Modified Sodium Montmorillonite Research Articles

STUDY OF MODIFICATION OF SODIUM MONTMORILLONITE FROM THE DARBAZINSK DEPOSIT

This article provides information about the possibility of studying modified sodium montmorillonite obtained on the basis of bentonite clays from the Darbazinsky deposit in order to use it as a modifier for the production of polymer composite materials. In the course of experimental studies, it was revealed that a feature of the structure of montmorillonite is that weakly bound water molecules are located between the layers and due to this the crystal lattice is mobile. The results of experimental studies of the modification of montmorillonite in the presence of sodium at a temperature of 353 K, characterized by high values of cation exchange, are presented and it is determined that the modified montmorillonite is 95 mg-eq/100 g with an average diameter of silicate plates ~ 77 nm, which are suitable as a modifier for the production of composite polymer materials

Simultaneous Removal of Heavy Metals from Wastewater Using Modified Sodium Montmorillonite Nanoclay.

Sodium montmorillonite nanoclay particles were modified by 3-aminopropyltrimetoxysilane using a physical vapor deposition method and applied for the simultaneous removal of Cd, Zn, Pb and Ni heavy metals from wastewater samples. Experiments were performed in both batch and column systems. Several parameters that influence the removal efficiency, such as the pH, contact time, amount of adsorbent, interfering ions, flow rate of sample passage and eluent solvent, were evaluated and optimized. The results showed that the adsorption isotherms obeyed Langmuir isotherms for all heavy metals. Also, interfering ions did not influenced the removal efficiency. Finally, modified nanoclay successfully could remove all heavy metals from real wastewater samples to near completeness.

Dielectric, transport and thermal properties of clay based polymer‐ nanocomposites

The polymer nanocomposite films (PNC) with varying amounts of organically modified sodium montmorillonite (DMMT) clay in poly(methyl methacrylate) (PMMA) based polymer matrix were prepared by solution cast technique. Dielectric measurements were carried out on these films as a function of frequency at 30°C and 100°C. The addition of clay significantly improved the ionic conductivity. Transport parameters, such as the diffusion coefficient (D), number density (n) and mobility (μ) of charge carriers were determined using a new approach, which is based on impedance spectroscopy. The temperature‐dependent dc conductivity, relaxation and mobility plots obey the Arrhenius rule. The results suggest that the higher ionic conductivity of these PNC films at elevated temperature is not only due to increased mobility of ions, but it is accompanied by a significant increase in carrier concentration. Analysis of DSC thermogram reveals a very high percentage of amorphous content for all samples. A good correlation among dielectric permittivity, carrier concentration, mobility and ionic conductivity has also been observed. POLYM. ENG. SCI., 58:220–227, 2018. © 2017 Society of Plastics Engineers

Unusual exfoliation of layered silicate clays by non-aqueous amine diffusion mechanism

The organic ionic exchange intercalation of smectite clays is conventionally performed in water swelling conditions. Here we report a different mechanism for modifying the smectite clays in alcohol solvents. The modification of sodium montmorillonite with poly(oxyethylene-oxypropylene)-amines (POA-amine) were compared for the differences between in water and in alcohol. In water, the intercalation of hydrophobic poly(oxypropylene)-rich amines in the silicate galleries expands the interlayer spacing up to 10 nm and even to exfoliation (featureless in X-ray diffraction pattern) with over 5 amine equivalents, where as hydrophilic poly(oxyethylene)-rich amines could only intercalate in a low spacing of 1.8 nm. On the other hand, all of the POA-amines in isopropanol afford the exfoliation with over, 3 amine equivalents. The mechanism of this unexpected exfoliation is explained by the thermodynamic formations of an imaginary membrane surrounding the clay units, followed by amine diffusion from the solvent into the clay galleries.

Anodic stripping voltammetric measurement of trace cadmium at antimony film modified sodium montmorillonite doped carbon paste electrode

In this work, a simple and reliable electrochemical method for the determination of cadmium using an antimony film modified sodium montmorillonite (NaMM) doped carbon paste electrode (Sb/NaMM-CPE) was described. Due to the strong cation exchange ability and adsorptive characteristics of NaMM and excellent electroanalytical performance of the antimony film, the new electrode significantly enhanced the sensitivity for detection of Cd(II) and exhibited superior performance in comparison with the bare carbon paste electrode, antimony film modified carbon paste electrode (Sb/CPE), and NaMM modified carbon paste electrode (NaMM-CPE). Some parameters such as the composition of the paste, pH of the measure solution, the Sb(III) concentration, deposition time, and deposition potential that influenced the response of cadmium were investigated and the procedure was optimized for cadmium determination. This electrode, combined with square-wave anodic stripping voltammetry, displayed excellent linear behavior in the examined concentration range of 4.0–150.0μgL−1 Cd(II) (R2=0.998) with a detection limit of 0.25μgL−1. The Sb/NaMM-CPE was successfully applied to the determination of cadmium ion in tap water sample.

