Microporous and Mesoporous Materials xxx (xxxx) xxx Please cite this article as: H. Bekhti, Microporous and Mesoporous Materials, https://doi.org/10.1016/j.micromeso.2019.109866 Available online 4 November 2019 1387-1811/© 2019 Published by Elsevier Inc. Adsorption of CO 2 over MgOImpregnated NaYzeolites and modeling study H. Bekhti a , H. Bouchafaa b , R. Melouki c , A. Travert d , Y. Boucheffa a, * a Laboratoire d’Etude Physico-Chimique des Mat� eriaux et Application � a l’Environnement (LEPCMAE), Facult� e de Chimie, Universit� e des Sciences et de la Technologie Houari Boumediene (USTHB), BP 32, El-Alia, Bab-Ezzouar, Alger, Algeria b Laboratoire des Sciences et G� enie des Mat� eriaux (LSGM), Facult� e de G� enie M� ecanique et G� enie des Proc� ed� es, Universit� e des Sciences et de la Technologie Houari Boumediene (USTHB), BP 32, El-Alia, Bab-Ezzouar, Alger, Algeria c Ecole Militaire Polytechnique, BP. 17, Bordj El-Bahri, Alger, Algeria d Laboratoire Catalyse et Spectrochimie, CNRS-ENSICAEN-Universit� e de Caen, 6 Boulevard Marechal Juin, Caen Cedex, 14050, France A R T I C L E INFO Keywords: NaY zeolite Adsorption Carbon dioxide Impregnation Modeling ABSTRACT Adsorption isotherms of CO 2 are volumetrically measured at temperatures close to ambient (30, 35, 40 and 45 � C) over MgO impregnated NaY zeolites, in order to highlight the effect of MgO impregnation rate on the adsorbed quantities. XRD analysis displays a good preservation of the zeolitic structure after impregnation. Textural parameters are determined by both adsorptiondesorption isotherms of N 2 at 196 � C and adsorption isotherms of CO 2 at 30 � C. The result of the impregnation rate effect shows that 2% of MgO seems to be the better rate for the capture of CO 2 . This is confrmed by the evolution of isosteric heats, which reveals a high strength interaction and heterogeneity of zeolitic sites adsorption. The modeling of CO 2 adsorption isotherms based on various isotherms (singlesite Langmuir, dualsite Langmuir, multisite Langmuir, Sips, JensenSeaton, Toth, UNILAN and Freundlich) highlights a good corre- lation with all models based on the hypothesis of heterogeneity of adsorption sites. 1. Introduction The greenhouse gas (GHG) emissions in the environment are recently the major problem all over the world. Carbon dioxide (CO 2 ) is the most important greenhouse gas produced by the human activities. Various CO 2 capture technologies have been proposed to retain this gas, in particular by absorption (by post-combustion [1], pre-combustion [2] or oxy-combustion [3]) or by membrane separation [4,5]. However, these technologies present certain disadvantages related to the selectivity during the treatment of important gas fows and for the dangers which they cause for the environment. The processes based on the use of the zeolitic adsorbents prove to be more interesting for the selectivity, which they offer towards CO 2 . These materials can be employed in the separation [6], but also for the puri- fcation [7]. The faujasite (FAU) framework structure including X and Y zeolites are one of the most industrially important zeolitic adsorbents. CO 2 adsorption over X zeolite modifed by occlusion of oxides has been studied to determine the effect of the addition of small quantities of oxides on the adsorption equilibrium and energy [8–10]. Moreover, occlusion of small alkali or alkaline earth oxide in the supercages can increase both base strength of zeolites, by the creation of new basic sites and adsorption capacity [8–16]. The use of alkaline earth metal oxide (MgO) included in faujasite (X or Y) for instance, is justifed considering its basic character, thermal stability and its regeneration properties compared to NaX or NaY zeolite [10,14,15]. This study devoted to the CO 2 adsorption over MgO impregnated NaY zeolites aims, on the one hand, to check the behavior of this adsorbent towards CO 2 at low temperature, on the other hand, to un- derstand the effect of the impregnation rate on the adsorption capacity. The textural properties of materials are characterized by N 2 adsorption-desorption at 196 � C for the determination of the pore volume, the specifc surface area and other textural parameters. It is known that for narrow microporosity, many authors use the CO 2 adsorption as a complement to N 2 adsorption at 196 � C [17–26]. Indeed, in some cases, N 2 characterization is not appropriate because of the limited adsorption due to the existence of diffusional restrictions [18]. * Corresponding author. E-mail address: youcef.boucheffa@gmail.com (Y. Boucheffa). Contents lists available at ScienceDirect Microporous and Mesoporous Materials journal homepage: http://www.elsevier.com/locate/micromeso https://doi.org/10.1016/j.micromeso.2019.109866 Received 8 August 2018; Received in revised form 6 October 2019; Accepted 1 November 2019