Alteration of smectites induced by hydrolytic exchange

Clay Minerals ◽  
2005 ◽  
Vol 40 (1) ◽  
pp. 15-24 ◽  
Author(s):  
S. Ramirez ◽  
D. Righi ◽  
S. Petit
Keyword(s):  
Infrared Spectroscopy ◽  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Relative Increase ◽  
Exchange Capacity ◽  
Capacity Analysis ◽  
Soluble Salts ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mixed Layers

AbstractHydrolytic exchange was performed experimentally on four smectitic clays to evaluate the extent of clay alteration induced by this process and the associated ‘auto-transformation’ of H+ clays. Clay samples were Na-saturated and submitted to 10, 50 and 100 wetting-drying (WD) cycles and characterized after treatment using X-ray diffraction (XRD), infrared spectroscopy (FTIR) and cation exchange capacity analysis. Evidence for hydrolytic exchange was given by increasing amounts of exchangeable Mg2+ and precipitation of Na soluble salts for samples subjected to 100 WD cycles. Results indicated a decrease in the interlayer charge after 10 WD cycles but no further decrease was observed after 50 and 100 WD cycles. For one sample, XRD data indicated a decrease in the proportion of the smectite phase and a relative increase in the concentration of illite-smectite mixed layers also present in the sample. The results suggested that the reaction induces first a decrease in the layer charge and then a partial dissolution of some smectite layers.

Influence of Alkaline Activation over Swelling and Cation Exchange Capacity on Bentonites

2010 ◽  
Vol 660-661 ◽  
pp. 1064-1069 ◽  
Author(s):  
Jeane A. Rosário ◽  
Laura A. Silva ◽  
Gabriel Beraldi G. Moura ◽  
Marivone Gusatti ◽  
Raquel B. Lima ◽  
...  
Keyword(s):  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Sodium Content ◽  
Exchange Capacity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Types ◽  
Methylene Blue Test ◽  
Bentonite Clays ◽  
Mechanochemical Reactions

The performance of the alkaline processes on the properties of cation exchange capacity (CEC) and swelling was studied in three different types of bentonite from Brazil, Argentina and Mozambique. Alkaline activations were performed by means of mechanochemical reactions with solutions of NaOH and Na2CO3, to increase the sodium content of bentonite clays and, thus, improve the properties above. Clay samples were characterized by X-ray diffraction, to obtain the constituent phases. Activated samples were evaluated according to their cation exchange capacity – determined by the methylene blue test, and swelling index – measured by the Foster’s method. Results showed that the activation improved the properties of all bentonite types, especially the Brazilian clay, which achieved the most significant raises. There was also an indication that the type of clay affect the processing.

Powder x-ray diffraction study of a cryptomelane-type manganic acid and its alkali cation exchanged forms

1993 ◽  
Vol 8 (12) ◽  
pp. 3145-3150 ◽  
Author(s):  
Masamichi Tsuji ◽  
Sridhar Komarneni
Keyword(s):  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Lattice Parameter ◽  
Exchange Capacity ◽  
Alkali Cation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Steep Decrease ◽  
Exchange Properties ◽  
Good Agreement

Cryptomelane-type manganic acid (CMA), H2Mn8O16 · 2.4H2O, with a theoretical cation exchange capacity of 2.70 meq/g, was prepared and its cation exchange properties were studied as a function of XM which is defined by the ratio of uptake in meq/g to the theoretical capacity. Plots of the corrected selectivity coefficients log KHM vs the fractional exchange M for alkali metal ions on a 2 × 2 type tunnel-structured manganic acid showed a gradual decrease in small XMM regions and a steep decrease in large XMM) were 0.92 for Li+, 0.74 for Na+ and K+, 0.67 for Rb+, and 0.44 for Cs+. These maximums have been attributed to steric limitation as well as a limit on the expansion of the crystal lattice. Some x-ray diffraction (XRD) data of alkali cation exchanged forms were in good agreement with the XRD data of synthetic alkali CMA phases as given in the cards by the Joint Committee on Powder Diffraction Standards (JCPDS). The lattice parameter a0 has been found to depend on the exchanged amounts and the nature of the cations involved, while the c0 value remained almost the same irrespective of the amount of exchange or the nature of the cations.

