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Eric Masson - One of the best experts on this subject based on the ideXlab platform.
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UV powder coatings containing synthetic Ag-Beidellite for antibacterial properties
Applied Clay Science, 2014Co-Authors: Vanessa Maurin, Céline Croutxé-barghorn, Xavier Allonas, Jocelyne Brendle, Julia Bessieres, André Merlin, Eric MassonAbstract:The preparation of antibacterial UV powder coatings dedicated to wood based panels is described in the present study. Two experimental methods were investigated: the generation of silver nanoparticles during the polymerization of UV powders and the introduction of a silver modified Beidellite within UV powder formulations. While the first method leads to some nanoparticle aggregation, this phenomenon was avoided with the second approach. Antibacterial activity was thus ensured by the presence of Beidellite modified with silver cations. XRD, X-ray fluorescence, SEM/EDX and TEM analyses allowed a complete characterization of the Ag-Beidellite before its incorporation within UV powder formulations. Real-time-FTIR spectroscopy fitted with an environmental cell was used to monitor the reactivity of UV powder formulations under UV light and temperature control. Resulting coatings were finally characterized by UV spectroscopy, DMA in tension mode, XRD, TEM and antimicrobial analyses. It was shown that the fully cured and homogeneous coatings exhibit high thermomechanical properties and antibacterial activity.
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UV powder coatings containing synthetic Ag-Beidellite for antibacterial properties
Applied Clay Science, 2014Co-Authors: Vanessa Maurin, Céline Croutxé-barghorn, Xavier Allonas, Jocelyne Brendle, Julia Bessieres, André Merlin, Eric MassonAbstract:The preparation of antibacterial UV powder coatings dedicated to wood based panels is described in the present study. Two experimental methods were investigated: the generation of silver nanoparticles during the polymerization of UV powders and the introduction of a silver modified Beidellite within UV powder formulations. While the first method leads to some nanoparticle aggregation, this phenomenon was avoided with the second approach. Antibacterial activity was thus ensured by the presence of Beidellite modified with silver cations. XRD, X-ray fluorescence, SEM/EDX and TEM analyses allowed a complete characterization of the Ag-Beidellite before its incorporation within UV powder formulations. Real-time-FTIR spectroscopy fitted with an environmental cell was used to monitor the reactivity of UV powder formulations under UV light and temperature control. Resulting coatings were finally characterized by UV spectroscopy, DMA in tension mode, XRD, TEM and antimicrobial analyses. It was shown that the fully cured and homogeneous coatings exhibit high thermomechanical properties and antibacterial activity.
Jocelyne Brendle - One of the best experts on this subject based on the ideXlab platform.
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UV powder coatings containing synthetic Ag-Beidellite for antibacterial properties
Applied Clay Science, 2014Co-Authors: Vanessa Maurin, Céline Croutxé-barghorn, Xavier Allonas, Jocelyne Brendle, Julia Bessieres, André Merlin, Eric MassonAbstract:The preparation of antibacterial UV powder coatings dedicated to wood based panels is described in the present study. Two experimental methods were investigated: the generation of silver nanoparticles during the polymerization of UV powders and the introduction of a silver modified Beidellite within UV powder formulations. While the first method leads to some nanoparticle aggregation, this phenomenon was avoided with the second approach. Antibacterial activity was thus ensured by the presence of Beidellite modified with silver cations. XRD, X-ray fluorescence, SEM/EDX and TEM analyses allowed a complete characterization of the Ag-Beidellite before its incorporation within UV powder formulations. Real-time-FTIR spectroscopy fitted with an environmental cell was used to monitor the reactivity of UV powder formulations under UV light and temperature control. Resulting coatings were finally characterized by UV spectroscopy, DMA in tension mode, XRD, TEM and antimicrobial analyses. It was shown that the fully cured and homogeneous coatings exhibit high thermomechanical properties and antibacterial activity.
