Hierarchical structure of nanoporosity of Mexican natural zeolites of clinoptilolite type

Gabriela Itzel-Hernandez, Miguel Angel Hernandez, Roberto Portillo, Vitalii P. Petranovskii, Alexey N. Pestryakov, Efrain Rubio

Research output: Contribution to journalArticle

Abstract

The relevance of the research is caused by the large number of newly discovered zeolite fields in Mexico. For practical use of these ma terials, the appropriate characteristics are required, in which experimental models are proposed that provide reliable and usable data for each of the declared deposits. The main aim of this research work is to evaluate the adsorption capacity of natural clinoptilolite zeolites from different deposits in Me xico to assess their nanoporosity and to evaluate whether they have some mesoporous voids. Objects of the research are zeolite tuffs from seven different deposits located in Mexico. These deposits are poorly studied and charac terized by a complex mineral composition of rocks. Methods. Zeolites were studied by XRD, Scanning Electron Microscopy, energy dispersive spectroscopy, thermogravimetric methods and Differential scanning calorimetry. All samples were also studied by N2 adsorption method. The surface areas of BET, Langmuir, and tplots of all the investigated zeolites were estimated. The total pore volume was estimated in accordance with the Gurvitsch rule. The microporosity of these natural zeolites was measured using the DA highresolution adsorption method. Information on the distribution of micropore sizes was obtained from the data of the isothermal adsorptiondesorption. Research results. The nanoporosity of natural clinoptilolite zeolites from new deposits is estimated using traditional experimental methods such as DRX, SEM, EDS and HRADS of N2 at the boiling point of liquid nitrogen. The latter method evaluates texture parameters, in which micropores are estimated by tgraphs. The nanopore distribution is determined using the recently proposed approximation, called diffe rential adsorption curves. Studies of TGA and DSC show the presence of three types of adsorbed water: adsorbed water in macropores, water adsorbed in the outer region of zeolite (mesopores) and water adsorbed in micropores. This behavior was confirmed by N2 adsor ption: microporous filling, multilayered formation on the outer surface of zeolite tuff, and the phenomenon of capillary condensation arising in macropores.

Original languageEnglish
Pages (from-to)107-117
Number of pages11
JournalBulletin of the Tomsk Polytechnic University, Geo Assets Engineering
Volume329
Issue number10
Publication statusPublished - 1 Jan 2018

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Keywords

  • Characteristic adsorption energies
  • Clinoptilolite
  • Mesoporosity.
  • Nanoporosity
  • Natural zeolite

ASJC Scopus subject areas

  • Materials Science (miscellaneous)
  • Fuel Technology
  • Geotechnical Engineering and Engineering Geology
  • Waste Management and Disposal
  • Economic Geology
  • Management, Monitoring, Policy and Law

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