Interlayer Space Of MMT Research Articles

Montmorillonite Membranes with Tunable Ion Transport by Controlling Interlayer Spacing.

Membranes incorporating two-dimensional (2D) materials have shown great potential for water purification and energy storage and conversion applications. Their ordered interlayer galleries can be modified for their tunable chemical and structural properties. Montmorillonite (MMT) is an earth-abundant phyllosilicate mineral that can be exfoliated into 2D flakes and reassembled into membranes. However, the poor water stability and random interlayer spacing of MMT caused by weak interlamellar interactions pose challenges for practical membrane applications. Herein, we demonstrate a facile approach to fabricating 2D MMT membranes with alkanediamines as cross-linkers. The incorporation of diamine molecules of different lengths enables controllable interlayer spacing and strengthens interlamellar connections, leading to tunable ion transport properties and boosted membrane stability in aqueous environments.

Enhanced the permeability of water invasion sandstone by effectively inhibiting the swelling and dispersion of montmorillonite

The long-term effect of protecting water-sensitive reservoirs and enhancing permeability of water invasion reservoir is still an urgent practical problem to be solved. Here, an imidazolium Gemini ionic liquid (IL), PEG-DC8Im, with octyl as tail chain and polyoxyethylene chain as bridging group, was synthesized to inhibit the hydration, swelling and dispersion of clay minerals. The PEG-DC8Im could exert excellent anti-swelling ability (93.82 %) and outstanding washable capacity (cumulative decrease of anti-swelling rate after being washed five times: 1.32 %) at the concentration of 60 mmol/L. The inhibition effect of 20 mmol/L PEG-DC8Im was significantly better than that of 250 mmol/L KCl at 90 °C. And the PEG-DC8Im could intercalate into the interlayer space of MMT through cation exchange to play an inhibition effect, where zeta potential of MMT particles was reduced and then the dispersion ability of MMT was weakened. Subsequently, the anionic polymer poly(AM/AA) was found to cooperate with PEG-DC8Im to improve the inhibition effect for MMT swelling and dispersion, in which poly(AM/AA) was not intercalated into the interlayer of MMT, and only adsorbed on the surface of the particles to encapsulate the MMT particles. Simultaneously, the apparent viscosity and thixotropy of the composite solution were enhanced. Besides, after the treatment of PEG-DC8Im, the displacement pressure decreased and the permeability of sandstone cores increased due to the inhibition of clay mineral hydration, revealing the enhancement of injectivity. Finally, the pore connectivity of the core increased and the water wettability was weakened. The treatment of PEG-DC8Im was conducive to the discharge of invasive water in reservoir and the improvement of the reservoir permeability. Overall, PEG-DC8Im has a good application prospect as permeability-enhancing clay stabilizers.

Synergistic effect of hybrid montmorillonite materials on the wear resistance of natural rubber/butadiene rubber composites

AbstractThe wear resistance of rubber composite materials has always been the focus of research. The wear resistance will not only affect the service life of products and the safety of equipment, but also have an important impact on the environment. In this work, the preparation and properties of wear‐resistant rubber nanocomposites based on natural rubber (NR) were studied. It is dedicated to improving the wear resistance of NR composites. On this basis, the dispersibility of montmorillonite (MMT) hybrid materials in NR‐based rubber composites was explored. SiO2@MMT, SiO2@MMT@KH560, PDA@GO, and MMT@GO hybrid materials were prepared, and the hybrid materials were applied to the NR/butadiene rubber (NR/BR) system, and NR/BR/hybrid material composite materials were successfully prepared. The results show that the interlayer spacing of MMT in hybrid materials increases, which effectively improves the dispersibility of MMT in rubber matrix. The tensile strength of NR/BR/MMT@GO composite material increased by 12%, the elongation at break increased by 25%, the DIN abrasion decreased by 16.5% compared with the optimum wear rubber formula, and the wear resistance was greatly improved. This work provides a feasible way for the design of functional polymer composites.

