Synthesis, characterization, and application of MgO/ZnO nanocomposite supported on activated carbon for photocatalytic degradation of methylene blue

In this study, nano-sized ZnO/MgO composites at different ratios were synthesized based on sol–gel method under ultrasonic radiation, and then combined with as-prepared activated carbon (AC). The prepared materials were characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectrometry, and Brunauer–Emmett–Teller surface area measurements. The photocatalytic activity of the prepared nanocomposites was tested on the decolorization of methylene blue (MB) aqueous solutions. The dye photo-decolorization process was studied considering the influence of experimental parameters such as catalyst concentration, ZnO/MgO/AC ratio, pH, and MB adsorption rate. The resulting material composition with the best catalytic activity towards the MB photo-decolorization was ZnO doped with 10 % MgO and 10 % AC. The complete photo-oxidation of a 1 × 10−5 mol l−1 MB solution, at natural pH and room temperature, was achieved in <20 min, nearly 60 min faster than the ZnO photo-assisted process. Experimental results show that ZnO/MgO/AC nanoparticles possess high photocatalytic activity in comparison with universal catalysts.