Enhanced photocatalytic degradation of anionic and cationic dyes using alpha-cyclodextrin cross-linked titanium dioxide nanoparticles

In this work, an efficient photocatalyst based on alpha-cyclodextrin cross-linked titanium dioxide nanoparticles (αCD- en/TiO2 NPs) was synthesized and used for photocatalytic degradation of rhodamine B (RhB) and methyl orange (MO). Results of field emission scanning electron microscopy (FESEM), energy dispersive X-Ray (EDX), X-ray diffraction (XRD) and transmission electron microscopy (TEM) that the TiO2 NPs were effectively altered with α-CD. The experiments were carried out to study the factors influencing the photocatalytic degradation, such as the initial concentration of the dye solution, pH, illumination time and catalyst dose. The experimental results showed that the rate of degradation of the dyes under UV irradiation was considerably enhanced using αCD -en/TiO2 NPs compared to those degraded by the pure TiO 2. The α-CD could increase the excited states lifetimes of the unreactive guests and facilitate electron transfer from the excited dye to TiO 2 conduction band. The results indicated that the first- order kinetic model well describes the degradation of the dyes by αCD -en/TiO2 NPs. When α -CD was presented in the TiO2 structure, the photocatalytic reaction rate constants for RhB and MO dyes were 5.92 and 4.23 times higher, respectively. In addition, the αCD-en/TiO2 NPs can be used for several times in real application as an effective photocatalyst. The proposed photocatalyst has been successfully applied to remove model dyes from aqueous solutions with satisfactory results.

کلیدواژه ها:

αCD-en/TiO2 NPs ، Photocatalytic degradation ، Anionic dye ، Cationic dye ، Wastewater treatment.