Effects of polycarboxylate superplasticizer equipped with β-cyclodextrin as the terminal group on the fluidity of montmorillonite-containing cement paste

In this study, β-Cyclodextrin (β-CD) as the terminal group was grafted on polyoxyethylene (PEO) via click reaction for preparing monovinyl β-Cyclodextrin monomer (β-P). Then β-P was employed to synthesize a polycarboxylate superplasticizer with β-CD grafted on the side chain [PAA-g-(β-P) n HPEG]. The functional groups, molecular weights, and molecular weight distributions of synthesized copolymers PAA-g-(β-P) n HPEG were characterized by Fourier transform infrared spectra (FT-IR), 1H nuclear magnetic resonance spectroscopy (1H NMR), and gel permeation chromatography (GPC). The dispersion performance of PAA-g-(β-P) n HPEG in cement paste containing montmorillonite (MMT) clay was tested. Sorption measurement and X-ray diffraction (XRD) analysis revealed that the PAA-g-(β-P) n HPEG intercalated less into the interlayer space of MMT than PAA-g-HPEG only with PEO as the side chain. β-CD as the terminal group grafted on the end of the side chain of PCE effectively hindered PCE sorption on MMT and enhanced the clay-tolerance property of PAA-g-(β-P) n HPEG. This study offered a new idea in designing polycarboxylate superplasticizers to lower their clay sensitivity.

Polyurethaneacrylate/montmorillonite nanocomposites

In order to create polymer nanocomposites with high performance on the basis of polyurethaneacrylates (PUA) with montmorillonite (MMT), three methods of chemical modification of the layered silicate surface have been developed. The first modification method is based on using of two different functional modifiers (organophilic and reactive), the second method is based on modification with synthesized by us compound which contains urethane groups, and the third one in based on using synthesized by us modifier containing urethane and other reactive groups. Exchange capacity of the MMT surface was determined by adsorption of indicator “methylene blue”. Intercalation of modifier into the interlayer space of MMT was confirmed by X-ray analysis; the content of organic component in the modified MMT (MMT/M) was determined by thermogravimetric analysis. The resulting organoclay is purposed for the formation of nanostructured composites based on cross-linked polyurethane acrylates with improved physical and mechanical properties. The obtained polyurethaneacrylate nanocomposites with different type MMT/M exhibit the increased in 1,6–2,6 times tensile strength as compared to original polymer matrix. WAXS method has proved an intercalation of modifier into MMT interlayer space (increased distance between layers after modification), as well as the total exfoliation of MMT in PUA matrix, characterized by the disappearance of the absorption peak which is responsible for layered structure.

Flame‐retardant behavior and mechanism of theSBR/MMTcomposites modified by melamine matrix modifier

AbstractMelamine quaternary ammonium salt (MQAS), a novel flame‐retardant intercalation modifier, was used to prepare the flame‐retardant organic montmorillonite (FOSM), and which was added to SBR by a two‐roll mixing and molding process to prepared the SBR/FOSM composites. The synergistic flame‐retardant effects of sodium‐based montmorillonite (MMT) and MQAS were investigated by the various methods. The LOI value of SBR was only 19.1%, and FOSM‐4 increased the LOI value of SBR to 24.3%. The cone calorimetry test showed that compared with SBR, the total heat release and the peak heat release rate of SBR/FOSM were reduced by 81.39% and 86.08%, respectively. The analysis of MMT after modification showed that the grafting rate of MQAS was about 10% and the interlayer spacing of MMT was enlarged by about 20%. The synergy of MQAS and MMT not only effectively solves the violent droplet of pure SBR combustion, but also avoids the curling problem of only adding MMT. The char morphology and TG‐FTIR showed that FOSM had dual flame‐retardancy in the condensed phase and the gas phase. The synergistic flame‐retardant effect of phosphorus‐free flame‐retardant modifier and MMT will open up new possibilities for flame‐retardant elastomer composites.

Organically modified montmorillonite improves interfacial compatibility between PLLA and PGA in bone scaffold

Slowly degradable poly(l-lactide) (PLLA) and fast degradable polyglycolic acid (PGA) are expected to bring an intermediate degradation rate through their blending towards bone regeneration. However, PLLA is thermodynamically immiscible with PGA, resulting in poor interfacial bonding and phase separation. In this study, montmorillonite (MMT) was modified by octedacy trimethyl ammonium chloride (denoted as OMMT) and then introduced into PLLA/PGA scaffold to improve the compatibility between PLLA and PGA. On one hand, MMT possesses layered spacing structure, thus accommodating the intercalated polymer chains. On the other hand, the modification can enlarge the interlayer spacing of MMT, which is beneficial for the intercalation of PLLA and PGA molecules chains. Noticeably, the intercalated PLLA and PGA molecules chains move restrictedly in MMT interlayer, which is attributed to that the NH2 group in OMMT not only formed hydrogen bonding with OH group of PLLA but also formed hydrogen bonding with OH group of PGA. Consequently, PLLA and PGA are forced to be compatible through the action of OMMT. The results demonstrated that the scaffold had two distinct melting peaks corresponding to PLLA and PGA, respectively. Meanwhile, there was no obvious sheet-like inclusion structure in the fractured surface of the scaffold, indicating that the interfacial compatibility between PLLA and PGA was significantly improved. Correspondingly, the tensile strength and tensile modulus of the scaffold were increased by 110% and 70%, respectively. In addition, the scaffold exhibited good cytocompatibility for human osteoblast-like MG-63 cells adhesion and proliferation.

