Surface chemistry–microstructure–rheology of high and low crystallinity KGa-1b and KGa-2 kaolinite suspensions

Au, Pek-Ing; Clode, Peta L.; Smart, Roger St. C.; Leong, Yee-Kwong

doi:10.1016/j.colsurfa.2015.08.013

Cited by 15 publications

(3 citation statements)

References 56 publications

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“…Ice crystals were believed to have affected the microstructure of STx-1b CaMnt gels obtained by cryo-SEM imaging published by Au and Leong (2016). These hexagonal crystals fractured the clay gel microstructure, producing large pores and channels (Au et al, 2015a;Au & Leong, 2016;Du et al, 2018;Leong et al, 2018). The purpose of the present study, therefore, was to obtain artefact-free microstructures of STx-1b CaMnt gels by preventing ice-crystal formation by means of subjecting the gel samples to very high pressure and ultra-fast cryofreezing (Du et al, 2018;Leong et al, 2018;Wyss et al, 2004).…”

Section: Introductionmentioning

confidence: 95%

Microstructure and Time-Dependent Behavior of STx-1b Calcium Montmorillonite Suspensions

Leong

Liu

et al. 2021

Clays and clay miner.

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CaMnt is much less important than NaMnt due to its limited commercial applications. The time-dependent property of NaMnt gel has been studied extensively as it is exploited in many applications such as drilling mud and viscosity-modifier applications. In contrast, the time-dependent property of CaMnt suspension and the factors affecting it are largely unknown. The speciation of Ca2+ ions is one such factor to be evaluated. In the current study, pH and solids concentration were examined and then used to validate a recent theory on clay gel time dependency. The results supported the theory that a strong electrostatic double layer (EDL) repulsion in the 3-D network is needed to reorganize the structure and drive it toward the state of minimum free energy. The 12 wt.% CaMnt (STx-1b) gel displayed time-dependent behavior at pH 5 but not at its natural pH of 8.4. At pH 5, the interlayer Ca2+ ions became fully hydrated and desorbed from the platelet surface. This enhanced the EDL repulsion between the platelets. At pH >6.5, the positively charged hydrolysis product Ca(OH)+ began to form and was adsorbed, partially neutralizing the permanent layer charge and weakening the repulsion. However, at 19.4 wt.% solids, the gel displayed pronounced time-dependent behavior despite the high natural pH of 8. The platelets were much closer together, allowing the EDL force to operate and effect structural reorganization. The microstructure of these CaMnt gels showed high platelet concentrations interacting to form a relatively open structure. The microstructure of a kaolin (KGa-2) suspension which showed no time-dependent behavior even after 1 day of ageing revealed the importance of particle morphology and layer charge on time dependency. Its 3-D structure was formed by relatively thick, layered platelets with a low layer charge.

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Section: Introductionmentioning

confidence: 95%

Microstructure and Time-Dependent Behavior of STx-1b Calcium Montmorillonite Suspensions

Leong

Liu

et al. 2021

Clays and clay miner.

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“…The kaolinite sample used in this study is the KGa-2 kaolinite, which was originally sourced by the University of Western Australia from the Source Clay Repository of the Clay Mineral Society. KGa-2 kaolinite has an average particle size of approximately 0.5 µm (Hassan et al, 2006), a specific area of 10.05 ± 0.02 m2/g (BET N2 method) and a corresponding CEC of 2.0 meq/100 g clay (Au et al, 2015). Its structural formula is [(Al3.80Ti0.13Fe 3+ 0.07)(Si3.84Al0.16)O5(OH4)] (Mermut, 2001).…”

Section: Materials and Sample Preparationmentioning

confidence: 99%

Water and ion diffusion in partially-water saturated compacted kaolinite: Role played by vapor-phase diffusion in water mobility

Wang

Savoye

Ferrage

et al. 2022

Journal of Contaminant Hydrology

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“…The authors declare that there are no conflicts of interest. and aggregates, as compiled from experimental data published in the literature: phytolith (Nguyen et al, 2014), allophane (Kameda, 2021), ferrihydrite (Kawamoto et al, 2021), goethite (Hiemstra et al, 2007), kaolinite (Au et al, 2015), quartz (Kaya and Yukselen, 2005).…”

Section: Declaration Of Competing Interestmentioning

confidence: 99%

Aggregation reduces the release of bioavailable silicon from allophane and phytolith

Meunier

Delvaux

2022

Geochimica et Cosmochimica Acta

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Surface chemistry–microstructure–rheology of high and low crystallinity KGa-1b and KGa-2 kaolinite suspensions

Cited by 15 publications

References 56 publications

Microstructure and Time-Dependent Behavior of STx-1b Calcium Montmorillonite Suspensions

Microstructure and Time-Dependent Behavior of STx-1b Calcium Montmorillonite Suspensions

Water and ion diffusion in partially-water saturated compacted kaolinite: Role played by vapor-phase diffusion in water mobility

Aggregation reduces the release of bioavailable silicon from allophane and phytolith

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