Interlayer Of MMT Research Articles

Organic matter and clay interaction in a meromictic lake: Implications for source rock OM preservation (Lac Pavin, Puy-de-Dôme, France)

Investigation of organic matter (OM) preservation mechanisms is crucial for understanding organic accumulation in sedimentary environments. We focus here on the contribution of organo-clay interaction in such preservation. Most studies addressing this issue deal with organo-mineral complexes which have settled, omitting consideration of early aggregation within the water column. We therefore investigated the sorption of OM on montmorillonite (Na MMt) and kaolinite (Kaol) immersed in a permanently stratified water column (Lake Pavin, France). The two types of clay samples were kept immersed for different lengths of time and characterized via analytical methods suited for the organic phase [pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS), GC-MS, Fourier transform infrared spectroscopy (FT-IR) and dissolved organic carbon (DOC) analysis], as well as for the mineral phase [X ray diffraction (XRD) and microprobe elementary cartography]. Results suggest that strong organo-clay interaction occurred within the water column to a varying extent depending on water physicochemical conditions and the mineral phase typology. A higher concentration of DOC was observed in the proximal environment of the clay traps, suggesting an attractive effect induced by the clay minerals. Lipid compounds sorbed during the immersion were essentially fatty acids and aromatic compounds. Their distributions were closer to a phytoplankton signature than allochtonous pedogenetic OM.The sorption was particularly efficient in the O2 transition zone, with a greater amount of OM on Na-MMt than Kaol. This was principally due to the high specific surface area and cationic exchange capacity (CEC) of the 2/1 clay mineral. Besides, XRD characterization revealed an increase in Na MMt interlayer spacing, which did not necessarily correspond to organic intercalation.The study confirms that the sorption of dissolved OM cannot alone explain the preservation of hydrocarbon-rich OM in such a lacustrine environment. Indeed, the sorbed OC was very low compared with the amount proposed by several authors as an expression of the monolayer equivalent principle.

Investigation of Intercalation of Sodium-Montmorillonite with Octadecyl Trimethyl Ammonium Bromide Surfactant

Sodium-montmorillonite (Na+-MMT) was intercalation modified with octadecyl trimethyl ammonium bromide (OTAB) in aqueous suspension via an ion exchange mechanism. Fourier transform infrared spectroscopy (FTIR) study indicates that OTAB is successfully intercalated into Na+-MMT layers and/or adsorbed on the surface of Na+-MMT. X-ray diffraction (XRD) analysis revealed that the interlayer spacing of the Na+-MMT was extended with the content of OTAB increasing, and the maximum spacing can reach about 3.80 nm. Results of scanning electron microscopy (SEM) analysis reveals the morphologies change from spherical-like particles to high-aspect ratio flakes after modification. Different configurations of OTA+ chains within MMT interlayer are proposed based on the above analysis. The results of contact angle and the dispersion analysis show that the surface wettability of Na+-MMT is converted from hydrophilic to organophilic.

Comparison Study on the Effect of Interlayer Hydration and Solvation on Montmorillonite Delamination

The effect of water and isopropanol intercalation on montmorillonite (MMT) delamination was investigated in order to compare the roles of hydration and solvation in the delamination. Transmittance results showed that water has a significant effect on the delamination of MMT compared with isopropanol. This observation was attributed to the difference of the intercalation of water and isopropanol. Thermogravimetric (TG) results illustrate that the intercalation mass of water was greater than that of isopropanol when the pressure remained constant. Weighing test results show that the intercalation mass of water was smaller than that of isopropanol when the volume of MMT remained constant. Molecule dynamic simulation results show that the water and isopropanol molecules were interacting with Na+ and siloxane surface of MMT, respectively. It was demonstrated that the hydration of the MMT interlayer followed two steps: in step 1, the Na+ in the interlayer was hydrated, thereby expanding the interlayer spacing; in step 2, additional water molecules were absorbed into the expanded interlayer space. It was found that step 2 could not be actuated until the completion of step 1. For the solvation of the MMT interlayer with isopropanol, however, only one step was required, in which isopropanol was absorbed onto the siloxane sites of the interlayer while maintaining the interlayer spacing.

