Photocatalytic degradation of methylene blue dye using biogenic copper oxide nanoparticles and its degradation pathway analysis

Abstract

In order to remove the toxic organic dyes from the environment, biogenic inorganic semiconductor nanoparticle based photocatalyst has drawn attention due to its low cost, simplicity, eco-friendliness, high efficiency and ease of process. Herein, Copper oxide nanoparticles (CuO NPs) were prepared by using Syzygium Cumini seed extract as reducing as well capping agent. The formed CuO NPs were characterized by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), B.E.T isotherm, UV–Visible spectroscopy, Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS) analysis. The CuO NP’s photocatalytic activities have been analyzed with methylene blue (MB) degradation. The effect of the catalyst for MB degradation has been optimized at various catalyst amount, dye concentration and pH environments. The results showed that, the CuO NPs can effectively degrade 97 % of MB in 60 min, following pseudo first order kinetics, while the rate constant was found to be 0.06 min−1. The present catalyst material showed 95 % MB degradation with similar morphology of freshly prepared catalyst even after five consecuetive reuse cycles and worked effectively over a wide pH range. The degradation pathway of MB was studied through the HR-MS technique.