Kind Of Clay Research Articles

A comparative study of thermal and morphological properties of polyhydroxybutyrate/bentonite clay and polyhydroxybutyrate/organically modified nanoclay composites

AbstractBacterial biopolymers are polymeric materials that are produced by microorganisms. Due to its inherent brittleness and slow crystallization rate, it has limited industrial applications. Polyhydroxybutyrate (PHB) composites have been created to tackle these problems by combining non‐modified clay and organically modified nanoclay. In this study, 3 wt % of two different kinds of clays were incorporated to PHB through melt mixing method to prepare composites of PHB/bentonite Clay (BC) and PHB/organically modified nanoclay (Cloisite 30B (C30B)). The characteristics of PHB and its composites were investigated to study their thermal, rheological, morphological, surface properties and biodegradability. The study showed that the incorporation of C30B and BC into the PHB matrix improved the crystallization temperature to 97.30 and 96.82°C respectively as compared to the crystallization temperature of the PHB matrix as 88.79°C. The increased result of storage modulus (G') and loss modulus (G") in its rheological analysis confirmed that there was proper melt intercalation in case of both PHB/C30B and PHB/BC composite. The morphological characteristics results provide less coagulation and good clay distribution over the polymer matrix which leads to improved contact angle of 66.60° and 68.15° in case of PHB/BC and PHB/C30B respectively. Further both the composites and PHB film showed biodegradation characteristics. In the realm of nanocomposite films for various applications, where the cost is the major consideration, the PHB/BC composite films are promising economical solution in place of high cost PHB/C30B nanocomposite films.Highlights The BC/PHB and C30B/PHB composite films were developed using a micro‐compounder. Each films having a thickness 0.6 mm was extruded using a die. Uniform dispersion of clay is characterized from SEM. PHB with clay, boosted complex viscosity, storage, and loss modulus. PHB decomposes readily in compost, as do PHB/C30B and PHB/BC composites.

Exploring the potential of clay catalysts in catalytic pyrolysis of mixed plastic waste for fuel and energy recovery

Developing low-cost and high-activity catalysts is one of the keys to promoting the catalytic pyrolysis of waste plastics to fuels for plastic recycling. This work studied the effect of clay as the catalyst on mixed plastic pyrolysis for fuel and energy recovery. Four kinds of clay, including nanoclay, montmorillonite, kaolin, and hydrotalcite, were used as catalysts for the pyrolysis of mixed plastic consisted of polyethylene terephthalate, polystyrene, polypropylene, low-density polyethylene, and high-density polyethylene. The product yield and distribution varied with different clay in pyrolysis. The highest yield of oil was 71.0 % when using montmorillonite as the catalyst. While the highest contents of gasoline range hydrocarbons and diesel range hydrocarbons in the oil were achieved when using kaolin and nanoclay, respectively as catalysts. For the gas products, the CO, C2H4, C2H6, C3H6, and C4H10 increased with decreased CO2 in the gaseous products when using clay as catalysts. In general, the mild acidity of clay catalyst was essential to improve the oil yields and the proportion of the gasoline or diesel range fuels in the catalytic pyrolysis of mixed plastic waste.

Dyeing Jumput Batik Using Clay Media From the Malo Region, Bojonegoro

Indonesian clay, with red color type was one kind of clay with wide distribution and yet to be well managed. The clay can be used as natural coloring material as a substitute for the textile dyes. This study aims to determine the effect of soaking time on the color produced and the effect of clay solution composition on the color produced. The variable used in this research is the variation of the solution composition (1kg/ 1 L, 1kg/ 2L, 1kg/ 3L) and variation of soaking time (24 hours, 48 hours, and 72 hours). The results of the research show that on the solution composition variation obtained the most concentrated color at 1kg/ 1L solution, and at the soaking time variation obtained the most concentrated color at 72 hours with the intensity of light that can penetrate the fabric is very small.