Development of High‐Strength Soy Protein Adhesives Modified with Sodium Montmorillonite Clay

AbstractThis study investigated the high strength of a soy protein adhesive system with good flowability at high protein concentration. Sodium montmorillonite (Na MMT), the most widely used silicate clay, was incorporated into viscous, cohesive soy protein adhesives at concentrations ranging from 1 to 11 % (dry basis, w/w). Hydroxyethyl cellulose was used as a suspension agent to stabilize the soy protein and nano clay to be the dispersion system. The interaction between soy protein and Na MMT was characterized by XRD, FTIR, Zeta potential and DSC. Results indicated that soy protein molecules were adsorbed on the surface of the interlayer of Na MMT through hydrogen bonding and electrostatic interaction. The soy protein/Na MMT adhesives had the intercalation structure with Na MMT contents ranging from 1 to 11 %. Adhesion strength, specifically wet adhesion strength, of soy protein adhesives at isoelectric point (pI) was significantly improved by the addition of Na MMT. It is believed that the physical cross‐linking reactions between soy protein and Na MMT mainly contribute to the improved adhesion performance of soy protein adhesives. Wet adhesion strength increased from 2.9 MPa of control soy protein adhesive to 4.3 MPa at 8 % Na MMT. An increase of pH beyond pI value resulted in decreased adhesion strength due to increased surface charges of soy protein and slightly reduced affinity of soy protein on the nano clay surface.

Synthesis and Detoxifying Properties of Pectin-Montmorillonite Composite

Pectin-montmorillonite (Pec-MMT) composites have been prepared and characterized by physical–chemical methods. Coating of the surface of MMT with pectin was confirmed by SEM and IR-spectroscopy. Pectin significantly affects the specific surface area and porosity of the composites. XRD study of the prepared composites has showed the shifting on basal spacing in the spectrum of Pec-MMT indicating intercalation of the polymer into the MMT interlayers. The synthesized composites have demonstrated the detoxifying ability to normalize blood cellular composition of rats after cobalt intoxication.

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.

Study on the differences of Na- and Ca-montmorillonites in crystalline swelling regime through molecular dynamics simulation

The swelling of Na- and Ca-montmorillonites (MMTs) has been studied through energy optimization and molecular dynamics simulations with the Universal Force Field (UFF) in this work. It was performed to reveal the interlayer spacing and water density in the interlayer as the function of water molecules increasing from 0 to 96, and the structural and diffusive properties of interlayer species when formed one-, two-, three-layer hydrates in interlayer. The results presented the swelling pattern of the MMTs, and the process of that water molecules formed layers in MMT interlayers. It has been found that Ca-MMT had a stronger hydration swelling than Na-MMT in the crystalline swelling regime, which might be due to that Ca2+ had a larger hydrated radius than Na+. Water molecules in the interlayers of Na-MMT had a larger self-diffusion coefficient than those of Ca-MMT at the same water content. Moreover, Na+ had a higher self-diffusion coefficient than Ca2+. It was demonstrated that the difference at the swelling of the two MMTs was attributed to that Ca2+ had a stronger hydration than Na+ in the MMT interlayers.

Chitosan-collagen/organomontmorillonite scaffold for bone tissue engineering

A novel composite scaffold based on chitosan-collagen/organomontmorillonite (CS-COL/OMMT) was prepared to improve swelling ratio, biodegradation ratio, biomineralization and mechanical properties for use in tissue engineering applications. In order to expend the basal spacing, montmorillonite (MMT) was modified with sodium dodecyl sulfate (SDS) and was characterized by XRD, TGA and FTIR. The results indicated that the anionic surfactants entered into interlayer of MMT and the basal spacing of MMT was expanded to 3.85 nm. The prepared composite scaffolds were characterized by FTIR, XRD and SEM. The swelling ratio, biodegradation ratio and mechanical properties of composite scaffolds were also studied. The results demonstrated that the scaffold decreased swelling ratio, degradation ratio and improved mechanical and biomineralization properties because of OMMT.

An environmental friendly and biodegradable shale inhibitor based on chitosan quaternary ammonium salt

Abstract In this paper, the inhibition of chitosan quaternary ammonium salt (HTCC) in the drilling fluid was studied. The inhibition was evaluated by linear swelling test, mud making test and rolling recovery. The results indicated that the inhibition of HTCC was better than polyether amino, which be used widely in the oil flied as the excellent shale inhibitor. Especially HTCC is an environmental friendly and biodegradable. The inhibition mechanism of HTCC was investigated by Fourier transform infrared spectroscopy, X-ray diffraction, Scanning electron microscopy, Zeta potential, Gel strength measurement analysis. The negative charge in the surface of montmorillonite (MMT) was neutralized by the positive charge. HTCC was absorbed and coated in the surface and intercalated in the interlayer of MMT, which reduced the hydration repulsion of diffuse electric double layer and leaded to the inhibiting hydration of clay. Hydrogen bonding between hydroxyl, amino groups in the HTCC and the surface of clay can be formed in the process. The coordination of electrostatic interaction and hydrogen bonding prevented the water molecules from the gallery of clay, which resulted from the absorption and intercalation of HTCC in the surface and interlayer of MMT. The high molecular weight of HTCC was coated in the surface of MMT, which further expelled the hydration swelling of clay. It kept the high inhibition even if the ether bond hydrolysis partly in high temperature, comparing to polyether amino which the inhibition be reduced.

