Synergetic effect of adsorption on degradation of malachite green dye under blue LED irradiation using spiral‐shaped photocatalytic reactor

BACKGROUND: The present study focus on the development and feasibility of a blue light emitting diodes (LEDs) source based slurry type spiral‐shaped photocatalytic reactor for degradation of malachite green (MG) dye using P25 Degussa TiO₂ . The influence of operational parameters such as amount of catalyst loading, initial concentration of dye, and pH of the medium has been studied for optimization of MG dye degradation. RESULTS: The photocatalytic degradation of malachite green dye under separate irradiation by blue and by ultraviolet LED was nearly the same (∼76%). The photocatalytic activity using blue LED irradiation was observed due to the synergistic effect of MG dye adsorption on P25 Degussa, which extends the spectral response of TiO₂ to the visible region (449 nm). The optimized degradation of 20 mg L‐¹ dye was observed at pH 8 using 0.5 g L‐¹ of catalyst under irradiation by ultraviolet and blue LEDs for 1 h and 3 h, respectively. CONCLUSION: It was found that the synergistic effect of adsorption of malachite green dye on TiO₂ surface helped to enhance photocatalytic degradation under blue LED irradiation. The application of a blue LED for photocatalytic degradation of malachite green dye is economical and feasible compared with use of an ultraviolet LED. © 2014 Society of Chemical Industry