Kwaśna modyfikacja gruzińskiego heulandytu naturalnego

Vladimer Tsitsishvili; Ketevan Ebralidze; Nanuli Dolaberidze; Nato Mirdzveli; Manana Nijaradze; Zurab Amiridze; Bela Khutsishvili

doi:10.29227/IM-2024-01-54

Vladimer Tsitsishvili Georgian National Academy of Sciences, 52, Rustaveli Ave., 0108, Tbilisi, Georgia https://orcid.org/0000-0003-2592-0973
Ketevan Ebralidze Petre Melikishvili Institute of Physical and Organic Chemistry, I.Javakhishvili Tbilisi State University, 31 A.Politkovskaia Str., 1086 Tbilisi, Georgia https://orcid.org/0000-0002-4663-6245
Nanuli Dolaberidze Petre Melikishvili Institute of Physical and Organic Chemistry, I.Javakhishvili Tbilisi State University, 31 A.Politkovskaia Str., 1086 Tbilisi, Georgia https://orcid.org/0000-0001-6479-2156
Nato Mirdzveli Petre Melikishvili Institute of Physical and Organic Chemistry, I.Javakhishvili Tbilisi State University, 31 A.Politkovskaia Str., 1086 Tbilisi, Georgia https://orcid.org/0000-0002-1755-5024
Manana Nijaradze Petre Melikishvili Institute of Physical and Organic Chemistry, I.Javakhishvili Tbilisi State University, 31 A.Politkovskaia Str., 1086 Tbilisi, Georgia https://orcid.org/0000-0003-0882-500X
Zurab Amiridze Petre Melikishvili Institute of Physical and Organic Chemistry, I.Javakhishvili Tbilisi State University, 31 A.Politkovskaia Str., 1086 Tbilisi, Georgia https://orcid.org/0000-0002-6875-2773
Bela Khutsishvili Petre Melikishvili Institute of Physical and Organic Chemistry, I.Javakhishvili Tbilisi State University, 31 A.Politkovskaia Str., 1086 Tbilisi, Georgia https://orcid.org/0000-0003-3685-9506

DOI: https://doi.org/10.29227/IM-2024-01-54

Słowa kluczowe: Kwasowanie, Skład chemiczny, Zeolity, Materiały filtracyjne

Abstrakt

Acid treatment is a powerful tool for improving the performance of natural zeolites, and the purpose of our work was to study chemical composition, structure and properties of acid-treated heulandite from the Tedzami-Dzegvi deposit. Samples of heulandite-containing tuff from the Rkoni plot with zeolite phase content up to 90%, consisting of heulandite and chabazite in a ratio of 8:1, and having chemical composition described by empirical formula |Na0.25K0.06Ca0.19Mg0.15)|[AlSi3.6O9.2].3H2O were treated with hydrochloric acid solutions with concentration up to 2.0 N. It was established that acid treatment leads to significant dealumination (the molar ratio of Si/Al increases from 3.6 to 9.5) and decationization (the total charge per aluminium atom decreases from 1 to 0.68), sodium and magnesium are mainly leached, calcium and potassium does not take part in the decationization process. Powder X-ray diffraction patterns show that hydrochloric acid solutions with a concentration up to 2.0 N do not lead to amorphization of the zeolite microporous crystal structure, but can gradually dissolve it. The adsorption of water vapor indicates the availability of micropores for the entry of small polar molecules, benzene adsorption shows a slight increase of hydrophobicity of the surface as a result of acid treatment. Nitrogen adsorption-desorption isotherms show acid-mediated sharp increase of adsorption in micropores and of the surface area, as well as changes in the mesoporous system, leading to the prevalence of pores with a diameter of 3 – 10 nm. The concentration of dilute solutions of hydrochloric acid is determined, which provides availability of micropores for large ions and nonpolar molecules, but at which dealumination is insignificant and ion-exchange capacity remains at a sufficient level. Materials obtained by acid treatment of heulandite can be used as adsorbents, ion exchangers, and carriers of biologically active substances and metal ions.