High Montmorillonite Content Research Articles

Stabilisasi Tanah Lempung Ekspansif dengan Menggunakan Campuran Soda Api (NaOH) pada Tanah Dasar di Daerah Godong - Purwodadi Km 50 Kabupaten Grobogan

Tinggi rendahnya tingkat kembang dan susut tanah lempung ekspansif ditentukan oleh kandungan montmorillonite yang sering menimbulkan masalah pada bangunan. Tujuan dari penelitian ini adalah menganalisa komposisi campuran soda api yang terbaik untuk memperbaiki sifat ekspansif tanah lempung. Penelitian ini menggunakan larutan soda api (NaOH) sebagai stabilisator dengan melalui proses pemadatan Modified Proctor. Hasil terbaik diperoleh pada 25 x tumbukan, nilai dari indeks properties menunjukkan peningkatan, Uji UCS menunjukkan penurunan, Uji CBR dengan perendaman 7 hari dengan campuran soda api 10% menunjukkan hasil yang terbaik, sedangkan nilai Tekanan Mengembang dan Potential Mengembang mengalami penurunan yang signifikan.

Composite Polymer-Clay Hydrogels Based on Bentonite Clay and Acrylates: Synthesis, Characterization and Swelling Capacity

Clay minerals, especially montmorillonite, as well as bentonite minerals with a high content of montmorillonite, have the highest ability to adsorb various organic compounds. In the East Kazakhstan region, the Manyrak deposit has huge deposits of “pink” bentonite clay (BC) with 70% of montmorillonite, extensively studied back in the 70-80-s. Now it is successfully useful in the organo-polymer composition as a mineral filler of polymer composite materials (PCM) and finds the application as domestic sorbents for the group extraction of non-ferrous ions in the purification of industrial sewage and drinking water. This article presents the results of research of creating polymer-clay composite materials based on domestic bentonite clay with improved sorption characteristics. The polymeric matrix of the composites consists of acrylates ‒ polyacrylic and polymethacrylic acids (PAA and PMAA). BC-PAA and BC-PMAA gels were obtained by radical polymerization “in situ” using the intercalation method (and wi thout it). Preliminary intercalation forms more homogeneous and interconnected composite gels. An increase in the content of the clay component and the cross-linking agent in the starting mixture results in a higher cross-linking rate and compaction of the composite gels. The behavior of the swelling of gels under the influence of temperature, pH, ionic strength indicates their polyelectrolyte character with dominant hydrogen bonds and partial hydrophobic interactions (the latter is improved in the case of BC-PMAA). The preparation of composite gels based on local BC and PAA and PMAA expands the range of composite materials and can be used as sorbents for wastewater treatment.

Characterization of hexadecyltrimethylammonium-organoclay and its individual components by thermal techniques

The properties of the materials determine their potential applications. The aim of this article is to study the properties of the organoclays using simple and rapid technologies. Organoclays with different surfactant loadings (SL) were synthesized using an Argentine bentonite with a high content of montmorillonite (Bent) and hexadecyltrimethylammonium bromide as cationic surfactant. The samples were characterized using thermal techniques. The results revealed that the hydrophilicity of the organoclays decreases with increasing SL until the SL reaches 0.8 times the cation exchange capacity of the clay; and remains constant at a higher surfactant load. The stability of organoclays was inversely proportional to the SL of each sample. The layers showed a stabilization of approximately 40\(^{\circ }\)C for their structural transformation temperature, caused by the presence of the surfactant. In addition, at a SL <1.0 the surfactant presented a ‘liquid-like’ structure in the interlayer space, whereas at a SL >1.0 the structure was ‘solid-like’.

ORGANOCLAY-BASED ADDITIVE FOR PAINTWORK MATERIALS

Ponte Academic JournalJan 2017, Volume 73, Issue 1 ORGANOCLAY-BASED ADDITIVE FOR PAINTWORK MATERIALSAuthor(s): Petukhova N.A. ,Loganina V.I., Skachkov Y.P.J. Ponte - Jan 2017 - Volume 73 - Issue 1 doi: 10.21506/j.ponte.2017.1.5 Abstract:The information about the technology of organo-mineral additive based on clay with a high content of montmorillonite. Given the limited reserves bentonit clay, used of organic- additives on based multimineral clays with a high content of montmorillonite. Are established the concentration of plasticizer by the change of surface tension of the plasticizer solution. Shows the use of organoclay in the formulation of polystyrene paints. Comparative properties of polystyrene paints modified with organoclay and coatings on their basis are given. Download full text:Check if you have access through your login credentials or your institution Username Password

