Effect Of Montmorillonite Research Articles

Mechanical and thermal properties of glass fiber reinforced polymer-clay nanocomposites

Abstract The effect of Montmorillonite (MMT) nanoclay on static mechanical and thermal characteristcs of glass fiber-reinforced polymer (GFRP) composites is studied. The static tensile properties of epoxy/MMT nanoclay, which are important properties of GFRP composites, are investigated. The predicted stress-strain curves of epoxy with 0 and 1 wt.% of nanoclay follow experiments. The predicted elastic modulus and tensile strength of epoxy with 3 wt.% of nanoclay are 74 and 230% higher than neat epoxy. For GFRP composites with 0, 1, 3, and 5 wt.% of MMT nanoclays, the measured tensile strengths are 587, 600, 628, and 724 MPa, and flexural strengths are 626, 726, 906, and 542 MPa. For composites with former nanoclays, interlaminar shear strengths are 23, 25, 31, and 28 MPa, and Izod impact strengths are 83, 94, 207, and 145 kJ/m2. Thus, mechanical strengths of composites with 0–5 wt.% of nanoclays improve considerably than pristine sample. The predicted static tensile stress-strain curves of GFRP composites with above nanoclays follow experimental behavior. For GFRP composites with 0 and 1 wt.% of MMT nanoclays, glass transition temperatures are 91 and 101°C, and storage moduli at ambient temperature are 35 and 41 GPa. The thermal conductivities of GFRP composites with 0, 1, and 3 wt.% of MMT nanoclays at ambient temperature are 0.32, 0.36, and 0.42 W/(m·K). Thus, thermal properties of composites are affected significantly on addition of nanoclays.

Enhanced diclofenac abatement by ferrate in the presence of montmorillonite: Trapping in-situ formed Fe(III)

Ferrate (Fe(VI)) is an environmentally-friendly chemical oxidant employed in water and wastewater treatment. The effect of montmorillonite (MMT) on the abatement of diclofenac (DCF) by Fe(VI) was studied. Results indicate that the presence of 200 mg/L MMT enhanced the second-order rate constant for the reaction between DCF and Fe(VI) from 117 to 219 M-1 s-1 at pH 7.6, whereas no significant enhancement was observed for silicon dioxide and kaolinite. In-situ formed Fe(III) from Fe(VI) decay played important roles on the enhanced oxidation of DCF by Fe(VI). In addition, no enhancement was observed in phosphate buffer since phosphate could sequester Fe(III). A similar enhancement of DCF abatement by Fe(VI) in the presence of MMT can be observed using preformed Fe-MMT. Adsorbed Fe(III) which is present in the form of FeOOH can increase the layer spacing of MMT from 11.4 to 15.0 Å. In-situ formed Fe-MMT increases the oxidation efficiency of methylphenyl sulfoxide, a probe compound. Addition of 50 mg/L MMT during Fe(VI) oxidation can increase the yield of reactive high-valent iron intermediates (e.g., Fe(IV) and Fe(V)) by 43%. This work provides new insights into Fe(VI) application in pre-oxidation for the abatement of micropollutants in water treatment processes.

Effects of montmorillonite on the loading and release of Piper betle L. extract applied for wound dressing based on chitosan/polyvinyl alcohol