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UV powder coatings containing synthetic Ag-Beidellite for antibacterial properties
Applied Clay Science, 2014Co-Authors: Vanessa Maurin, Céline Croutxé-barghorn, Xavier Allonas, Jocelyne Brendle, Julia Bessieres, André Merlin, Eric MassonAbstract:The preparation of antibacterial UV powder coatings dedicated to wood based panels is described in the present study. Two experimental methods were investigated: the generation of silver nanoparticles during the polymerization of UV powders and the introduction of a silver modified Beidellite within UV powder formulations. While the first method leads to some nanoparticle aggregation, this phenomenon was avoided with the second approach. Antibacterial activity was thus ensured by the presence of Beidellite modified with silver cations. XRD, X-ray fluorescence, SEM/EDX and TEM analyses allowed a complete characterization of the Ag-Beidellite before its incorporation within UV powder formulations. Real-time-FTIR spectroscopy fitted with an environmental cell was used to monitor the reactivity of UV powder formulations under UV light and temperature control. Resulting coatings were finally characterized by UV spectroscopy, DMA in tension mode, XRD, TEM and antimicrobial analyses. It was shown that the fully cured and homogeneous coatings exhibit high thermomechanical properties and antibacterial activity.
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tensile and water barrier properties of cassava starch composite films reinforced by synthetic zeolite and Beidellite
Journal of Food Engineering, 2013Co-Authors: Pierre C Belibi, Jocelyne Brendle, Jean T Daou, J M B Ndjaka, Laure Michelin, Blaise Nsom, Bernard DurandAbstract:Composites films were prepared by the casting method using native cassava starch plasticized with glycerol and 3D or 2D synthetic fillers i.e. Beta zeolite and Na-Beidellite type 2:1 phyllosilicate. Special attention was paid to the effect of the filler contents and type on the mechanical and barrier properties. It was shown that films reinforced with lyophilized Beta zeolite presented both high water solubility (WS) and water vapor permeability (WVP) values than the pristine starch whereas an improvement on the WVP was found for composites prepared from Na-Beidellite or from non lyophilized Beta zeolite. For the two types of fillers, a drastic increase of the mechanical properties (especially in the Young’s modulus) was observed.
Hiromoto Nakazawa - One of the best experts on this subject based on the ideXlab platform.
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compositional gap in dioctahedral trioctahedral smectite system Beidellite saponite pseudo binary join
Clays and Clay Minerals, 1999Co-Authors: Hirohisa Yamada, Katsuaki Yoshioka, Kenji Tamura, Kazuko Fujii, Hiromoto NakazawaAbstract:A series of hydrothermal experiments were performed to determine the phase relations on the Beidellite-saponite pseudo-binary join. Quenched glasses with stoichiometric dehydrated compositions of an Na-rich smectite on the join were heated at 250–500°C for durations of 1–151 d at 100 MPa. Time-temperature diagrams showed that immiscibility occurs between dioctahedral smectite (Beidellite) and trioctahedral smectite (saponite) below 400°C. Thus, smectite with intermediate chemical composition was considered as metastable in this system. Above 400°C the assemblage of regularly interstratified saponite-chlorite, quartz, and feldspar was recognized in the intermediate chemical compositional region of this join. On the Beidellite side of this join, Beidellite and mixed-layer phases of smectite and a regular interstratification of montmorillonite-Beidellite, are possible phases that occur at <300°C. They readily reacted to form a mixture of dioctahedral rectorite plus quartz at 300°C. This assemblage then reacted to a dioctahedral “mica”, which can expand with glycol and quartz. On the saponite side of this join, a single phase, saponite, existed at <400°C, and transformed to saponite plus trioctahedral rectorite with aging and increasing temperature of synthesis. The alteration was affected strongly by the chemical composition of the binary system.
