Chemically modified smectites

By P. Komadel. Clay minerals, 2003

228 citations recorded by the source corpus.

Abstract This paper summarizes recent results obtained on chemical modifications of smectites. These include replacement of exchangeable cations with protons, a process connected with smectite autotransformation - attack of protons on the layers and liberation of central atoms from the octahedral and tetrahedral sheets, causing modification of the acid sites on the particles. More severe modifications occur during dissolution in inorganic acids, when the layers are dissolved and threedimensional amorphous silica is formed. The negative charge on the smectite layers can be increased via reduction of structural Fe(III) to Fe(II) or decreased via fixation of small exchangeable cations, such as Li+, upon treatment at elevated temperatures. Heating for 24 h at different temperatures between 100 and 300ºC leads to a series of chemically similar materials of different charge, prepared from the same parent mineral. Such series are suitable for investigation of the effect of the layer charge on selected properties of smectites. Fe(II) can be partly stabilized in reduced smectites by Li fixation upon heating.

Subfields: Biomaterials, Materials Chemistry, Renewable Energy, Sustainability and the Environment

View Paper: https://www.semanticscholar.org/paper/0a4f03abbdaeb831228233909366caca6ed98d88

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In Biomaterials

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In Renewable Energy, Sustainability and the Environment

Citations in the corpus

Advances in alkali-activation of clay minerals (2020, methodology): “This process has been used most extensively for smectites, which causes dehydroxylation and dissolution of the octahedral sheet, and turns the tetrahedral sheet into a “three-dimensional framework of protonated amorphous silica” [182].”
Experimental Study of Montmorillonite Structure and Transformation of Its Properties under Treatment with Inorganic Acid Solutions (2017, background): “Therefore, the structural units comprised of the tetrahedral sheet fragments are released from the 2:1 structure, which corresponds to “Si–Ofree” vibrations—1095 cm−1 [11,15,21,50].”