Synthesis and Characterization of TiO2-Beta Heterogeneous Nanocomposites and its Kinetic Effect onto Congo-red Photocatalytic Degradation Process

In this study, zeolite Beta was used to prepare the TiO2-Beta binary composite. Different ratios of these two components nanocomposite were prepared, and the optimal weight ratio, including 70% TiO2 and 30% Beta zeolite was applied respectively. The prepared nanocomposite was characterized using the methods including FT-IR, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and X-ray diffraction (XRD). The photocatalytic degradation of Congo-red under UV light assessed with the prepared TiO2-Beta nanocomposites. The results revealed that the nanocomposite with a weight percentage of TiO2/Beta 70 to 30 exhibited higher photocatalytic degradation than that of 50%. Besides, the synthesized nanocomposite had a higher photocatalysis performance than that of TiO2 nanoparticles. The role of pH and loading of TiO2/Beta nanocomposite with a weight ratio of 70:30 investigated on the Congo-red degradation. The results showed that the highest Congo-red degradation efficiency achieved in the range of pH 4.6 to 4.6, and it increased to a maximum value by raising the amount of nanocomposite to a value that reaches the limit concentration of 1.2 gr/L. In addition, the effect of the Congo-red initial concentration on the kinetic constant evaluation of photodegradation by TiO2/Beta nanocomposite with a weight percent of 70:30, indicated that the degradation process can be described using Langmuir-Hinshelwood kinetic model, and the estimation of apparent rate constants with respect to different concentrations of the Congo-red based on the first-order kinetic model, showed that the apparent rate constant of the Congo-red degradation reduced by increasing its initial concentration. Furthermore, the ability to recover the TiO2/Beta nanocomposite indicated that after four consecutive use of nano photocatalyst, the degradation efficiency decreased only about 5 %.