Efficient removal of piroxicam and ketoprofen by acid-modulated iron(III) metal-organic frameworks

Pharmaceutical substances such as piroxicam and ketoprofen have been detected in worldwide water sources, posing an emerging risk to environmental health. Therefore, developing a low-energy and effi-cient method to remove these pollutants from the environment is necessary. Herein, the adsorption of piroxicam and ketoprofen from water has been investigated by using a series of modulated metal-or-ganic frameworks, namely MIL-126 synthesized in the presence of various amounts of acetic acid. The material synthesized with 1 equivalent of the acid modulator, MIL-126-1AA, has been found to show impressive adsorption activities, irrespective of its lower surface area than the other MOF samples stud-ied. MIL-126-1AA exhibits maximum adsorption capacities of 209.65 mg g-1 for piroxicam and 452.49 mg g-1 for ketoprofen, respectively. Such high adsorption capacities can be attributed to the per-manent porosity of MIL-126, an optimal amount of defects, as well as a delicate balance of non-covalent interactions between the MOFs and the adsorbates, as revealed from the adsorption studies and X-ray photoelectron spectroscopic analysis. Additionally, the durability of the adsorbents allows them to be reusable after multiple cycles without significant decrease in the adsorptive performance, further high-lighting their potentials for the remediation of pharmaceuticals and other organic pollutants from the environment.(c) 2023 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.