Crystal Structure of a Sodium Sorption Complex of Zeolite X Containing Linear Na<sub>3</sub><sup>2+</sup>Clusters

Shibata, Wayne; Seff, Karl

doi:10.1021/jp971279h

Cited by 39 publications

(13 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…One water at O(5) near the sodalite center coordinates to both Na + ions at 2.72(2) Å and hydrogen bonds to both hydronium ions at 2.94(4) Å to give a grouping that may be viewed as a (H 3 O + ) 2 H 2 O(Na + ) 2 cluster filling each sodalite cavity (see Figures 3 and 4). The Na(I′)-O(3) distances are 2.329(15) Å, somewhat longer than the corresponding distances in the crystal structures of dehy- (2) drated Na-X (2.276(9) Å) 8,9 and those of Na-X containing linear Na 3 2+ clusters (2.242(7) Å), 22 probably because of the higher coordination number (four) of Na + ions at site I′ in this structure. O(I′) lies relatively farther inside the sodalite cavity than Na(I′) because H 3 O + is larger than Na + .…”

Section: ) Crystal 1 Na 60 (H 3 O) 32 (H 2 O) 24 Si 100 Al 92 O 384mentioning

confidence: 78%

Hydronium Ions in Zeolites. 1. Structures of Partially and Fully Dehydrated Na,H₃O−X by X-ray and Neutron Diffraction

and¹,

Seff²,

Olson³

et al. 1999

J. Phys. Chem. B

Self Cite

View full text Add to dashboard Cite

The crystal chemistry of hydronium ions in zeolite X has been investigated by single-crystal X-ray and powder neutron diffraction. By titration of Na 96 Si 96 Al 96 O 384 with HCl, a break in the pH was observed at 6.35, at about 33 H 3 O + ions per unit cell. The structure of zeolite X in equilibrium with 0.1 M aqueous Na + at pH 6.35 was determined by single-crystal X-ray diffraction techniques in the cubic space group Fd3 h at 20°C after partial dehydration (Na 60 (H 3 O) 32 (H 2 O) 24 Si 100 Al 92 O 384 , a ) 25.128(4) Å) and in Fd3 hm after complete dehydration (Na 60 H 32 Si 100 Al 92 O 384 , a ) 25.101(2) Å). In the partially dehydrated crystal, Na + ions are found at three different crystallographic sites and H 3 O + ions are found at two. Two different site I′ positions are occupied by 16 Na + and 16 H 3 O + ions, respectively, per unit cell; a water molecule bridges between two of each in each sodalite cage to give eight near tetrahedral (H 3 O + ) 2 H 2 O(Na + ) 2 clusters. Two different site III′ positions in the supercage are occupied by 16 Na + and 16 H 3 O + ions, respectively; a water molecule bridges between one of each to give 16 (H 3 O + )(H 2 O)(Na + ) clusters. Thus a structural basis for the great selectivity of zeolite Na-X for H 3 O + at near neutral pHs is demonstrated. The remaining 28 Na + ions are at site II. In the fully dehydrated single crystal, the 60 Na + ions are found at four crystallographic sites. Approximately 6 and 20 Na + ions per unit cell at sites I and I′, respectively, effectively fill the double six-rings. Thirty-two Na + ions fill site II and the remaining two are at site III′. To avoid Na + ions, at least 20 of the 32 H + ions per unit cell should be in the supercage. Finally, neutron diffraction of Na 54 (D 3 O) 42 Si 96 Al 96 O 384 • ∼ 80D 2 O at 10 K revealed the structures of the 16 D 3 O + ions in the sodalite units: D-O ) 1.13(1) Å and D-O-D ) 88(1)°. Each deuteron hydrogen bonds to a framework oxygen atom at 1.53(1) Å. The O‚‚‚O hydrogenbonding distance is 2.63(1) Å and the O-D‚‚‚O angle is 161°.