Metabentonite and metakaolin-based geopolymers/zeolites: relation between kind of clay, calcination temperature and concentration of alkaline activator

In this paper, the composition and properties of two different activated calcinated clays were investigated under selected curing conditions. The tendency of metabentonite and metakaoline to form geopolymers and zeolites was investigated by FTIR spectroscopy, TGA and DSC techniques, PXRD, HT-PXRD, SEM, and BET-N2 adsorption analyses. The selection of the optimal sample compositions was done on a basis of preliminary results obtained from bentonite and kaolin clays activated at calcination temperatures (700, 750, 800 °C) with a holding time of 3 h in a combination with different NaOH concentrations (5, 10, 20 mass%). In a more detailed examination, the samples calcined at a temperature of 800 °C with different NaOH concentrations were studied. For metakaolin-based samples, dominant geopolymer formation was achieved using 5 mass% NaOH. The zeolite amount increased concomitantly with the concentration of the alkali activator, whereas zeolite A and zeolite P were determined as the predominant phases. For metabentonite-based samples, 10 mass% NaOH concentration was found to be optimal by the means of geopolymer formation. At higher alkaline activator concentrations, the presence of zeolitic phases faujasite and gobbinsite was confirmed. However, the determined degree of crystallinity was significantly lower than in the corresponding activated metakaolin samples. With a gradual increase in NaOH concentration, the specific surface area of the metabentonite-based samples increased reaching a value of 218.95 m2 g−1 promising for adsorption applications. The opposite effect was observed for the metakaolin-based samples, and this result is caused by the increased formation of zeolite phases and corresponding changes in their channel dimensions.

Comparative Study of Protection Efficiency of C-Steel Using Polystyrene Clay Nanocomposite Coating Prepared from Commercial Indian Clay and Local Khulays Clay

This work aimed to compare the coating protection efficiency of C-steel using two kinds of clay: a local Khulays clay (RCKh) from Saudi Arabia and a commercial clay (CCIn) from India. Clay-based polymer nanocomposites have a unique layered structure, rich intercalation chemistry, and availability at low cost. They are promising reinforcements for polymers. The raw clay for both clay types was washed before being treated with NaCl to produce sodium clay (NaC). The cationic surfactant cetylpyridinium chloride (CPC) was then used to convert the NaC into the organoclay (OC) form. Polystyrene/organoclay nanocomposites (PCNs) were prepared by combining different concentrations of organoclay (1%, 3%, and 5% OC) in toluene solvent and polystyrene (PS) as the matrix. To ensure the success of the PCN modification process, the organoclay and PCN films were characterized using a variety of techniques, including Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The shifts in the FT-IR spectra after the CPC treatment of NaC confirmed the presence of CPC in the organoclay samples and the presence of OC in the PCNs. The exfoliated structure was obtained from the XRD spectrum for low clay loading (1–3% PCN), while the intercalated structure was the dominant form for the 5% PCN. The XRD results were confirmed by TEM images. To calculate the coating efficiency of the PCNs, various electrochemical methods were used. The electrochemical measurements included electrochemical impedance spectroscopy (EIS), the electrochemical frequency modulation (EFM) method, and Tafel plots. The PCN with a concentration of 1 wt.% OC has a fully exfoliated structure and higher coating efficiency than the PCNs with partially exfoliated structures (3 wt.% and 5 wt.%). It was found from the Tafel plots that commercial Indian clay has better corrosion protection (81.4%) than local Khulays clay (60.2%). A comparison with other studies using current density values shows that our results are superior to those of many studies.

Potential of using organic additive produced with kaolin-clay in bituminous roadways

Roadway performance can be improved through utilizing modified bitumens and/or modified bituminous mixtures within the structure. Regarding this view, Kaolin-containing-Organic Additive Material (K-c-OAM) has been synthesized chemically in the study. K-c-OAM is a new additive material obtained in laboratory conditions with the reaction of kaolin, a kind of clay, and ethylene glycol. 50/70 penetration grade neat bitumen has been modified by K-c-OAM in concentrations ranging from 1 % to 4 %. The effects of K-c-OAM on both bitumen and bituminous mixture properties have been investigated by experiments including rotational viscosity, penetration, softening point, ductility, Nicholson stripping and Marshall tests. Marshall Stability values of the bituminous mixtures have been found to be increased at a level varying between 6.4 % and 9.5 % by K-c-OAM modified bitumens. In areas where hot climate is not dominant, K-c-OAM modified roadway pavements can said to provide better performance according to the laboratory findings.

