Magnetic sustentation as an adsorption characterization technique for paramagnetic metal-organic frameworks

Nowadays, there are many reliable characterization techniques for the study of adsorption properties in gas phase. However, the techniques available for the study of adsorption processes in solution, rely on indirect characterization techniques that measure the adsorbate concentration remaining in solution. In this work, we present a sensing method based on the magnetic properties of metal-organic frameworks (MOFs) containing paramagnetic metal centres, which stands out for the rapidity, low cost and in situ direct measurement of the incorporated adsorbate within the porous material. To illustrate this sensing technique, the adsorption in solution of four MOFs have been characterized: MIL-88A(Fe), MOF-74(Cu, Co) and ZIF-67(Co). Our simple and efficient method allows the direct determination of the adsorbed mass, as well as the measurement of adsorption isotherm curves, which we hope will greatly advance the study of adsorption processes in solution, since this method is independent of the chemical nature of the adsorbate that often makes its quantification difficult.

Automated summary

Nowadays, there are many reliable techniques available for the characterization of adsorption properties in the gas phase. However, for adsorption processes in solution, indirect characterization techniques are commonly used, which measure the remaining adsorbate concentration in the solution. In this study, a sensing method based on the magnetic properties of metal-organic frameworks (MOFs) containing paramagnetic metal centres is presented. This method allows for rapid, low-cost, and in situ direct measurement of the incorporated adsorbate within the porous material, enabling the determination of adsorbed mass and measurement of adsorption isotherm curves.