Mechanism of carboxymethyl chitosan hybrid montmorillonite and adsorption of Pb(II) and Congo red by CMC-MMT organic-inorganic hybrid composite

The carboxymethyl-chitosan-montmorillonite (CMC-MMT) organic-inorganic hybrid material was applied to adsorb Pb(II) and Congo red (CR) anionic dye from aqueous solution. Molecular dynamics(MD) simulation was carried out to reveal the mechanism of CMC hybrid MMT. The results suggested that CMC has been adsorbed on the interlayer space and surface of MMT, hydrogen bonds had been formed between hydroxyl & carboxyl groups of CMC with the surface of MMT, Van der Waals interaction was also existed, while amino groups of CMC hadn't obvious interaction with the surface of MMT. Batch experiments were executed to investigate the adsorption effect of CMC-MMT was compared with Na-MMT and CMC. The results showed that CMC-MMT exhibited the higher adsorption capacity than Na-MMT and CMC, The OH and COOH or NH2 groups of CMC chains may serve as electrostatic interaction active sites and coordination sites, which improved the adsorption performance of CMC-MMT on Pb(II)，and the insertion of CMC enlarged the inter-layer space of MMT, resulting in more surface active sites in the CMC-MMT hybrid composite, which increased the adsorption of organic pollutant CR. The kinetic and isotherm studies indicated that the pseudo-second-order and the Langmuir model well described the adsorption equilibrium of Pb(II) and CR on CMC-MMT.

Click chemistry to synthesize exfoliated xylan-g-quaternized chitosan/montmorillonite nanocomposites for retention and drainage-aid

In order to obtain new retention and drainage-aid agent, exfoliated xylan-g-QCS/MMT nanocomposites were prepared. Briefly, quaternized chitosan azide (QCS-N3) was intercalated into the layer of montmorillonite (MMT) to enlarge the interplanar gallery; subsequently, QCS-N3/MMT was grafted with xylan by click chemistry, during this process, the interlayer space of MMT was further increased till exfoliated. Subsequently, the exfoliated xylan-g-QCS/MMT was evaluated to act as retention and drainage-aid agent. The initial critical concentration of xylan-g-QCS/MMT was 0.01 mg/g in the adsorption behavior on cellulosic substrate. The maximum flocculation efficiency for CaCO3 was 37.41%. When dosages were about 0.01 mg/g, oSR values were the lowest. All these results show that retention and drainage-aid performance of xylan-g-QCS/MMT was better than only xylan, QCS or MMT. The study combined three kinds of natural resources to prepare organic/inorganic nanocomposites, providing a new method to develop papermaking additive and achieve high-value utilization of natural resources.

Investigation of organophilic montmorillonites supported palladium catalytic composites by combined positron annihilation lifetime spectroscopy and X-ray diffraction

A characterization of organophilic montmorillonite (OMMT) supports and organophilic montmorillonite supported palladium (Pd@OMMT) catalytic composites was carried out using positron annihilation lifetime spectroscopy (PALS) and X-ray diffraction (XRD). XRD method supplies the fundamental information on the interlayer spacing of OMMT. And PALS method supplies the complementary information on the free volume voids variations inside the interlayer space of OMMT, which is occupied with organic cations and Pd species. In PALS analyzing, the size of the channel-like free volume voids inside the interlayer space of OMMT are estimated by both cuboidal and cylindrical free volume voids models from o-Ps lifetime. The OMMT and Pd@OMMT composites show bigger interlayer spacing values (by XRD) but smaller free volume void size values (by PALS) than MMT. It should be due to the fact that the interlayer space becomes more crowded after organic modifier intercalation and Pd immobilization inside the interlayer space of MMT. The prepared Pd@OMMT catalytic composites show high activity and good recyclability in typical Heck coupling reactions. The correlations between the microstructure and catalytic performances of the organophilic montmorillonites supported palladium catalytic composites were discussed.