Study on the Effect of Moisture Content and Dry Density on Shear Strength of Silty Clay Based on Direct Shear Test

Silty clay is a kind of clay with more powder group than sand group, and its shear strength is mainly influenced by moisture content, dry density, and particle gradation. In this study, the deformation characteristics of silty clay under different normal pressure conditions were investigated from the perspective of control variables through indoor direct shear experiments. The results of the study show that with the same guaranteed moisture content, it can be seen from the fitted curves that with the increase of dry density, the arrangement of soil particles becomes more compact, the cementation between soil particles is strengthened, the shear strength increases, the occlusal friction increases due to the change of arrangement between soil particles, and the angle of internal friction and cohesion are relatively larger; in addition, when the dry density is the same, with the increase of moisture content, the soil becomes softer, and the form of water in the soil particles changes. In addition, when the dry density is the same, as the moisture content increases, the soil becomes softer, the presence of water between the soil particles changes, resulting in the weakening of the occlusion between the soil particles, the shear strength decreases, and the cohesion and the angle of internal friction relatively decrease.

A study to improve the compatibility of PCE with cement paste containing clay

Due to the stronger adsorption of polycarboxylate ether (PCE) superplasticizers to clay than cement particles, PCE fails to adjust the workability of cement paste containing clay. In this study, hexadecyl trimethyl ammonium bromide (CTAB) was used as an efficient clay-specific sacrificial agent to make PCE more compatible in cement paste containing Montmorillonite (Mt, one kind of clay). The experimental results indicated that CTAB can obviously improve the fluidity of cement paste containing Mt, with the increasing of spread diameter in the mini slump test. CTAB as a macromolecular compound with positive charge was able to interact with Mt by electrostatic adsorption, which was effective to hinder the hydration and swelling of Mt and therefore broke the absorption of Mt to PCE. In conclusion, CTAB has great potential to resolve the incompatibility of PCE to cement paste containing clay and contributes to the corresponding enhanced workability.

INFLUENCE OF EARTH COMPOSITION ON ADSORPTION CAPACITY OF METHYLENE BLUE DYE

Final properties of unfired earth are influenced by composition of earth mixtures. Methylene blue test could be useful method for analysis of earth composition. This would facilitate of designing unfired earth building structures because composition of natural earth is various. Principle of methylene blue test is measure of amount of adsorbed methylene blue dye by clay. The essential component of earth mixtures is clay because clay fulfils a function of binder. Experimental measure of adsorption capacity of individual kind of clay is described in this paper. Adsorption capacity was investigated in montmorillonite, kaolinite, illite-kaolinite and illite clays. The obtained results show that the adsorption capacity of clays is significantly different.

SOME CHARACTERISTICS OF BUILDING MATERIALS OF ANCIENT KYYIVAN MONUMENTS OF THE X-TH - THE XIІ-TH CENTURIES

The development of brickwork technique in ancient Kyyiv dates back to the X- th century. Old Rus` monuments’ masonry was made of large thin bricks called “plynfa” and lime-and-ceramic mortar. The size of the X-th – the XII-th brick sides varies from 27 to 36 cm, its thickness – from 2.5 to 4.5 cm.
 Different kinds of clay and loess extracted from the territory of Kyyiv and its vicinities were used as a raw material for brick and ceramic addition to mortar. That is why bricks in Kyyivan monuments differ in colour from light yellow to orange and dark red. Some gruss or cut straw were used as addition to fat clay.
 Limestone was brought to Kyyiv from Chernihiv area and lime mortar was produced in lime kilns situated near building sites. Ceramic addition to mortar called “tsemianka” was of refined clay, and crushed brick waste was used as well.
 Bricks were burnt under the temperature of 1000 – 1200 degrees C. That’s why bricks were very firm regardless of chink-like pores appeared as a result of hand-moulding of brick.
 The author took some investigation for the purpose to determine physical and mechanical properties of ancient bricks of Kyyivan monuments. Bricks were picked out of excavations or waste after building repairs. Small cubes were cut out of bricks with the height equal to brick thickness. Those samples were examined concerning their strength by compressing them perpendicularly to the sides the bricks were bedded in mortar.
 The strength of samples varied from 100 to 200-300 kg per sq.cm, water absorption was 10 % to 20 %. Some bricks taken from the Cathedral of the Assumption of Kyyiv-Pechersk monastery were the most firm. The strength of those samples was about 400-500 kg per sq. cm, their water absorption was the smallest, about 5.6 %.
 Because of high porosity and water absorption of building materials the surface of ancient masonry was exposed to destruction under the influence of temperature overfalls and precipitation, as it can be seen on the open parts of walls of the Old Rus` monuments. To prevent destruction of masonry, the walls of ancient monuments were covered with fine lime-and-ceramic mortar. Fragments of original plaster can be found on the walls of the XI-th century monuments St.Sophia Cathedral and St.Michael Church of Vydubychy monastery in Kyyiv.
 High level of well-developed building technique and high quality of building materials caused durability of ancient masonry and constructions in Kyyivan monuments, which preserved until nowadays.