In this study, we investigate the influence of montmorillonite (MMT) on the loading and release of Piper betle L. extract (PLE)–a medicinal herb containing active secondary metabolites with antibacterial, antioxidant, and anti–inflammatory effects. MMT (1 %, 3 %, 5 %) was blended into the chitosan/polyvinyl alcohol (CS/PVA) biocomposite film by the solution evaporation method, and then PLE was loaded onto this biocomposite using the immersion method. The tensile strength and the ability to absorb exudates of the CS/PVA film improved with the increase in MMT content. The MMT 3 % film was considered to have the best properties: good mechanical properties with a tensile strength of 27.44 ± 0.27 MPa and elongation at break of 14.57 ± 0.30 %, potential for wound dressing due to its ability to absorb wound exudate (swelling degree 61.70 ± 0.30 %) and a suitable water vapor transmission rate (1999 ± 47 g/m2·d). The presence of MMT (1 %, 3 %, 5 %) in the CS/PVA film led to an increase in the PLE loading efficiency of the films compared to the film without MMT, up to 1.65, 1.73, and 1.87 times, respectively. The MMT 3 % and 5 % films also exhibited a sustained PLE release effect for up to 24 h. MMT increased PLE bioavailability through bioactivity tests: antibacterial activity against both E. coli and S. aureus, antioxidant activity, effective healing of 2nd–degree burn wounds, and biocompatibility with the L929 fibroblasts cell line. The combination of physicochemical properties and biological activities proved that the MMT/PLE drug delivery system based on the CS/PVA biocomposite is promising for wound dressing.

Effect of montmorillonite K-10 catalyst on the synthesis of (E)-1-phenyl-3-(2-methoxyphenyl)-2-propen-1-one using the microwave irradiation method

Background: A research investigation was conducted to examine how the utilisation of the montmorillonite K-10 catalyst impacts the production of (E)-1-phenyl-3-(2-methoxyphenyl)-2-propen-1-one (PMPP) using the microwave irradiation method since the conventional method has not been successful. Objective: The aim of this research was to investigate the impact of employing the montmorillonite K-10 catalyst in the synthesis of PMPP using the microwave irradiation method. Method: The compound was created using the Claisen-Schmidt condensation technique through a nucleophilic addition reaction. Results: The result of the synthesis was a yellowish powder. The percentage of synthesis of PMPP using the microwave irradiation method was 4.98%, with a melting point of 53-54oC. The synthesised compounds were identified by UV-Vis, Infrared and H-NMR spectroscopy. Conclusion: Synthesis of PMPP with montmorillonite K-10 catalyst can be carried out using microwave irradiation. The synthesis using the montmorillonite K-10 catalyst gave a relatively small yield of (E)-1-phenyl-3-(2-methoxyphenyl)-2-propen-1-one compared to a strong base catalyst.

Effect of montmorillonite and humic acid on cotransport of g-C3N4 and lead: The role of triazine ring in lead adsorption and deposition in soil components

In the past few years, Graphitic carbon nitride (g-C3N4) has been produced on a large scale and has been widely used because of its excellent optical properties and physicochemical stability. It is easy to ignore the risk of g-C3N4 transport in the environment, including soil and groundwater, due to the non-toxicity of metals. Based on this situation, we investigated the effects of pumping flow rate, ionic strength, and the presence of lead (Pb) on the transport behavior of g-C3N4 in quartz sand, montmorillonite, and humic acid-coated sand through column experiments. The retention of g-C3N4 in the media and the adsorption mechanism of Pb onto g-C3N4 were analyzed by FTIR and XPS. The results showed that fast flow rate and low ionic strength were favorable conditions for the transport of g-C3N4. The cotransport experiment results showed that Pb reduced the outflow of g-C3N4 by more than 50%. Contrarily, 6.95%, 0.43%, and 11.01% Pb were hindered in quartz sand, montmorillonite, and humic acid-coated sand due to the presence of g-C3N4. Compared with the uncontaminated media, the recoveries of g-C3N4 in Pb contaminated quartz sand, montmorillonite, and humic acid-coated sand were reduced by 0.34%, 5.86%, and 15.34%, respectively. Concomitantly, which were attributed to the special triazine ring structure and the abundant bonding modes with soil components and Pb, g-C3N4 particles were easier to deposit in montmorillonite and humic acid-coated sand, and could be used as the carrier to release 6.70% and 5.64% Pb from contaminated quartz sand and humic acid-coated sand.