Modification of Montmorillonite with Polyethylene Oxide and Its Use as Support for Pd0 Nanoparticle Catalysts.

In this study, montmorillonite (MMT) was modified by intercalating polyethylene oxide (PEO) macromolecules between the interlayer spaces in an MMT-water suspension system. X-ray diffraction results revealed that the galleries of MMT were expanded significantly after intercalation of different loading of PEO. MMT/PEO 80/20 composite was chosen as the support platform for immobilization of Pd species in preparing novel heterogeneous catalysts. After immobilization of Pd species, the interlayer spacing of MMT/PEO (80/20) (1.52 nm) was further increased to 1.72 nm (Pd2+@MMT/PEO) and 1.73 nm (Pd0@MMT/PEO), confirming the well-immobilization of the Pd species in the interlayer spaces of PEO-modified MMT. High-resolution transmission electron microscopy (HR-TEM) observation results confirmed that Pd nanoparticles were confined inside the interlayer space of MMT and/or dispersed well on the outer surface of MMT. The conversion of Pd2+ to Pd0 species was evidenced by binding energy characterization with X-ray photo electron spectroscopy (XPS). The microstructure variation caused by the Pd immobilization was sensitively detected by positron annihilation lifetime spectroscopy (PALS) studies. The prepared Pd0@MMT/PEO (0.2/80/20) catalytic composite exhibits good thermal stability up to around 200 °C, and it showed high activities for Heck reactions between aryl iodides and butyl acrylates and could be recycled for five times. The correlations between the microstructure and properties of the Pd@MMT/PEO catalytic composites were discussed.

Montmorillonite with unique interlayer space imparted polymer scaffolds with sustained release of Ag+

Abstract Polyglycolic acid (PGA) has been a potential scaffold material due to its good biocompatibility and processibility, but its poor mechanical properties and over fast degradation restricted its application in bone repair. Meanwhile, it is worth noticing that bacterial infection is a common problem in bone repair. In this study, montmorillonite (MMT), with unique interlayer space, was introduced to PGA scaffolds prepared via additive manufacturing to address the problems. The results indicated MMT acted as rigid reinforcements dispersing well in the PGA matrix, which effectively transferred and absorbed the stresses in the matrix, thereby significantly increasing the compressive properties and hardness of the scaffolds. Moreover, MMT played the role of impermeable barriers in the matrix, hindering the diffusion of water and its attack on the matrix, which inhibited the hydrolysis and hence significantly decreased the degradable rate. More importantly, Ag+ was loaded into the interlayer space of MMT via ion exchange and was further chemically reduced to metallic Ag with higher stability. The impermeable layered structure of MMT presented dual barrier effects on the release of Ag+ via inhibiting the attack of water on Ag from outside and the diffusion of Ag+ from inside. Hence, the scaffolds exhibited a sustained Ag+ release and a long-lasting antibacterial property.

Synthesis, Characterization and in vitro Drug Release Studies of Sonolytically Intercalated Poly(o-anisidine)/Montmorillonite Nanocomposites

In the present study, in situ intercalation and polymerization of o-anisidine within montmorillonite (MMT) clay was carried out via ultrasonication using different loadings of o-anisidine (12.5 wt%, 25 wt%, and 50 wt%). Infrared (IR) spectra indicated successful incorporation of poly(o-anisidine) (PAnis) in MMT. Ultraviolet (UV)-visible spectra confirmed the polaronic state of nanocomposites, while X-ray diffraction (XRD) analysis revealed intercalation of PAnis in the interlayer space of MMT. Transmission electron microscope (TEM) and optical micrographs showed nanomorphology of prepared nanocomposites. The nanocomposites were modified by loading with anti-migraine drug in different concentrations to investigate the adsorption profiles in gastric fluid (pH 1.2) and intestinal fluid (pH 7.4). The adsorption profiles followed the Langmuir isotherm. Release kinetics followed zero order model and parabolic diffusion model in gastric fluid (pH 1.2) and intestinal fluid (pH 7.4). The nanocomposites were found to show fast release behavior and hold potential to be used as an effective antidepressant drug delivery vehicle.

