L., & Li, X. Y. (1997). Coordination forms and transformations of phosphate adsorbed by goethite surface on different pH. Acta Pedologica Sinica, 34(4), 367–374.Google Scholar
- Seshadri, B., Bolan, N. S., Choppala, G., Kunhikrishnan, A., Sanderson, P., Wang, H., Currie, L. D., Tsang, D. C. W., Ok, Y. S., & Kim, G. (2017). Potential value of phosphate compounds in enhancing immobilization and reducing bioavailability of mixed heavy metal contaminants in shooting range soil. Chemosphere, 184, 197–206.CrossRefGoogle Scholar
- Wei, Y., Zhang, L., Shen, L., & Hua, D. (2016). Positively charged phosphonate-functionalized mesoporous silica for efficient uranium sorption from aqueous solution. Journal of Molecular Liquids, 221, 1231–1236.Google Scholar
- Xu, J. G., Li, Y. Q., Yuan, B. L., Cui, H. J., & Fu, M. L. (2015). Synthesis and characterization of 3 D flower -like α-FeOOH nanostructures. Chemical Journal of Chinese Universities, 36, 48–54.Google Scholar