  Citation: Saif-ur-Rehman; Zaman, M.K.U.; Ahsan Waseem, M.; Zaman, S.U.; Shozab Mehdi, M. Deep Eutectic Solvent-Functionalized Mesoporous Silica SBA-15-Based Mixed Matrix Polymeric Membranes for Mitigation of CO 2 . Eng. Proc. 2021, 12, 61. https://doi.org/10.3390/ engproc2021012061 Academic Editor: Muhammad Tanveer Published: 12 January 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 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/). Proceeding Paper Deep Eutectic Solvent-Functionalized Mesoporous Silica SBA-15-Based Mixed Matrix Polymeric Membranes for Mitigation of CO 2 † Saif-ur-Rehman 1,2, * , Muhammad Khaliq U Zaman 3, *, Muhammad Ahsan Waseem 3 , Shafiq Uz Zaman 1,4 and Muhammad Shozab Mehdi 4 1 Department of Chemical Engineering, COMSATS University Islamabad, Lahore Campus, Defence Road, Off Raiwind Road, Lahore 54000, Pakistan; shafiqzaman029@gmail.com 2 Interdisciplinary Research Center of Biomedical Materials (IRCBM), COMSATS University Islamabad, Lahore Campus, Defence Road, Off Raiwind Road, Lahore 54000, Pakistan 3 Department of Chemical Engineering, University of Gujrat, Jalalpur Jattan Road, Gujrat, Punjab 50700, Pakistan; ahsanwaseem@uog.edu.pk 4 Department of Chemical Engineering, Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi 23640, Khyber Pakhtunkhwa, Pakistan; shozab@giki.edu.pk * Correspondence: saifzciit@gmail.com (S.-u.-R.); khaliqzaman@uog.edu.pk (M.K.U.Z.) † Presented at the 1st International Conference on Energy, Power and Environment, Gujrat, Pakistan, 11–12 November 2021. Abstract: In this research, a novel DES (choline chloride + decanoic acid) was synthesized, and SBA-15 was functionalized by the DES to form a DES-SBA filler to fabricate MMMs. DES-SBA-based MMMs at 5%, 10%, 15%, and 20% were synthesized and evaluated. The DES-SBA-based MMMs were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Gas permeation tests were applied to the pure and mixed gas samples, and the results of the permeability and selectivity (CO 2 /CH 4 , and CO 2 /N 2 ) of the membranes are reported. DES modification of SBA-15 increased the efficiency of the synthesized MMMs in comparison with the pristine polysulfone membrane. Keywords: SBA-15; deep eutectic solvent; carbon dioxide; permeability; selectivity 1. Introduction Human outputs have contributed to releasing a significant amount of carbon dioxide (CO 2 ) gas into the climate, which is the major cause of global warming and air pollu- tion [1].The typical sources of CO 2 emission include combustion of fossil fuels, natural gas streams, products of coal gasification, and biogas synthesis from anaerobic digestion [2]. As a result, it has turned out to be a big challenge for humankind to reduce CO 2 in the biosphere [3]. The major challenge faced on an industrial scale is the removal of harmful gases or contaminants from mixtures of several gases [4]. The most employed industrial techniques used for said purpose include pressure swing adsorption, chemical absorption by means of reactive solvents, and cryogenic separation [5], but these techniques involve considerably high capital costs and complex apparatus and consume large amounts of energy as compared to membranes [2]. In this study, a deep eutectic solvent was synthesized by mixing choline chloride with decanoic acid to modify SBA-15. This combination was used due to the amine and carboxyl groups of choline chloride and decanoic acid, respectively. The modified material, that is, the combination of hybrid materials of organic and inorganic compounds, was used as a filler and Polysulfone was used as a polymeric support in MMMs. The MMMs of different compositions were synthesized and evaluated by a gas permeation analyzer, and Eng. Proc. 2021, 12, 61. https://doi.org/10.3390/engproc2021012061 https://www.mdpi.com/journal/engproc