Adsorptive removal of heavy metal ions from aqueous solution by using green synthesized copper oxide nanoparticles

Abstract

Metal nanoparticles can be synthesized by “green synthesis” methods, an efficient and environmentally friendly process that involves combination of metal salt solution with plant extract. Due to low cost, ideal surface area, plenty of active sites, and high adsorption capabilities, copper oxide nanoparticles (CuO-NPs) have drawn a lot of attention as effective adsorbents. Our present study is primarily concerned about green synthesis route of producing copper oxide nanoparticles (CuO-NPs) from flower extract of Nyctanthesarbor-tristis. The prepared CuO-NPs was used in the adsorption of toxic metal ions including U(VI), Pb(II), Cr(VI), and Cd(II) from water samples was studied. Different analytical techniques like UV-visible spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy and field emission scanning electron microscopy has been used for analyzing the properties of prepared copper oxide nanoparticles. A batch experiment has also been conducted to determine the efficacy of the synthesized copper oxide nanoparticles toward the adsorption of toxic metal ions including U(VI), Pb(II), Cr(VI), and Cd(II) from water samples at various parameters, such as the impact of pH, contact time and adsorbent dosage. According to the results, the adsorption capacity (q_max) of CuO-NPs for U(VI), Pb(II), Cr(VI), and Cd(II) metal ions are 200, 155.27, 131.57 and 90.90 respectively. The kinetic studies showed that the pseudo-second order kinetics model has best fits to the data (R²= 0.85, 0.91, 0.89, 0.92 for U(VI), Pb(II), Cr(VI), and Cd(II) respectively. The study also included pseudo-first order, Elovich models and intra particle diffusion. In light of these findings, copper oxide nanoparticles were found to be a promising nano-adsorbent for the treatment of water.

Graphical Abstract

Keywords:

• Removal of toxic metal ions
• copper-oxide nanoparticles
• adsorption
• kinetic study

Acknowledgments

Komal Kashyap, one of the authors, expresses her sincere gratitude to the CSIR-UGC NET (File No. [09/1116(0007)/2018/EMR-I]), New Delhi, for awarded her a JRF-SRF fellowship. The authors would also acknowledge the Department of Chemistry at the National Institute of Technology Raipur in India for their research facilities.

Disclosure statement

The authors claim that they have no conflicts of interest to report.

Additional information

Funding

This work was supported by the CSIR-UGC NET (09/1116(0007)/2018/EMR-I).