Modified Rapeseed Oil/Al-Montmorillonite Composite Material: Preparation and Application in Leather Collagen

In this study, montmorillonite (MMT) was modified by aluminium sulfate via ions exchange method and aluminium-montmorillonite (Al-MMT) was obtained. Al-MMT was characterized by X-ray diffraction (XRD) and thermo gravimetric analysis (TGA). The results indicated that the interlayer spacing of MMT increased from 1.26 nm to 1.55 nm after being modified by Al3+. Then Al-MMT was introduced to modified rapeseed oil by an in-situ method. The results of TGA and XRD indicated that modified rapeseed oil (MRO) could smoothly enter the interlayer of Al-MMT and modified rapeseed oil/Al-montmorillonite (MRO/Al-MMT) composite material was prepared successfully. Finally, MRO/Al-MMT composite material was applied in the leather fatliquoring process of goatskin garment. Physical and mechanical properties and flame retardant performance of leather fatliquored by MRO/Al-MMT composite material were improved compared with those of leather fatliquored by MRO. And MRO/Al-MMT composite material was easily biodegradable compared with MRO.

Positron annihilation characteristics and catalytic performances of poly (vinyl alcohol) intercalated montmorillonite supported Pd0 nanoparticles composites

The microstructure of poly (vinyl alcohol)/ montmorillonite (PVA/MMT) matrices and Pd@PVA/MMT catalytic composite was characterized by positron annihilation spectroscopy (PAS) and other techniques, such as high resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), and X-ray photo electron spectroscopy (XPS). XRD and HR-TEM results showed that 20% was the saturation loading percentage of PVA intercalation into MMT. Ortho-positronium (o-Ps) annihilations were mainly distributed in the interlayer spacing of MMT and/or open spaces (free volume) of PVA. Below the saturation loading percentage of PVA (≤ 20%), it was found that the o-Ps annihilation lifetime became shorter after the intercalation of PVA chains into MMT layers. With further addition of PVA, the o-Ps annihilation lifetime became longer after the formation of exfoliated structure. The 20%-PVA/MMT matrix has been selected as the platform to further immobilize Pd specie for preparing novel 0.2%-Pd@20%-PVA/MMT catalytic composite. The effects of Pd immobilization on the microstructure of PVA/MMT matrices were also sensitively detected by PAS. The mean size of the micro-defects (from Tao-Eldrup model) increased from 0.28 nm (20%-PVA/MMT) to 0.29 nm (0.2%-Pd2+@20%-PVA/MMT or 0.2%-Pd0@20%-PVA/MMT), respectively. This increase in the size of the micro-defects of 20%-PVA/MMT matrix after Pd immobilization was mainly due to the replacement of the inter-molecular hydrogen bodings of PVA chains by the interactions formed between the PVA chains and Pd species. The prepared 0.2%-Pd0@20%-PVA/MMT catalytic composite showed excellent catalytic efficiency and recyclability in both Heck-type and Sonogashira-type coupling reactions. The correlations between the microstructure and performance of the 0.2%-Pd0@20%-PVA/MMT composite were thoroughly discussed.

Hybrid iron montmorillonite nano-particles as an oxygen scavenger

Iron nanoparticles supported on montmorillonite (MMT-Fe) were synthesized via the reduction by sodium borohydride of iron salts dissolved in a suspension of MMT. The MMT-Fe black powder collected after the evaporation of the solvent was analysed by Transmission Electron Microscopy, which revealed the formation of aggregates of metallic nanoparticles with an average size of 57 ± 17 nm dispersed on the surface of MMT. According to the X-ray diffraction, no iron ions are intercalated in the interlayer spacing of MMT, and no other crystalline species are formed. 57Fe Mössbauer spectroscopy evidences the formation of mainly zero valent iron in the form of iron boride. The O2 absorption kinetic of the synthesized powders was found to follow a second-order law. The study of the O2 absorption properties of as-synthesized, dried and stored (40 days) powders shows reaction constant (k), coefficient of proportionality (n) and O2 absorption capacities of the same order of magnitude. The O2 absorption capacity of the as-synthesized, dried and stored powders were found equal to 0.20 ± 0.01, 0.14 ± 0.03 and 0.09 ± 0.00 g O2 per g of iron, respectively. The initial absorption rate was found within the range [0.5–1.5]% O2 min−1 g−1.

