Rapid Transformation of Carcinogenic 4-Nitrophenol by Nanoparticles Synthesized Using Recycled Copper Waste: A...

Novel Cu/Cu₂O-nanoparticles have been synthesized by the most economical electrochemical method utilizing metallic waste. 4-NP is a toxic pollutant affecting both animal and plant kingdom, necessitating its elimination from environment. This study demonstrates that the prepared nano-catalysts efficiently catalyse the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) at room temperature under light condition. Further, the reduction process generates amine derivatives, which are intermediates in many industrial processes. This manuscript adheres to the principles of the circular economy by generating nanoparticles through the repurposing of metallic waste discarded by both industry and domestic users. Using scrapped copper from discarded air conditioner (AC) copper tubes as electrodes, we employed an electrochemical technique to develop Cu/Cu₂O nanoparticles. The synthesized nanoparticles were characterized using field emission scanning electron microscopy (FE-SEM), transmission electron (TEM), EDX spectroscopy, powder x-ray diffraction (P-XRD), Fourier transformation infrared (FTIR) spectroscopy, x-ray photoelectron spectroscopy (XPS), Raman spectroscopy, cyclic voltammetry (CV), and Brunauer-Emmett-Teller (BET) analysis. Our study confirms 99% conversion of harmful 4-NP to 4-AP in a rapid reaction time of 5 min. Synthesized nanoparticles can be reused up to four times without losing catalytic activity. UV-vis spectroscopy demonstrated that reduction follows pseudo-second-order kinetics and adsorption follows Freundlich isotherm model.