Hexavalent chromium [Cr(VI)] is considered a serious environmental pollutant that possesses a hazardous effect on humans even at low concentrations. Thus, the development of a bifunctional material for ultratrace-selective detection and effective elimination of Cr(VI) from the environment remains highly desirable and scarcely reported. In this work, we explore an imidazolium-appended polyfluorene derivative PF-DBT-Im as a highly sensitive/selective optical probe and a smart adsorbent for Cr(VI) ions with an ultralow detection limit of 1.77 nM and removal efficiency up to 93.7%. In an aqueous medium, PF-DBT-Im displays obvious transformation in its emission color from blue to magenta on exclusively introducing Cr(VI), facilitating naked-eye colorimetric detection. Consequently, a portable sensory device integrated with a smartphone is fabricated for realizing real-time and on-site visual detection of Cr(VI). Besides, the imidazolium groups attached onto side chains of PF-DBT-Im are found to be highly beneficial for achieving selective and efficient elimination of Cr(VI) with capacity as high as 128.71 mg g^–1. More interestingly, PF-DBT-Im could be easily regenerated following treatment with KBr and can be recycled at least five times in a row. The main factor behind ultrasensitive response and excellent removal efficiency is found to be anion-exchange-induced formation of a unique ground-state complex between PF-DBT-Im and Cr(VI), as evident by FT-IR, XPS, and simulation studies. Thus, taking advantage of the excellent signal amplification property and rich ion-exchange sites, a dual-functional-conjugated polymer PF-DBT-Im is presented for the concurrent recognition and elimination of Cr(VI) ions proficiently and promptly with great prospects in environmental monitoring and water decontamination.

中文翻译：

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用于现场目视和超灵敏检测有毒六价铬的咪唑功能化共轭聚合物

六价铬 [Cr(VI)] 被认为是一种严重的环境污染物，即使在低浓度下也会对人体产生有害影响。因此，开发用于超痕量选择性检测和有效消除环境中 Cr(VI) 的双功能材料仍然非常令人期待，但很少有报道。在这项工作中，我们探索了一种带有咪唑鎓的聚芴衍生物 PF-DBT-Im，作为一种高灵敏度/选择性光学探针和一种 Cr(VI) 离子智能吸附剂，具有 1.77 nM 的超低检测限和高达 93.7% 的去除效率。在水介质中，单独引入Cr(VI)后，PF-DBT-Im的发射颜色从蓝色到洋红色发生明显的转变，有利于肉眼比色检测。因此，我们制作了一种与智能手机集成的便携式传感装置，用于实现 Cr(VI) 的实时、现场视觉检测。此外，PF-DBT-Im 侧链上附着的咪唑基团对于实现选择性、高效去除 Cr(VI) 非常有利，其容量高达 128.71 mg g ^–1。更有趣的是，PF-DBT-Im 在用 KBr 处理后可以很容易地再生，并且可以连续回收至少五次。 FT-IR、XPS 和模拟表明，超灵敏响应和出色去除效率背后的主要因素是阴离子交换诱导 PF-DBT-Im 和 Cr(VI) 之间形成独特的基态复合物学习。因此，利用优异的信号放大性能和丰富的离子交换位点，提出了一种双功能共轭聚合物PF-DBT-Im，用于高效、快速地同时识别和消除Cr(VI)离子，在该领域具有广阔的前景。环境监测和水净化。