Mechanistic outlook on thermal degradation of 1,3-dialkyl imidazolium ionic liquids and organoclays

Thermal decomposition of ionic liquid modified sodium montmorillonite clay proceed through an imidazole-2-ylidene (carbene) mediated mechanism with an activation energy of 195.6 kJ mol−1.

Effect of organic modifier type of montmorillonite on the poly (butyl acrylate-co-methyl methacrylate)/montmorillonite nanocomposite

Nanocomposites based on poly(BA-co-MMA) and organo-montmorillonite (OMt) were synthesized by semi batch emulsion polymerization. OMt was used directly after the organic modification of sodium montmorillonite (Mt). By this way, dispersion of OMt in emulsion polymerization was improved. OMts were prepared by organic modification of Resadiye Mt (bentonite) with five different quaternary ammonium salts (QAS) to observe the effect of structural difference on the poly(butyl acrylate-co-methyl methacrylate) nanocomposites. The affinity of OMts towards organic liquids was observed via swelling test in toluene and butyl acrylate (BA)-methyl methacrylate (MMA) mixture. OMt content in the nanocomposite as well as the effect of QAS structure and dosage was investigated. Good dispersion of OMt in copolymer films was obtained as demonstrated by X-ray diffraction and partially exfoliated OMt structure was determined through transmission electron microscope. Final nanocomposites had 47 wt% solids contents. Nanocomposite containing 2.3 wt% OMt modified with two 18 carbons alkyl chain at excess QAS amount resulted in higher increments of thermal, mechanical, barrier properties and glossiness for coating applications.

The Effect of a Novel Intumescent Flame Retardant-Functionalized Montmorillonite on the Thermal Stability and Flammability of Eva

A novel intumescent flame retardant-functionalized montmorillonite (PAB-MMT) was prepared by modification of sodium montmorillonite (Na-MMT) with an intumescent flame retardant (PAB) containing phosphorus-nitrogen structure. The results of X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) analysis indicated that PAB had intercalated into Na-MMT. The applications of this fact for improving the thermal stability and flammability of poly(ethylene-co-vinyl acetate) were investigated by thermogravimetric analysis (TGA), and microscale combustion calorimetry (MCC). Scanning electron microscopy (SEM) was carried out to learn the morphology of the char residue. The results showed that the addition of PAB-MMT into EVA could improve the flame retardancy of the EVA matrix. The peak heat release rate (PHRR) and total heat release (THR) were significantly reduced in comparison with those of other EVA composites. The TGA data showed higher char residue than other composites, which was the reason for the improved flame retardancy.

Enhanced adsorption of inorganic and organic pollutants by amine modified sodium montmorillonite nanosheets

Amine modified sodium montmorillonite nanosheets with increased basal space as versatile adsorbents for both organic and inorganic pollutants.

Correction: Enhanced adsorption of inorganic and organic pollutants by amine modified sodium montmorillonite nanosheets

Correction for ‘Enhanced adsorption of inorganic and organic pollutants by amine modified sodium montmorillonite nanosheets’ by Munusamy Thirumavalavan et al., RSC Adv., 2015, 5, 20583–20594.

Influence of surface modified nanoclay on electrochemical properties of PVDF-HFP composite electrolytes

Polymer electrolyte membranes have prepared for dye sensitized solar cells based on Polyvinylidene fluoride-co-hexaflouropropylene (PVDF-HFP) filled with silane modified Sodium montmorillonite (Na-MMT) nanofillers. Na-MMT nanoclay has modified using Aminopropyltrimethoxysilane and it is confirmed by FTIR and XRD. The XRD patterns of PVDF-HFP/Si-NaMMT proved that Si-NaMMT layers were completely exfoliated within the PVDF-HFP matrix. The influence of silane modified clay on the degree of crystallinity of the polymer matrix was studied by using DSC. The Electrochemical studies indicated that the addition of surface modified nanoclay increases the ionic conductivity up to 6.45 × 10−4 S/cm for 4 wt%, whereas the ionic conductivity about 1.14 × 10−4 S/cm with the addition of unmodified counterpart as the filler into the PVDF-HFP. The solid state dye sensitized solar cell has been fabricated by using silane modified Na-MMT/PVdF-HFP polymer nanocomposites electrolyte and Eosin-Y as a sensitizer. The photovoltaic characteristics showed an enhancement in open circuit voltage (Voc) from 0.26 to 0.32 V.