Hydrothermal clays and their influence on slope stability in residual soils of Southern Brazil

Clayey veins may develop in areas of hydrothermal activity by seepage of hot water through the soil and rock. In a slope located in Southern Brazil, such veins occur along the slip surface of some landslides. This paper aims to characterize this kind of clay and investigate its influence over the stability of that slope. An electro resistivity survey had been conducted to characterize the soil profile, and SPT boreholes were used to confirm geophysical data. An experimental laboratory campaign included the investigation of chemical, mineralogical, and geotechnical properties of these clay veins and the embedding residual soil. Drained shear strength of residual soil was measured through triaxial tests, and residual strength was measured for both materials using a ring shear apparatus. A series of limit equilibrium analyses were conducted to assess the role of clay veins on the slope stability. The geometrical discretization of veins is a difficult task, and an approach based on the assumption of overall shear strength is required to establish the operational shear strength parameters for this slope. A series of back analyses showed that failure surfaces consistent with those observed in the field were only reproduced when the adopted shear strength parameters of the soil mass were c’ = 5 kPa and φ’ = 20°. Considering the measured shear strength parameters of the hydrothermal clay c’ = (0 and φ’ = 8.5°) and the pattern in which the clay veins occur, it seems that they do not fully control the slope stability, but they significantly reduce the global cohesion and the average mass friction angle.

Physicochemical changes of lead(II) contaminated sand–clay mixture

In this study, the influence of lead nitrate as a hazardous environmental pollutant was studied through experimental tests to assess its physicochemical effects in soils. Artificially contaminated soil specimens were prepared using sand and two kinds of clays. Direct shear, consolidation, electrical resistivity and unconfined compression tests were conducted. In addition, the influence of lead cation on atterberg limits, pH and particle size distribution of soils was evaluated. Overall, the presence of lead ion in mixtures including bentonite increased the shear strength due to a flocculated structure and replacement of sodium cations by hydrogen ions which is along with the reduction of double-layer thickness. However, due to the broken bonds and rearranging of kaolinite particles to a weaker form, the strength of sand–kaolinite mixtures decreased with the increase of lead concentration. Based on the obtained results, with the addition of lead concentration, the compression index and electrical resistivity of all specimens decreased. Due to the acidic nature of positively charged lead cations, pH of the specimens directly affected and tended to a more acidic range. These findings indicate that the presence of lead ion improves the strength of some kinds of soils including bentonite and decreases the strength parameters of soils with kaolinite.

Shreds of Matter: Cormac McCarthy and the Concept of Nature

Shreds of Matter: Cormac McCarthy and the Concept of Nature

DIAGNOSTICS OF UNFIRED EARTH WITH METHYLENE BLUE TEST

Unfired earth is important historic building material. Final properties of unfired earth constructions are influenced by amount and kind of clay in earth mixtures. Methylene blue test is a method that helps determining the type and amount of clay in earth mixtures. This paper describes research focused on using methylene blue test for analysis of methylene blue dye absorption by montmorillonite clay. The first part of the paper describes principle of methylene blue test and course of experimental measurement. The second part deals with analysis of obtained results. On the basis of experimental measurement it can be stated that methylene blue test is influenced by the stirring time of earth samples with methylene blue solution and dependence between amount of methylene blue dye absorption and amount of montmorillonite clay in earth samples is linear.

