Template-free method for the synthesis of high-pore-volume γ-Al₂O₃ nanofibers in a membrane dispersion microreactor

Mesoporous γ-Al₂O₃ nanofibers with high pore volume and uniform pore size distributions were successfully synthesized via a template-free method in a membrane dispersion microreactor followed by calcination. The effects of crystal temperature, pH values, continuous phase concentration and washing solvent on the γ-Al₂O₃ nanofibers were carefully studied. The results showed that the as-obtained γ-Al₂O₃ nanofibers showed a length of 40–60 nm and a width of 3.2–3.4 nm, which were attributed to the high microscopic mixing rate in the membrane dispersion microreactor. Moreover, the precursors of γ-Al₂O₃ nanofibers treated with deionized water and mixed deionized water/alcohol solution had high pore volumes, reaching to 1.60 ml g⁻¹ and 2.00 ml g⁻¹, respectively. Furthermore, the adsorption performance of γ-Al₂O₃ nanofibers with high pore volumes was also investigated. These fibers showed an excellent adsorption capacity of 1323.68 mg g⁻¹ for the removal of Congo red from aqueous solution, thereby indicating their potential for applications in adsorption and other related areas. (paper)