show abstract

Section: ) Crystal 1 Na 60 (H 3 O) 32 (H 2 O) 24 Si 100 Al 92 O 384mentioning

confidence: 78%

Hydronium Ions in Zeolites. 1. Structures of Partially and Fully Dehydrated Na,H₃O−X by X-ray and Neutron Diffraction

and¹,

Seff²,

Olson³

et al. 1999

J. Phys. Chem. B

Self Cite

View full text Add to dashboard Cite

show abstract

“…The zeolite XRPD patterns were refined by the Rietveld method using the EXPGUI-GSAS software package (Toby, 2001;Larson & Von Dreele, 1997). We refined the cell parameters starting from the structural models proposed by Shibata & Seff (1997) for Na-X, Gramlich & Meier (1971) for Na-A, Felsche et al (1986) for hydroxysodalite (HS) and Gualtieri (2000) for phillipsite. We refined the XRPD data according to the following procedures: phase scales, background parameters, zero shift, cell parameters and peak profiles parameters ( Table 2).…”

Section: Methodsmentioning

confidence: 99%

Synthesis and characterization of Na-X, Na-A and Na-P zeolites and hydroxysodalite from metakaolinite

Novembre

Sabatino²,

Gimeno³

et al. 2011

Clay miner.

View full text Add to dashboard Cite

The present work deals with the hydrothermal synthesis of Na zeolites (Na-A, Na-X and Na-P) and hydroxysodalite using kaolinite calcined at 650°C as starting material. The focus was on definition of the most favourable conditions for the synthesis of zeolite Na-A and Na-X from metakaolin in order to economize on both energy (i.e. synthesis temperatures) and reaction time and to enlarge the field of pure and isolated synthesized phases. Metakaolin was mixed with calculated amounts of NaOH solution and sodium silicate and five sets of experiments were carried out at ambient pressure and 68±0.1°C varying the SiO2/Al2O3 ratio from 2.2 to 7. Optimal conditions for crystallization of Na-A zeolite from kaolinite were reached with a SiO2/Al2O3 ratio of 2.2 plus 4 M NaOH without adding sodium silicate; transformation into hydroxysodalite develops after ∼8 h. For SiO2/Al2O3 ratios between 4 and 7, crystallization of the separate Na-X zeolite phase could be achieved and transformation into Na-P and hydroxysodalite occurred after 382 h and 190 h, respectively. For SiO2/Al2O3 ratios between 5 and 6, transformation of metakaolin into Na-X plus Na-A, hydroxysodalite and Na-P occurred, and the field within which Na-A and Na-X zeolite exists overlapped that of the other zeolites.The products of synthesis were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), inductively coupled plasma optical emission spectrometry (ICP-OES), infrared spectroscopy (IR) and thermal analyses (TG-DTG-DTA).Obtaining pure Na-A and Na-X zeolite from kaolinite treated at low metakaolinitization temperature (650°C) and low hydrothermal synthesis temperature (68°C) represents a considerable economic advantage in terms of both energy and time.

show abstract

“…Due to the negative electronegativity of the [AlO 4 ] 5– tetrahedron, the cation Na + in the zeolite X acts to balance the negative charge . The cations in zeolites are the adsorption centers to CO 2 , and the influence of cation content (Na + ions) also occupied a dominant position during the adsorption process. , To investigate whether the cation content is affected by cyclic adsorption of CO 2 , SEM–EDS analysis of the zeolite X samples before and after adsorption was performed (Table ).…”

Section: Results and Discussionmentioning

confidence: 99%

“…The zeolite X (window size 7.4 Å) is a crystal composed of [SiO 4 ] 4– and [AlO 4 ] 5– tetrahedra and the structural unit is composed of eight β-type cages (2.2 Å) and adjacent β-type cages are linked through six rings by six oxygen bridges to connect with each other, forming a large supercage cavity accessible by a three-dimensional 12-ring pore system (Figure a). , The cation Na + in the zeolite X acts to neutralize the negative charge because of the negative charge of the [AlO 4 ] 5– tetrahedron . The interaction between the adsorbent and adsorbate leads to adsorption, mainly including dispersive force, electrostatic force, and chemical bond force.…”

