Characterization of a New Microporous Lithozincosilicate with ANA Topology

Park, So‐Hyun; Gies, Hermann; Toby, Brian H.; Parise, John B.

doi:10.1021/cm020226w

Cited by 17 publications

(11 citation statements)

References 28 publications

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“…can also be incorporated into the zeolite frameworks to form new zeolite structures. Notable examples are zinc-based silicate VPI-9 (VNI), 69 gallium-containing silicates TsG-1 (CGS) 70 and ECR-34 (ETR) 71 , borosilicate zeolites SSZ-58 (SFG) 72 , SSZ-53 (SFH) 73 , SSZ-60 (SSY), 74 and ITQ-52 (IFW), 41 beryllosilicate zeolite LSJ-10 (JOZ), 75 and Li-containing zeolites MFI, 76 ANA, 77 RUB-23, 78 and RUB-29, 79 etc. ECR-34 is a new gallosilicate zeolite, which possesses 1D extra-large 18-ring channels along the c-axis.…”

Section: Heteroatom Substitution In Silicates and Germanatesmentioning

confidence: 99%

Synthesis of new zeolite structures

2015

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The search for new zeolites is of continuous interest in the field of zeolite science because of their widespread application in catalysis and adsorption-separation. To this end, considerable efforts have been devoted to the preparation of new zeolites with novel porous architectures and compositions. Taking account of the key factors governing the formation of zeolites (e.g., guest species, framework elements, construction processes, etc.), several synthetic strategies have been developed recently. These allow the discovery of many new zeolites with unprecedented structural features, such as hierarchical pores, odd-ring numbers (11-, 15-rings), extra-large pores (16-, 18-, 20-, 28-, and 30-rings), chiral pores, and extremely complex framework topologies, etc. In this review, we will present the advances in the synthesis of new zeolite structures in the last decade, which are achieved by utilization of the synthetic strategies based on pre-designed structure-directing agents, heteroatom substitution, and topotactic transformations.

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Section: Heteroatom Substitution In Silicates and Germanatesmentioning

confidence: 99%

Synthesis of new zeolite structures

2015

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“…After having identified most of the partially occupied extraframework sites, a difference-Fourier synthesis indicated a position in tetrahedral coordination with a distance range of $ 2 Å to four different positions of framework O atoms, O1, O9 (Â 2) and O10. The position was denoted as LiF and inserted into the model as framework Li, on the basis of known lithosilicate structures (Park, Daniels & Gies, 2000;Park, Parise, Gies, Liu, Grey & Toby, 2000;Park et al, 2001Park et al, , 2002Park et al, , 2004. Another position found at this stage, and designated K2, lies very near to the framework, for example, d(K2-O3) ' 1.0 Å .…”

Section: Figurementioning

confidence: 99%

“…The extremely short distances between those Li cations and water molecules (Table 2) can be due to static disorder over the sites partially occupied (see supplementary material). The occu-pancy parameters of Li and disordered K/H 2 O were calculated with group-specific isotropic displacements of 0.01 and 0.03 Å 2 , respectively (see supplementary material), based on known zeolitic lithosilicate structures (Park, Daniels & Gies, 2000;Park, Parise, Gies, Liu, Grey & Toby, 2000;Park et al, 2002Park et al, , 2004. Owing to the high correlations between displacement and occupancy parameters of K, H 2 O and nonframework Li, there are uncertainties in their calculated occupancies with regard to the chemical composition of RUB-30.…”

Section: Figurementioning

confidence: 99%

Structural disorder of a new zeolite-like lithosilicate, K_2.6Li_5.4[Li₄Si₁₆O₃₈]·4.3H₂O

Boysen

Parise

2006

Acta Crystallogr Sect B

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The framework structure of the synthetic microporous lithosilicate RUB-30 (K(2.6)Li(5.4)[Li4Si16O38].4.3H2O) is similar to that of the fibrous zeolites such as natrolite, edingtonite and thomsonite, since all their frameworks include the same secondary structural building unit, the so-called 4-1 T5O10 cluster of tetrahedra. Unique to the structure of RUB-30, each 4-1 unit consists of a LiSi4O10 moiety within which the single [LiO4] tetrahedron is strictly segregated from the other four [SiO4] tetrahedra. The connection of neighboring 4-1 units through edge-sharing [LiO4] tetrahedra results in a new framework topology. The present work reports an ;average' structure of RUB-30 solved by synchrotron X-ray single-crystal diffraction data collected at a second-generation source. A superstructure with a x 2b x c (relative to the subcell quoted above) could be seen in X-ray diffraction data collected with better resolution and higher brightness at a third generation source. Diffuse streaks along k with l = odd and unusual superstructure hkl reflections, with k = odd and l = odd only, indicate a more complicated real structure of the material. To explain this observation we propose two different structure types which are statistically, but coherently, intergrown in RUB-30.

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“…Pollucite belongs to the analcime zeolite family4567, and is one of the best final storage options for radioactive Cs8910 because it has an appropriately sized channel and does not release the radioactive Cs + ions without complete destruction of the zeolite framework23. Figure 1 shows the channel system in pollucite and several Cs + ions.…”

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confidence: 99%

Final storage of radioactive cesium by pollucite hydrothermal synthesis

Yokomori

Asazuki

Kamiya

et al. 2014

Sci Rep

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The Fukushima nuclear accident has highlighted the importance of finding a better final storage method for radioactive cesium species. Cs is highly soluble in water, and can easily exchange with other alkali ions in zeolites or clays to form stable complexes. However, Cs+ is released from Cs+ complexes into water when surrounded by an excess of water. Pollucite may be the best final storage option for Cs+, but its typical synthesis requires heating to about 1200°C in air. Here, we show that the hydrothermal synthesis of pollucite can be completed at 300°C in three hours from any zeolite or clay. Furthermore, our procedure does not require ion exchange before synthesis. Radioactive Cs is usually found in complexes with clays. At that time, this method only requires calcium hydroxide, water, and three hours of hydrothermal synthesis, so the process is both inexpensive and practical for large-scale application. Pollucite is an analog of analcime zeolite, and contains a channel system 2.8 Å in diameter, which is formed by 6-oxygen rings. As the diameter of Cs+ is 3.34 Å and each Cs+ exists independently within a separate portion of the channel, Cs+ cannot exit the pollucite framework without breaking it.

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Characterization of a New Microporous Lithozincosilicate with ANA Topology

Cited by 17 publications

References 28 publications

Synthesis of new zeolite structures

Synthesis of new zeolite structures

Structural disorder of a new zeolite-like lithosilicate, K_2.6Li_5.4[Li₄Si₁₆O₃₈]·4.3H₂O

Final storage of radioactive cesium by pollucite hydrothermal synthesis

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Characterization of a New Microporous Lithozincosilicate with ANA Topology

Cited by 17 publications

References 28 publications

Synthesis of new zeolite structures

Synthesis of new zeolite structures

Structural disorder of a new zeolite-like lithosilicate, K2.6Li5.4[Li4Si16O38]·4.3H2O

Final storage of radioactive cesium by pollucite hydrothermal synthesis

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Structural disorder of a new zeolite-like lithosilicate, K_2.6Li_5.4[Li₄Si₁₆O₃₈]·4.3H₂O