Effect of montmorillonite and starch nanocrystals based biodegradable films loaded with lemongrass oil nanoemulsion on quality, enzymatic activity and shelf life of strawberry

The present study aims to determine the influence of montmorillonite (1.5% w/v MMT) and starch nanocrystals (1% w/v SNCs) based corn starch films loaded with lemongrass oil nanoemulsion (2% v/v LNE) on the shelf life and quality characteristics of strawberries (variety Tioga) stored at 4ºC for 8d. Results revealed that MMT and SNCs reinforcement enhanced tensile properties while reducing the WVTR of the films. Active nanocomposites provided superior shelf stability whereas control (unpackaged strawberry) demonstrated the highest quality deterioration in strawberries throughout storage. Amongst nanocomposites utilized, MMT/LNE based films exhibited the best preservative effects on the quality of strawberries, owing to their better barrier properties than SNCs/LNE. On the 8th day, MMT/LNE based films demonstrated highest retention of the physicochemical properties, phenolic content (69.50%), anthocyanin content (86.76%) and DPPH scavenging activity (67.60%). The activity of antioxidant enzymes (superoxide and catalase) was also preserved best with the MMT/LNE based films. Active nanocomposites reduced microbial growth with MMT/LNE films showing the least microbial progression. MMT/LNE and SNC/LNE loaded nanocomposites increased the strawberries’ shelf life up to 8 and 6 days, respectively in comparison to the control (4 days), illustrating the effectiveness of nanocomposites in maintaining postharvest quality of strawberries.

Montmorillonite as an Effective Stimulator of Plant Development in Soil Contaminated with Metsulfuron-Methyl

Currently, the widespread use of herbicides in agriculture creates a serious problem of further use of contaminated soils for growing various types of agricultural plants. Developing the research of aluminosilicates as detoxicants of herbicide residues contained in the soil, the effect of montmorillonite K-10 (MRT) on vegetative plants of spring rape and corn is studied in this work. It was shown that the introduction of MRT into the soil before sowing in low doses had a powerful stimulating effect on plant development, both in the presence of methsulfuron-methyl residues in the soil and in the absence of herbicide in the soil. The doses of the applied MRT were only 100–200 kg/ha, which created the prospect of widespread use of montmorillonite (bentonite) clays in crop production.

Carbonation properties of dredged slurry pre-dried with steel slag powder: Effects of clay minerals and organic acids

The carbonation properties of dredged slurry pre-dried with steel slag powder were investigated in this study, and steel slag powder was also involved in the drying process. However, it remains unclear how the interaction between steel slag and clay minerals or organic acids in the slurry affects the carbonation performance of the dried soil (DS), and the underlying mechanism needs elucidation. In this study, quartz, montmorillonite, and fulvic acid (FA) were used to prepare five types of artificial soil testing samples. The artificial soils were then made into slurry and dried using steel slag powder to obtain DS. The carbonated soil (CS) was attained by carbonation stabilization/solidification (S/S) of DS, and the effect of montmorillonite and/or FA on the optimal moisture content for carbonation (C-OMC) and the strength ratio of carbonation (Rcs) of the CS were evaluated by unconfined compressive strength. In addition, the mixed soil (MS), as the reference group of DS, was prepared by combining artificial dry soil directly with steel slag to help understand how the interaction between montmorillonite or FA and steel slag during the drying process. X-ray diffraction (XRD), thermogravimetry and derivative thermogravimetry (TG/DTG), and pH tests were used to characterize the changes of microscopic mineral and pH value during the drying process from MS to DS, and the carbonation process from DS to CS. The results showed that the existence and content of montmorillonite can reduce the carbonation efficiency of DS, and a small amount of FA is conducive to improving the carbonation efficiency of DS. By comparing the composition changes of DS and MS, it was confirmed that the interaction between steel slag and montmorillonite or FA existed in the drying process, and this interaction affected the carbonation performance of DS by changing the pH value of DS.

