Synthesis of Ni-CdO Nanostructured Material Using Artemisia afra Leaf (Ariti) Extract for the Removal of Rhodamine B (RhB) Dye from Aqueous Media

Abstract

Rhodamine B (RhB) is a water-soluble dye that is widely used in various industries. However, its high toxicity and environmental persistence make it a potential environmental pollutant. In this study, we investigated the removal of RhB from aqueous solution using Ni-CdO nanoparticles (Ni-CdO NPs) modified with artemisia afra (AA) plant extract. The CdO NPs and Ni–CdO nanocomposites (NCs) were successfully synthesized via green method in order to investigate their degradation performance against RhB dye. The crystal structure, functional groups, morphological change, and degradation efficiency of as-synthesized photocatalysts were characterized using XRD, FTIR, SEM and UV-Visible spectroscopic techniques, respectively. The results showed that Ni-CdO NPs modified with AA (Ni-CdO-AA NPs) exhibited excellent adsorption capacity for RhB, with a maximum degradation capacity of 120.6 mg/g. The degradation of the dyes was found to be a fast, spontaneous, and irreversible process. The degradation process was also found to be concentration, catalytic load, temperature and pH-dependent, with the maximum adsorption capacity occurring at 15 ppm, 0.35 g, 45 °C and 6.0 respectively. The Uv-vis result measure the absorption of UV-visible light by sample to get energy band gap that CdO and Ni-CdO-AA changed from 2.23 eV to 2.03 eV and 2.19 eV, respectively and the XRD patterns demonstrate sharp and intensive diffraction peak attribute to the existence of cubic CdO and Ni-CdO stucture revealed the dicreasing crystalline size from 28nm to 20nm after Ni-CdO NCs formation. The absorption spectrum reveals information about the molecular structure and SEM result showed that the surface morphology of the nanomaterials seems the agglomerated micron-scaled grains as compared to CdO NPs and Ni–CdO NCs. This approach offers a pathway to scalable, cost-effective, and eco-friendly wastewater treatment technologies