Biogenic of CuO nanoparticles using the plant extract  Ephedra Alata applied to the removal of methylene blue from wastewater, and its statistical physics analysis

Abstract

Water contaminants due to industrial organic dyes are posing serious human health and environmental problems. Adsorption technology has been widely used in wastewater remediation because of its simplicity, low cost, high effectiveness, and potential to use eco-friendly, non-toxic materials. Herein, the work presents an experimental and theoretical study of the adsorption process of Methylene Blue (MB) dye onto new biogenic copper oxide nanoparticles (CuO NPs) from Ephedra Alata plant extract. The CuO NPs were synthesized via a green chemistry approach and characterized by FE-SEM, EDXS, TEM, XRD, UV–Visible, FTIR, and Raman spectroscopies. The biosynthesized CuO-NPs present a large surface area, nanosize, and a monoclinic structure with phenolic, flavonoid, and hydroxyl groups on the surface. Adsorption tests were carried out under optimal conditions such as pH (7), dye concentration (10 mg/L), and adsorbent dose (0.02 g) to remove the most methylene blue dye from the solution. Adsorption isotherms showed that the capacity of MB adsorbed onto the biosynthesized CuO-NPs increased to 110 and 133.75 mg/g by increasing the temperature to 293 and 323 K, respectively. These experimental data were modeled using statistical physics theory in order to describe the steric and energetic factors involved in the removal of dye, as well as the adsorption mechanism. The modeling analysis demonstrated that MB adsorbed on the CuO-NPs adsorbent surface in a non-parallel orientation. Additionally, the investigated showed the energies of adsorption less than 40 kJ mol− 1. According to adsorption energy values, this mechanism progresses by physical adsorption. In summary, green synthesized CuO-NPs are potential materials for organic chemical removal from wastewater treatment.