Citation: Almotiry, S.; Alhogbi, B.G.; Abdel Salam, M.; Jaremko, M. UiO-67 Metal–Organic Framework as Advanced Adsorbent for Antiviral Drugs from Water Environment. Catalysts 2024, 14, 573. https:// doi.org/10.3390/catal14090573 Academic Editor: Jorge Bedia Received: 8 July 2024 Revised: 6 August 2024 Accepted: 19 August 2024 Published: 29 August 2024 Copyright: © 2024 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). catalysts Article UiO-67 Metal–Organic Framework as Advanced Adsorbent for Antiviral Drugs from Water Environment Sitah Almotiry 1,2 , Basma G. Alhogbi 1, * , Mohamed Abdel Salam 1, * and Mariusz Jaremko 3 1 Chemistry Department, Faculty of Science, King Abdulaziz University, P.O. Box 80200, Jeddah 21589, Saudi Arabia; sitah_saad@yahoo.com 2 Department of Chemistry, College of Science, Qassim University, P.O. Box 1162, Buraidah 51452, Saudi Arabia 3 Environmental Science and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), P.O. Box 4700, Thuwal 23955, Saudi Arabia; mariusz.jaremko@kaust.edu.sa * Correspondence: balhogbi@kau.edu.sa or alhogbib@gmail.com (B.G.A.); masalam16@hotmail.com (M.A.S.) Abstract: Metal–organic frameworks (MOFs) have attained significant usage as adsorbents for antivi- ral medicines in contemporary times. This study focused on synthesizing a UiO-67 metal–organic framework using the hydrothermal method. The synthesized framework was then characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), ther- mogravimetric analyses (TGA), and zeta potential measurements. The UiO-67 was then employed for the purpose of assessing the efficiency of various adsorption factors in the removal of antiviral medicines from aqueous solutions, including drugs such as ritonavir (RTV) and lopinavir (LPV), which were extensively used for the treatment of coronavirus (COVID-19) during the pandemic. The variables examined were the quantity of adsorbent used, different pH of the solution, temperature, and contact duration. The experimental findings indicate that the highest level of RTV elimination was 91.2% and of experimental adsorption capacity (q e ,exp ) was 9.7 mg/g and for LPV this was 85.9%, and (q e ,exp ) 8.9 mg/g, using 50 mg of UiO-67 at a pH 8, temperature of 298 K, and for 120 min. The impact of contact duration and temperature on the kinetics of adsorption was examined by employing pseudo-first-order and pseudo-second-order kinetic models. The experimental results showed a good match with the pseudo-second-order kinetic model with value of R 2 0.99 and the q e ,calc was 9.7 RTV and 8.9 mg/g LPV, which is a good match with q e ,exp . Also, based on diffusion kinetic studies, the adsorption was confirmed to be catalytic in nature on the surface of the UiO-67 MOFs. A thermodynamic analysis of adsorption was conducted, whereby calculations for the Gibbs free energy change (∆G), enthalpy change (∆H), and entropy change (∆S) were performed. The positive ∆H values confirm the endothermic nature of the adsorption of RTV and LPV by UiO-67. The ∆G values exhibited negativity across all temperatures, suggesting the spontaneous nature of the adsorption process of RTV and LPV by UiO-67 from an aqueous solution. UiO-67 was shown to be highly effective in extracting RTV and LPV from real environmental samples. Keywords: COVID-19 drugs; ritonavir; lopinavir; metal–organic frameworks UiO-67; catalytic adsorption 1. Introduction Over the past few decades, there has been a growing recognition of pharmaceutical compounds and their metabolites as a major source of water pollution, exerting a consid- erable influence on the worldwide environment [1,2]. The substantial utilization of some pharmaceutical compounds in recent years has resulted in an escalation of their levels in urban wastewater [3,4]. Among the widely used antivirals are ritonavir (RTV) are lopinavir (LPV) [5,6]. These pharmaceuticals have gained attention as emerging organic contaminants (EOCs) because of their recent utilization in the treatment of COVID-19 [7–9]. Also, LPV and RTV were detected in the wastewater effluent (41.0 ng/L and 4.8 ng/L), downstream Catalysts 2024, 14, 573. https://doi.org/10.3390/catal14090573 https://www.mdpi.com/journal/catalysts