Organo-bentonites with improved cetyltrimethylammonium contents

Clay Minerals ◽  
2014 ◽  
Vol 49 (5) ◽  
pp. 683-692 ◽  
Author(s):  
F. Kooli
Keyword(s):  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Interlayer Spacing ◽  
Exchange Capacity ◽  
Organic Cations ◽  
Basal Spacing ◽  
Water Mixture ◽  
X Ray Diffraction ◽  
X Ray

AbstractOrgano-bentonites were prepared using a bentonite and an aqueous cetyltrimethylammonium hydroxide solution. The ratio of the surfactant (in mmoles) to the cation exchange capacity varied from 0.5 to 20, with 20 being the highest ratio ever reported in the literature. At high surfactant to cation exchange capacity ratios, the interlayer spacing increased to 3.75 nm due to the formation of a paraffin-type bilayer of surfactant cations, which was shown to be mainly in gauche conformations using solid state 13C CP/NMR. When the exchange reaction was carried out in a methanol-water mixture, the expansion of the organo-bentonites depended on the concentration of methanol (% by volume). The decomposition temperatures of the organic cations depended on the basal spacing of the organo-bentonites, and in situ X-ray diffraction revealed that the basal spacing of our organo-bentonites was stable up to 210°C. Above this temperature, the basal spacing shrunk to 1.47 nm due to decomposition of the surfactants.

scholarly journals The smectitic minerals in a bentonite deposit from Melo (Uruguay)

Clay Minerals ◽  
2003 ◽  
Vol 38 (1) ◽  
pp. 25-34 ◽  
Author(s):  
L. Calarge ◽  
B. Lanson ◽  
A. Meunier ◽  
M. L. Formoso
Keyword(s):  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Total Surface Area ◽  
Exchange Capacity ◽  
X Ray Diffraction ◽  
Interlayer Cation ◽  
Cation Composition ◽  
High Charge ◽  
X Ray ◽  
Diffraction Patterns

AbstractA nearly monomineralic 1.5 m thick bentonite bed sampled in Melo (Uruguay) appears to be a pure high-charge montmorillonite: [Si3.94Al0.06](Al1.40Fe3+0.11Ti0.02Mg0.49Mn0.01)O10 (OH)2Na0.01K0.08Ca0.18. However, contrasting swelling behaviours have been demonstrated by fitting the experimental X-ray diffraction patterns which were recorded on oriented preparations of the same sample in different saturation states. According to the expandability of the layers in the Ca-, K- and K-Ca-saturated (i.e. saturated first with K+ and subsequently with Ca2+) states, three ‘layer types’ were defined. Low-, intermediate-, and high-charge layers are fully, partly, and not expandable, respectively, after K-saturation. Collapse of high-charge layers is not reversible after subsequent Ca-saturation, probably because of tetrahedral substitutions. These three different layer types are segregated in two distinct randomly interstratified mixed-layer phases. Total surface area and cation exchange capacity are shown to depend on the interlayer cation composition.

REACTIONS OF PHOSPHATE WITH ALUMINUM AND WYOMING BENTONITE

1969 ◽  
Vol 49 (2) ◽  
pp. 231-240 ◽  
Author(s):  
M. D. Webber ◽  
J. S. Clark
Keyword(s):  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Major Part ◽  
Aluminum Phosphate ◽  
Exchange Capacity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Aluminum Complexes ◽  
Phosphate Phase ◽  
Wyoming Bentonite

Reactions between phosphate, Al and Wyoming bentonite in aqueous suspensions were studied under two conditions: (1) H3PO4 was added after interlayer hydroxy aluminum complexes had been formed by the addition of Ca(OH)2 to AlCl3 + bentonite suspensions; and (2) H3PO4 was added to AlCl3 + bentonite suspensions before the addition of Ca(OH)2. The suspensions were aerated and maintained at 25 °C.When H3PO4 was added after the formation of hydroxy aluminum complexes, the results were not significantly different from those when Ca(OH)2 was added to suspensions containing both AlCl3 and H3PO4. Phosphate was removed from solution and an interlayer hydrous aluminum phosphate was formed which increased the d(001) spacings of the bentonite. The amount of phosphate removed from solution increased to a maximum with increasing amounts of H3PO4 added and over this range there was no change in cation exchange capacity (CEC). Large amounts of H3PO4 increased the CEC of the bentonite. A major part of the reaction was completed within 24 hours and the values of pH changed only slightly from 1 to 120 days.Values of the (Al) (OH)2(H2PO4) ion product measured after aging for 14 days were larger than would have been maintained by crystalline variscite, but X-ray diffraction studies showed no evidence for formation of a separate crystalline phosphate phase.

scholarly journals Soil Development under Continuous Agriculture at the Morrow Plots Experimental Fields from X-ray Diffraction Profile Modelling

Soil Systems ◽  
2018 ◽  
Vol 2 (3) ◽  
pp. 46 ◽  
Author(s):  
Eleanor Bakker ◽  
Fabien Hubert ◽  
Michelle M. Wander ◽  
Bruno Lanson
Keyword(s):  
Cation Exchange ◽  
Relative Proportion ◽  
Mineral Dissolution ◽  
Continuous Cropping ◽  
X Ray Diffraction ◽  
Diffraction Profile ◽  
Size Fractions ◽  
X Ray ◽  
Fine Clay ◽  
Mixed Layers

