Green synthesis of functional nanocomposites from laboratory waste for environmental remediation and antimicrobial performance

Copper-based nanocomposites have emerged as multifunctional materials owing to their remarkable catalytic, antimicrobial, and electronic properties. Their ability to generate reactive oxygen species, interact with microbial membranes, and facilitate electron transfer makes them promising candidates for both environmental and biomedical applications. In this study, nanocomposites of Cu₂O–Cu(OH)₂ were synthesized by utilizing the end-product, cuprous thiocyanate (CuSCN), of an undergraduate laboratory experiment as a precursor material. Following initial collection, purification, and characterization, the precursor, CuSCN, was chemically converted into nanocomposites through a controlled synthesis route using cetyltrimethylammonium bromide (CTAB), a cationic surfactant, as a capping/stabilizing agent. The nanocomposites were characterized using X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and UV–vis absorption spectroscopy to evaluate the structural, morphological, and functional properties of the material. The synthesized nanocomposites measuring 190 nm by TEM showed promising microbicidal activity against various Gram-positive and Gram-negative bacterial strains. The copper nanocomposites were found to possess significant catalytic efficiency (~ 93%) in degrading the Congo red (CR) dye, a toxic azo dye, and further exhibited acceptable biocompatibility with mammalian cells, indicating the potential of this low-cost, upcycled material for environmental remediation and biomedical applications. This work highlights the value of educational experiment outcomes as viable resources for the development of advanced nanomaterials.