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Although the Mesozoic rocks of the Transdanubian Range have been the subject of a multitude of different studies, mineralogical research is largely underrepresented. The clay mineralogy of Lower Jurassic (especially the Pliensbachian and Toarcian) strata was broadly investigated earlier; however, systematic high-resolution clay mineralogical studies remain scarce. Here we present a mineralogical study focusing on the Upper Pliensbachian strata of the Lókút-Hosszúárok section, located near the Eplény Manganese Ore Field. We identified dioctahedral smectite, randomly interstratified illite/smectite, illite as 10 Å phyllosilicate, quartz and cristobalite. Based on our new results we propose that the smectite was formed by aging of Mg or Fe hydroxide-silica precipitates. The smectite and cristobalite were presumably formed from the siliceous tests of radiolarians, whose abundance was controlled by a local upwelling system. The occurrence of Pliensbachian smectite in the Lókút outcrop shows similarities with the Úrkút smectites known from both Pliensbachian and Toarcian strata, which implies that similar processes controlled the sedimentation during the Pliensbachian as well as during the black (gray) shale-hosted ore accumulation in the Eplény and Úrkút basins.

Objective research : compare the efficacy of different types of therapy for rotavirus gastroenteritis in children. Materials and methods. A study was carried out, the design of which corresponded to the case–control type. The main group is children hospitalized in a hospital with laboratory confirmed rotavirus infection (35 cases), who were prescribed a modern regimen of therapy that included a low-carbohydrate diet, rehydration with low osmolar oral solutions, dioctahedral smectite, probiotic containing Saccharomyces boulardii. For each child of the main group was selected another patient (control), the corresponding sex, age, the period from the onset of the disease to admission to hospital, and the degree of dehydration. Patients of the control group (n=35) were assigned a traditional «old» therapy regimen, including a diet corresponding to Table No. 4 in Pevznur, oral rehydration solutions with osmolality of 282 mOsm/l, anthibacterial therapy (ceftriaxone), dioctahedral smectite and pancreatin at age-dependent doses. The duration of the observation was 5 days. Results : By the 5th day of treatment, the normalization of the stool was recorded in 91.4% [95% CI 82.1–100.7], 32/35 in the main group and 71.4% [95% CI 56.5–86.3], 25/35 children in the control (p

The first step of a dehydroxylation reaction of a medium-charged dioctahedral smectite model is studied by means of ab initio molecular dynamics simulations. Combining the Car–Parrinello-like–Born–Oppenheimer molecular dynamics method with metadynamics, we find two previously proposed mechanisms (dubbed on-site and cross). We confirm the existence of an intermediate state where the tetrahedral structure is deformed, a feature that is also present in the final (semidehydroxylate) state of this reaction. This shows that the thermal transformations of phyllosilicates are more complex than often assumed, which will be relevant when elucidating the mechanisms of other transformations of these materials.

The article presents the results of research on the study of clinical effectiveness and impact on intestinal microbiocenosis dioctahedral smectite (Neosmektin®) of acute intestinal infectious of bacterial, viral, and mixt etiology. The clinical studies have shown that the additional inclusion in the complex therapy for children this enterosorbent has a pronounced detoxification and antidiarrheal effect, reducing the duration of the acute period of the disease increases sanitize effectiveness of the therapy against pathogens and contributes to the normalization of microbiocenosis intestine.

Acute infectious diarrhea is one of the most frequent illnesses in children. According to actual recommendations, use of the oral rehydration solutions is advised and as a supplement dioctahedral smectite, probiotics of well-documented use or zinc. However antibiotics and chemotherapeutics are often abused.

Diarrhea treatment with either Lactobacillus GG (LGG) or smectite as an adjuvant to standard rehydration therapy has proven efficacy. In countries where both LGG and smectite are available, concomitant use is frequently practiced. We investigated whether LGG plus smectite is superior to LGG alone in the management of children with acute gastroenteritis (AGE). A double-blind, placebo-controlled, randomized trial was performed. Children aged 4 to 60 months with AGE received LGG 6 × 109 colony forming units/day plus randomly either smectite (3 g) or placebo as an adjuvant to the standard rehydration therapy. Of the 88 children randomized, 81 (92 %) were available for intention-to-treat analysis. The duration of diarrhea in the LGG/smectite group (n = 44) compared with the LGG/placebo group (n = 37) was similar (P = 0.43). There were no significant differences between the study groups for the secondary outcomes, with three exceptions. On day 4, in the LGG/placebo group compared to the LGG/smectite group, there was significantly reduced stool frequency (P = 0.03). While there was a significant (P = 0.05) difference in stool consistency on the Bristol Stool Form Scale on day 4, it was not of clinical relevance. Finally, in the LGG/smectite group compared to the LGG/placebo group, there was a significantly shorter duration of intravenous therapy after randomization (P = 0.02). No adverse events were observed in the study groups. Conclusion: LGG plus smectite and LGG alone are equally effective for treating young children with AGE. Combined use of the two interventions is not justified.

