Predicting dye-adsorption capacity of hydrogen titanate nanotubes via one-step dye-removal method of novel chemically-activated catalytic process conducted in dark

Abstract

The dye-adsorption capacity of various adsorbents has been traditionally determined via conducting the equilibrium dye-adsorption/desorption experiments. We demonstrate here a new method for precisely predicting the dye-adsorption capacity of hydrothermally processed semiconductor-oxide nanotubes, such as the hydrogen titanate, which involves the use of one-step dye-removal method of novel chemically-activated catalytic process conducted in the dark. The methylene blue (MB) dye-adsorption capacity of hydrogen titanate nanotubes has been determined to be 121 mg g 1 via the conventional method which is comparable with that (114 mg g 1) predicted via the one-step dye-removal method of novel chemically-activated catalytic process conducted in the dark. The equilibrium MB adsorption on the surface of hydrogen titanate nanotubes follows both the Langmuir and Freundlich isotherms and the pseudo-second-order kinetics at the initial solution-pH of 10 although the amount of surface-coverage by the MB dye supports only the Langmuir model