Morphological factors affecting the permeation resistance of nanocomposite blend films

The micro- and nanoscale morphologies of thin nanocomposite films comprising an immiscible nylon 6/polyethylene blend reinforced with modified sodium montmorillonite were found to substantially affect water vapor transmission rates (WVTRs). Maleic anhydride-grafted high-density polyethylene was incorporated as a compatibilizer between the nylon and polyethylene phases. Preferential incorporation of an organosilicate nanoclay in the nylon phase had a secondary effect on the overall blend morphology and thermal properties. Different degrees of phase continuity in the nanocomposite blend system were studied for their effect on WVTRs by varying the relative viscosities of the polymer phases. Transmission electron and atomic force microscopy were utilized to reveal the morphologies of the nanocomposite blends. POLYM. ENG. SCI., 54:1341–1349, 2014. © 2013 Society of Plastics Engineers

Synthesis and characterization of TiO2–Montmorillonite/Polythiophene-SDS nanocomposites: Application in the sonophotocatalytic degradation of rhodamine 6G

Titanium dioxide–montmorillonite/Polythiophene–sodium dodecyl sulphate (TiO2–Mt/PTP–SDS) nanocomposites were synthesized via the in situ intercalative oxidative polymerization of thiophene (TP) in TiO2–Mt clay and CHCl3 solvent using anhydrous ferric chloride (FeCl3) at ambient temperature for 24h in the presence of anionic surfactant SDS at a ratio by mass of 20% of TP/TiO2–Mt. The TiO2–Mt was obtained by the modification of sodium montmorillonite (Na-Mt) with titanium isopropoxide (Ti (OPri) 4) at 50°C for 3h. The products obtained were characterized using different techniques, such as Fourier Transform Infrared Spectroscopy (FTIR), X-ray Fluorescence Analysis (XRF), X-ray diffraction (XRD), and Environmental Scanning Electron Microscopy (ESEM), which proved the successful intercalation of polythiophene in the TiO2–MT in the presence of anionic surfactants. The degradation of rhodamine 6G (R6G) in aqueous solutions was investigated kinetically in the presence of catalysts under Sun-test simulator at 400W/m2, sonocatalysis at 500kHz (30W), and sonophotocatalysis. The findings revealed that the TiO2–Mt/PTP20%-SDS catalyst exhibited good levels of photocatalytic, sonocatalytic, and sonophotocatalytic degradability for R6G. The synergistic effect between the two techniques was observed using TiO2–Mt/PTP20%-SDS (w %) as a catalyst, and the kinetic results indicated that enhanced degradation rate constants were achieved particularly with sonophotocatalytic processes.

Potential application of dodecylamine modified sodium montmorillonite as an effective adsorbent for hexavalent chromium

Clay materials are well suited for heavy metal adsorption in view of their excellent surface area and cation exchange capacity. In this paper, we report the detailed study on the adsorption of hexavalent chromium using dodecylamine intercalated sodium montmorillonite as a potential adsorbent. The adsorption involves primarily the electrostatic interaction of hydrogentetraoxochromate(VI) anion with the protonated dodecylamine and the surface hydroxyl groups of the clay material. The pseudo second order kinetic model fits the experimental data and an adsorption capacity of 23.69mgg−1 was obtained from the Langmuir isotherm model. The exothermically favorable spontaneous adsorption process and the decrease in entropy explain the thermodynamics of the adsorption. The adsorbent could be regenerated using NaOH and column adsorption studies provide a sample break through volume of 300mL on a laboratory scale. The adsorbent could be utilized for the successful removal of chromium from tannery wastewater.

A Meticulous Study on the Adsorption of Mercury as Tetrachloromercurate(II) Anion with Trioctylamine Modified Sodium Montmorillonite and Its Application to a Coal Fly Ash Sample

Clay materials have hogged the limelight for their effectiveness in environmental remediation. In this paper, we report an effective solid phase extraction method for mercury based on the adsorption of tetrachloromercurate(II) anion with trioctylamine intercalated onto sodium montmorillonite. The adsorption is facile in acidic medium, and the adsorbent was well characterized by diverse physicochemical and spectroscopic techniques. Various isotherm models were employed to correlate the experimental adsorption data. The electrostatic interaction between HgCl42- and the protonated amine is well supported by a Langmuir isotherm model with a maximum adsorption capacity of 140.84 mg g–1. The ordered transition state that arises due to the proximity of the HgCl42- and the positively charged amine is accompanied by a decrease in the translational entropy of the system. The N2 adsorption–desorption isotherm study revealed the mesoporous nature of the adsorbent, and the thermodynamically favorable adsorption proces...

