Synthesis, Characterisation and Photocatalytic Properties of ZnO/Carbonaceous Gelatin-Based Aerogel Material for Dyes Degradation in Water

Abstract

In this work, new ZnO/Carbonaceous gelatin-based aerogel (ZnO/CGA) materials with different weight ratios were prepared, and their photocatalytic properties were evaluated. The gelatin used was extracted from hide waste of tanneries. Compared to the pure ZnO, all the ZnO/CGA materials prepared exhibited higher degradation efficiency for methylene blue (MB), ZnO(50%)/CGA showed the optimal performance among them. Adding CGA to ZnO reduces the band gap to 3.28 eV, promotes the effective dispersion of ZnO particles, enhances electrons conduction, and minimizes the e⁻/h⁺ pair recombination. The impacts of solution pH, dye concentration, catalyst mass, UV irradiation time, and the presence of H₂O₂, organic solvents (ethanol and acetone), and salts were investigated. The highest degradation rate (99.25%) of MB dye at 20 mg.L^-1 was achieved by using 0.5 g.L^-1 of ZnO(50%)/CGA, operating at pH 6 for a duration of 3 hours. Moreover, the catalyst demonstrated reusability and stability across multiple cycles. The innovative addition of carbonaceous gelatin-based aerogel (CGA) to ZnO not only improves photocatalytic performance but also contributes to the sustainable use of tannery waste as a precursor material.