Section: Results and Discussionmentioning

confidence: 99%

“…43,44 The cation Na + in the zeolite X acts to neutralize the negative charge because of the negative charge of the [AlO 4 ] 5− tetrahedron. 38 The interaction between the adsorbent and adsorbate leads to adsorption, mainly including dispersive force, electrostatic force, and chemical bond force. The adsorption by zeolite X is a polar physical adsorption, which is mainly electrostatic.…”

Section: Energy and Fuelsmentioning

confidence: 99%

See 1 more Smart Citation

Zeolite X Adsorbent with High Stability Synthesized from Bauxite Tailings for Cyclic Adsorption of CO₂

Qiang

Yang

et al. 2019

Energy Fuels

View full text Add to dashboard Cite

A CO 2 adsorbent of zeolite X with high crystallinity, regular octahedron morphology, and a large Brunauer− Emmett−Teller (BET) surface area of 736 m 2 g −1 was synthesized from bauxite tailings at 110 °C for 16 h with n(SiO 2 /Al 2 O 3 ) fixed at 3.2. The CO 2 adsorption capacities at 273 and 303 K of zeolite X were 7.3 and 6.1 mmol g −1 , respectively. Moreover, multiple CO 2 adsorption cycles at 298 K were conducted to investigate the stability and lifetime of the synthesized zeolite X. The result showed that CO 2 capture could reach up to 6.3 mmol g −1 after 11 adsorption−desorption cycles, which was dropped by only 1.6% compared to that after the first cycle. Furthermore, 11 N 2 adsorption cycles at 77 K on zeolite X were subsequently measured to detect the microstructure of zeolite X in each cycle; it possessed excellent stability and regenerability with a stable BET surface area and micropore volume after multiple adsorption cycles. In addition, the original zeolite X and the zeolite X after multiple cycles of adsorption were successively characterized with X-ray diffraction, scanning electron microscope, and Fourier transform infrared measurements and the results demonstrate that microstructures of zeolite X after 6 and 11 CO 2 adsorption cycles were not destroyed, respectively. Hence, the low-cost zeolite X synthesized from solid waste bauxite tailings could be widely used for large-scale industrial greenhouse gas capture. Moreover, it as a promising adsorbent is urgently needed for the cyclic adsorption processes in view of its extremely stable performance.

show abstract

Crystal Structure of a Sodium Sorption Complex of Zeolite X Containing Linear Na₃²⁺Clusters

Cited by 39 publications

References 33 publications

Hydronium Ions in Zeolites. 1. Structures of Partially and Fully Dehydrated Na,H₃O−X by X-ray and Neutron Diffraction

Hydronium Ions in Zeolites. 1. Structures of Partially and Fully Dehydrated Na,H₃O−X by X-ray and Neutron Diffraction

Synthesis and characterization of Na-X, Na-A and Na-P zeolites and hydroxysodalite from metakaolinite

Zeolite X Adsorbent with High Stability Synthesized from Bauxite Tailings for Cyclic Adsorption of CO₂

Contact Info

Product

Resources

About

Crystal Structure of a Sodium Sorption Complex of Zeolite X Containing Linear Na32+Clusters

Cited by 39 publications

References 33 publications

Hydronium Ions in Zeolites. 1. Structures of Partially and Fully Dehydrated Na,H3O−X by X-ray and Neutron Diffraction

Hydronium Ions in Zeolites. 1. Structures of Partially and Fully Dehydrated Na,H3O−X by X-ray and Neutron Diffraction

Synthesis and characterization of Na-X, Na-A and Na-P zeolites and hydroxysodalite from metakaolinite

Zeolite X Adsorbent with High Stability Synthesized from Bauxite Tailings for Cyclic Adsorption of CO2

Contact Info

Product

Resources

About

Crystal Structure of a Sodium Sorption Complex of Zeolite X Containing Linear Na₃²⁺Clusters

Hydronium Ions in Zeolites. 1. Structures of Partially and Fully Dehydrated Na,H₃O−X by X-ray and Neutron Diffraction

Hydronium Ions in Zeolites. 1. Structures of Partially and Fully Dehydrated Na,H₃O−X by X-ray and Neutron Diffraction

Zeolite X Adsorbent with High Stability Synthesized from Bauxite Tailings for Cyclic Adsorption of CO₂