TITANATE NANOTUBES PRODUCED FROM MICROWAVE-ASSISTED HYDROTHERMAL SYNTHESIS: CHARACTERIZATION, ADSORPTION AND PHOTOCATALYTIC ACTIVITY

A microwave-assisted hydrothermal (MAH) method was employed to synthesize TiO2 nanotubes (TNTs) and these were compared to the conventional hydrothermal (CH) method. The nanotubes were characterized for their crystallinity, morphology, surface area and photocatalytic activity. The TiO2 P25 was used for comparison purposes and efficiently degraded both dyes. However, methylene blue was adsorbed on the nanotube surfaces, which can be attributed to the electrostatic interaction between the cationic methylene blue and the negatively charged TNT surface. On the other hand, all nanotubes had a photocatalytic performance with methyl orange (anionic dye). Additional degradation was observed for nanotubes synthesized via the MAH method at 150 degrees C. This can be directly related to their larger surface area. Adsorption mechanisms of TNTs were also discussed by applying the Langmuir and Freundlich isotherm. The results show an efficient dye wastewater treatment through the application of TNT photocatalyst.