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

Abstract

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/HNO<inf>3</inf>, 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. © 2024 Society of Chemical Industry (SCI).