Facile Green Synthesis of Copper Oxide Nanoparticles and Their Rhodamine-b Dye Adsorption Property

Abstract

Adsorption has gained more popularity in wastewater treatment because the process is non-toxic, cheap, and highly efficient. Environmental and human-friendly adsorbents specifically have a vast prospective. Hence, in the present study, copper oxide nanoparticles (CuONPs) synthesized with Wedelia urticifolia leaf extract were used as adsorbents for Rhodamine-b (RhB) dye. The biomolecules responsible for the synthesis were predicted from Fourier transform infrared (FT-IR) analysis while UV–Visible (UV–Vis) spectroscopy, Dynamic laser spectroscopy (DLS), X-ray diffraction (XRD), and Transmission electron microscopy (TEM) techniques were used for particle characterization. The results revealed that the synthesized nanoparticles are crystalline and spherical with a size of less than 40 nm. The dye adsorption characteristics from the aquatic environment were investigated at room temperature under different doses of CuONPs, initial concentration of RhB dye, and contact time, and over 99% of RhB dye removal was achieved. The adsorption process of RhB dye onto the as-synthesized CuONPs was accurately described by the Freundlich isotherm and pseudo-second-order kinetic models. In summary, the as-synthesized nanoparticles possess an excellent ability for RhB adsorption, and hence these nanoparticles can be used as inexpensive, promising, and potential alternatives to traditional wastewater treatment techniques.