Polypeptide and copper oxide nanocomposite hydrogel for toxicity elimination of wastewater

In this experimental study, a novel bionanocomposite of gelatin as a polypeptide hydrogel consisting of copper (II) oxide nanomaterial (GL–CuO) was prepared. After dispersing the synthesized CuO nanoparticles (NPs) within the GL aqueous solution, they were cross-linked by the addition of a formaldehyde solution. The resulting GL–CuO nanocomposite hydrogels were further characterized by FESEM, EDX, XRD, XPS, and FTIR. The FESEM micrographs confirmed the uniform distribution of CuO NPs in the hydrogel matrix, with dimensions ranging from 60 to 80 nm. The XRD patterns confirmed the presence of the monoclinic crystalline form of CuO NPs embedded in the GL hydrogel. The GL–CuO catalyst was tested in the reduction of two azo dyes. All the reactions were carried out in the presence of a strong reducing agent, NaBH4, with the catalyst demonstrating high activities toward methyl orange and congo red with reaction rate constants of 9.91 × 10−1 min−1 and 5.8 × 10−1 min−1, respectively. The reduction of these dyes was followed by UV–visible spectroscopy that confirmed complete reduction of the dye.