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Compositional Gap in Dioctahedral-Trioctahedral Smectite System: Beidellite-Saponite Pseudo-Binary Join
Clays and Clay Minerals, 1999Co-Authors: Hirohisa Yamada, Katsuaki Yoshioka, Kenji Tamura, Kazuko Fujii, Hiromoto NakazawaAbstract:A series of hydrothermal experiments were performed to determine the phase relations on the beidettite-saponite pseudo-binary join. Quenched glasses with stoichiometric dehydrated compositions of an Na-rich smectite on the join were heated at 250-500~ for durations of 1-151 d at 100 MPa. Time- temperature diagrams showed that immiscibility occurs between dioctahedral smectite (Beidellite) and trioctahedral smectite (saponite) below 400~ Thus, smectite with intermediate chemical composition was considered as metastable in this system. Above 400~ the assemblage of regularly interstratified saponite-chlorite, quartz, and feldspar was recognized in the intermediate chemical compositional region of this join. On the Beidellite side of this join, Beidellite and mixed-layer phases of smectite and a regular interstratification of montmorillonite-Beidellite, are possible phases that occur at
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Isothermal Treatments of Regularly Interstratified Montmorillonite-Beidellite at Hydrothermal Conditions
Clays and Clay Minerals, 1993Co-Authors: Hirohisa Yamada, Hiromoto NakazawaAbstract:A glass in the intermediate composition of montmorillonite and Beidellite, 50/50 in mole ratio, was treated under a hydrothermal pressure of 100 MPa, in the temperature range from 250 to 500°C and durations from 2 to 129 days. The phases identified in the products were plotted in a time-temperature-transformation (TTT) diagram. The TTT diagram showed that the regularly interstratified montmorillonite-Beidellite (r.i.M-B) was a metastable phase above the temperature of 350°C and changed to the assemblage of Na-rectorite + saponite + quartz, through the intermediate assemblage of Beidellite + saponite + quartz. The TTT diagram suggested also that the r.i.M-B might be a stable clay mineral below the temperature of 300°C in the middle region of montmorillonite-Beidellite pseudo-binary system, although the laboratory confirmation of the mineral stability was not easy for the sluggish reaction.
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Isothermal treatments of regularly interstratified montmorillonite-Beidellite at hydrothermal conditions
1993Co-Authors: Hirohisa Yamada, Hiromoto NakazawaAbstract:Abstract--A glass in the intermediate composition ofmontmorillonite and Beidellite, 50/50 in mole ratio, was treated under a hydrothermal pressure of 100 MPa, in the temperature range from 250 to 500 ~ and durations from 2 to 129 days. The phases identified in the products were plotted in a time-temperature-transformation (TTT) diagram. The TTT diagram showed that the regularly interstratified montmoril-lonite-Beidellite (r.i.M-B) was a metastable phase above the temperature of 350 ~ and changed to the assemblage of Na-rectorite + saponite + quartz, through the intermediate assemblage of Beidellite + saponite + quartz. The TTT diagram suggested also that the r.i.M-B might be a stable clay mineral below the temperature of 300 ~ in the middle region of montmorillonite-Beidellite pseudo-binary system, al-though the laboratory confirmation of the mineral stability was not easy for the sluggish reaction. Key Words--Hydrothermal condition, Isothermal treatments, Regularly stratified montmorillonite-bei-dellite
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Hydrothermal synthesis of Beidellite from aluminosilicate glass by varying water/solid ratio
Mineralogical Journal, 1991Co-Authors: Hirohisa Yamada, Katsuaki Yoshioka, Hiromoto NakazawaAbstract:Beidellite was synthesized from sodium aluminosilicate glass at a hydrothermal pressure of 100 MPa and at temperatures of 250, 300, 350, 400 and 450°C. The initial water/solid ratio of the starting materials was varied in the range 0.155 to 2.17. The run products were analyzed by the powder X-ray diffraction (XRD) method. Correlations among the water/solid ratio, temperature of synthesis, yield of Beidellite and its crystallinity indicated: (1) Amount of water intercalated in the structure was limited to three layers even in water-excess condition of synthesis at high pressure and temperature. (2) Beidellite, crystallized from glass by hydration, was in the form of a two-dimensional flake. The dimensions and thickness of a flake were independent of the temperature of synthesis and the water/solid ratio, and were not increased by further hydration.