Experimentation, optimization, and predictive analysis of compressive behavior of montmorillonite nano‐clay/unsaturated polyester composites

AbstractThe effect of montmorillonite (MMT) nano‐clay as reinforcement in unsaturated polyester resin (UP) matrix composite was investigated under compression loading to explore the impact of MMT nano‐clay wt% in the compressive behavior of UP‐MMT nano‐clay composite. UP‐MMT nano‐clay composite samples were prepared with a varied filler content of 0.5 to 3 wt% using dual‐mixing methods, which are mechanical stirring and ultrasonic agitation. Static uniaxial compression tests were conducted using cylindrical‐shaped samples to obtain the compressive behavior of the UP‐MMT nano‐clay composites. The results of experimentation record a considerable improvement in compressive characteristics of UP‐MMT nano‐clay composites compared to pure UP matrix. The UP‐MMT nano‐clay composite samples were viewed under transmission electron microscope (TEM) to know the dispersion of MMT nano‐clay in the composites. The nano‐platelets were well dispersed and intercalated in the UP‐MMT nano‐clay composite samples below 1 wt% MMT nano‐clay loading. The optimum wt% of MMT nano‐clay in the UP‐MMT nano‐clay composite for improved compressive stress at yield and modulus were noted as 0.60 and 0.61 wt% respectively. Moreover, a mathematical model using Halpin–Tsai‐Jumahat equations was utilized to predict the compressive properties of UP‐MMT nano‐clay composites, which are in closer agreement with the experimental results.

Stabilizing performance of montmorillonite on fish gelatin-monascorubins system by labyrinth effect

Natural monascorubins could be used in various fields but are unstable under heat, pH, etc., with limited application. Fish gelatin could disperse monascorubins, which could be further stabilized by montmorillonite. Effect of montmorillonite was studied by CIElab color, zeta potential, particle sizes, SEM, contact angle, antibacterial activity, thermal/chemical resistance, and the stabilizing mechanism was explored by FTIR, XRD, Raman and molecular simulation. Montmorillonite effectively strengthened gelatin-monascorubin system by labyrinth effect based on hydrogen bond, host-guest interaction and complexation, thereby reducing sizes with nano structure and increasing specific surface area, antibacterial activity and thermal/chemical stability. High-content montmorillonite made the nanocomplex system to have outstanding shear-thinning behavior, excellent thixotropy and proper yield stress, and to illustrate potential as edible inks. This nanocomplex system performed well in handwriting and massive screen printing, with great surface fastness. Structure based on fish gelatin and montmorillonite indicates promise in dispersing and stabilizing functional materials with broad industrial application value.

Effects of montmorillonite (MMT) on the crystallization behavior of poly(L-lactic acid) (PLLA) by variable-temperature FTIR coupled with difference spectrometry, PCMW2D and 2DCOS analyses

Effects of montmorillonite (MMT) on the crystallization behavior of poly(L-lactic acid) (PLLA) were investigated by variable-temperature FTIR spectroscopy. The variations of carbonyl band (1800–1720 cm−1) of different PLLA/MMT nanocomposites were focused due to its strong intensity and the involved abundant structure information. Difference spectrometry was used to evaluate the structural variations of PLLA after introducing MMT, and perturbation correlation moving window two-dimensional analysis (PCMW2D) split the temperature range into two sub-regions, i.e., 32–116 ℃ and 116–152 ℃, on the basis of the spectral variation. Two-dimensional correlation spectroscopy (2DCOS) was further applied to such sub-regions in order to find the change order between varied PLLA polymorphs. The results showed that less addition of MMT (≤3%) would lead to a well-exfoliated structure, which not only had no nucleation effect for PLLA, but also delayed the cold crystallization to a higher temperature compared with the one of pure PLLA. However, a higher addition of MMT (≥5%) would lead to an intercalated structure, which acted as a nucleating agent and thus advanced the cold crystallization to a lower temperature. Nevertheless, the introduction of MMT cannot affect the phase transition order between the amorphous, the intermediate, the α′- and the α′-PLLAs based on 2DCOS results.