Montmorillonite/Poly (L-Lactide) microcomposite spheres as reservoirs of antidepressant drugs and their controlled release property

This work evaluates intercalation of Nortriptyline (NT) and Venlafaxine (VFX) in an interlayer gallery of Na+-MMT (Montmorillonite), which was further compounded with Poly (L-Lactide) (PLLA) to form microcomposite spheres (MPs) for oral controlled drug delivery. The XRD patterns, thermal and spectroscopic analyses indicated intercalation of drugs into the MMT interlayer that was stabilized by electrostatic interaction. No significant changes in structural and functional properties of drugs were found in the MMT layers. In vitro drug release studies showed controlled release pattern.

Geometrical and Electronic Properties of Hydrated Sodium Montmorillonite and Tetracycline Montmorillonite from DFT Calculations

The adsorption of fully protonated tetracycline (TC) using Na montmorillonite (Na-MMT) as an adsorbent is studied by DFT calculations. Geometric, electronic, and magnetic properties are analyzed. To the best of our knowledge, this is the first theoretical DFT research about Na-MMT as an adsorbent of TC cationic species. Two Na-MMT models are considered: dry and hydrated Na-MMT. The incorporation of four water molecules in the interlayer space results in the expansion of the d001 parameter from 10.13 Å (dry) to 12.81 Å (hydrated). Finally, when TC molecule is adsorbed in the basal space of MMT, the increment of the d001 parameter is about 10 Å respect to the hydrated model. Dry and hydrated Na-MMT present a nonmagnetic (μ = 0 μB) and semiconductor behavior. Nevertheless, the TC-MMT system becomes conductor, and presents a very important magnetic moment (μ = 10.60 μB). After TC adsorption in MMT a potential valley with a slight depth in the MMT interlayer is generated. For this reason, it is proposed that TC adsorption would provide active sites for the adsorption of new species (like Na ions and water molecules).

Surfactant-modified montmorillonite by benzyloctadecyldimethylammonium chloride for removal of perchlorate

Abstract A high adsorption capacity (0.90 mmol/g) of perchlorate was achieved on organo-montmorillonites (organo-MMTs) through modification by benzyloctadecyldimethylammonium chloride (BODMA-Cl), which typically possesses a long alkyl chain and a benzene ring. With increase in the amount of BODMA-Cl added, the XRD and FTIR results showed that the BODMA+/BODMA-Cl achieved a lateral bilayer, pseudo-trilayer and tilted paraffin-like bilayer configurations in the MMT interlayer space with improvement of ordered arrangement, and the formation of bilayers and/or micelles on the external surface also was demonstrated by TG-DTA and zeta potential curves. The EDX spectra of resultant products and adsorption isotherms of perchlorate on organo-MMTs suggested that a larger content of BODMA-Cl resulted in synthesized adsorbent with a greater adsorption capacity, because neutral BODMA-Cl is predominantly responsible for ion exchange with perchlorate. The maximum adsorption capacity was attained not only by enhanced affinity between BODMA+ and metallic layer of MMT, but also by increasing density of intercalated BODMA-Cl which is caused by hydrophobic interactions through long alkyl chains and π–π interactions through benzene rings among BODMA+/BODMA-Cl. It was also emphasized that the high adsorption capacity of perchlorate on organo-MMTs was achieved with a rapid adsorption rate and stably maintained against variations in temperature, initial solution pH and co-existing competitive anion.

