Understanding the Role of Triblock Copolymers for the Synthesis of Mesoporous Alumina, and Its Adsorption Efficiency for Congo Red



Mesoporous alumina (MA)was synthesized by sol–gel based evaporation-induced self-assembly process using aluminum isopropoxide as alumina source in the presence of three different types of triblock copolymers (TBCs), F68, F127, and L64. The role of different TBCs as surfactants on thermal, crystallization, textural, and microstructural properties of the alumina powders was studied. To understand the effects of different copolymers, the adsorption efficiency of the samples for Congo red (CR) was studied. For all the surfactants, the XRD results showed the stability of γ-Al2O3 phase up to 1000°C for 1 h dwell time. A maximum value (431.8 m2/g) of Brunauer–Emmet–Teller surface area was obtained for the 400°C-treated powder prepared from F68 surfactant. The transmission electron microscopy micrograph exhibited worm-like mesoporous structures of the 400°C-treated powders prepared from F68 and F127 surfactants. The adsorption performance for CR of the 400°C-treated powders for different surfactants was in the order of F68 > F127 > L64. A tentative mechanism was illustrated to understand the roles of different block copolymers on the properties of the prepared MA.