Nano scale zerovalent nickel: Green synthesis, characterization, and efficient removal of lead from aqueous solution

Abstract

Lead is one of the toxic heavy metal pollutants and if present in water above its permissible limit can lead to various neurodevelopmental and cardiovascular disorders in human beings. The objective of the present work is removal lead ions from aqueous solution using novel nickel nanoparticles (AONi) prepared by green synthesis from testa extract of Annacardium occidentale which acts as an eco-friendly adsorbent. The physicochemical properties of AONi nanoparticles were characterized through UV-Visible spectroscopy, FTIR analysis, SEM-EDS, XRD, and HR-TEM analysis. The adsorption capacity of AONi nanoparticles and the effect of pH, adsorbent and adsorbate dosage, and contact time are studied by batch experiments and analyzed by Langmuir and Freundlich adsorption isotherm. The correlation coefficient, R² = 0.99 is in agreement with Freundlich’s multilayer adsorption. The separation factor, R_L of Langmuir isotherm is 0.20, which also indicates favorable adsorption. Kinetic studies further confirm that the adsorption follows a pseudo-second-order mechanism.

Keywords:

• Annacardium occidentale
• lead adsorption
• nickel nanoparticles
• multilayer
• adsorption
• testa

Acknowledgments

The authors are thankful to Dr. A. M. Rawani, Director, National Institute of Technology, Raipur for facilities of laboratory and library. One of the authors Ch Chandra gratefully acknowledges the JRF awarded by UGC, New Delhi, and SAIF, IIT Bombay for providing the facility for HR-TEM analysis.