Michael Descostes - One of the best experts on this subject based on the ideXlab platform.
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on exchange reactions of major inorganic cations (H+, Na+, Ca2+, Mg2+ and K+) on Beidellite: Experimental results and new thermodynamic database. Toward a better prediction of contaminant mobility in natural environments
Applied Geochemistry, 2015Co-Authors: Valentin Robin, Daniel Beaufort, Paul Sardini, Olivier Regnault, Tertre Emmanuel, Michael DescostesAbstract:To our knowledge, no thermodynamic database is available in the literature concerning ion-exchange reactions occurring in low-charge smectite with tetrahedral charge (Beidellite). The lack of this information makes it difficult to predict the mobility of contaminants in environments where Beidellite and major cations, which act as competitors with contaminants for sorption on the clay phase, are present. The present study proposes a multi-site ion exchange model able to describe experimental data obtained for H+ and the four major cations (Na+, Ca2+, Mg2+ and K+) found in natural waters interacting with a
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ion exchange reactions of major inorganic cations h na ca2 mg2 and k on Beidellite experimental results and new thermodynamic database toward a better prediction of contaminant mobility in natural environments
Applied Geochemistry, 2015Co-Authors: Daniel Beaufort, Valentin Robin, Paul Sardini, Emmanuel Tertre, Olivier Regnault, Michael DescostesAbstract:To our knowledge, no thermodynamic database is available in the literature concerning ion-exchange reactions occurring in low-charge smectite with tetrahedral charge (Beidellite). The lack of this information makes it difficult to predict the mobility of contaminants in environments where Beidellite and major cations, which act as competitors with contaminants for sorption on the clay phase, are present. The present study proposes a multi-site ion exchange model able to describe experimental data obtained for H + and the four major cations (Na + ,C a 2+ ,M g 2+ and K + ) found in natural waters interacting with a <0.3 lm size fraction of Na-Beidellite. The nature of the sites involved in the sorption processes is assessed using qualitative structural data. Moreover, the effect of the charge location in the smectite on the selectivity coefficient values is discussed by comparison with the results reported in the literature for smectite characterized by octahedral charge (montmorillonite). The new thermodynamic database proposed in this study is based on the same total sorption site density and distribution of sites regardless of the cations investigated. This database is valid for a large range of physico-chemical conditions: a [1–7] pH range, a total normality higher than 5 � 10 � 3 mol/L corresponding to a flocculated state for water/clay systems, and when sorption of ions pairs can be neglected. Note that this study provides evidence that a thermodynamic database describing ion exchange reactions between H + and the four major cations of natural water for smectite cannot be valid irrespective of the total normality of the aqueous phase because smectite can form different phases (e.g., floc, gel) when immersed in aqueous system. The model proposed can be easily included in reactive transport software and is applied in the present study to predict the evolution of Beidellite surface composition toward major inorganic cations in the context of mining site remediation. Finally, the new thermodynamic database proposed could be used for a better understanding of ion-exchange reactions occurring in many environments where Beidellite is present, from soils to smectite-bearing sedimentary formations.
