Effective degradation of Reactive Blue 21 and Reactive Red 195 by copper(II) oxide nanoparticles biosynthesized by pistachio hulls extract.

Textile dyes such as Reactive Blue 21 and Reactive Red 195 are complex organic compounds widely used in the fabric industry, which often cause significant environmental pollution due to their resistance to conventional wastewater treatment methods. The aim of this study is photo-degradation of these organic dyes by copper (II) oxide nanoparticles (CuO-NPs) that biosynthesized via a method based on pistachio hulls extract. The synthesized nanoparticles were characterized by various techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS), and ultraviolet-visible (UV-Vis) spectroscopy. The characterization results confirm the formation of homogeneous, spherical, crystalline CuO-NPs with an average size of approximately 90 nm. The high quality of CuO-NPs synthesized using pistachio hull extract is attributed to the presence of natural reducing and capping agents in the extract. These agents play a dual role: they reduce the copper precursor to CuO-NPs and simultaneously stabilize the nanoparticles by preventing agglomeration. The biosynthesized CuO-NPs showed high photocatalytic activity in degrading organic dyes under UV light irradiation. Specifically, the degradation efficiencies reached about 83% for Reactive Blue 21 and 75% for Reactive Red 195 after 180 min of irradiation.