Innovative Synthesis of Aluminum Oxide Impregnated Carbon Nanotube Membranes for Effective Cr(VI) Removal

A facile method of synthesizing aluminum oxide-impregnated carbon nanotubes membrane is reported. In the first step, various loadings (1 to 20%) of aluminum oxide <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\text{Al}_{2}\mathbf{O}_{3})$</tex> were impregnated on the surface of multiwall carbon nanotubes (MWCNTs). In the second step, the impregnated MWCNTs were compacted at 200-300MPa and sintered at <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$1200-1400^{\circ}\mathbf{C}$</tex> to procedure the disk-shaped membrane. The fabricated membranes have the advantage of producing a network of tightly held CNTs that can utilize the excellent properties of nanotubes for applications in water treatment. The fabricated membranes were employed for the removal of Cr(VI) ions from a large volume of water in a continuous filtration setup. The effect of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{Al}_{2}\mathbf{O}_{3}$</tex> loadings on the characteristics of the prepared membrane was also evaluated. Membrane with 10% <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{Al}_{2}\mathbf{O}_{3}$</tex> content exhibited better Cr(VI) ions removal.