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Occurrence of authigenic Beidellite in the Eocene transitional sandy sediments of the Chu-Saryssu basin (South-Central Kazakhstan)
Sedimentary Geology, 2015Co-Authors: Valentin Robin, Daniel Beaufort, Benoit Hebert, Paul Sardini, Emmanuel Tertre, Olivier Regnault, Michael DescostesAbstract:Abstract This paper describes the petrographic properties and the clay mineralogy of Eocene sandy sediments of the Chu-Saryssu basin (South-Central Kazakhstan), in which dioctahedral smectite formed during shallow burial diagenesis (eogenesis). Evidence from petrography and clay mineralogy supports the successive occurrence of kaolinite and dioctahedral smectite during the eogenetic processes, which may have resulted from a change from wet and humid to semi-arid or arid climatic conditions. An original result of this study is the predominantly beidellitic nature of the authigenic smectite, which was determined via X-ray diffraction (XRD, using the Hofmann–Klemen test) and Fourier transform infrared spectroscopy (FTIR) investigations and chemical microanalysis. The crystal-chemical investigations indicate a rather homogeneous chemical composition of the smectite at the regional scale, and the following unit formula is proposed: (Si4 +3.65Al3 +0.35)(Al3 +1.65Fe3 +0.21Mg2 +0.14)O10(OH)2Na+0.10Mg2 +0.11Ca2 +0.04K+0.07. This type of smectite has been interpreted as representative of mixed layers of montmorillonite and Beidellite. The fact that the smectite that formed primarily in the unconsolidated sandy sediments is close to Beidellite, rather than montmorillonite, may have a major impact on the rate of further illitization in the Chu-Saryssu basin. Indeed, the crystal chemistry of Beidellite is more favorable to illitization, and the presence of this mineral provides new insights concerning the different rates of illitization between sandstones and shale formations observed worldwide.
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Ion exchange reactions of major inorganic cations (H+, Na+, Ca2+, Mg2+ and K+) on Beidellite: Experimental results and new thermodynamic database. Toward a better prediction of contaminant mobility in natural environments
Applied Geochemistry, 2015Co-Authors: Valentin Robin, Daniel Beaufort, Paul Sardini, Emmanuel Tertre, Olivier Regnault, Michael DescostesAbstract:To our knowledge, no thermodynamic database is available in the literature concerning ion-exchange reactions occurring in low-charge smectite with tetrahedral charge (Beidellite). The lack of this information makes it difficult to predict the mobility of contaminants in environments where Beidellite and major cations, which act as competitors with contaminants for sorption on the clay phase, are present. The present study proposes a multi-site ion exchange model able to describe experimental data obtained for H + and the four major cations (Na + ,C a 2+ ,M g 2+ and K + ) found in natural waters interacting with a
Ray L. Frost - One of the best experts on this subject based on the ideXlab platform.
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Thermogravimetric analysis of tetradecyltrimethylammonium bromide-modified Beidellites
Journal of Thermal Analysis and Calorimetry, 2015Co-Authors: Yet Hong Lim, Balázs Zsirka, Erzsébet Horváth, Janos Kristof, Sara J. Couperthwaite, Ray L. Frost, Godwin A. AyokoAbstract:The surfaces of natural Beidellite clay were modified with cationic surfactant, tetradecyltrimethylammonium bromide, at different concentrations. The organo-Beidellites were analysed using thermogravimetric analysis which shows four thermal oxidation/decomposition steps. The first step of mass loss is observed from room temperature to 130 °C due to the dehydration of adsorbed water. The second step of mass loss between 130 and 400 °C is attributed to the oxidation step of the intercalated organic surfactant with the formation of charcoal. The third mass loss happens between 400 and 500 °C which is assigned to the loss of hydroxyl groups on the edge of clays and the further oxidation step of charcoal. The fourth step is ascribed to the loss of structural OH units as well as the final oxidation/decomposition step of charcoal which takes place between 500 and 700 °C. Thermogravimetric analysis has proven to be a useful tool for estimating loaded surfactant amount.
