Benzene, toluene, ethylbenzene, and p-xylene (BTEX) are hazardous volatile organic compounds mostly released from fuel combustion, paint gas emissions, and biomass burning. In this work, it is studied the BTEX sorption influence on the surface reactivity of a new kind of nanoporous composite, prepared via an in situ functionalization of SBA-15 with a Mg–Al calcined hydrotalcite (HTC). During its preparation, Mg/Al mixed oxides are indeed formed and dispersed on the SBA-15 surface with non-blockage porosity. Furthermore, the physicochemical surface properties are exalted from its precursors and it is synergistically favorable for the BTEX sorption at low pressure and temperature.

Carbon dioxide (CO 2 ) is considered one of the most important greenhouse gases in the study of climate change. CO 2 adsorption was studied using the gas chromatography technique, while the Freundlich and Langmuir adsorption models were employed for processing isotherm data in the temperature range of 473-573 K. The isosteric heat of adsorption was calculated from the Clausius-Clapeyron equation. Moreover, the thermodynamic properties ∆G, ∆U, and ∆S were evaluated from the adsorption isotherms of Langmuir using the Van't Hoff Equation. The four soil samples were recollected from San Juan Amecac, Puebla, Mexico, and their morphologies were investigated through X-ray diffraction (XRD) and N 2 adsorption at 77 K. The SJA4 soil has a crystalline Kaolinite phase, which is one of its non-metallic raw materials, and N 2 isotherms allowed for the determination of pore size distributions and specific surface areas of soil samples. The Barrett-Joyner-Halenda (BJH) distribution of pore diameters was bimodal with peaks at 1.04 and 3.7 nm, respectively. CO 2 adsorption showed that the SJA1 soil afforded a higher amount of adsorbed CO 2 in the temperature range from 453 to 573 K followed by SJA4 and finally SJA2, classifying this process as exothermic physisorption.

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ZnO nanoparticles ranging from 2 to 10 nm were grown on ZSM-5 and mordenite zeolite hosts with different SiO2/Al2O3 molar ratios (MR). Formation of ZnO nanoparticles in the samples was confirmed by TEM. XRD and nitrogen adsorption measurements revealed that the zeolite structure is not destroyed. Surface Zn concentration was calculated from XPS data. ZnO nanoparticles in the zeolite matrix were studied by UV-Vis, diffuse reflectance and cathodoluminescence (CL) spectroscopies. CL revealed three different emissions from ZnO nanoparticles, approximately 3.1, 2.8 and 2.5 eV. The ZnO band-edge emission was associated with blue defects-related and oxygen vacancies emissions. The generation of the point defects at the interface explains the presence of this blue band.

Emissions of carbon dioxide (CO 2 ) and nitrogen dioxide (NO 2 ) in recent years has been increased considerably. One way to reduce the concentration of these greenhouse gases in the atmosphere is adsorptive capture. This paper describes the main results of adsorption of N 2 , NO 2 , and CO 2 on epistilbite, both natural and on samples that were chemically treated at various concentrations of HCl. Data on the adsorption of CO 2 and NO 2 were evaluated by the Freundlich and Langmuir equations. Additionally, the thermodynamic parameters of adsorption were calculated, including the degree of interaction of the zeolite samples with gases by gradually changing the isosteric heat capacities of adsorption. The acid treatment improves the adsorption capacity of epistilbite with respect to NO 2 and CO 2 , due the replacement of large extra-framework cation by small H + ions. The improvement in the distribution of pore sizes in epistilbite samples was calculated by the method of Barrett-Joyner-Halenda. The sample H1 that was prepared in a moderately concentrated acid showed the best behavior in the CO 2 adsorption processes, while the natural EPIN material preferably adsorbs NO 2 . 2 of 11 be found. It is well known that natural zeolites are cheap, but they have a variable composition and contain impurities, whereas synthetic zeolites are pure substances, but are expensive ones. Thus, when choosing a certain type of zeolite for practical application, it is necessary to decide how to minimize costs, but in such a way as to get the maximum effect. Synthetic and natural zeolites are commercially employed in view of their unique properties, such as ion-exchange, adsorption, molecular sieve, and catalytic activity, which are directly related to the properties of zeolite frameworks [4,5]. An incentive to choose a particular type of natural zeolite can be their really useful properties, and the fact that they are quite common in deposits. The most common natural zeolites are natrolite (NAT), analcime (ANA), chabazite (CHA), clinoptilolite (CLI), phillipsite (PHI), and stilbite (STI) [6]. Nevertheless, in recent years, geologists have discovered new significant sedimentary sources of zeolites all over the world. That is why we select natural epistilbite (IZA type code EPI) for this study.There are many types of zeolites around the world, natural and synthetic; these materials are classified according with the number of tetrahedral members in the rings, forming their channels. Those in which the pores are formed from eight tetrahedral units are named as small pore zeolites, whilst if they have 10 member rings, these are called medium pore zeolites, in the case of 12 members, they are large pore zeolites (12-membered rings), and, finally, those presenting more than 12 members in tetrahedral coordination are defined like extra-large pore zeolites. Another way of classifying zeolites is related to the number of channel directions in zeolite crystals; if the zeolite channels are in one, two, or three different directions, then, such ze...