This work aims at determining the effect of hydrous strain produced by a continuous, in situ, hydration–dehydration cycles, using a variation of relative humidity (%RH) rate here, variable (%RH), on the cation exchange process in the case of Na rich-montmorillonite. This goal is accomplished in two steps. First, the starting material (Na rich-montmorillonite) is reported “in situ” at variable RH values in order to prepare and characterize a final stressed product that will be used later in the selective exchange study, in the case of solution containing (Cu 2+ , Co 2+ ). An XRD profile modeling approach is used to describe all structural changes caused by the environmental evolution of the RH rate. The quantitative analysis of XRD patterns is achieved through an indirect method, which is based on the comparison of experimental XRD patterns with calculated ones. This investigation allows us to determine several structural parameters related to the nature, abundance, size, position and organization of exchangeable cation and water molecule in the interlamellar space along the c * axis.

The objectives in the present study were to evaluate the therapeutic effect of dioctahedral smectite(smectite) against calf diarrhea caused by pathogenic E. coli and/or Salmonella typhimurium. Of this study, twenty calves (aged 2-3 months) with diarrhea were used to estimate the efficacy of smectite on calf diarrhea with 20% smectite suspension in PBS. Calves were administered with 10 ml smectite suspension three times a day after feeding, and fecal samples were collected at the gate of treatment and on 1st, 2nd, 3rd, 4th, and 5th day after administration. On the 5th day after treatment of smectite suspension, the treated group significantly reduced diarrhea index compared to control group (P

This paper aims at characterizing hydration behaviour and structural properties of a dioctahedral smectite (i.e. Wyoming montmorillonite), used in the context of naturel barrier for municipal waste disposal sites, and which is saturated by heavy metals cations coming from wastewater solution. Hydration of the 2+ , Pb 2+ , Zn 2+ , Co 2+ , Cd 2+ and Ni 2+ saturated specimens. There are heavy metal cations that are characterized by high natural abundance. The qualitative XRD investigation under room conditions (~ 35%RH) showed a similar hydration behaviour characterized by presence of three principal hydration states: 1 W, 2 W and 1 W-2 W (i.e. One, two and intermediate water layers hydration state, respectively). In order to highlight the specific hydration properties of each complex, we have studied by quantitative XRD analysis the hydration evolution under controlled relative humidity. Obtained result showed the possibility to distinguish between sample saturated with Na, Cu and Pb for high RH values (≈ 75%). For Ni, Zn, Cd and Co we have shown similar hydration behavior in all explored RH's range except the Ni 2+ cation which presents a homogeneous 3 W hydration state for 75%RH.

Degradation of methylene blue (MB) using pillared TiO2 onto spent bleaching clay has been conducted. Activation of deoiled spent bleaching clay (DSBC) has been done using acid, followed by pillarization with TiO2 using rarasaponin from Klerak fruit as surfactant. From the X-ray diffraction results show the mineral on DSBC is rectorite with dioctahedral mica layer and dioctahedral smectite with ratio 2:1. This molecule have formula Na.Al4(Si, Al)8.O20.(OH)4. H2O and after calcinations the pattern TiO2 was appearance at 2θ: 27.4460°, 36.0850°, 54.3216° and 56.6403°. In order to test the catalytic performance of Ti-DSBC for photodegradation of MB under UV light was conducted under several reaction conditions. The highest degradation of MB was 90 % within 50 minutes and Ti-DSBC can be reused until 5 cycles with percent degradation MB was 84 %.

