Packed Bed Photoreactor for the Removal of Water Pollutants Using Visible Light Emitting Diodes

A packed bed photoreactor was developed using a structured photocatalyst active under visible light. The packed bed reactor was irradiated by visible light-emitting diodes (LEDs) for the evaluation of photocatalytic activity in the removal of different types of water pollutants. By using a flexible LEDs strip as the external light source, it was possible to use a simple cylindrical geometry for the photoreactor, thereby enhancing the contact between the photocatalyst and the water to be treated. The visible light active structured photocatalyst was composed by N-doped TiO2 particles supported on polystyrene spheres. Photocatalytic results showed that the almost total methylene blue decolorization was achieved after 120 min of irradiation. Moreover, the developed packed bed photoreactor was effective in the removal of ceftriaxone, paracetamol, and caffeine, allowing it to reach the almost total degradation of the pollutants and a total organic carbon removal above 80% after 180 min of visible light irradiation.