Physicomechanical, thermal and dielectric properties of eco‐friendly starch‐microcrystalline cellulose‐clay nanocomposite films for food packaging and electrical applications

AbstractPotato starch (PS) films reinforced with microcrystalline cellulose (MCC) were prepared with casting solution, and the effect of montmorillonite (MMT) clay in different proportions (1, 3, 5 and 10 wt%) using nanofiller was established. The films were investigated by Fourier transform ınfrared (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), tensile strength, opacity, colour, water vapour permeability and solubility. Tensile strength for nanocomposite films depending on the clay content was increased significantly from 0.64 to 1.89 MPa. The water vapour permeability of nanocomposite films was improved compared to the PSMCC blend without MMT. Also, dielectric properties and electrical conductivity of films were studied. The dielectric permittivity (έ), the dielectric loss (ε˝) and the electrical conductivity (σ) increased with increasing MMT content at frequencies between 100 Hz to 10 kHz. This nanocomposite with improved functional properties could be used in potential food packaging materials and electrical applications.

Chitosan-clay nanocomposite as a drug delivery system of ibuprofen

Chitosan/montmorillonite nanocomposite films were prepared by the solvent evaporation method to immobilize the drug ibuprofen (IBU) and delay its release in a medium that simulates the environment of the gastrointestinal tract. The effects of montmorillonite, at different mass proportions (10, 20, and 50%), on the morphological and physical properties of the films were studied. The samples were characterized by X-ray diffraction (XRD), Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), degree of swelling, drug encapsulation, and drug release efficiency. According to the XRD it was evidenced that the incorporation of montmorillonite to chitosan led to the formation of nanocomposites of ordered morphology. The infrared spectra confirmed the good interaction between montmorillonite and chitosan by the formation of nanocomposites. This fact, which favored the imprisonment of the IBU, reduced the diffusion coefficient in the studied systems. The micrographs comproved the formation of dense and uniform films. The controlled release profile, especially for the nanocomposite with 10% clay mass, showed a slow drug release rate. The incorporation of montmorillonite at different proportions produced different morphologies, with good encapsulation efficiency and an adequate profile for the controlled release of the drug.

Modification of montmorillonite and its effect on the thermal stability of PP/APP

The effect of montmorillonite (Mt) and the treated montmorillonite (MtT) with sulfuric acid on the efficiency of nanoparticles of ammonium polyphosphate (APP) has been studied. Five samples containing different percentage of montmorillonite are prepared and other five samples containing treated montmorillonite also prepared. The chemical analysis (XRF), the spectroscopic measurements (XRD and IR) and the morphology (SEM) studied have been performed to identify the sulfuric acid treatment for the montmorillonite on the chemical composition and on the structure of the montmorillonite layers. The results have been revealed that the acid treatment changes the layered structure of montmorillonite and no effects on the chemical composition. The thermogravimetric analysis (TGA) is used to evaluate the ammonium polyphosphate (APP)/ montmorillonite (Mt) or APP/ montmorillonite treatment (MtT) as flame retardants for Polypropylene (PP). The results show that both treated and untreated montmorillonite when mixed with APP accelerate the first step of the thermal degradation. Also, it is indicated that the time of degradation increased by adding treated or untreated montmorillonite to APP in the following sequence PP

Effect of MMT on Flame Retardancy of PLA/IFR/LDH Composites

Nano filler synergistic intumescent flame retardant (IFR) system is an effective way to improve the flame retardant properties of polymer. In this study, the effects of montmorillonite (MMT) on the flame retardant properties of polylactic acid/layered double hydroxides (PLA/LDH) and PLA/IFR/LDH were investigated. The results show that both LDH and LDH/IFR can reduce the peak heat release rate (HRR) of PLA and prolong the combustion time of PLA; When a proportionate MMT is introduced into PLA/LDH and PLA/IFR/LDH systems, respectively, MMT will not only affect the degradation process of PLA composites during combustion, but also the PLA composites can form a more stable carbon layer during combustion, which could decrease the peak HRR and prolong combustion time of PLA composite. Furthermore, when 0.5 wt% MMT is incorporated, the peak HRR of LDH/ IFR/LDH composite is reduced by 16.17% and the combustion time is prolonged by about 70 s. This study can provide an opportunity to further optimize the properties of intumescent flame retardant polymer.