Stabilisasi Tanah Lempung dengan Mengunakan Larutan Asam Sulfat (H2so4) pada Tanah Dasar di Daerah Godong - Purwodadi Km 50 Kabupaten Grogogan

An expansive clay soil material that is composed of various minerals include kaolinite, montmorillonite and illite group. Mineral montmorilinite have the sensitivity to the effects of the water is very easy to expand and contract. High and low levels of development (swelling) and shrinkage (shrinkage) expansive clay is determined by the high and low content of montmorillonite on expansive clay granules. Because of these properties are very high content of montmorillonite often cause problems in the building. This study uses a solution of sulfuric acid (H2SO4) as a stabilizer through the compaction process Modified Proctor on OMC Proctor standard by the number of collisions each is 10 x, 25 x and 56 x, and the amount of additional water in cc on dry ground, with variations in increments of 100%, water by 90%:10% H2SO4, water by 80%: 20% H2SO4 and water by 90%: 30% H2SO4. This research was conducted testing-testing in the laboratory include: physical properties, mechanical properties. swelling pressure, swelling potential and CBR with curing and no curing. Results of the test-the test, can increase the value of physical and mechanical properties, while pergujian against swelling pressure and swelling potential is not significantly increased.

Experiment Analysis on the Mechanical Properties of the Horizontally Stratified Mudstone

In order to analyze the physical and mechanical properties of the stratified mudstone, the specimens are collected from southwest Nanning , Guangxi, China. X-ray diffraction is used to analyze the mineral composition, the high montmorillonite content affects softening and expansion behavior of the mudstone. The strength tests show that the strength of stratified mudstone is low. When weakness layer exists in the mudstone, the strength is controlled by the soft layer. By long-term immersion in water, the strength will be approximately 76% to 85% reduction. The uniaxial compressive strength tests show that the ratio between soft layer and hard layer under natural is 0.17. The ratio between soft layer and hard layer under saturation is 0.10, under air seasoning is 0.42.

High montmorillonite content may affect soil microbial proteomic analysis

We studied the effects of high montmorillonite content in soil on the proteomic analysis of Cupriavidus metallidurans CH34 inoculated into model soils, containing a montmorilonite gradient. Bacterial proteomic analysis was conducted by two-dimensional gel electrophoresis (2-DE) coupled to mass spectrometry. The results showed that increasing the montmorillonite content in artificial soil the bacterial viability did not affect but the amount of extracted proteins and the number of protein spots in 2-DE decreased. Higher soil montmorillonite content also affected the protein identification, likely due to montomrillonite-induced conformational changes in proteins or degradation. Therefore the development of soil proteomics needs to increase the studies of interaction between protein and soil components as clays or humic substances. This experiment showed how the use of a model study can be an help to achieve more information about the complexity of soil and the fate of proteins in soil.

Multifunctional Nanoclay Hybrids of High Toughness, Thermal, and Barrier Performances

To address brittleness of nanoclay hybrids of high inorganic content, ductile polymers (polyethylene oxide and hydroxyethyl cellulose) and montmorillonite (MTM) have been assembled into hybrid films using a water-based filtration process. Nacre-mimetic layered films resulted and were characterized by FE-SEM and XRD. Mechanical properties at ambient condition were studied by tensile test, while performance at elevated temperature and moisture conditions were evaluated by TGA, dynamic vapor sorption, and dynamic thermomechanical and hygromechanical analyses. Antiflammability and barrier properties against oxygen and water vapor were also investigated. Despite their high MTM content in the 60-85 wt % range, the hybrids exhibit remarkable ductility and a storage modulus above 2 GPa even in severe conditions (300°C or 94% RH). Moreover, they present fire-shielding property and are amongst the best oxygen and water vapor barrier hybrids reported in the literature. This study thus demonstrates nanostructure property advantages for synergistic effects in hybrids combining inexpensive, available, and environmentally benign constituents.