Investigation on Intercalation Modification of Sodium-montmorillonite by Cationic Surfactant

Investigation on Intercalation Modification of Sodium-montmorillonite by Cationic Surfactant

Application of Cellulose-Clay Composite Biosorbent toward the Effective Adsorption and Removal of Chromium from Industrial Wastewater

Biopolymer composites are known for their utility in diverse applications. In this paper, we report an effective methodology for the detoxification of chromium using cellulose-montmorillonite composite material as the adsorbent. The interaction of surfactant modified sodium montmorillonite (NaMMT) with cellulose biopolymer is followed by the subsequent adsorption of Cr(VI) from aqueous solution as bichromate anion onto the surface of the biocomposite material. The composite adsorbent was characterized comprehensively using Fourier transform infrared spectroscopy (FT-IR), Energy dispersive X-ray spectrometry (EDX), X-ray diffraction (XRD) and Branauer-Emmett-Teller (BET) isotherm studies. The material exhibited a maximum adsorption capacity of 22.2 mg g–1 in accordance with the Langmuir isotherm model. The mesoporous nature of the material was ascertained from the nitrogen adsorption isotherm study and the adsorption process was in accordance with second order kinetics. The spontaneity of the adsorption pr...

A Study of Thermal Stability and Electromaganetic Shielding Behavior of Polyaniline-P-Toluene Sulfonic Acid/Montmorillonite Nanocomposites

Intrinsically conductive polymer-Polyaniline had high conductivity and many other properties, such as environmental stability and rather simple synthesis. In addition, doping with organic acids could enhance its processing, so it had wide range of applications, such as solar cells, antistatic and electromagnetic interference shielding. In this study, the organic amine 1-Dodecylamine (DOA) modification of sodium montmorillonite (NA+-MMT), and conducting polymer / layered silicate salt nanocomposites (PANI-PTSA/DOA-MMT) had been prepared by doping aniline with organic acid (PTSA), then added organic clay. The thermal, electrical properties and EMI effects of nanocomposites had discussed by XRD, TEM, EMI, TGA analysis, conduction measure and EMI tested. The results indicated the organo-clay interlayer distance expanded from 1.29 to 1.8 nm, and DOA-MMT dispersed in the material, that formed an exfoliated nanocomposite. The thermal stability of nanocomposites depended on content of DOA-MMT, material had the better thermal stability when DOA-MMT load was 5 wt. %. The nanocomposites had the best conductivity when DOA-MMT load was 1 wt. % as well as the electromagnetic shielding effectiveness was increase with increase in conductivity. In addition, the electromagnetic shielding of nanocomposites also depended on thickness and frequency of electromagnetic wave, the electromagnetic shielding was increased with increase in thickness and frequency.

Impact of high pressure treatment on the structure of montmorillonite

The modification of sodium montmorillonite after a high pressure pasteurization treatment was followed by X-ray diffraction, FTIR spectroscopy and thermogravimetric analysis. Regardless of the treatment intensity (300 and 800MPa), the structure of montmorillonite was clearly modified. Such changes should be taken into consideration when binging montmorillonite–polymer nanocomposites into contact with food.

Preparation and properties of organo‐modifier free PET/MMT nanocomposites via monomer intercalation and in situ polymerization

AbstractIn order to prevent the properties, especially transparency, color and health security, of PET/clay nanocomposites from being deteriorated due to the thermal degradation of clay organo‐modifer, we had directly modified sodium montmorillonite (Na+‐MMT) with PET's monomer, bis (hydroxyethyl) terephthalate (BHET) which had a degradation temperature higher than 400°C, and successfully prepared the hybrids via in situ polymerization. Nanodispersion of clay and the intercalated morphology were determined, and compared with PET/Na+‐MMT hybirds in which Na+‐MMT was directly added without any treatment. Improved mechanical properties and Tg were observed for the prepared PET/ BHET‐modified clay composites. More importantly, the film produced from the composites had the same transparency as that of pure PET even when 2 wt% of clay was added. Non‐isothermal and isothermal crystallization experiments showed a very good neculation capability of the nano‐dispersed clay, particularly at higher crystallization temperatures. Copyright © 2009 John Wiley & Sons, Ltd.