Background Acute diarrhea is a sudden diarrhea which lasts less than seven days on babies and children. The standard treatment by WHO in managing acute diarrhea is still not satisfactory for parents whose infants and children suffering from the disease. Dioctahedral smectite is expected to decrease the volume, frequency, and duration of diarrhea. Objective To assess the clinical effects of dioctahedral smectite in infants with acute diarrhea. Methods A double-blind, randomized clinical controlled trial was performed on six to 12 months-old infants who were hospitalized in Sanglah Hospital, Denpasar due to acute diarrhea .The subjects were divided into two groups. The treatment group was given standard management with adjuvant dioctahedral smectite while and control group was given standard management with placebo. Results From 68 infants enrolled in this study, the mean duration of diarrhea was significantly shorter in treatment group compared to placebo group [39.03 hours (SD 2.03) vs 70.58 hours (SD 3.78), mean difference 31.6 (95% CI 22.90 to 40.19), P=0.001]. The RRR was 50%, and ARR was 29%. Kaplan-Meier survival analysis showed that duration of acute diarrhea was shorter in treatment group [36 hours (SD 1.7) versus 72 hours (SD 4.18), mean difference 36.0 (95% CI 21.81 to 50.19), log rank test, P

Acute gastroenteritis represents a major cause of morbidity and mortality worldwide among children, and rehydration treatment has been one of the cornerstones in the management strategy. The natural clay dioctahedral smectite (Smecta) increases intestinal barrier function and is effective against infectious diarrhoea in children. The purpose of this work was to compare the efficacy and tolerance of Lithuanian children's diarrhoea treatment with dioctahedral smectite combined with hypotonic oral rehydration solution (ORS)--Gastrolit--versus Gastrolit alone to establish the influence of Smecta on serum electrolyte balance in young children with diarrhoea and mild or moderate dehydration.Smecta combined with ORS (study group) and ORS alone (control group) were evaluated in a multicentre, open, randomized trial in 54 children aged 6-48 months hospitalized for acute diarrhoea (mostly rotavirus aetiology) and signs of mild and moderate dehydration. The main outcomes examined were duration of diarrhoea, fever, number of vomiting episodes, and serum electrolyte balance before and after treatment.The mean duration of diarrhoea was significantly shorter in the study group (42.3 +/- 24.7 h) than in the control group (61.8 +/- 33.9 h). No side effects of Smecta were observed. The changes of sodium, potassium, chloride and calcium concentrations after treatment were minimal and in the normal range.Smecta significantly reduced the duration of diarrhoea, was safe and well tolerated, and had no impact on the adsorption of electrolytes. Smecta could be used together with ORS in children suffering from acute gastroenteritis (without uncontrollable vomiting) with mild and moderate dehydration.

To compare the efficacy of dioctahedral smectite and iodine glycerin (DSIG) cream with topical mouth rinse (composed of saline, gentamicin and Vitamin B12) in treatment of chemotherapy induced oral mucositis (OM).A total of 130 intensive chemotherapy or stem cells transplantation induced OM patients were recruited. Among these patients, 67 patients received topical mouth rinse and 63 patients received DSIG cream treatment. The OM would be treated on the OM appearance and sustained for 5 days. OM severity was measured daily using The American Oncology Nursing Society recommended Oral Assessment Guideline (OAG) score system.Compared with topical mouth rinse treatment, a significant lower OAG score was observed in DSIG cream treated patients. Specifically, the OAG scores were respectively 12.1 ± 1.1, 12.0 ± 1.2, 11.3 ± 1.3 and 10.4 ± 1.3 from day 2 to day 5 in topical mouth rinse treatment subgroup. Correspondingly, the OAG scores were respectively 10.2 ± 1.0, 9.3 ± 0.9, 8.5 ± 0.6 and 8.0 ± 0.2 for DSIG cream treatment subset (all P0.05). Importantly, compared with topical mouth rinse treatment, the DSIG cream significantly shortened OM repair time (4.68 ± 0.98 vs. 8.76 ± 1.80 days, P0.001). After 5 days treatment, 54 patients (85.7%) obtained complete regression with an OAG score ≤8, and 7 patients (11.1%) had partial regression with an OAG score of 9-10 in DSIG cream treatment subgroup. However, only 2 patients (3.0%) obtained completed regression and 32 patients (47.8%) had partial regression in topical mouth rinse treatment cohort. Moreover, no serious side-effect was observed in both cohorts.Compared with topical mouth rinse, DSIG cream significantly lowered the OAG score and shortened OM duration.

