Eco-friendly synthesis of Cynomorium coccineum extract for controlled production of copper nanoparticles for sorption of methylene blue dye

Abstract

A biological extract of Cynomorium coccineum was used for the synthesis of copper nanoparticles using copper sulphate as a starting matter. Fourier transform infrared spectroscopy (FT-IR) showed the presence of the functional groups characteristics of biological extract, i.e., triterpenes, phenolics, flavonoids, and other reducing agents. SEM analysis showed that the surface of the particles were clusters and rough. The Elemental analysis by energy-dispersive X-ray (EDX) proved the purity of the particles, showing the presence of elemental copper oxide which was surrounded with some elements of the plant. X-ray diffraction (XRD) pattern confirmed that the crystalline nature of the particles was affected by temperature. The average crystallite size was calculated to be about 14.2 nm. The total weight loss registered within the thermogravimetric (TG) analysis was 52.8%, suggesting that about 47.2% of the metallic copper is present in the prepared copper nanoparticles which supported the data reported within EDX analysis. The adsorption characteristics of the nanoadsorbents were examined using methylene blue as adsorbate and the bio-sorption capacity reached 64 mg/g at room temperature. The values of B and bt, calculated from Temkin equation, increased with the increase in temperature (295–328 K), indicating endothermic adsorption and strong dye-nanoadsorbent interaction. The mean free energy (E = 100–129.1 kJ/mol), calculated from Dubinin-Radushkevich indicated that the chemisorption is the process involved for the adsorption of methylene blue. In summary, the results obtained in this study deliver the design and the synthesis of new materials for removing pollutants. Keywords: Biological, Cynomorium coccineum, Nanoparticles, Nano-adsorbent, Molecular solute-solvent interactions, Molecular-level (microscopic) interactions in solutions