Removal of Pharmaceuticals from an Aqueous Matrix by Adsorption on Metal-Organic Framework MIL-100(Cr)

In this work, the new class of porous materials MIL-100(Cr) was synthetized using a solvent-free methodology to evaluate the removal of the pharmaceutical contaminants Paracetamol, Ibuprofen, Metformin, or Carbamazepine from aqueous sources. This adsorbent was characterized by thermogravimetric analysis, Fourier transform infrared spectroscopy with attenuated total reflectance, Raman spectroscopy, nitrogen adsorption-desorption, and X-ray photoelectron spectroscopy. The characterization technique results indicated that the synthesized MIL-100(Cr) has a non-uniform structure of different sizes as well as a low crystallinity structure and is thermally stable up to similar to 300 degrees C with a surface negatively charged in the assay pH range and the presence of two types of cavities, pentagonal and hexagonal, with sizes of 1.10 nm and 1.49 nm. The results of adsorption demonstrated higher values of Carbamazepine, Paracetamol, and Ibuprofen on MIL-100(Cr) with values of 21 mg L-1, 20 mg L-1, and 17 mg L-1, respectively, while in the case of Metformin, a lower value of 12 mg L-1 was observed. The differences in the adsorption values were explained by different interactions between the pharmaceutical compounds and the MIL-100(Cr), such as pi-pi and electrostatic interactions and hydrogen bonds. Despite the low crystallinity observed in MIL-100(Cr), due to synthesis solvent-free methodologies used, this material maintains the structural and physicochemical characteristics required to be utilized as an adsorbent of pharmaceutical contaminants from aqueous solutions.