Partition and characterization of cadmium on different particle-size aggregates in Chinese Phaeozem

Organic-mineral complexations can be isolated from bulk soil by physical disaggregation followed by density fractionation for further examination of the patchy nature of aggregates distributed in soil. Phaeozem, which is a specific regional soil in China with high organic matter, was selected for fractionation into particle-size aggregates with clay, silt, fine sand and coarse sand. Partition and characterization of the adsorbed Cd in the bulk soil and various aggregates of Phaeozem were investigated by Fourier-transform infrared (FTIR) spectrometry, X-ray diffraction (XRD) and sequential extraction. The results indicated that Cd could be differently partitioned into various particle-size aggregates, which could be characterized by FTIR and XRD with the same results. Clay had the highest adsorption capacity for the relevant high content of montmorillonite, kaolinite and chlorite, as well as organic matter and cation exchange capability. The fine fraction had the greatest potential availability and mobility of Cd because it was primarily absorbed on the surface of kaolinite. The texture of Phaeozem likely contributed to the metal fate and behavior in the soil environment, as well as other properties such as organic matter, cation exchange capacity and surface area.

How do the shape of clay and type of modifier affect properties of polymer blends?

AbstractPolyamide 6/ethylene–propylene–diene metallocene terpolymer/(ethylene–propylene–diene copolymer)‐graft‐(maleic anhydride) blends with clay (3 and 5 wt % depending on the formulation), different clays (montmorillonite and sepiolite) and different surface functionalization (ammonium salts and silanes) were studied to analyze the effect of the shape of clay and type of modifier on their properties. The results have shown that sepiolite has higher influence on the morphology and on the mechanical properties than montmorillonite. In that sense, blends with 3 wt % of sepiolite have reached the best balanced properties, i.e., tensile modulus and impact strength, than their homologous with montmorillonite. Furthermore, the blends with 3 wt % of sepiolite have reached the highest mechanical properties compared with blends with higher montmorillonite content. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Modelling the swelling and osmotic properties of clay soils. Part I: The phenomenological approach

Clay soils with a high montmorillonite content in their mineralogical composition are characterized by swelling and osmotic properties like biological tissues and polyelectrolyte gels. These phenomena are caused by the very high specific surface (≈760 m 2/g) and the negative electric charge of montmorillonite lamellae, which determine an interaction with the charge of the ions present in the pore solution. The interest in modelling the behavior of such soils is related to the evaluation of their performances as hydraulic and contaminant barriers in landfill and soil remediation applications. The theoretical approach of the thermodynamics of irreversible processes is applied to find suitable phenomenological constitutive equations, under the assumptions of a unidimensional geometry, infinitesimal strains of the solid skeleton and isothermal conditions. The approach is related to a saturated porous medium, whose voids are filled by an electrolyte solution containing an unspecified number of ions. To make the approach purely phenomenological, the parameters introduced into the constitutive equations are expected to be measured by macroscopic experimental tests, without any specification of the physical and chemical phenomena that occur at the pore scale. The constitutive equations allow the coupled transport and consolidation problem to be formulated for a clay barrier.

Modelling the swelling and osmotic properties of clay soils. Part II: The physical approach

The increasing use of clays, with a high montmorillonite content in their mineralogical composition, as hydraulic and contaminant barriers for landfill and soil remediation applications needs to be supported by an adequate theoretical modelling of the mechanical behaviour and transport properties, in order to assess the expected performances in the long term. The framework of the thermodynamics of irreversible processes was adopted in a companion paper to derive phenomenological constitutive equations for a clay soil characterised by swelling and osmotic phenomena, without specifying any of the physical mechanisms that occur at the pore scale. In this paper, a physical approach is proposed in order to provide an interpretation of the phenomenological parameters, obtained from laboratory tests. The soil structure is assumed to be constituted by montmorillonite lamellae, that can be aggregated to form the so-called tactoids, which have a slit-like geometry. Chemical equilibrium is assumed to be established between the bulk electrolyte solution and the internal pore solution at the macroscopic scale, so that the hydraulic pressure and ion concentrations can be evaluated through the Donnan equations. Water and ion transport is described at the pore scale through the generalised Navier–Stokes equation and the generalised Nernst–Planck equations, respectively. Mechanical behaviour is modelled taking into account intergranular contact stresses. The approach is applied to interpret literature experimental results, showing how it can reduce the number of tests that need to be carried out and provide insight into the physical mechanisms that determine the observed phenomena.