A series of acid catalysts was prepared by heating of NH4-saturated montmorillonite at 200-600 °C for 24 h. Their catalytic activity was tested in acetylation of 3,4,5-trimethoxybenzaldehyde with acetic anhydride. This reaction is sufficiently sensitive to modification of the catalyst and thus suitable for testing catalytic activity of modified montmorillonites. Most of the prepared catalysts were able to catalyse the test reaction and produce diacetate in higher than 50% yields. The most active catalyst was obtained after heating at 300 °C. It was slightly less effective than commercially available acid-activated K10 catalyst.

Consideration of XRD, TEM, AEM, and analytical data reported in the literature indicates that dioctahedral aluminous smectite and illite form two separate solid solutions that differ chemically from one another primarily by the extent of Al substitution for Si, the amount of interlayer K, and the presence of interlayer H2O. The data indicate that limited dioctahedral-trioctahedral and dioctahedral-vacancy compositional variations occur in both minerals. Excluding interlayer H2O and based on a half unit cell [i.e., O10(OH)2], natural dioctahedral smectite and illite solid solutions fall within the compositional limits represented by A0.3 ${\rm{R}}_{1.9}^{3 + }$ Si4O10(OH)2-AR2+ R3+ Si4O10(OH)2-A0.25 ${\rm{R}}_{0.3}^{2 + }{\rm{R}}_{1.8}^{3 + }$ Al0.25Si3.75O10(OH)2 for smectites and A0.8 ${\rm{R}}_{1.9}^{3 + }$ Al0.5Si3.5O10(OH)2-A0.55 ${\rm{R}}_{0.45}^{2 + }{\rm{R}}_{1.55}^{3 + }$ Al0.1Si3.9O10(OH)2-A0.9 ${\rm{R}}_{0.3}^{2 + }{\rm{R}}_{1.8}^{3 + }$ Al0.9Si3.1O10(OH)2 for illites, where A represents either monovalent cations or divalent cations expressed as their monovalent equivalent (e.g., Ca2+/2); R2+ stands for the divalent cations Mg2+ and Fe2+ and R3+ refers to the trivalent cations Al3+ and Fe3+. Taking account of these compositional limits, smectite and illite solid solutions can be described in terms of nine and six thermodynamic components, respectively, all of which are consistent with both the law of definite proportions and the concept of a unit cell. Thermodynamic components that can be used to describe natural smectite solid solutions in terms of a half unit cell [i.e., O10(OH)2] can be expressed as NaAl3Si3O10(OH)2, NaAl3Si3O10(OH)2 ·4.5H2O, Al2Si4O10(OH)2, Fe2Si4O10(OH)2, Mg3Si4O10(OH)2, Fe3Si4O10(OH)2, K3AlSi4O10(OH)2, KAl3Si3O10(OH)2, and Ca0.5Al3Si3O10(OH)2. Of these, NaAl3Si3O10(OH)2 ·4.5H2O provides explicitly for the presence of interlayer H2O in the mineral. Thermodynamic components representing illite solid solutions in natural systems can be written for a half unit cell as KAl3Si3O10(OH)2, KMg3AlSi3O10(OH)2, KFe3AlSi3O10(OH)2, Al2Si4O10(OH)2, KFe2AlSi3O10(OH)2, and K3AlSi4O10(OH)2. The calculations and observations summarized below indicate that neither smectite nor illite occur in nature as stoichiometric phases and that the two minerals do not form a mutual solid solution corresponding to mixed-layered illite/smectite.

Structural rearrangements for dioctahedral smectite after thermal treatment were investigated. The notable structural changes accompanying removal of interlayer water are contraction of basal spacing, migration of interlayer cation into silicate layer and expansion of b-parameter. The important factor affecting the migration of interlayer cation is considered to be turbostatic stacking of adjacent silicate layers. The dehydroxylated structures of octahedral sheet are similar to those of other dioctahedral clay minerals having 2:1 layer structure, that is, removal of 2OH- as H2O and relocation of residual O2- to the same level as that of the octahedral cations.

