Ion-imprinted thiosalicylichydrazide-based sorbents for selective recognition of mercury(II) ions

BACKGROUND: The study of removing heavy metals from water through the use of chelating adsorbents is an emerging and critical area of research. However, the challenge lies in the lack of specificity that these adsorbents often exhibit towards individual metals. RESULTS: In addressing this challenge, we have synthesized a novel chelating polymer, thiosalicylichydrazidine-modified poly(acrylonitrile-co-divinylbenzene) copolymer (TSH-P), demonstrating a high affinity for Hg2+ ions. The crosslinking of the Hg2+/TSH-P complex with a glyoxal crosslinking agent effectively encapsulates Hg2+ ions, stabilizing the functional chelating groups within the coordination geometry of Hg2+. The ions were subsequently removed with EDTA/HNO3, producing a sorbent imprinted with Hg2+ ions (Hg-IIP). Analytical techniques were employed for a detailed examination of each synthesis step, confirming the successful chelation of Hg2+. Notably, the synthesized Hg-IIP showed significant selectivity for Hg2+ over other metal cations, with an optimal adsorption pH of 5 and a maximum capacity of 350 mg g(-1). The adsorption process was found to closely follow the Langmuir isotherm model, with kinetics that adhered to the pseudo-second-order model. Conclusion: This study introduces a highly selective chelating polymer for the removal of Hg2+ ions from water, highlighting its effectiveness and potential for specificity in heavy metal remediation. The use of analytical techniques to confirm the successful synthesis and chelation process, alongside the demonstrated selectivity and high capacity of the sorbent, underscores the polymer's utility in addressing the challenge of removing heavy metals from aqueous solutions. (c) 2024 Society of Chemical Industry (SCI).