Preparation and properties of barium clinoptilolite

Hawkins, Daniel B.; Ordonez, Jose L.

doi:10.1016/0025-5408(72)90251-6

Cited by 6 publications

(2 citation statements)

References 3 publications

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“…However, studies on ion-exchange with large bivalent cations like Ba 2+ (ionic radius 1.35 Å) are rare [9,10]. Hawkins and Ordonez [11] first prepared Ba-exchanged clinoptilolite and observed substantial decrease in the intensity of 020 diffraction line. Later, Petrov et al [12] refined the structure of Ba-exchanged sedimentary clinoptilolite using powder XRD data and proved the distribution of barium ions in the plane of symmetry of the structure at around the potassium position (site M3 according to Koyama and Tackeuchi [7]) replacing the K + ions.…”

Section: Introductionmentioning

confidence: 99%

Powder XRD Structural Study of Ba2+ Modified Clinoptilolite at Different Stages of the Ion Exchange Process Conducted at Two Temperature Regimes—Room Temperature and 90 °C

et al. 2020

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Partial and almost complete barium exchange on clinoptilolite is performed and structurally studied for different durations (2 h, 24 h, 72 h, 168 h, 12 d, 22 d) at room temperature and 90 °C of the ion exchange process. Continuing ion exchange up to the 22nd day is proved by EDS analyses data and powder XRD (intensity changes of 020 and 200 peaks). Rietveld structure refinement was first performed on the maximum Ba exchanged clinoptilolite at 90 °C for 22 days (3.04 atoms per unit cell). Four barium positions and 9 H2O sites were refined. The split positions Ba2 and BaK (around M3 site in channel C) were found mostly occupied by 2.23 atoms per unit cell. The rest of refined samples showed different occupations of the positions of incoming Ba2+ and outgoing cations (Na+, Ca2+, K+, Mg2+) during ion exchange, describing extra-framework cationic movements, which are released easily without preferable directions. The exchanges at 90 °C and room temperature were found proceeding similarly up to the 2nd hour, but then at room temperature the process is slowed and at 22nd day 1.64 barium atoms per unit cell are structurally refined.

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Section: Introductionmentioning

confidence: 99%

Powder XRD Structural Study of Ba2+ Modified Clinoptilolite at Different Stages of the Ion Exchange Process Conducted at Two Temperature Regimes—Room Temperature and 90 °C

et al. 2020

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“…As noted by Bish & Boak (2001), who elaborated on the hul and cpt nomenclature, there has been controversy regarding the distinction between the two minerals since the early studies on these minerals and even after their crystal structures were completely understood. Various empirical methods and approaches based on the framework chemistry, exchangeable-cation composition, thermal stability, thermogravimetry, proton nuclear magnetic resonance (NMR) spectroscopy and X-ray diffraction (XRD) data have been utilized to describe and distinguish hul and cpt (Mason & Sand, 1960;Mumpton, 1960;Shepard & Starkey, 1966;Merkle & Slaughter, 1968;Alberti, 1972;Alietti, 1972;Boles, 1972;Hawkins & Ordonez, 1972;Alietti et al, 1974Alietti et al, , 1977Hawkins, 1974;Alberti & Vezzalini, 1983;Bish, 1984Bish, , 1988Gottardi & Galli, 1985;Armbruster & Gunter, 1991;Boak et al, 1991;Esenli & Kumbasar, 1994, 1998Valueva, 1994;Ward & McKague, 1994;Bish & Boak, 2001;Christidis et al, 2003;Spiridonov et al, 2015).…”

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The surface characteristics of natural heulandites/clinoptilolites with different extra-framework cations

Esenli,

Ekinci Şans,

Erdoğan

et al. 2023

Clay miner.

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Natural tuff samples in western Anatolia (Türkiye) originating from Miocene rhyolitic–pyroclastic rocks with >80 wt.% heulandite/clinoptilolite zeolites were investigated for their surface characteristics determined according to nitrogen adsorption after degassing at 150°C (specific surface area, pore volume and pore diameter). Additionally, these surface characteristics were correlated with the cationic compositions of the heulandite/clinoptilolite group minerals. The examined samples were characterized by two main pore diameters that were not related to specific surface area and pore volume but were partially related to the types and occupancy of extra-framework cations. One set of samples has a pore diameter of ~24 Å, total cation content (Na + K + Ca + Mg) ranging from 3.46 to 4.40 and a (Na + K)/(Ca + Mg) ratio ranging from 0.34 to 0.92. The total cation contents and (Na + K)/(Ca + Mg) ratios of the remaining samples with a pore diameter of ~37 Å are 4.30–5.08 and 1.48–2.85, respectively. After degassing at 300°C, there is a slight difference in the pore diameters of these two sets of samples (~37 and 38 Å). The pore sizes of the samples with a (Na + K)/(Ca + Mg) ratio < 1 (heulandite composition) increased from 24 to 36–38 Å with increasing degassing temperature, whereas the pore sizes of the samples with a (Na + K)/(Ca + Mg) ratio > 1 (clinoptilolite composition) increased from 37 to only 38–39 Å. However, there is no correlation between the Si/Al ratios and the cation-exchange capacities of the samples and their surface characteristics obtained by degassing at the two temperatures.

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Studies on natural clinoptilolites—I

Araya

Dyer

1981

Journal of Inorganic and Nuclear Chemistry

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Preparation and properties of barium clinoptilolite

Cited by 6 publications

References 3 publications

Powder XRD Structural Study of Ba2+ Modified Clinoptilolite at Different Stages of the Ion Exchange Process Conducted at Two Temperature Regimes—Room Temperature and 90 °C

Powder XRD Structural Study of Ba2+ Modified Clinoptilolite at Different Stages of the Ion Exchange Process Conducted at Two Temperature Regimes—Room Temperature and 90 °C

The surface characteristics of natural heulandites/clinoptilolites with different extra-framework cations

Studies on natural clinoptilolites—I

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