4.4.1. Methylene Blue Degradation

The apparatus used for carrying out of the photocatalytic degradation reactions consisted of a double jacket cylindrical reactor with a 230 mL volume, which circulated with cold water to maintain the ambient reaction. A volume of 200 mL of aqueous solution of methylene blue (MB, 10 mg L<sup>−</sup>1) and 200 mg of photocatalysts were used for each reaction experiment. A 300 W Xenon arc lamp (Müller Electronik-Optik, Moosinning, Germany) was used both as the UV/vis light source and as the vis light source by placing a UV cut-off filter (≥410 nm) in the light path. The lamp was started 30 min before the degradation experiments to ensure maximum emission. Aliquots (1.5 mL) of the suspensions were collected at given time intervals (0, 2, 4, 6, 8, 10, 15, and 30 min), centrifuged to remove the solid, and analyzed immediately with the UV–Vis spectrophotometer.
