Design of β-cyclodextrin modified TiO2 nanotubes for the adsorption of Cu(II): Isotherms and kinetics study.

This paper builds on previous literature showing the interesting adsorptive properties of TiO 2 nanotubes. It further explores the positive effect of β -cyclodextrin on these properties. Hence, β -cyclodextrin modified TiO 2 nanotubes were successfully prepared and characterized by XRD, N 2 physisorption at 77 K, Raman, FTIR-ATR, 1 H NMR, TEM and EPR. The adsorptive interaction of Cu(II) with materials was investigated in aqueous solution at pH 9.25 (NH 4 + /NH 3 ). The main conclusion is that copper(II)-ammonia complexation equilibria play an important role in the adsorption process. The β -cyclodextrin was found to improve the Cu(NH 3 ) 4 2+ adsorption mainly by retarding its precipitation to high concentrations values (>400 mg L −1 ). Adsorption experimental data showed good fit with the pseudo-second-order model and the Langmuir isotherm model. [ABSTRACT FROM AUTHOR]