Synthesis and Adsorbent Properties of Silica-Titanate Nanoarchitectures Produced by Unrolling Titanate Tubular Sheets

Microporous and mesoporous nanocomposites based on silica and titanate are obtained by unrolling sodic titanate nanotubes. The opened titanate sheets are then spaced by introducing surfactant species via ion exchange and introducing silica species between the unrolled titanate nanotubes. The characterization indicates an organic-inorganic hybrid intermedi-ate resulting from the surfactant in perpendicular accommodation between the open tubular sheets. Stabilizing the silica spacers resulted in a microporous and mesoporous nanoarchitecture forming voids between the unrolled titanate sheets with a higher specific surface (714 m2 g-1) than that of the pristine titanate nanotube (58 m2 g-1). The adsorptive properties of the synthesized silica-titanate nanoarchitectures are reported using Methylene Blue (MB) and Rhodamine B (RhB) dyes. It was revealed that the adsorption capacity against RhB is substantially increased for the nanocomposite (65%), compared to titanate nanotubes (13%). The kinetic analysis suggests that the pseudo-second-order kinetic model best describes the adsorption dynamics. Freundlich adsorption isotherm best fits the adsorption data, which suggests that adsorption does not occur onto uniform sites but in multilayers onto nanocomposites.

Automated summary

Microporous and mesoporous nanocomposites based on silica and titanate were synthesized by unrolling sodic titanate nanotubes and introducing surfactant species and silica species between the unrolled titanate nanotubes. The resulting nanoarchitectures exhibit higher specific surface areas and improved adsorption capacities compared to the pristine titanate nanotubes. Kinetic and isotherm analyses indicate that the adsorption process follows pseudo-second-order kinetics and occurs through multilayer adsorption onto the nanocomposites, rather than onto uniform sites.