Photocatalytic decouloration of malachite green dye by application of TiO2 nanotubes

The nanotubes of titania were synthesized in a hydrothermal system and characterized by scanning electronic microscopy (SEM), FT-IR, FT-Raman, and surface charge density by surface area analyzer. These nanomaterials were applied to photocatalyse malachite green dye degradation. Photodegradation capacity of TiO2 nanotubes was compared to TiO2 anatase photoactivity. Malachite dye was completely degraded in 75 and 105 min of reaction photocatalysed by TiO2 nanotubes and TiO2 anatase, respectively. Catalysts displayed high photodegradation activity at pH 4. TiO2 nanotubes were easily recycled whereas the reuse of TiO2 anatase was not effective. Nanotubes maintained 80% of their activity after 10 catalytic cycles and TiO2 anatase presented only 8% of its activity after 10 cycles.