Titel und Inhaltsverzeichnis 1 Einleitung 2 Material und Methoden 3 Ergebnisse 4 Diskussion 5 Zusammenfassung 6 Literaturverzeichnis, Hintergrund: Das Epithel des Gastrointestinaltraktes ist eine wichtige Barriere zwischen Organismus und der Außenwelt. Erkrankungen des Gastrointestinaltraktes gehen mit einer Störung der gastrointestinalen Barrierefunktion und Permeabilität einher. Bakterielle Endotoxine stehen möglicherweise in Zusammenhang mit der Pathogenese dieser Erkrankungen. Methoden: Es wurde ein Modell zur experimentellen Schädigung der Colonmucosa entwickelt sowie weiterhin die Wirkung von Lipopolysacchariden und der Effekt von Diosmectit und transforming growth factor (TGF-ß1) auf die intakte und experimentell geschädigte menschliche Dickdarmschleimhaut im Ussing-Experiment untersucht. Ergebnisse: Salzsäure (HCl) wurde in aufsteigenden Konzentrationen von 20 - 45 mmol/l dem untersuchten Gewebe auf der mucosalen Seite zugesetzt. In Konzentrationen von 20 und 25 mmol/l zeigte sich kein Effekt auf die untersuchte Schleimhaut, in Konzentrationen von 30 und 35 mmol/l zeigte sich initial ein deutlicher Abfall des Gewebewiderstands. Im weiteren Zeitverlauf stieg der transepitheliale Widerstand auf Werte von 99% (30 mmol/l HCl) bzw. 75% (35 mmol/l HCl) des Ausgangswertes an. In Konzentrationen von 40 und 45 mmol/l zeigte sich ein irreversibler Abfall des Gewebewiderstandes. LPS bewirkte an der intakten Schleimhaut bei serosaler und beidseitiger Zugabe innerhalb von ca. 90 Minuten einen deutlichen Anstieg des Kurzschlussstromes. Bei mucosaler Gabe konnte kein Effekt auf den Isc beobachtet werden. Nach vorheriger Exposition mit HCl 35 mmol/l mucosal bewirkte LPS einen signifikanten Anstieg des Kurzschlussstromes. TGF-ß1 und Diosmectit konnten in unseren Versuchen einen Effekt auf die intakte und experimentell geschädigte Darmschleimhaut weder nachweisen noch widerlegen. Schlussfolgerungen: Die mucosale Exposition mit HCl in einer Konzentration von 35 mmol/l stellt ein geeignetes Modell zur experimentellen Schädigung der Mucosa dar. Die von LPS vermittelte gesteigerte Sekretion des Epithels könnte eine Erklärung für die bei Chronisch-entzündlichen Darmerkrankungen häufig begleitenden Diarrhöen sein., Background: Inflammatory bowel diseases can be associated with high endotoxin levels due to epithelial barrier disfunction. Therefore the effects of Lipopolysaccharide (LPS) on epithelial transport and barrier function of intact and experimentally injured human istal colon were studied with Ussing technique. Methods: Intact human mucosa was experimentally injured by mucosal exposition to Hydrochloric acid in concentrations from 20 to 45 mmol/l. The effects of LPS, TGF-ß and diosmectite on intact and injured epithelia were studied in the Ussing chamber model. Results: Mucosal addition of HCl in concentrations of 20 and 25 mmol/l had no effect on epithelia. HCl (30 and 35 mmol/l) resulted in a decrease of transepithelial resistance which was within 180 min nearly complete reversible. 40 and 45 mmol/l resulted in an irreversible damage of epithelia. Studying intact epithelia LPS 10µg/ml given serosal and simultaneous mucosal and serosal resulted in a significant increase of short-circuit current (Isc) within 90 min. Mucosal addition of LPS had no effect on Isc. Examining experimentally injured epithelia by HCl in a mucosal concentration of 35 mmol/l LPS (mucosal addition) resulted in a sigificant increase of Isc. In this study we could not describe an effect of TGF-ß and diosmectite on intact or experimentally injured epithelia. Conclusions: Mucosal addition of HCl in a concentration of 35 mmol/l was taken as a valid model for experimental epithelial injury. LPS stimulated Ion secretion in our experimental studies with intact and injured epithelia. Therefore LPS could contribute to diarrhea in inflammatory bowel diseases.