Preparation and Application Performance Study of High Purity Montmorillonite

In order to research the colloidal and thixotropic performance of the inorganic gel prepared by high purity montmorillonite, this study uses the moderate grade bentonite ores from Weifang (China) as raw material. Two-stage hydrocyclone classification was applied to obtain the high purity montmorillonite with its content of 94.8 per cent. In contrast to other methods of montmorillonite purification, two-stage purification by hydroclone has the advantages of larger throughput and easily achieving auto-control in industry, and products with different montmorillonite content can be obtained by this method. And then the inorganic gel was prepared by the prepared high purity montmorillonite , its colloidal and thixotropic performances were further studies. Research results show that the inorganic gel belongs to plastic body liquidity, the viscosity decreases with the increase of the shear rate, the static and dynamic shearing stress values are 33.98 Pa and 91.89 Pa respectively, and the thixotropic value is 95.2 dyne·s/cm2, which indicates that it has preferable colloidal and thixotropic performance. Montmorillonite inorganic gel prepared by bentonite with high montmorillonite content and low- layer charge has better gel performance. The application result of inorganic gel in dentifrice and medicine shows that it has excellent effect.

Apoptosis and cytotoxicity of oligo(styrene-co-acrylonitrile)-modified montmorillonite

To evaluate the cytotoxic effect and the mechanism of the apoptosis of oligo(styrene-co-acrylonitrile)-modified montmorillonite (PSAN-MMT), the present study is focused on the involvement of anti-proliferation, lactate dehydrogenase release, apoptosis level, caspase 3 activity, transcriptional activity of apoptosis-related gene and apoptosis-related protein and mRNA level. Non-cytotoxic montmorillonite (MMT) incubated cells were used as control. Little cytotoxicity was observed in PSAN-MMT treated cells, and lower level of apoptosis was induced by PSAN-MMT when cells were incubated with high montmorillonite content (1g/L). The apoptosis seemed to follow a transcription-dependent route by activating proapoptotic genes such as p53 and p21. The modified MMT could be a promising candidate of biosafety controlled-release carrier for large drug molecules and for gene delivery.

Advances on the knowledge of the buffer/backfill properties of heavily-compacted GMZ bentonite

GMZ bentonite has been selected as a potential material for the construction of engineered barrier in the Chinese program of geological nuclear waste disposal, for its high montmorillonite content, high cation exchange capacity (CEC) and large specific surface etc. Studies on mineralogy and chemical composition, mechanical properties, hydraulic behavior, swelling behavior, thermal conductivity, microstructure and volume change behavior of GMZ bentonite were performed from 1980s. Based on a review of the former studies, achievements on experimental and theoretic results obtained on compacted GMZ bentonite specimens including basic properties, thermal, hydraulic and mechanical behaviors are presented in this paper. Results show the thermal conductivity of GMZ bentonite and the bentonite-based mixtures influenced by its dry density, water content, mixture of other materials and degree of saturation etc. Water retention capacity of highly-compacted GMZ bentonite decreases as the temperature increases under confined and unconfined conditions. The hysteretic behavior in the water retention curves of the compacted GMZ bentonite is not so significant at 20 or 40 °C. The unsaturated hydraulic conductivity of compacted GMZ bentonite under unconfined conditions is higher than that of under confined conditions. This is possibly induced by the difference in the mechanism of microstructural changes during hydration under different confining conditions. The compaction curves for GMZ bentonite with different dry densities are clearly step-phased. And the optimum water content for GMZ bentonite is about 15%. An exponential relationship between swelling pressure and dry density of highly-compacted GMZ bentonite was determined for the prediction of swelling pressure. Furthermore, the void ratio after swelling for unconfined sample also can be predicted using diffuse double layer (DDL) theory.

Engineering geological properties of altered rocks and implications for railway construction in the Sanjiang orogenic belt, Southwest China

The Yunnan-Tibet Railway, currently under construction, crosses five altered rock zones in the Sanjiang orogenic belt, southwestern China. They are mainly montmorillonitized rock zones formed by hydrothermal alteration. Based on field investigation and laboratory tests, this paper presents the geological characteristics and engineering properties of the altered rocks encountered during the construction of the railway. Being characterized by a high montmorillonite content, high degree of alteration, high physico-chemical activity and high swelling potential, these rocks always lead to engineering geological problems. The concept of “alteration coefficient” is put forward; the greater the alteration coefficient, the higher the alteration degree and swelling potential. Countermeasures are proposed to tackle the engineering problems during tunnel construction caused by the altered rock.