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Application of organo-Beidellites for the adsorption of atrazine
Applied Clay Science, 2015Co-Authors: Emily Grundgeiger, Yet Hong Lim, Ray L. Frost, Godwin A. AyokoAbstract:The surfaces of natural Beidellite were modified with cationic surfactant octadecyl trimethylammonium bromide at different concentrations. The organo-Beidellite adsorbent materials were then used for the removal of atrazine with the goal of investigating the mechanism for the adsorption of organic triazine herbicide from contaminated water. Changes on the surfaces and structure of Beidellite were characterised by X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and BET surface analysis. Kinetics of the adsorption studies were also carried out which show that the adsorption capacity of the organoclays increases with increasing surfactant concentration up until 1.0 CEC surfactant loading, after which the adsorption capacity greatly decreases. TG analysis reveals that although the 2.0 CEC sample has the greatest percentage of surfactant by mass, most of it is present on external sites. The 0.5 CEC sample has the highest proportion of surfactant exchanged into the internal active sites and the 1.0 CEC sample accounts for the highest adsorption capacity. The goodness of fit of the pseudo-second order kinetic confirms that chemical adsorption, rather than physical adsorption, controls the adsorption rate of atrazine
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adsorption of the herbicide simazine on moderately acid activated Beidellite
Applied Clay Science, 2010Co-Authors: Blain Paul, Ray L. Frost, Dongjiang Yang, Xuzhuang Yang, Huaiyong ZhuAbstract:This study focuses on acid activated Beidellite and its adsorption ability for the herbicide simazine. After acid activation, the non-silicon atoms, such as Al, Mg, and Fe, which are located in the octahedral sheet, and sodium ions between the clay mineral layers were leached from the parent clay mineral. The basal spacing increased after acid activation. The acid activated Beidellites were used to remove simazine from water. The simazine molecules can enter into the destroyed alumino silicate interlayer spaces and can be adsorbed from contaminated water.
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The effect of increasing layer charge on the infrared absorption spectra of synthetic Beidellites
Journal of Materials Science Letters, 2000Co-Authors: Jacob Kloprogge, L. Hickey, Ray L. FrostAbstract:Beidellite is a dioctahedral Al-smectite with the general formula (0.5Ca, Na, K)(Al)Si(Al)O- (OH)·nHO. The infrared absorption spectra of a range of synthetic Beidellites with varying layer charges are studied to investigate the effect of the layer charge, brought about by changes in the tetrahedral substitution of Si by Al, on the infrared spectra. In general, the OH-stretching vibrations are affected by the octahedral cations to which the OH-groups are bonded and by the configuration and charge distribution in the neighbouring tetrahedral layers.
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Infrared emission spectroscopy of Al-pillared Beidellite
Applied Clay Science, 1999Co-Authors: Jacob Kloprogge, Ray L. FrostAbstract:The structural changes of synthetic Beidellite and Al13-pillared analogues during dehydroxylation were studied using infrared emission spectroscopy (IES). The OH-stretching region is characterised by 2 OH-stretching modes around 3605 cm−1 and 3650 cm−1. These bands strongly decrease in intensity upon dehydroxylation of the Beidellite up to 700–750°C. The Al13-pillared Beidellite shows stronger OH-stretching bands, while the silanol band, originally visible in the Beidellite spectra, is absent. The OH-stretching mode of the Al13 is visible around 3450 cm−1 and a very broad band is present around 3200 cm−1 assigned to water molecules in the Al13 pillar. This band quickly disappears upon heating to 300°C while the OH-stretching band at 3450 cm−1 diminishes in intensity. The presence of two different OH-groups in Beidellite is also reflected in the OH-bending modes around 880 cm−1 and 916 cm−1 and in the OH-libration modes around 770 cm−1 and 804 cm−1 in the infrared (IR) absorption spectra. These bands show an intensity decrease upon dehydroxylation of the clay. Similar, slightly shifted, bands are observed in the IR emission spectra. Significant differences between the Beidellite and its pillared analogue are the splitting of the single band at 814 cm−1 into two bands at 812 cm−1 and 830 cm−1 and the bands associated with Al–OH modes show increased intensities for the pillared Beidellite. These results show that upon calcination the pillars dehydroxylate, thereby releasing protons which are able to diffuse through the tetrahedral sheet into the octahedral sheet where they interact with the structural OH-groups and form water. In addition, the formation of Si–OH– groups is observed in the IR emission spectra of the Al13-pillared Beidellite indicating that these protons can also interact with Si–O–Al bonds upon calcination and form new Si–OH–Al bonds. A reaction between the Al13 pillar and the protonated Si–OH–Al linkage will yield Altetrahedral–O–Alpillar linkages.