The applicability of clinoptilolite zeolites in controlling the emission of greenhouse gases (GHGs) such as CO₂, the most significant GHG, is investigated herein. In this research, Mexican natural zeolites (ATN) originating from an Atzinco deposit in the state of Puebla were used. Samples of modified clinoptilolite (ATH4, ATH3, ATH2 and ATH1) were obtained from the starting material by acid treatment of various intensities. Inverse gas chromatography was used to evaluate CO₂ adsorption in clinoptilolite, natural and chemically modified. Adsorption of CO₂ was investigated in the temperature range of 433–573 K, using a TCD detector, and He as a carrier gas. The experimental CO₂ adsorption data were processed by Freundlich and Langmuir equations. The degree of interaction between CO₂ and the dealuminated clinoptilolite samples was examined through the evaluation of the isosteric enthalpy of adsorption. This calculation was made by using the Clausius–Clapeyron equation, which established the following sequence: ATH1 > ATH2 > ATH4 > ATN > ATH3. The nanoporosity of these clinoptolite zeolites from new deposit in sedimentary rocks was studied through HRADS adsorption of N₂. Simultaneously, these zeolites were, respectively, characterized by XRD, EDS, and SEM. Micropores are described by the Dubinin–Asthakov distribution. Various adsorption mechanisms that occur in these nanoporous materials at different relative pressures can be visualized. The quantitative determination of starting mineral is described as: Ca-Clinoptilolite (88.76%) >> Montmorillonite (11.11%) >> quartz (0.13%). The Si/Al molar ratio after acid treatment is: ATH4 > ATH2 > ATN > ATH3 > ATH1. The Langmuir specific surface area (A_SL) varies as follows: ATN > ATH2 > ATH4 > ATH3 > ATH1. At the same time, the V_Σ values are as follows: ATN > ATH4 > ATH3 > ATH1 > ATH2.

Se obtuvieron polvos de trióxido de tungsteno (WO3) mediante un sistema de HFCVD (Hot Filament Chemical Vapor Deposition). Los polvos exhibieron tres diferentes coloraciones (azul rey, azul cielo y amarillo), debido al cambio del gas precursor usado (argón (Ar) o argón con vapor de agua (Ar+ H2O) o aire). Los polvos fueron evaluados por Difracción de Rayos-X (DRX) para la determinación de su estructura cristalina, su morfología fue observada mediante Microscopia Electrónica de Barrido (MEB), la composición química elemental se obtuvo por Espectroscopia de Energía Dispersiva (EDS). Por último, se analizaron las bandas de los enlaces presentes en el material con ayuda de Espectroscopia RAMAN. Estas técnicas lograron evidenciar la presencia del trióxido de tungsteno en los polvos obtenidos.

The study presents experimental results on the adsorption of endosulfan in new natural zeolite deposits from Mexico. The adsorption of this herbicide was evaluated using inverse gas chromatography with a thermal conductivity detector and helium as the carrier gas. The experimental adsorption data were analyzed using the Langmuir and Freundlich equations in their linear form over a temperature range of 413–573 K. The study also estimated thermodynamic parameters such as the Free Energy of Gibbs (ΔG), isosteric enthalpy of adsorption (ΔH), and entropy change (ΔS) within this temperature range. The results indicated that the zeolites studied had a low adsorption capacity for this herbicide under the experimental conditions. The study also quantitatively determined the presence of starting minerals, with Na-Mordenite and Na-Clinoptilolite being the most prevalent, followed by Ca-Chabazite, Ca-Clinoptilolite, and Montmorillonite, with Quartz being present in low amounts. The NMOR zeolite underwent ion exchanges with AgNO₃ to produce the Ag-MOR zeolite and assess its herbicide adsorption capacity. Another mineral, Ca-Stilbite, was present in higher quantities than Ca-Clinoptilolite and Quartz.

The aim of this study was to analyze the Si/Al ratio in titanium dioxide (TiO2) and Zeolite composites (Erionite, Clinoptilolite and Mordenite) and its influence on carbon dioxide (CO2) adsorption, seeking to optimize materials for greenhouse gas capture. Composites were synthesized by the sol-gel method, varying the proportions of TiO2 and zeolites (25-75 and 75-25) as a function of weight. They were characterized using techniques such as Energy Efficiency Spectroscopy (EDS) to determine the Si/Al ratio, X-ray diffraction for crystal size, and N2 adsorption for surface area. The results showed that, in most of the composites, the Si/Al ratio decreases compared to the original zeolites, except in those based on Mordenite, which maintain high values due to their greater chemical stability. The decrease in the Si/Al ratio was correlated with an increase in the CO2 affinity, especially in the TiO2-Erionite composites, which presented the lowest Si/Al values (3.29) and higher adsorption capacity. In contrast, composites with Mordenite exhibited a lower CO2 affinity, but a higher surface area (456 m2/g). In conclusion, the Si/Al ratio is a key parameter to optimize CO2 adsorption, and the intrinsic properties of each zeolite significantly affect the composite performance. These materials have potential for applications in environmental mitigation technologies.

ZnO-zeolite composites were synthesized and characterized by sol-gel method and X-ray diffraction (XRD). Different proportions of clinoptilolite, mordenite, erionite and chabazite with ZnO were analyzed. The results show that the addition of zeolites affects the crystal structure, particle size (32.3-66.5 nm), dislocation density and microdeformations. Rietveld refinement confirmed variations in the lattice parameters. It is concluded that these materials can improve the dispersion and stability of ZnO, being promising for catalysis and gas purification.