Interlayer configuration of ionic liquids in a Ca-montmorillonite as evidenced by FTIR, TG-DTG, and XRD analyses

Ionic liquids (ILs) have attracted much attention in the scientific community during the past two decades. However, studies of interactions between Earth materials and ILs have been limited. In this study, the uptake and interlayer configuration of ILs on a high charge Ca-montmorillonite (MMT) were systematically studied using TG-DTG, FTIR, and XRD analyses. The intercalation protected the ILs from thermal decomposition, resulted in an increase in their thermal stability in comparison to ILs adsorbed on the surfaces. The results from TG-DTG, FTIR, and XRD all pointed to a change in mechanisms and interlayer configurations as the chain length, input amounts, and initial concentrations of ILs changed. A higher decomposition temperature in TG analyses and a large blue shift of selected FTIR bands agreed well with the cation exchange mechanism at lower IL loading levels. Accompanying cation exchange the interlayer water was completely removed. Hydrophobic interactions and admicelle adsorption were responsible for IL uptake beyond the cation exchange capacity of the MMT. A pseudo-trilayer configuration was suggested based on XRD analyses for the intercalation of ILs with a chain length of 12 carbons at the sorption maximum and that of 16 carbons at medium sorption levels. A paraffin-like conformation with an almost vertical orientation was suggested for the configuration of IL with a chain length of 16 carbons in the interlayer of MMT at the sorption maximum.

Stability and pH-independence of nano-zero-valent iron intercalated montmorillonite and its application on Cr(VI) removal

Composite of nano-zero-valent iron and montmorillonite (NZVI/MMT) was prepared by inserting NZVI into the interlayer of montmorillonite. The unique structure montmorillonite with isolated exchangeable Fe(III) cations residing near the sites of structural negative charges inhibited the agglomeration of ZVI and result in the formation of ZVI particles in the montmorillonite interlayer regions. NZVI/MMT was demonstrated to possess large specific surface area and outstanding reducibility that encourage rapid and stable reaction with Cr (VI). Besides, the intercalation also makes NZVI well dispersed and more stable in the interlayer, thereby improving the reaction capacity by 16 times. The effects of pH value, initial concentration of Cr (VI) and reaction time on Cr (VI) removal have also been investigated in detail. According to PXRD and XPS characterization, NZVI/Cr (VI) redox reaction occurred in the interlayer of MMT. The study of NZVI/MMT is instrumental to the development of remediation technologies for persistent environmental contaminants.

Flammability, thermal and physical-mechanical properties of cationic polymer/montmorillonite composite on cotton fabric

The flammability, thermal and mechanical properties on cotton fabric were improved by being finished with the composite containing montmorillonite. To this aim, polymer dimethyl diallyl ammonium chloride-allyl glycidyl ether (PDMDAAC-AGE) was prepared and its structure characterized by Fourier transform infrared (FT-IR) and Nuclear magnetic resonance (1H NMR). The quaternary ammonium salt copolymer/montmorillonite composite (PDMDAAC-AGE/MMT) was obtained by polymer intercalation method. The X-ray diffraction (XRD) indicated that the MMT interlayer spacing increased after the polymer intercalation. Composite materials were loaded onto the cotton fabrics by a dip-pad-dry method. The thermo gravimetric analysis (TGA), vertical flame test and limiting oxygen index (LOI) results showed that the thermal and flammability properties of the cotton fabric were improved after it was finished with the composite. Tensile testing revealed an increase on mechanical properties of the finished fabric, but the physical properties hardly changed from the bending length and whiteness results. Scanning electron microscope (SEM) and energy disperse X-ray spectroscope (EDX) results verified the improvement of those properties due to the presence of montmorillonite in the composite.

Preparation and Research of α-Fe/Montmorillonite Magnetic Material

α-Fe/montmorillonite (MMT) magnetic material was successfully prepared by the in-situ pillared-reduction method. The composite material was characterized by X-ray diffraction (XRD), laser particle size analyzer and other instruments. The magnetic property was researched by saturation magnetization. The results showed that: when 0.1mol/L hydroxyl-Fe was added as pillared agent, hydroxyl-Fe and cation of the MMT exchanged, leading to the inter-layer spacing expanded to 1.41nm and reached saturated pillared point. MMT interlayer hydroxyl-Fe was completely restored to α-Fe grains of 116nm when reducing agent was 0.2mol/L and produced α-Fe/MMT composite material. The average particle size of the composite was 5.529μm, the specific saturation magnetization was 0.812emu/g (9×103A/moutside magnetic field) and exhibited ferromagnetism.