Using the clay slip game in art therapy: a sensory intervention

ABSTRACT The goal of the present study was to achieve a better understanding of the experience of playing with slip and the ways in which participants experience the Clay Slip Game and how they perceive the therapeutic qualities of the material, thus including the potential for art therapists to add the Slip Game to their toolbox. Ten experienced qualified art therapists and 48 art therapy students took part. All participants engaged in the Slip Game during the study and reported their experiences in an interview (therapists) or in written personal reflections (students). Data analysis adhered to the principles of Grounded Theory [Charmaz (2006). Constructing grounded theory: A practical guide through qualitative analysis. London: Sage Publications]. The findings indicate that the experience of the Slip Game is mainly a sensory (tactile), playful, pleasant and calming experience of making without the need to produce an end product. The experience is more internal (meditative) and stimulates feelings of regression. The therapeutic qualities of the material, as discussed by the participants, are related to the regressive and sublimative processes afforded by the material, and as a material that enables sensory, behavioural, emotional, and motor regulation. Plain-language summary Art therapy is a type of psychotherapy that uses artistic materials and creative processes in the therapeutic process. Since art materials are the primary tools through which the art therapy processes occur, therapists need to have an in-depth understanding of the art materials they offer to their clients [Moon (2010). Materials & media in art therapy: Critical understandings of diverse artistic vocabularies. New York, NY: Routledge]. Slip is a mixture of water with an additional substance that produces a thick and saline-type paste [De Montmollin (2010). The barbotine game-challenge of creativity. Antwerpen.]. It can be made by diluting and filtering any kind of clay to make it semi-fluid. Playing with slip as a distinct and separate technique was defined as a ‘game’ by Daniel De Montmollin, a ceramicist. De Montmollin created the Slip Game as a way to help people free themselves from internal and external censorship or criticism. The goal of this study was to understand the participants’ experience of the Slip Game and whether they found the process therapeutic. Forty-eight art therapy students and 10 art therapists took part in the study. After engaging in the Slip Game, the art therapists reported their experiences in an interview and the students wrote personal reflections. These were then analysed using Grounded Theory. The findings show that the participants experienced the Slip Game as mainly sensory and reported it was pleasant, calming, playful and tactile, a way of ‘making’ without the need to produce an end product. They also found the experience to be meditative, that it stimulated feelings of regression and felt that engaging with slip also improved behaviour, emotional control and fine hand-movement skills.

Artificial ligament made from silk protein/Laponite hybrid fibers

With developments in tissue engineering, artificial ligaments are expected to be future materials for anterior cruciate ligament (ACL) reconstruction. However, poor healing of the intraosseous part after ACL reconstruction significantly hinders their applications in this field. In this study, a bioactive clay Laponite (LAP) was introduced into the regenerated silk fibroin (RSF) spinning dope to produce functional RSF/LAP hybrid fibers by wet-spinning. These RSF/LAP hybrid fibers were then woven into artificial ligament for ACL reconstruction. The structure and mechanical properties of RSF/LAP hybrid fibers were extensively studied by different means. Results confirmed the presence of LAP in RSF fibers and revealed that the addition of LAP slightly deteriorated the comprehensive mechanical properties of RSF fibers. However, they were still much tougher (with higher breaking energy) than those of degummed natural silkworm silk that was earlier used for making artificial ligament. The artificial ligament woven from RSF/LAP hybrid fibers showed better cytocompatibility and osteogenic differentiation with mouse pre-osteoblasts in vitro than those made from degummed natural silkworm silks and pure RSF fibers. Furthermore, in vivo study in a rat ACL reconstruction model demonstrated that the presence of LAP in the artificial ligament could significantly enhance the graft osseointegration process and also improve the corresponding biomechanical properties of the artificial ligament. Based upon these results, the RSF/LAP hybrid fibers, which can be mass produced by wet-spinning process, are believed to have a great potential for use as artificial ligament materials for ACL reconstruction. Statement of SignificanceIn this study, we successfully introduced Laponite (LAP), a kind of clay that has the function of osteogenic induction, into regenerated silk fibroin (RSF) fibers, which was prepared by a mature wet-spinning method developed in our lab. We believe that through artificial spinning, additional functional components can be added into RSF fibers, which one can hardly achieve with natural silks. We showed that the artificial ligament woven from RSF/LAP hybrid fibers had better cytocompatibility and osteogenic differentiation for mouse pre-osteoblasts in vitro, and significantly enhanced the graft osseointegration process and improved the corresponding biomechanical properties in a rat ACL reconstruction model in vivo, compared to those artificial ligaments made from degummed natural silkworm silks and pure RSF fibers.

