Research on Photocatalytic Degradation of Methyl Orange by a β-Cyclodextrin/Titanium Dioxide Composite

Abstract

A photocatalytic composite of β-cyclodextrin/titanium dioxide (β-CD/TiO2) was synthesized via the photoinduced assembly method in this work. The morphology of the composite was characterized by scanning electron microscope (SEM) and transmission electron microscopy (TEM), respectively. The chemical composition was detected by fourier transform infrared spectroscopy (FTIR). By means of phenolphthalein probe technique and back titration method, the contents of active β-CD (2.0%) and TiO2 (0.0971±0.0006 g/0.1 g) in the prepared β-CD/TiO2 composite were obtained. In order to investigate deeply the role of β-CD in TiO2 photocatalytic system, 100 mL of 0.1 mmol L -1 methyl orange (MO) aqueous solution was used as the organic pollutant, the photocatalytic activity of β-CD/TiO2 and pure TiO2 were assessed under the same conditions. The results showed that the degradation time of β-CD/TiO2 was 43% shorter than that degraded by the aqueous solution containing only TiO2. β-CD/TiO2 demonstrated a better photocatalytic activity. The kinetics of photocatalytic degradation of MO by β-CD/TiO2 and pure TiO2 was studied. In addition, the degradation efficiency of MO by β-CD/TiO2 was still above 85% after recycling for 5 times.

Study of visible-light photocatalytic degradation of 2,4-dichlorophenoxy acetic acid in batch and circulated-mode photoreactors

“…Therefore, β-CD can promote the charge transfer rate from the photo-excited TiO 2 to the electron acceptor guest molecule [17]. Because β-CD plays electron-donating and hole-capturing roles when binding to TiO 2 colloids, which lead to photocatalytic efficiency enhancement and charge-hole recombination restriction [29,32,33]. Furthermore, when the unreacted guests are placed inside the cyclodextrins cavity, their excited states durability will be extended.…”