Synthesis and microwave absorbing characteristics of flake‐like polypyrrole filled composites in X‐band

Polypyrrole (PPy)/montmorillonite (MMT) nanocompounds were prepared by in situ chemical oxidative polymerization of pyrrole in the presence of MMT. The results indicate PPy is intercalated into MMT interlayers and the morphology of obtained PPy in nanocompounds is changed to flake‐like rather than granular particles as pristine PPy. The resultant PPy/MMT nanocompounds and pristine PPy were used as microwave absorbing filler separately to prepare microwave absorbing PPy/MMT and PPy epoxy composites. The results indicate PPy/MMT epoxy composites exhibit much better microwave absorbing properties than those filled by pristine PPy. The maximum reflection loss of 20 wt% PPy/MMT filled composite is −32.63 dB at 10.55 GHz with a matching thickness of 2.8 mm, and the effective absorption bandwidth with the reflection loss below −10 dB is from 8.6 GHz to 12.4 GHz, which almost covers the whole X‐band. We postulated that the morphology change of PPy in PPy/MMT and its better dispersion may be responsible for the enhancement of microwave absorption. POLYM. COMPOS., 37:532–538, 2016. © 2014 Society of Plastics Engineers

A novel material of cross-linked styrylpyridinium salt intercalated montmorillonite for drug delivery.

A facile synthesis of a styrylpyridinium salt (SbQ)/montmorillonite (MMT) via cationic exchange interactions between styrylpyridinium species (specifically SbQ) and MMT platelets is reported in this work. The SbQ-MMT solutions were irradiated under ultraviolet (UV) light for a specific time to obtain the cross-linked SbQ-MMT materials. Scanning electron microscopy and atomic force microscopy analyses revealed the structures and morphologies of MMT and modified MMT. X-ray diffraction and transmission electron microscope analyses indicated that the basal spacing increased from 1.24 to 1.53 nm compared with the pristine MMT, which proved that SbQ had interacted with MMT. Thermal gravimetric analysis curves showed that the amount of SbQ in the MMT interlayers was 35.71 meq/100 g. Fourier transform infrared spectroscopy also confirmed the intercalation of SbQ species into MMT interlayers, and UV spectroscopy was used to follow up the cross-linking of SbQ-MMT. This novel material has potential applications in drug delivery, and it can also be used as an additive to improve the mechanical properties of polymers.

Influence of physical state of intercalating agents on intercalation process of high speed airflow pretreated montmorillonite in supercritical carbon dioxide

The work aimed at studying the effect of scCO2 processing technology on basal spacing, surface morphology and thermal stability of sodium montmorillonite (MMT) that were pretreated with high speed airflow pulverization method and then modified using myristyltrimethylammonium bromide (MTAB) and tetradecyltrihexylphosphonium chloride (TDTHP) with scCO2 as the medium. X-ray diffraction (XRD) showed that physical state of intercalating agents played an important role on the intercalation process in scCO2. Solid-state MTAB could hardly intercalate into the interlayer of pretreated MMT (PMMT), though addition of co-solvent benefited the intercalation to some extent. However, liquid TDTHP could intercalate into the interlayer of PMMT easily even without co-solvent and the basal spacing of TDTHP-modified PMMT was larger than that of MTAB-modified PMMT. Scanning electron micrographic (SEM) showed the large compact structure for MMT broke into small random structures after airflow processing and some smaller tactoids and more dispersed structures can be observed for both MTAB-modified PMMT and TDTHP-modified PMMT compared to unprocessed MMT. For TDTHP–PMMT, many clay platelets that were separated from the tactoidal structure and more dispersed structure were observed, which may be helpful for MMT exfoliation and dispersion in polymers. Thermogravimetric analysis (TG) demonstrated that TDTHP-modified PMMT was up to 100°C more stable than MTAB-modified PMMT. These results are very important and relevant to the preparation and application of MMT/polymer nanocomposites.

Removal of cobalt(II) ion from aqueous solution by chitosan–montmorillonite

Montmorillonite (MMT) modified with chitosan (CTS, molecular weight=5×104) was applied to remove heavy metal cations by using Co2+ as a model ion. An increase in MMT interlayer distance observed from X-ray diffraction indicates the intercalation of CTS into MMT. Together with the results of scanning electron microscopy and Fourier transform infrared spectroscopy, it was concluded that the composite material of CTS and MMT (CTS–MMT) was prepared successfully. The mass ratio of CTS to MMT had a strong influence on the adsorption performance of CTS–MMT. The highest adsorption value of 150mg/g was obtained over the composite material with CTS to MMT mass ratio of 0.25, which is much higher than those reported in other studies. The adsorption isotherms and kinetic results indicated that Co2+ was adsorbed over CTS–MMT in a multilayer model, and the chemical sorption of Co2+ was determined to be the rate-limiting step.