Simultaneous remediation of Cr and Ni from waste water using efficient Schiff-base resin bis(2-methoxy-1-napthaldehy)-O-phenylene diimine as an adsorbent

Abstract

In this study, we report the synthesis of a Schiff base, bis(2-methoxy-1-napthaldehy)-o-phenylene diimine (BMNOPhen), and a Schiff-base resin, bis-2-methoxy-1-napthaldehy-o-phenylenediimine (PMBMNOPhen). The materials were characterized via different spectroscopic techniques; CHN analysis, FT-IR, TGA, EDS, SEM, and XRD to analyze the structure and surface morphology and crystallographic evolution of the polymeric resin. The synthesized resin was used for uptake studies with Ni(II) and Cr(VI) ions. The optimum conditions were determined by different parameters used to describe the effects of uptake including initial concentration, temperature, time, and pH through batch adsorption methods. Different functional groups like azomethine, OH, and amine present in the Schiff-based resin structure contain donor N and O atoms which can coordinate cationic metal ions, supported by the active adsorption of chromium(VI) and nickel(II). The isotherm data are informative and useful for calculating and modeling adsorption capacity and exploring the mechanism of removal by the adsorbent Different types of adsorption isotherms like Langmuir, Freundlich, and kinetic studies were used on environmental water samples. The polymeric resin PMBMNOPhen was used for elimination of Cr(VI) and Ni(II) ions in real water samples from different agricultural cities of Sindh (Province of Pakistan) such as Sanghar, Tando-Adam, Kotri, and Jamshoro.

KEYWORDS:

• Adsorption
• chromium
• nickel
• isotherms
• Langmuir

Acknowledgments

This work was supported by the Dr. M.A. Kazi Institute of Chemistry, Sindh, University Jamshoro, Pakistan. The authors are grateful to H.E.J. Research Institute of Chemistry, International Centre for Chemical and Biological Sciences, University of Karachi, Pakistan, providing research facilities at organic chemistry laboratories, and support for performing analysis on different instruments, and authors are also thankful to the Department National Centre of Excellence in Analytical Chemistry, Sindh University Jamshoro, Microbiology department Sindh, University Jamshoro and material Science Department of Mehran University of Engineering and Technology, Jamshoro, Pakistan, for providing infrastructure and other facilities to carry out research.

Author statement

All authors contributed to the study conception and design. The material preparation data collection and analysis were performed by Dr. Moina Akhtar, Dr. Aamna Balouch and Dr. Khalid M. Khan. The first draft of the manuscript was written by Dr. Nasira Liaquat Rajput. All authors read and approved the final manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.