Synergistic Effect of Chitosan and Titanium Dioxide on the Removal of Toxic Dyes by the Photodegradation Technique

The photodegradation of three different types of dyes like an anionic dye, a cationic dye, and a zwitterionic dye, namely, Reactive Red 2 (RR), Methylene Blue (MB), and Rhodamine B (RB), respectively, have been carried out using chitosan/TiO2 composite (CTC). The as-synthesized CTC was characterized by Fourier transform infrared (FTIR) spectral studies, scanning electron microscopy (SEM), energy dispersive analysis of X-ray (EDAX), BET, X-ray diffraction (XRD), and thermal analysis (thermogravimetric analysis (TGA) and differential thermal analysis (DTA)). The enhanced photocatalytic activity of CTC for the degradation of the dyes was attributed to the synergistic effect of TiO2 and chitosan (CS). The photodegradation experiments were carried out by varying different parameters such as irradiation time, dosage, pH, initial dye concentration, coexisting ions, hydrogen peroxide, and light intensity. The kinetic behavior was described in terms of the Langmuir–Hinshelwood model. The confirmation of mineralization of dyes has been studied by measuring chemical oxygen demand (COD).