Effects of Montmorillonite and Gentamicin Addition on the Properties of Electrospun Polycaprolactone Fibers.

Electrospinning was used to obtain multifunctional fibrous composite materials with a matrix of poly-ɛ-caprolactone (PCL) and 2 wt.% addition of a nanofiller: montmorillonite (MMT), montmorillonite intercalated with gentamicin sulphate (MMTG) or gentamicin sulphate (G). In the first stage, the aluminosilicate gallery was modified by introducing gentamicin sulfate into it, and the effectiveness of the intercalation process was confirmed on the basis of changes in the clay particle size from 0.5 µm (for MMT) to 0.8 µm (for MMTG), an increase in the interplanar distance d001 from 12.3 Å (for MMT) to 13.9 Å (for MMTG) and altered clay grain morphology. In the second part of the experiment, the electrospinning process was carried out in which the polymer nonwovens with and without the modifier were prepared directly from dichloromethane (DCM) and N,N-dimethylformamide (DMF). The nanocomposite fibrous membranes containing montmorillonite were prepared from the same polymer solution but after homogenization with the modifier (13 wt.%). The degree of dispersion of the modifier was evaluated by average microarray analysis from observed area (EDS), which was also used to determine the intercalation of montmorillonite with gentamicin sulfate. An increase in the size of the fibers was found for the materials with the presence of the modifier, with the largest diameters measured for PCL_MMT (625 nm), and the smaller ones for PCL_MMTG (578 nm) and PCL_G (512 nm). The dispersion of MMT and MMTG in the PCL fibers was also confirmed by indirect studies such as change in mechanical properties of the nonwovens membrane, where the neat PCL nonwoven was used as a reference material. The addition of the modifier reduced the contact angle of PCL nonwovens (from 120° for PCL to 96° for PCL_G and 98° for PCL_MMTG). An approximately 10% increase in tensile strength of the nonwoven fabric with the addition of MMT compared to the neat PCL nonwoven fabric was also observed. The results of microbiological tests showed antibacterial activity of all obtained materials; however, the inhibition zones were the highest for the materials containing gentamicin sulphate, and the release time of the active substance was significantly extended for the materials with the addition of montmorillonite containing the antibiotic. The results clearly show that the electrospinning technique can be effectively used to obtain nanobiocomposite fibers with the addition of nonintercalated and intercalated montmorillonite with improved strength and increased stiffness compared to materials made only of the polymer fibers, provided that a high filler dispersion in the spinning solution is obtained.

Montmorillonite-Hydrochar Nanocomposites as Examples of Clay–Organic Interactions Delivering Ecosystem Services