Permeability Characteristics of Model Clay-Based Cutoff Wall Backfills

Clay-based cutoff walls have been widely applied in the landfills or site remediations. The factors that affect the hydraulic conductivity of cutoff walls formed by mixing formation with clays are still unclear. Aiming at the issue, the Fujian standard sand was used to simulate the formation and three kinds of clays were taken as the additive and slurry material for mixing and pouring. Then the hydraulic conductivity and pore size distributions were measured. The results indicated when the Clay C formed the cutoff walls with the model formation, there was a critical clay additive amount Ccr corresponding to the minimum porosity, and there would be great change in the descent velocity of the hydraulic conductivity k before and after critical clay additive amount Ccr. In regard to Clay A and Clay B, the critical clay additive amount Ccr of sand-clay specimens didn’t appear as the additive amount of Clay A and Clay B reached 25%. For Clay A and Clay B, the pore size distributions of sand-clay specimens were relatively identical, and their hydraulic conductivity k declined with decreasing porosity n. However, the pore size distributions of the mixture corresponding to Clay C gradually widened with the increasing additive amount, and they would develop towards the smaller pore size. Meanwhile, P50 also declined correspondingly, and there was poor correlation between porosity n and hydraulic conductivity k. Comparatively speaking, the microscopic pore structure of the model formation improved by Clay C was the most obvious, and Clay C raising the sealing effectiveness of model formation was also best.

MECHANICAL PROPERTIES OF RAMMED EARTH WITH RESPECT TO CLAY MIXTURE COMPOSITION

Unfired earth is a traditional building material, but it is less used than other building materials, such as concrete or steel. But the use of unfired earth is experiencing a renaissance. ammed earth is a type of unfired earth and is usually used for load bearing structures. This paper descries an experimental determination of the tensile bending strength and compressive strength of the rammed earth specimens with known compositions. Mechanical properties are dependent on these compositions (kind of clay, amount of clay, amount of mixture water). Laboratory specimens were produced without inorganic binders or fibrous admixtures. We observed higher tensile bending strengths and lower compressive strengths in specimen mixtures containing more clay. The obtained results were evaluated in a context of a previous research. The results were also compared with results published by another author.

CO2 Adsorption of Materials Synthesized from Clay Minerals: A Review

The aim of this work is to make a brief review of the adsorption of CO2 on modified clay minerals. Previous researchers have used different clay modifications, either by making changes in the structure by a reaction with another product or by the addition of a catalyst to improve their CO2 adsorption capacity. In order to obtain high values of CO2 uptake, some researchers have been incorporated amines-speices such as (3-aminopropyl)triethoxysilane (APTES), tetraethylenepentamine (TEPA) and a branched polyethylenimine (PEI) by grafting or impregnation. The synthesis of an adsorbent from mineral clays can generate an increase in its porosity and in its textural properties. These investigations differ in a number of factors such as the kind of clay, the operating conditions, y and the nature of the impregnated compound. The role of these factors in the CO2 adsorption capacity will be considered in detail in this review.

A novel colorful sepiolite-based superhydrophobic coating with excellent mechanical and chemical stability and self-cleaning property

Abstract Clay, which is a well-stocked mineral, has often been applied to colorful coatings. Sepiolite is a kind of clay that has excellent properties but has not being reported as a color paint. In this study, a colored paint composed of sepiolite, cationic dye, and organosilanes was sprayed with epoxy resin to form a colorful superhydrophobic coating. The low surface energy of organosilane and the micro-nano microstructure of the coating can form bubbles between the solid and liquid, endowing the coating with good water repellency and with a self-cleaning property. In addition, for aqueous solutions with pH ranging from 1 to 13, the contact angle (CA) of the coating remained greater than 150°. The chemical stability of the coating was very good and did not fade, even after immersion in 1 M NaOH or HCl solution for 24 h. The scratch test on the coating did not destroy the superhydrophobicity of the coating. Additionally, the coating had good mechanical durability, and its CA was still greater than 150° after 50 times of tape test.