Synthesis and thermal oxidative degradation of a novel amorphous polyamide/nanoclay nanocomposite

A novel amorphous polyamide/montmorillonite nanocomposite based on poly(hexamethylene isophthalamide) was successfully prepared by melt intercalation. Wide angle X-ray diffraction and transmission electron microscopy showed that organoclay containing quaternary amine surfactant with phenyl groups was delaminated in the polymer matrix, resulting in well-dispersed morphologies even at high montmorillonite content. Thermal oxidation behavior of the polymer nanocomposites was studied by thermogravimetric analysis (TGA), and the chemical evolution in the solid residue was monitored by elemental analysis and Fourier transform infrared spectroscopy (FTIR). TGA results showed that the addition of well-dispersed organoclay resulted in a substantial increase (30 °C) in the onset degradation temperature of the nanocomposites as compared to the homopolymer. Elemental analysis on the solid residue indicated that the presence of nanoclay resulted in char formation with greater thermal stability. FTIR spectra showed that thermal degradation in air occurred via both oxidative and non-oxidative mechanisms simultaneously. In the homopolymer, the oxidative mechanism was more dominant. However, with the addition of well-dispersed organoclay, the non-oxidative pathway became more significant. Hence the presence of delaminated nanoclay layers could effectively retard thermo-oxidative degradation of the amorphous polymer by constraining the polymer chains and slowing down the rate of oxygen diffusion through the nanocomposites, but it was not as effective in hindering the non-oxidative degradation reaction pathway.

Morphology and mechanical properties of a novel amorphous polyamide/nanoclay nanocomposite

AbstractA novel amorphous polyamide/montmorillonite nanocomposite based on poly(hexamethylene isophthalamide) was successfully prepared by melt intercalation. Wide angle X‐ray diffraction and transmission electron microscopy showed that organoclay containing quaternary amine surfactants with phenyl and hydroxyl groups was delaminated in the polymer matrix resulting in well‐exfoliated morphologies even at high montmorillonite content. Differential scanning calorimetry results indicated that clay platelets did not induce the formation of a crystalline phase in this amorphous polymer. Tensile tests demonstrated that the addition of nanoclay caused a dramatic increase in Young's modulus (almost twofold) and yield strength of the nanocomposites compared with the homopolymer. The nanocomposites exhibited ductile behavior up to 5 wt % of nanoclay. The improvement in Young's modulus is comparable with semicrystalline aliphatic nylon 6 nanocomposites. Both the main chain amide groups and the amorphous nature of the polyamide are responsible for enhancing the dispersion of the nanofillers, thereby, leading to improved properties of the nanocomposites. The structure‐property relationship for these nanocomposites was also explored. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 2605–2617, 2008

Selection and Basic Properties of the Buffer Material for High‐Level Radioactive Waste Repository in China

AbstractRadioactive wastes arising from a wide range of human activities are in many different physical and chemical forms, contaminated with varying radioactivity. Their common features are the potential hazard associated with their radioactivity and the need to manage them in such a way as to protect the human environment. The geological disposal is regarded as the most reasonable and effective way to safely disposing high‐level radioactive wastes in the world. The conceptual model of geological disposal in China is based on a multi‐barrier system that combines an isolating geological environment with an engineered barrier system. The buffer is one of the main engineered barriers for HLW repository. It is expected to maintain its low water permeability, self‐sealing property, radio nuclides adsorption and retardation properties, thermal conductivity, chemical buffering property, canister supporting property, and stress buffering property over a long period of time. Bentonite is selected as the main content of buffer material that can satisfy the above requirements. The Gaomiaozi deposit is selected as the candidate supplier for China's buffer material of high level radioactive waste repository. This paper presents the geological features of the GMZ deposit and basic properties of the GMZ Na‐bentonite. It is a super‐large deposit with a high content of montmorillonite (about 75%), and GMZ‐1, which is Na‐bentonite produced from GMZ deposit is selected as the reference material for China's buffer material study.

Gas intrusion in saturated bentonite – A thermodynamic approach

A homogeneous and isotropic model of pressure response in saturated bentonite with high montmorillonite content is presented. The model is based on basic thermodynamic relations and is characterized by one single function, P s( w), the measured swelling pressure for a given water ratio. It is applied to gas intrusion in saturated bentonite, a process of great practical interest, and gives both a simple criteria for gas intrusion as well as providing a theoretical framework for interpreting gas migration experiments. The predictions of the model are found to agree well with literature data on Wyoming type bentonite (MX-80).