Impregnation of different lanthanides in a covalent organic framework (RIO-55) to a chemical determination of dopants substances

Ionic Covalent Organic Frameworks are a special subgroup that has risen as promising materials for innovative applications. In parallel, some of the so-called Reticular Innovative Organic compounds (RIOs), which are ionic and non-ionic porous materials have been used with great versatility, for several purposes. In this work, the ionic dye-based RIO-55 was chosen to capture a series of lanthanides (Eu, Gd, Dy, and Tb) from water, observing their affinity with the lattice and the performance of the adsorbent. Thus, the higher adsorbed amount was referred to as Eu³⁺ (Q_max = 370 mg/g), as well as the best affinity (K_L = 5x10⁻³), following the Langmuir model. The impregnated Eu³⁺@RIO-55 was used for chemical sensing, capturing dopant molecules (ephedrine and dopamine) from water, showing great performance, even after some reuse cycles. In addition, some initial fluorescence tests were performed using RIO-55 and Eu³⁺@RIO-55 to observe the spectrum before and after lanthanide impregnation.