Covalent Organic Framework for Uranium Detection Using Colorimetry: A Simple Chemistry Experiment for Undergraduate Students

The objective of this study was successfully achieved by engaging undergraduate students in the preparation and application of covalent organic frameworks (COFs) for the colorimetric detection of uranium. The COFs were synthesized via a one-step condensation reaction followed by nucleation, both of which were accessible and manageable for undergraduate training. Characterization of the COFs and the subsequent experimental procedure were conducted with students, and the resulting data were analyzed and plotted using Origin software. The interaction between COFs and uranium ions demonstrated their effectiveness as a sensor, with a UV–visible absorption spectrophotometer used as the primary detection method. This approach achieved an average limit of detection (LOD) of 1.74 μM with a concentration range of 2.1–13.8 μM. This work highlights several key advantages: (i) the use of a straightforward and environmentally friendly condensation method for COFs preparation, (ii) the feasibility of a 72 h nucleation process suitable for undergraduate laboratory practice, and (iii) the adoption of a colorimetry detection method that is sensitive, cost-effective, and easy to operate. Overall, this experiment provided students with valuable experience in material synthesis, data analysis, and application of UV–visible absorption spectroscopy for real-world environmental challenges, thereby strengthening both their experimental and conceptual understanding of chemistry.