Impact of continuous cropping on clay mineralogy was assessed on a collection of unfertilized soil samples from the Morrow Plots experimental fields covering 110 years of long crop rotations. Evolution of mineralogy was quantitatively determined by fitting X-ray diffraction (XRD) patterns from four size fractions (50–2, 2–0.2, 0.2–0.05 and <0.05 µm) of the surface horizon (0–20 cm). The mineralogy of the three clay subfractions (2–0.2 µm, 0.2–0.05 µm and <0.05 µm) consists mainly of coexisting illite-smectite-chlorite whose compositions range from discrete illite (in the 2–0.2 µm subfraction) to discrete smectite (in the <0.05 µm subfraction). Mixed layers of similar compositions were used to fit XRD data from all clay subfractions. With decreasing size fractions, both the size of the coherent scattering domains and the proportion of illite-rich mixed layers decrease, thus accounting for the higher cation exchange measured in the <0.05 µm subfraction compared to other clay subfractions. The analysis of fine clay subfractions (<0.2 µm or lower) provided key information and constraints to a complete and accurate description of the bulk <2 µm fraction. Additional constraints derived from chemical treatments (K-saturation and heating) proved to be especially useful to propose a reliable structure model for these fine clay subfractions because of their weakly modulated diffraction signature. Mineralogy of all subfractions considered is essentially stable over the studied period (1904–2014), with the relative proportion of the different clay layer types (illite, smectite, kaolinite, chlorite) showing no significant evolution in the bulk <2 µm fraction. A century of continuous cropping thus results essentially in an increase of fine clay particles (<0.05 µm) and a decrease of the 0.2–0.05 µm subfraction, indicative of clay mineral dissolution and consistent with observed increase of cation exchange capacity with time. The relative proportion of the bulk <2 µm fraction is nearly constant over the studied period, indicative of minimal export of clay phases.

A lithium-bearing aluminian regular mixed layer montmorillonite-chlorite from Huy, Belgium

Clay Minerals ◽  
1974 ◽  
Vol 10 (3) ◽  
pp. 135-144 ◽  
Author(s):  
G. Brown ◽  
P. Bourguignon ◽  
J. Thorez
Keyword(s):  
Mixed Layer ◽  
Cation Exchange Capacity ◽  
Structural Formula ◽  
Exchange Capacity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Saturated Clay ◽  
Bluish Green ◽  
Image Position ◽  
Green Clay

AbstractA bluish-green clay found in veins cutting across brecciated slates of the Llanvirnian stage at Huy, Belgium, is shown by X-ray diffraction and chemical analysis to be a lithium-bearing, aluminium-rich, regular mixed layer montmorillonite-chlorite with associated pyrophyllite, nacrite and quartz and smaller amounts of calcite and ankerite. The cation exchange capacity of the purified air-dry magnesium saturated clay is 49 mEq/100 g and its structural formula isThe problem of the nomenclature of regular mixed layer montmorillonite-chlorites is discussed.

SEM, XRF, XRD, Nitrogen Adsorption, Fosters Swelling and Capacity Adsorption Characterization of Cloisite 30 B

2012 ◽  
Vol 727-728 ◽  
pp. 1591-1595 ◽  
Author(s):  
Aline Cadigena Lima Patrício ◽  
Marcílio Máximo da Silva ◽  
Anna Karoline Freires de Sousa ◽  
Mariaugusta Ferreira Mota ◽  
Meiry Glaúcia Freire Rodrigues
Keyword(s):  
Quaternary Ammonium ◽  
Cation Exchange Capacity ◽  
Nitrogen Adsorption ◽  
Exchange Capacity ◽  
X Ray Diffraction ◽  
Oil And Grease ◽  
X Ray ◽  
Quaternary Ammonium Cations ◽  
Cloisite 30B

Cationic surfactants, such as quaternary ammonium cations, have been used, in order to ameliorate the oil sorption capacity of inorganics materials, such as clays. Clays modified with quaternary ammonium cations (organoclays) have better performance in sorption, remove oil and grease from water at seven times the rate of activated carbon, as well as they can be used like perforation fluids of oil wells to the oil base, lubricants, among others industries. This work aims characterize the Cloisite 30B using various techniques: X-Ray Diffraction (XRD), Specific Surface Area (BET) and Cation Exchange Capacity. Different organic solvents, namely gasoline, diesel and kerosene were used in order to investigate the clays compatibility after orgophilization.

Sign in / Sign up

Export Citation Format

Share Document