One-step synthesis of a benzothiadiazole-based nonbranching functionalized covalent organic framework and its application in efficient removal of Hg2

• Published in: Dalton transactions : an international journal of inorganic chemistry 2023-08, Vol.52 (32), p.11035-11041
• Main Authors: Li, Guizhen, Cao, Yuanzhe, Zhang, Bo, Zhang, Qiang, Hu, Yingyuan, Zhao, Xin
• Format: Article
• Language: English
• Subjects: Adsorbents; Adsorption; Crystallinity; Mercury (metal); Porous materials; Synthesis
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/d3dt02083e

In recent years, a variety of adsorbents have been developed for Hg2+ removal. However, these adsorbents are unsatisfactory for adsorption due to narrow and irregular pore channels or poor adsorption capacity and low stability. Therefore, it is worth exploring a porous Hg2+ adsorbent material with high adsorption performance and stability. In this study, a benzothiadiazole-based nonbranching functionalized covalent organic framework (COF) material (TPS-COF) by one-step synthesis was reported, which exhibited a high specific surface area of 1564 m2 g−1, high crystallinity and stability attributed to its high conjugated linkage structure of benzothiadiazole. In addition, due to the rich S and N elements of the benzothiadiazole unit, it exhibited excellent adsorption performance on Hg2+, including excellent adsorption amount (1040 mg g−1), high initial adsorption rate (448 mg g−1 min−1) and very short adsorption equilibrium time (10 min), with an efficient removal rate of Hg2+ in the pH range of 2–8. After desorption, the TPS-COF still retained good pore stability, adsorption capacity, and reusability. Such a one-step synthetic unbranched functionalization strategy provides further insights to achieve a good balance between the high crystallinity, functionality and stability of COFs.