Mercury (Hg²⁺), a heavy metal ion, is considered one of the most toxic metals on earth and is widespread as an environmental pollutant. Various promising adsorbents have been developed with accessible chelating sites and high affinity for heavy metal ions. Herein, we utilized the advantages of covalent organic frameworks (COFs) and designed benzobisthiazole-bridged (BBT) fluorescent COFs (FCOFs) for Hg²⁺ sensing applications. The BBT-FCOF nanosheets has a π-π transition, effective electron transfer, and enhanced delocalization within the π orbitals of the BBT ring. It emits a white fluorescence enabling real-time detection of Hg²⁺ metal ions. The excellent sensing property of BBT-FCOF nanosheets was attributed to the high sensitivity towards Hg²⁺; this was confirmed by the x-ray photoelectron spectroscopy binding energy of sulfur and nitrogen atom in BBT-FCOF. The limit of detection of Hg²⁺ was 30 ppb, which is very low compared to other published methods. ICP-mass measurement also proved that BBT-FCOF nanosheets removed almost 99% of Hg and BBT-FCOF distribution coefficient (Kd) was calculated to be 5 × 10⁵ g⁻¹. The recyclability test proved that HCl effectively removed the adsorbed Hg²⁺ metal ions from BBT-FCOF nanosheets, making it a useful tool for real-time Hg²⁺ detection and removal from waste water.

汞 (Hg ²⁺ ) 是一种重金属离子，被认为是地球上毒性最强的金属之一，并且作为环境污染物广泛存在。已经开发出各种具有可接近的螯合位点和对重金属离子的高亲和力的有前途的吸附剂。在此，我们利用共价有机骨架 (COF) 的优势并设计了用于 Hg ²⁺传感应用的苯并双噻唑桥 (BBT) 荧光 COF (FCOF) 。BBT-FCOF 纳米片在 BBT 环的 π 轨道内具有 π-π 跃迁、有效的电子转移和增强的离域化。它发出白色荧光，可实时检测 Hg ²⁺金属离子。BBT-FCOF 纳米片的优异传感性能归因于对 Hg ²⁺的高灵敏度; BBT-FCOF中硫和氮原子的X射线光电子能谱结合能证实了这一点。Hg ²⁺的检测限为 30 ppb，与其他已发表的方法相比非常低。ICP 质量测量也证明 BBT-FCOF 纳米片去除了几乎 99% 的 Hg，并且 BBT-FCOF 分配系数 (Kd) 计算为 5 × 10 ⁵  g ^-1。可回收性测试证明，HCl 有效地去除了BBT-FCOF 纳米片中吸附的 Hg ²⁺金属离子，使其成为实时检测和去除废水中Hg ²⁺的有用工具。