The present study was designed to investigate the clinical efficacy and safety of dioctahedral smectite in Chinese patients with chronic functional diarrhoea and to compare this activity to a probiotic preparation. Patients diagnosed with chronic functional diarrhoea (Rome II criteria), exclusion of blood, ova/parasites in the stool and a normal colonoscopy were included. After a 1-week period of baseline without any medication, they were prescribed three sachets of dioctahedral smectite 3 g, administered 1 h after the meals (Group A), or two capsules of Bifico 210mg (Group B) for 28 consecutive days. Efficacy of the treatments was assessed on frequency of bowel movements and consistency of stool, as compared to baseline. Four hundred and ten patients were included (258 males, 152 females; mean age 43.8+/-13.9 years): 208 in Group A and 202 in Group B. In Group A, the mean number of stool per day decreased from 3.5+/-1.0 at baseline to 2.0+/-0.9 and from 3.3+/-1.0 to 2.2+/-0.9 in Group B (z = 2.699; P = 0.007). Decrease in stool number was significant with both treatments but more important with smectite at week 2 and remained significant throughout the treatment period. Stool consistency, assessed by the Bristol scale, also improved significantly over the treatment period, as compared to baseline (z = 3.310, P = 0.001). Dioctahedral smectite appeared in this study to be an effective and safe treatment of chronic functional diarrhoea, its effect starting during the first week of treatment and consisting in a decrease in the frequency of daily bowel movements and improvement of stool consistency. Moreover, dioctahedral smectite displays a prolonged action after disruption of the treatment that may interfere with the natural course of the disease.

The formation of an interstratified structure in dioctahedral smectite was assumed to be influ- enced by (1) the overall layer charge density and its distribution in the structure, (2) the solvation energy of the cation, and (3) the nature of the solvation agent. By holding factors (2) and (3) constant it was possible to calculate the average local charge densities QA, QC, and QE which are necessary for formation of 10-, 14-, and 16.8-fk mixed-layer phases in potassium-treated and ethylene glycol (EG) saturated smectites. The values ofQA, QC, and QE were 1.99, 1.2, and 0.56 esu/unit cell, respectively. Ammonium-treated smectites saturated with EG gave corresponding mean local charge densities of 2.7, 1.6, and 0.72 esu/unit cell. Cal- culations were made under the limiting condition QA > QC > QE > 0. For K-smectites saturated with EG, Qtot = 1.99pA + 1.2pC + 0.56pE, where Qtot is the total charge (esu/unit cell), and pA, pC, and pE are probability coefficients for 10-, 14-, and 16.8- phases in the in- terstratified structure. The above equation calculated with the aid of least squares and without the limiting condition yields Qtot = 2.05pA + 1.29pC + 0.33pE.

Corrensite or ‘corrensite-like’ minerals occur in dike-intruded shales and siltstones of the Montana Group and Colorado Group (Early Cretaceous) in Western Montana. The < 1 µm size fraction of one specimen of this “corrensite-like” material has been studied in detail. X-ray diffraction data and chemical analysis indicate that this specimen is a regular or nearly regular interstratification of chlorite and dioctahedral smectite. Also described are other samples, which contain corrensite and additional phases. These samples were taken at several localities where basic dikes have intruded these shales and siltstones.

Summary Red soil-like layers intercalated amid basaltic flows from the Miocene-Pleistocene in the Galilee, Israel, were examined. Micromorphological features which can be related to (a) translocation of materials, and (b) biological activity, and are therefore of distinct pedological origin, identify two of the layers as paleosols. Absence of these features and preservation of the fabric of the parent basalt serve to identify the third layer as an edaphoid. A fourth layer consists of an edaphoid superimposed on a paleosol. The edaphoids are composed almost entirely of a dioctahedral smectite. In two of the paleosols dioctahedral smectites predominate. In the third kaolinite and haematite are present also in considerable amounts. The presence of quartz in the paleosols is attributed partly to precipitation from Si-rich solutions percolating the upper basalt layer and partly to aeolian contamination. In all the layers the free iron is predominantly in an anhydrous form. Similarity in the clay mineral composition of the Plio-Pleistocene paleosols with that of contemporaneous basaltic soils is taken to indicate similarity in climatic conditions of formation. Differentiation between paleosols and edaphoids cannot be made by the use of a single criterion but must be based on corroborative evidence derived from micromorphological and mineralogical examinations.

Mixed-layer pyrophyllite/smectite, a member of the Al-smectite reaction series, has been synthesized from Ca- and Na-saturated Wyoming montmorillonite by treating the clay hydrothermally in a run solution containing Al 3+ . Temperatures for synthesis ranged between 320°C and 400°C at autoclave pressures, and run times ranged between 3 and 30 days. Reaction towards pyrophyllite was favored by increasing run time, temperature and concentration of Al 3+ . Calculated diffraction profiles for random and ordered pyrophyllite/smectite are presented.

International audience; This paper aims at characterizing the structural evolution of a dioctahedral smectite (i.e. Wyoming montmorillonite) saturated by Na+, Cu2+or Pb2+. Hydration properties of the