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 absorbents is an emerging and critical area of research. However, the challenge lies in the lack of specificity that these absorbents often exhibit towards individual metals. Results In addressing this challenge, we have synthesized a novel chelating polymer, thiosalicylic hydrazidine‐modified poly(acrylonitrile‐co‐divinylbenzene) copolymer (TSH‐P), demonstrating a high affinity for Hg2+ ions. The cross‐linking of the Hg2+/TSH‐P complex with a glyoxal cross‐linking 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 such as FTIR, NMR, XPS, and SEM 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 absorption pH of 5 and a maximum capacity of 350 mg/g. 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. This article is protected by copyright. All rights reserved.