Efficacy of biomaterial based photocatalytic composite in treating dye pollutants

A biomaterial based photocatalytic composite, hydroxyapatite–TiO2–ZnO (HAp-TiO2–ZnO) has been developed following a solid-state combustion method while its efficacy was investigated through the photodegradation of (i) aquatic solution of synthetic dye, methylene blue (MB); and (ii) real textile dye effluent. The degradation profile was explored considering several factors, e.g.: (i) initial dye concentration; (ii) illumination span; (iii) dose of photocatalyst; and (iv) pH of targeted dye solution. The photodegradation was performed in both indoor and outdoor environment using halogen lamp (500 W) and sunlight respectively. Observed photodegradation revealed that though the photocatalytic composite effectively decomposed methylene blue at various extents under different experimental conditions but a dose of 0.5g photocatalyst/100 mL substrate solution (10×10-6 M methylene blue solution at pH 4) expedited optimal degradation (~ 97%) at 2 hours’ time interval. On the other hand though it was possible to degrade the textile effluent to some extent by illuminating through halogen lamp and sunlight but the success rate did not exceed 50%. Bangladesh J. Sci. Ind. Res.53(2), 139-144, 2018