Unexpected behavior during methylene blue adsorption over H-titanate nanotubes and nanosheets

Abstract

2D titanate nanosheets (H-TNS) and 1D titanate nanotubes (H-TNT) were synthesized by using a simple hydrothermal technique to effectively adsorb cationic methyl blue (MB) dye from aqueous solutions. These nanomaterials were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The effects of pH values, contact time, and the initial concentration of the dye on the adsorption behavior were investigated. The studies on the equilibrium and the kinetic behavior of adsorption are also included in this work. Various equilibrium adsorption models (including the Langmuir and the Freundlich models) and kinetic models were adopted to correlate the experimental data taken in the present study. The results showed that the adsorption capacity of methylene blue was 7.25 mg g⁻¹ and 6.67 mg g⁻¹ for H-TNT and H-TNS, respectively. Moreover, the effects of the morphology of titanate, the initial concentration of the dye, and the temperature of the solution on the chromatic behavior of cationic methylene blue dye were investigated. Finally the reusability of the nanomaterials was also tested.