Enhancement removal of tartrazine dye using HCI-doped polyaniline and TiO2-decorated PANI particles

HCl-doped polyaniline (HCl-PANI) and titanium dioxide decorated with. polyaniline (TiO2-decorated PANI) with different TiO2:PANI ratios were chemically prepared and utilized for the. removal of tartrazine (TZ) dye from a. synthetic aqueous solution. The mechanism of preparation of the sample suggested that aniline was adsorbed on the TiO2 surface before the. polymerization process took place. Samples were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive x-ray spectroscopy. and x-ray diffraction.. The results showed that HCl-PANI and TiO2-decorated PANI have an amorphous structure. The thermal stability of the. prepared samples was characterized using thermo-gravimetric (TG) analysis. HCl-PANI is stable up to 200 degrees C and the relative weight. per. cent of PANI in the TiO2-decorated PANI was. 20, 25, 40 and 45%. The removal activity of TiO2-decorated PANI via TZ azo dye was investigated under UV light irradiations and compared with HCl-PANI and TiO2 particles. The results indicated the superiority of the TiO2-decorated PANI over pure HCl-PANI and TiO2. However, the excessive PANI percentage tends to form a relatively thick layer, and even aggregates on the surface of TiO2. This hinders the migration of excited electrons from the outer PANI layer to the inner TiO2 particles, which consequently leads to a. decrease in. the removal efficiency. A possible mechanism for the removal oxidative degradation is. also mentioned.