ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Novel chitosan–naphthalimide–amino acid fluorescent powder for selective detection and removal of Hg²⁺/Hg⁺ and Fe²⁺ in aqueous solution

Lin Zhang, Xinyue Jiao, Huijuan Zhang, Suyan He, and Xinjian Cheng

School of Chemistry and Environmental Engineering, Wuhan Institute of Technology, Wuhan, China

E-mail: zhjminda@mail.scuec.edu.cn

Received: 20 May 2022  Accepted: 18 July 2022

Abstract:

Heavy metal ions are harmful to the environment and the human beings and other creatures. Fluorescent agents play important roles in the detection of heavy metals. Chitosan-based fluorescent probes were synthesized and investigated in this work. Firstly, 4-bromo-1,8-naphthimide was introduced into chitosan through nucleophilic addition–elimination reaction, and then the Br was replaced by amino acid through substitution reaction. By this way, three chitosan–naphthalimide–amino acid fluorescent probes were obtained consequently. The structure and fluorescence properties of macromolecular probes were characterized and confirmed. These macromolecules have good selectivity and sensitivity to Hg²⁺/Hg⁺, and Fe²⁺ ions. When Hg⁺/Hg²⁺ ions are present, the probe P1 produces a significant increase in fluorescence intensity. The LOD of P1 to Hg⁺ and Hg²⁺ are 1.66 × 10⁻⁶ M and 1.60 × 10⁻⁶ M, respectively. When Fe²⁺ ions exist with the presence of P2 and P3 probes, P2 and P3 show significant fluorescence quenching, and their LODs are 1.09 × 10⁻⁶ M and 6.65 × 10⁻⁷ M, respectively. And these three chitosan derivatives also have good adsorption effect on ions, the maximum adsorption capacity of mercury can reach 108.7 mg/g, and the maximum adsorption capacity of ferrous iron can reach 52.0 mg/g. This mechanism of recognition and adsorption is formed as the complexation of N and ions on the probe. In this article, a material with good recognition, and removal of Hg⁺/Hg²⁺ and Fe²⁺ is developed, which also provides a way for the potential remediation of heavy metal polluted water.

Keywords: Fluorescent chitosan; Naphthalimide; Amino acid; Heavy metal detection

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-022-02385-9

Chemical Papers 76 (11) 7037–7049 (2022)