Acta Phys. -Chim. Sin. ›› 2015, Vol. 31 ›› Issue (9): 1815-1822.doi: 10.3866/PKU.WHXB201507201


Fast Adsorption Removal of Congo Red on Hierarchically Porous γ-Al2O3 Hollow Microspheres Prepared by Microwave-Assisted Hydrothermal Method

Long-Hui. NIE1,2(),Qiao. TAN1,Wei. ZHU1,Qi. WEI1,Zhi-Kui. LIN1   

  1. 1 School of Chemistry and Chemical Engineering, Hubei University of Technology, Wuhan 430068, P. R. China
    2 The Synergistic Innovation Center of Catalysis Materials of Hubei Province, Wuhan 430068, P. R. China
  • Received:2015-04-03 Published:2015-09-06
  • Supported by:
    the National Natural Science Foundation of China(51572074);Natural Science Foundation of Hubei Province, China(2011CDB079);Hubei College Student Innovation Training Project, China(201310500017);Open Fund of Key Laboratory of Catalysis andMaterials Science of the State Ethnic Affairs Commission & Ministry of Education, South-Central University for Nationalities, China(CHCL12003)


Hierarchical nanostructured γ-Al2O3 hollow microspheres were synthesized from KAl(SO4)2 and urea precursors by the microwave-assisted hydrothermal (MAH) method at 180 ℃ for 20 min followed by calcination at 600 ℃ for 2 h. The as-prepared sample was used to remove the organic dye Congo red (CR) from aqueous solution. The results showed that the obtained γ-Al2O3 hollow microspheres are about 0.8-1.0 μm in diameter with a shell thickness of approximately 200 nm. The γ-Al2O3 hollow microspheres have a high surface area of 243 m2·g-1 and a hierarchical meso-macroporous structure, which is beneficial for mass transfer in liquid processes. Therefore, the prepared γ-Al2O3 hollow microspheres exhibit faster adsorption and enhanced adsorption performance for CR than particles prepared by the hydrothermal method and commercial γ-Al2O3. The adsorption kinetic data follow the pseudo-second-order equation and the equilibrium data fit well to the Langmuir model. The maximum adsorption capacity (qmax) of the obtained γ-Al2O3 hollow microspheres calculated by the Langmuir model is up to 515.4 mg·g-1 at 25 ℃. The γ-Al2O3 hollow microspheres prepared by the microwave-assisted hydrotherm method show promise as an adsorbent for environmental applications due to their hierarchical porous structure, high surface area, large pore volume, and adsorption capacity.

Key words: Hierarchically porous material, γ-Al2O3, Congo red, Adsorption kinetics