Microporous PILCs — Synthesis, pillaring mechanism and selective cation exchange

Stöcker, Melanie; Seyfarth, Lena; Hirsemann, Dunja; Senker, Jürgen; Breu, Josef

doi:10.1016/j.clay.2009.11.013

Cited by 20 publications

(13 citation statements)

References 31 publications

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“…This effect would be more important for a higher layer charge and, consequently, result in the greater retention we observe. This is similar to the so-called "ring mechanism" proposed by Weiss et al 42 for kaolinite intercalation, which was also observed for Hec by Stocker et al 43 Due to the large size of the tactoid, intercalation occurs along all edges of the particle instead of via a "one-sided wedge" mechanism. These results show a larger dependency on layer charge for CO 2 adsorption and swelling compared to what has been observed for H 2 O adsorption and/or swelling.…”

Section: ■ Results and Discussionsupporting

confidence: 84%

CO₂ Adsorption Enhanced by Tuning the Layer Charge in a Clay Mineral

et al. 2021

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Due to the compact two-dimensional interlayer pore space and the high density of interlayer molecular adsorption sites, clay minerals are competitive adsorption materials for carbon dioxide capture. We demonstrate that with a decreasing interlayer surface charge in a clay mineral, the adsorption capacity for CO 2 increases, while the pressure threshold for adsorption and swelling in response to CO 2 decreases. Synthetic nickel-exchanged fluorohectorite was investigated with three different layer charges varying from 0.3 to 0.7 per formula unit of Si 4 O 10 F 2 . We associate the mechanism for the higher CO 2 adsorption with more accessible space and adsorption sites for CO 2 within the interlayers. The low onset pressure for the lower-charge clay is attributed to weaker cohesion due to the attractive electrostatic forces between the layers. The excess adsorption capacity of the clay is measured to be 8.6, 6.5, and 4.5 wt % for the lowest, intermediate, and highest layer charges, respectively. Upon release of CO 2 , the highest-layer charge clay retains significantly more CO 2 . This pressure hysteresis is related to the same cohesion mechanism, where CO 2 is first released from the edges of the particles thereby closing exit paths and trapping the molecules in the center of the clay particles.

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Section: ■ Results and Discussionsupporting

confidence: 84%

CO₂ Adsorption Enhanced by Tuning the Layer Charge in a Clay Mineral

et al. 2021

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“…The fluorohectorite used was synthesized via melt synthesis. 16,26,27 The high purity reagents (in total y4 g) of SiO 2 (Merck, fine granular, calcined), MgF 2 (Chempur, 99.99%), MgO (Alfa Aesar 99.95%), Li 2 SiO 3 (Alfa Aesar 99.95%), and Na 2 O-2SiO 2 -glass were weighed into a molybdenum crucible in an Ar atmosphere in accordance with a stoichiometric composition of [Na 0.85 ] inter [Mg 2.15 Li 0.85 ] oct [Si 4 ] tet O 10 F 2 (target composition). Na 2 O-2SiO 2 -glass was produced by melting Na 2 CO 3 (Aldrich, 99.9%) and SiO 2 (Merck, fine granular, calcined) in a 1:2 molar ratio at 1050 uC for 10 h to ensure complete release of carbon dioxide.…”

Section: Methodsmentioning

confidence: 99%

Single crystal structure refinement of one- and two-layer hydrates of sodium fluorohectorite

2012

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Crystal structures of both one-and two-layer hydrates of sodium fluorohectorite were refined against single crystal data for the first time because melt synthesis yielded a sodium fluorohectorite showing little stacking disorder as compared to natural clays. In both hydrate phases, the relative shift of adjacent 2:1 layers is fixed by hydrogen-bonding between water molecules coordinated to interlayer cations and basal oxygen atoms of tetrahedral sheets encompassing the interlayer space. Despite some apparent diffuse scattering, a decent single crystal refinement of the semi-ordered structure of the onelayer hydrate is achieved, revealing structural details of the interlayer spacing for the first time. For the two-layer hydrate the structural model proposed for vermiculites is confirmed but a different ordering pattern of interlayer [Na(H 2 O) 6 ] + is suggested. While in the two-layer hydrate sodium cations reside at the centre of the interlayer space, in the one-layer hydrate sodium is displaced from the centre of the interlayer space either towards the upper or towards the lower tetrahedral sheet. This displacement allows for coordination to the hexagonal cavity on one side while the coordination sphere of sodium is completed by three coordinating water molecules on the other side. These three water molecules in turn are involved in hydrogen bonding to the opposite tetrahedral sheet.

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“…However, many important activities that involve high salt concentrations include fertilization-related farming, industrial saline water discharge and seawater immersion, all of which can possibly affect the fate and translocation of TCs in the environment. In addition, previous studies have indicated that iron-intercalated clay materials are a promising functionalized material for applications in a variety of fields, e.g., various catalysts and/or adsorbents for the removal of a variety of pollutants and soil remediation (Yuan et al, 2008;Stöcker et al, 2010;Gil et al, 2011;Wallis et al, 2011;Zhou, 2011Zhou, ,2011Zhou and Keeling, 2013). Therefore, the objective of this study is to determine if ironintercalated montmorillonite (Fe-Mt) derived from naturally occurring Na + -montmorillonite (Mt) is an efficient adsorbent for TC retention, with a detailed characterization of the bulk/surface/pore structures of the material, and to demonstrate how the two impacting factors, i.e., the solution pH and anions, can mediate the TC adsorption on FeMt in comparison with Mt and ferrihydrite.…”

Section: Introductionmentioning

confidence: 99%

Effects of the pH and anions on the adsorption of tetracycline on iron-montmorillonite

Xie

et al. 2016

Applied Clay Science

157

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Microporous PILCs — Synthesis, pillaring mechanism and selective cation exchange

Cited by 20 publications

References 31 publications

CO₂ Adsorption Enhanced by Tuning the Layer Charge in a Clay Mineral

CO₂ Adsorption Enhanced by Tuning the Layer Charge in a Clay Mineral

Single crystal structure refinement of one- and two-layer hydrates of sodium fluorohectorite

Effects of the pH and anions on the adsorption of tetracycline on iron-montmorillonite

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Microporous PILCs — Synthesis, pillaring mechanism and selective cation exchange

Cited by 20 publications

References 31 publications

CO2 Adsorption Enhanced by Tuning the Layer Charge in a Clay Mineral

CO2 Adsorption Enhanced by Tuning the Layer Charge in a Clay Mineral

Single crystal structure refinement of one- and two-layer hydrates of sodium fluorohectorite

Effects of the pH and anions on the adsorption of tetracycline on iron-montmorillonite

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Product

Resources

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CO₂ Adsorption Enhanced by Tuning the Layer Charge in a Clay Mineral

CO₂ Adsorption Enhanced by Tuning the Layer Charge in a Clay Mineral