Integration of ratiometric, ultrafast, sensitive detection as well as rapid and efficient removal of tetracycline based on a novel Zn (II) functionalized magnetic covalent organic framework.

Background: Based on the low volatility and refractory nature of Tetracycline (TC), excessive use leads to its continuous accumulation in water environments, posing serious risks to the ecological environment and human health. Although a very limited number of nanomaterials capable of simultaneously detecting and removing TC have been fabricated, they generally exist issues associated with a single detection signal ("on" or "off") or low adsorption rates with low adsorption capacities. As a result, it is crucial to develop a reliable technique to achieve ratiometric detection as well as rapid and efficient removal of TC.

Results: Herein, a novel Zn (II) Functionalized magnetic covalent organic framework (FeO@COF@Zn) was created. As the role of a fluorescent probe, it had excellent characteristics of ratiometric (F/F), ultrafast response (1 min), and ultra-low detection limit (16 nM). As the role of an adsorbent, it demonstrated a high capacity of adsorption (414.94 mg/g) in the pH-neutral range, fast kinetics (10 min), desirable regeneration capability, and convenient magnetic separation. By theoretical and experimental analysis, the detection and adsorption mechanism for TC was systematically revealed. Moreover, as an attempt, FeO@COF@Zn showed it potential for crop remediation by adsorbing TC-contaminated water.

Significance: This work demonstrates the exceptional performance of Zn-functionalized fluorescent COF for ratiometric, ultrafast, sensitive detection as well as rapid and efficient removal of TC, thereby illustrating its significant potential for the rapid monitoring and treatment of TC contamination.