Trimethylphenylammonium-modified montmorillonite: efficient hybrid adsorbent for removal of U(VI) from carbonate- and sulfate-containing solutions

Montmorillonite (MMT) clay was modified using the hydrothermal method through the intercalation and adsorption of the trimethylphenylammonium bromide (TMPA) and applied for the removal of U(VI) from the carbonate- and sulfate-containing solutions using batch experiments. The hydrothermal technique provides a simple, fast, and efficient route for the successful preparation of TMPA-MMT. The prepared adsorbent was characterized by FTIR, XRD, SEM, and TGA techniques. The increasing interlayer space of MMT from 1.20 to 2.02 nm occurs as a result of TMPA intercalation. The modification of MMT by a TMPA surfactant enhanced adsorption capacity of U(VI) species from sulfate- and carbonate-containing solutions over a wide range of pH. The highest capacity for adsorption of U(VI)-carbonate and U(VI)-sulfate complexes was around 38 and 26 mg/g, respectively. The outer-sphere surface complexation is probably dominant mechanism in adsorption of anionic uranyl carbonate and sulfate species. These findings proposed that TMPA-MMT can be applied as an efficient and potential adsorbent for the removal of uranyl anionic species from carbonate- and sulfate-containing aqueous solutions.

Insights into asphaltene aggregation in the Na-montmorillonite interlayer

This study aimed to provide insights into the diffusion and aggregation of asphaltenes in the Na-montmorillonite (MMT) interlayer with different water saturation, salinity, interlayer space and humic substances. The molecular configuration, density profile, diffusion coefficient and aggregation intensity were determined by molecular dynamic simulation, while the 3D topography and particle size of the aggregates were characterized by atomic force microscopy. Results indicated that the diffusivity of asphaltenes was up to 5-fold higher in the MMT interlayer filled with fresh water than with saline water (salinity: 35‰). However, salinity had little impact on the asphaltene aggregation. This study also showed a marked decrease in the mobility of asphaltenes with decrease in the pore water content and the interlayer space of MMT. This was more pronounced in the organo-MMT where the humic substances were present. The co-aggregation process resulted in the sequestration of asphaltenes in the hollow cone-shaped cavity of humic substances in the MMT interlayer, which decreased the asphaltene diffusion by up to one-order of magnitude and increased the asphaltene aggregation by about 33%. These findings have important ramifications for evaluating the fate and transport of heavy fractions of the residual oil in the contaminated soils.

Electrospun montmorillonite modified poly(vinylidene fluoride) nanocomposite separators for lithium-ion batteries

Composite separators of poly(vinylidene fluoride) (PVDF) with different contents of montmorillonite (MMT) for Li-ion batteries have been fabricated by electrospinning. The morphology, function group, crystallinity, and mechanical properties of membranes were investigated by scanning electron microscope (SEM), Fourier Transform infrared spectra (FT-IR), differential scanning calorimetry (DSC), and tensile test, respectively. Interlayer spacing of MMT in polymer was characterized by X-ray diffraction (XRD). In addition, the results of electrochemical measurements suggest that PVDF/MMT-5% composite membrane has maximum ionic conductivity of 4.2mScm−1, minimum interfacial resistance of 97Ω, and excellent electrochemical stability. The cell comprising PVDF/MMT-5% composite membrane shows higher capacity and more stable cycle performance than the one using commercial Celgard PP membrane.

Effect of mechanochemical treatment on structure and electrical properties of montmorillonite

This study investigates the effect of grinding on the structure of montmorillonite (MMT). Both XRD and IR analyses indicate a gradual breakdown of the mineral layers and a decrease of the crystallinity with grinding. The prolonged grinding is accompanied with an amelioration of oxidant capacity of MMT which could be attributed to the conversion of structural Fe2+ to Fe3+ cations caused by adsorbed atmospheric oxygen and/or to the exposition of more Fe3+ cation to the surface of the mineral. The evolution of acidity of MMT during grinding has been carried out by determining the point of zero charge (pHpzc) of MMT and the pH of the aqueous suspension of MMT. It was shown that pHpzc increases with grinding from 6.2 to 8.1 respectively for untreated MMT and that ground for 30 min. On the other side the pH of MMT suspension increases from 4.75 to 8.18 respectively for untreated MMT and that ground for 75 min. These two results indicate that acidity of MMT has been lost during grinding. TGA analysis shows that the thermal decomposition of the ground MMT for 90 min takes place in a single step. This behavior has been explained by the formation of less tightly bound hydroxyl groups. Electrical and dielectric properties have been studied using impedance spectroscopy. It has been established that grinding is accompanied by an increase of dc conductivity and dielectric constant in the range of MHz. Moreover, it has been observed a shift of bound water relaxation frequency to lower frequency. These changes could be attributed to the enhancement of mobility of interlayer cations and to the perturbation of the state of interlayer water which could be connected to the defects in the octahedral sheet rather than being entirely localized at the interlayer space of MMT.