Novel floating ZnO/alumina foam photocatalyst: a realistic approach for sustainable dye degradation in wastewater.

In the present investigation, a highly porous pure α-Al2O3 foam (92% porosity) was fabricated using a thermo-foaming method. Later, zinc oxide (ZnO) nanorods were grown on the α-Al2O3 foam by a solvothermal method to produce ZnO nanorod-decorated alumina foam (ZnO-Al2O3). The morphologies and crystallographic orientations of pure α-Al2O3 and ZnO-Al2O3 foams were verified using Field Emission Scanning Electron Microscopy (FESEM) and X-ray diffraction (XRD), respectively. The photocatalytic degradation of methylene blue (MB) was evaluated using pristine Al2O3 foam and ZnO-Al2O3 foam under optimized conditions. ZnO-Al2O3 foam exhibited a degradation efficiency of approximately 57%, which was significantly higher than the ∼27% achieved by the pure Al2O3 foam. The synergistic interaction between ZnO's photocatalytic activity and the structural support provided by the alumina scaffold plays an important role in the degradation of the dye. The ZnO-Al2O3 foam utilizes both adsorption and photocatalytic degradation, whereas the Al2O3 foam removes dyes only through physical adsorption. The ZnO-Al2O3 foam provides an effective photocatalyst and a real-life solution for mitigating water pollution.