AbstractClay–organic interaction is an important natural process that underpins soil ecosystem services. This process can also be tailored to produce clay–organic nanocomposites for industrial and environmental applications. The organic moiety of the nanocomposites, typically represented by a toxic surfactant, could be replaced by hydrochar formed from biomolecules (e.g. glucose) via hydrothermal carbonization. The effect of montmorillonite (Mnt) and glucose dosage on hydrochar formation, however, has not been clarified. In addition, the mechanisms by which Mnt-hydrochar nanocomposites (CMnt) can detoxify and remove carcinogenic Cr(VI) from aqueous solution are not well understood. In the current study, research milestones in terms of clay–organic interactions are summarized, following which the synthesis and characterization of CMnt for Cr(VI) adsorption are outlined. Briefly, 1 g of Mnt was reacted with 75 mL of glucose solution (0.1, 0.2, 0.3, 0.4, 0.5, and 0.6 mol L−1) by hydrothermal carbonization at 200°C for 16 h. The resultant CMnt samples were analyzed for chemical composition, functional groups, morphological features, and Cr(VI) adsorptive properties. Mnt promoted the conversion of glucose to hydrochars, the particle size of which (~80 nm) was appreciably smaller than that formed in the absence of Mnt (control). Furthermore, the hydrochars in CMnt had an aromatic structure with low hydrogen substitution and high stability (C/H atomic ratio 0.34–0.99). The weakened OH (from hydrochar) and Si–O–Si stretching peaks in the Fourier-transform infrared (FTIR) spectra of CMnt are indicative of chemical bonding between Mnt and hydrochar. The CMnt samples were effective at removing toxic Cr(VI) from acidic aqueous solutions. Several processes were involved, including direct reduction of Cr(VI) to Cr(III), complexation of Cr(III) with carboxyl and phenolic groups of hydrochar, electrostatic attraction between Cr(VI) and positively charged CMnt at pH 2 followed by indirect reduction of Cr(VI) to Cr(III), and Cr(III) precipitation.

The effect of montmorillonite in graphene oxide/chitosan nanocomposite on controlled release of gemcitabine

The effect of montmorillonite in graphene oxide/chitosan nanocomposite on controlled release of gemcitabine

Effect of montmorillonite on the oxidative stability of polyphenylene sulfide fibers prepared by melt spinning

Masterbatches of polyphenylene sulfide (PPS)/organic montmorillonite (MMT) composites were produced via melt blending. A self-made spinning equipment was then used to produce the PPS/organic MMT composite fibers by melt spinning directly from the masterbatches. X-ray diffractometer and transmission electron microscope were used to examine the dispersibility of organic MMT. The morphology, tensile property, crystallization behavior, and oxidative stability of PPS fibers were investigated. The results indicated that organic MMT could be uniformly distributed in the PPS matrix to form a mixed dispersion of intercalated and exfoliated structure and influence the longitudinal surface morphology of fibers to become rough. The roughness of composite fibers surface was proportional to the content of organic MMT. The organic MMT nanolayers could act as the heterogeneous nucleating agents to improve the crystallization, and the crystallity of composite fibers increased with the increase of organic MMT content. The breaking strength of composite fibers first increased and then decreased by increasing the amount of organic MMT. After the oxidation treatment, the breaking strength of neat PPS fibers and composite fibers declined, but the degree of breaking strength loss for composite fibers is lower than that of neat PPS fibers. The dynamic oxidation induction temperature of composite fibers also showed a significant increase by adding organic MMT. Moreover, the addition of organic MMT could limit the chemical combination of element sulfur and oxygen, retard the generation of sulfoxide groups, and induce the conversion of sulfur atoms from C-S bond to sulfone for improving oxidative stability.

Effects of montmorillonite and anatase TiO2 support on CeO2 catalysts during NH3-SCR reaction

Abstract Cerium supported on titanium oxides are regarded as the most potential alternative catalysts for removing NOx by selective catalytic reduction. However, their poor catalytic activity in low and high temperature range seriously limit their practical applications. Herein, a series of hybrid catalysts (xCe-Ti/Mt) combining certain amount of CeO2 supported on montmorillonite (Mt) and anatase TiO2 were prepared by sol-gel method for NH3-SCR reaction. xCe-Ti/Mt showed excellent catalytic activity in the temperature range of 275 °C–450 °C. The catalysts were studied by XRD, SEM, BET, XPS, H2-TPR and NH3-TPD techniques. The characterization results verified that the integration of montmorillonite and anatase TiO2 can obviously increase the surface acidity, H2 consumption, the ratio of chemisorbed oxygen Oα/(Oα+Oβ) and Ce3+/(Ce3++ Ce4+). These were believed to be the causes that promote the NH3-SCR performance of the samples. The effect of Ce concentration on the NH3-SCR reaction was also explored, the catalyst of 6Ce-Ti/Mt exhibited the best catalytic activity over the samples.