Abstract Plant-based materials are reported to have a wide range of applications in the environmental and biomedical sectors. In this report, we present an economic and environmentally friendly supported turmeric powder (TP) biomass for the support of Ag, Ni and Cu nanoparticles (NPs) designated as Ag@TP, Ni@TP and Cu@TP. The in situ syntheses of the stated NPs were achieved in aqueous medium using NaBH₄ as a reducing agent. The prepared NPs were applied for the degradation of o-nitrophenol (ONP), m-nitrophenol (MNP), p-nitrophenol (PNP), methyl orange (MO), Congo red (CR), rhodamine B (RB) and methylene blue (MB). Initially, Ag@TP, Ni@TP and Cu@TP were screened for the MO dye and antibacterial activity, where Ag@TP displayed the strongest catalytic activity for MO and bactericidal activities as compared to Ni@TP and Cu@TP. The quantity of metal ions adsorbed onto the TP was investigated by atomic absorption spectroscopy. The Ag@TP, Ni@TP and Cu@TP were characterized through X-ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, thermal gravimetric analysis (TGA), energy-dispersive X-ray spectroscopy (EDS) and field emission scanning electron microscope (FESEM) analysis.