Facile preparation of hierarchical hollow structure gamma alumina and a study of its adsorption capacity

The hierarchical shell and hollow core structure gamma alumina (gamma-Al2O3) with high adsorption affinity toward organic pollutants was fabricated via a facile homogeneous precipitation method. The microstructure, morphology, and functional groups of the as-synthesized gamma-Al2O3 were characterized in detail. The N-2 adsorption-desorption measurement (BET) experimental result showed the surface area of gamma-Al2O3 (Al90-600) is 320.6 m(2)/g and the average pore size is 17.8 nm. The effects of reaction parameters on the synthesis of hierarchical hollow structure were systematically investigated. The dye removal ability of this adsorbent was determined by batch adsorption procedure. The isotherms and kinetics of adsorption process were determined and analyzed in detail, which were found to obey the Langmuir isotherm model and the pseudo-second-order for both the Congo red (CR) and Methyl orange (MO). The maximum adsorption capacity of gamma-Al2O3 for CR is 835.0 mg/g, which is higher than that of many other previously reported hierarchical structured adsorbents. This facile synthetic approach is a very promising way for the design and synthesis of the typical hierarchical hollow structure materials with powerful adsorption capacity for the removal of organic contaminants from wastewater. (C) 2013 Elsevier B.V. All rights reserved.