Catalytic Degradation of Toxic Rhodamine B and Safranin O Dyes With Green Synthesized Copper Nanoparticles

In the sphere of science and technology, nanotechnology stands out as a rapidly advancing field, characterized by the manipulation of metal and metal oxide materials at scales of $$\le$$ 100 nanometres. In the present study, copper nanoparticles (CuNPs) were synthesized through a green method using the aqueous extract of Vernonia amygdalina leaves as a natural reducing and capping agent, after which the catalytic degradation of toxic organic dyes, namely, Safranin O commonly known as basic red 2 (SO-BR2) and Rhodamine B (RhB), in the presence of NaBH4 was evaluated. The synthesized CuO NPs were characterized using UV‒Vis, FT-IR, XRD, and SEM techniques, and their results confirmed the successful synthesis of the nanomaterial a via the plant-assisted method with characteristic peak of Cu-O bond interaction at 809 cm⁻¹ a band gap of 3.71 eV, a mean crystalline size of 2.406 nm and varied morphologies with medium agglomeration. The catalytic degradation of SO-BR2 and RhB by the CuNPs in the presence of NaBH4 exhibited maximum efficiencies of 97.74 ± 0.0410% and 94.22 ± 0.0408%, respectively, under the optimized conditions. Kinetic studies revealed strong correlation coefficients close to 1 for both pseudo-zero and pseudo-first order kinetics models, indicating that both models effectively describe the reaction dynamics during the catalytic degradation of dyes on CuNPs. Furthermore, the nanocatalysts exhibited excellent reusability and stability over four cycles. The results demonstrate the potential of green-synthesized CuNPs as a cost-effective and environmentally friendly solution for organic dye degradation, highlighting their promising application in addressing dye pollution in aqueous environments.