Microwave-Aided Green Synthesis of ZrO2/ZnO/AC Nanocomposite for Catalytic Degradation of Organic Dye

In this work, a simple green method was followed to prepare ZrO 2 /ZnO/AC nanocomposite with the aid of plant extract as a capping and stabilizing agent for the nanoparticles. The prepared nanocomposite was characterized with different techniques such as Fourier transform infrared (FTIR), ultraviolet–visible spectroscopy (UV-Vis), dynamic light scattering (DLS), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), scanning electron microscope (SEM), thermal gravimetric analysis (TGA), and nitrogen adsorption for surface area. The successful formation of ZrO 2 /ZnO and loading it on the surface of activated carbon (AC) was confirmed by XRD, UV-Vis, EDS, and SEM images. Different degradation tests were performed under different conditions including the mass of the catalyst, pH, the concentration of dye solution and H 2 O 2 used, and the catalyst. Blank tests ensured the necessity of both catalyst and H 2 O 2 for the degradation to start. ZrO 2 /ZnO/AC was the best compared to ZrO 2 /ZnO, and AC with a degradation of 68% compared to 3% and 36%, respectively. The performance of ZrO 2 /ZnO was almost negligible confirming the importance of combining nanoparticles with suitable support. Furthermore, the highest degradation efficiency using ZrO 2 /ZnO/AC was achieved at a pH of 2 with degradation of 80% compared to 67% at a pH of 10, since the surface will be positively charged leading to a higher reaching rate of MO anions to the surface. Also, the highest performance was achieved when 0.8% of H 2 O 2 was used with degradation of 91%. Despite the lower degradation in this work compared to what has been reported in the literature, it is still very promising since it was achieved under a stagnant and dark environment, which makes it a promising candidate for treating huge bodies of wastewater stored in dark places or containers.