Abstract
We present the photocatalytic decoloration of Rhodamine B (RhB) dye with the nanocomposites such as TiO2, ZnO, TiO2/β-cyclodextrin (β-CD) and ZnO/β-CD. Band gap energy of nanocomposites was calculated by UV-DRS analysis and the results showed that the band gap energy of ZnO/β-CD nanocomposite is lower than that of other catalysts. The microstructures of the nanocomposites have been characterized by PXRD and FE-SEM analyses. The results showed that crystallinity and surface morphology of metal oxides (MO) (say, TiO2 and ZnO) are not changed in MO/β-CD nanocomposite systems. GC–MS results showed that the photocatalytic decoloration of RhB follows the steps such as N-deethylation, cleavage of chromophore and mineralization of dye.
Highlights
Rhodamine B (RhB) is a highly water soluble, basic red dye of xanthene class
We present the photocatalytic decoloration of Rhodamine B (RhB) dye with the nanocomposites such as TiO2, ZnO, TiO2/b-cyclodextrin (b-CD) and ZnO/b-CD
Since b-CD can include the RhB into its cavity and adsorbed onto the surface of metal oxides (MO), it could play a role as bridge or channel for RhB to get onto the MO surface and accumulate the higher concentrations, which makes the decoloration of RhB more easy and effective in the presence of hydroxyl radicals produced during photocatalytic decoloration processes
Summary
Rhodamine B (RhB) is a highly water soluble, basic red dye of xanthene class. It is found as a reddish violet powder and comes under the trade name of D and C red no. 19 (molecular formula = C28H31ClN2O3; molecular weight = 479.02). The effect of various parameters such as initial dye concentration, irradiation time, amount of catalysts and pH have been investigated on the photocatalytic decoloration of RhB in the presence of TiO2/b-CD and ZnO/b-CD as a photocatalyst and the results were compared with bare TiO2 and ZnO.
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