Bentonite Interlayer Research Articles

A self-growing “Polysulfide-Phobic” interface constructed by in-situ gelation of organic bentonite interlayer to suppress shuttle effect in lithium-sulfur batteries

The shuttle effect of polysulfides hinders the long-term operation of lithium-sulfur batteries (LSBs). As the secondary current collector, the conductive interlayer can achieve induced fixation of polysulfide within a certain range, but the mechanism of action is limited by bearing saturation of the interlayer on polysulfide. In this work, the limited gelation of organic bentonite (OB) in the electrolyte is utilized to construct an in-situ gel-type physical barrier. During the initial discharge activation stage, the gel layer gradually evolves into a "Polysulfide-Phobic" repulsive layer by trapping free Lithium-polysulfides (LiPSs). Due to the strong repulsion between the "Polysulfide-Phobic" layer and free polysulfide anions, the spatial distribution of LiPSs in the positive electrode region is changed. In addition, the physical barrier effect of the gel interlayer and the chemisorbed action on LiPSs ensure the stability of the "Polysulfide-Phobic" layer during the discharge stage, while the low electronic conductivity avoids the risk of oxidation decomposition of the interface during the charging stage, which is verified by in-situ Raman. The Cells with OB interlayers show excellent cycle stability (515.5 mAh g−1 after 300 cycles) under high loading conditions (5 mg cm−2, E/S ≈ 7.5 μL mg−1). This strategy of sacrificing initial efficiency to build an electrostatic repulsion layer in exchange for long-term stability is profitable, providing a new approach to addressing the shuttle effect.

Synthesis and characterization of chitosan-bentonite biocomposite: Parametric optimization and adsorption potential

The study investigates the fabrication of chitosan-bentonite biocomposites through an ultrasonic-assisted technique. The influence of the chitosan: bentonite molar ratio, ultrasonication temperature, and ultrasonication time on the yield of biocomposites was assessed and juxtaposed using the response surface methodology, employing both Box Behnken design (BBD), and central composite design (CCD) methodologies. The pristine compounds and synthesized biocomposites were characterized using various spectral techniques viz. Fourier transform infrared (FT-IR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The optimal conditions for the synthesis of biocomposites were: uni-molar ratio of chitosan: bentonite, ultrasonication temperature of 60 °C, and ultrasonication time of 30 min. BBD demonstrated a slightly better fit (R² > 0.981) as compared to CCD (R² > 0.936). Additionally, the error values for BBD and CCD were determined to be 0.307 and 0.459, respectively, highlighting the higher accuracy of the BBD model compared to the CCD model. The structural analysis through FT-IR and XRD revealed the intercalation of chitosan into the bentonite interlayer. TGA indicated elevated thermal stability and increased resistance of the biocomposites toward degradation. Furthermore, the consistent bonding mechanism observed between chitosan and bentonite remained unchanged regardless of the molecular weight variations. The results revealed that synthesized biocomposites have the potential to be exploited as adsorbents for the removal of pesticides, dyes, drugs, and heavy metals from aqueous solution, demonstrating their application in wastewater remediation technology.

Enhanced adsorption of phenol using graphene oxide-bentonite nanocomposites: Synthesis, characterisation, and optimisation

Wastewater treatment is crucial because it causes harm to the environment of human beings. Adsorbents are faulted by low adsorption capacity and difficult recovery due to organic pollutants. This study aims to improve adsorption capacities using bentonite and other environmentally friendly and economically feasible adsorbents. To do this, using Hammer's approach, bentonite was subjected to an acidic treatment (1.5 M H2SO4) and then hybridized with synthetic graphene oxide (GO). Integrating GO nanosheets within the interlayer of acid-activated bentonite and depositing them onto the exterior surface using a simple ultrasonic-assisted method successfully created a graphene oxide-bentonite nanocomposite. GO, and its composites (at 5 and 10 wt%) were characterized using ATR-FTIR, BET, XRD, FE-SEM, and AFM studies. The results demonstrated that GO with a single-layer thickness of 0.618 nm could be successfully fabricated. We employed energy-dispersive X-ray spectroscopy (EDX) to detect changes in chemical composition before and after phenol adsorption. It was thoroughly studied how essential factors, including adsorbent dosage, pH, agitation period, and beginning phenol concentration, affected adsorption behavior. An obvious increases of the adsorption capacities from 30.69 to 46.43 mg/g were achieved under ideal circumstances of pH 6, an 8-hour contact duration, and doses of 0.3 g and 0.2 g for GO-MB5 and GO-MB10 composites, respectively. The pseudo-second-order kinetic and Langmuir equilibrium isotherm models efficiently described the adsorption process. More notably, the synthesized adsorbents could be successfully regenerated and used without major capacity losses after six cycles. This study highlights the effectiveness of GO-bentonite nanocomposites as effective adsorbents for environmental treatment.

A novel glutaraldehyde cross-linked chitosan@acid-activated bentonite composite for effective Pb (II) and Cr (VI) adsorption: Experimental and theoretical studies

In this study, a novel glutaraldehyde cross-linked chitosan@acid-activated bentonite composite (CsG@AAB) was synthesized from crab waste, glutaraldehyde, and acid-activated bentonite (AAB). The as-obtained composite was used as an adsorbent for the efficient removal of Pb(II) and Cr(VI) from the aqueous solutions. The adsorbent was characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and Braeuer–Emmett–Teller (BET) analyses. The effects of factors such as initial metal ion concentration, contact time, temperature, adsorbent dosage, and pH on Pb(II) and Cr(VI) adsorption were investigated, and related adsorption parameters were determined. Characterization results indicate that chitosan entered into the bentonite interlayer. BET surface area and point of zero charge (pHPZC) of the biocomposite were 85.2 m2/g and 6.3, respectively. Both metal ions uptake was rapid while adsorption was highly dependent on solution pH. The monolayer adsorption capacity was 452.78 mg g−1 for Pb(II) and 284.14 mg g−1 for Cr(VI), respectively at 25 °C. The adsorption kinetics were explained using the PSO model. The adsorption thermodynamic process was endothermic and spontaneous. The adsorption mechanism was explained by theoretical calculations and was in good agreement with the experimental results. Physisorption (van der Waals force, pore-filling), chemisorption (both inner and outer-sphere complexes), ion exchange, electrostatic interaction, and surface precipitation were the main mechanisms of metal ions adsorption. The results of this study suggest that the CsG@ AAB composite is promising for Pb(II) and Cr(VI) uptake and can be potential adsorption for decontamination of other pollutants from real wastewater streams.

Large-scale laboratory investigation of the performance of a novel isolation particle layer for offshore final disposal sites

The complex seabed conditions and ocean environment pose significant challenges to the material selection and construction of bottom liners for offshore final disposal sites. To overcome the challenges, this study proposed a novel isolation particle layer for offshore final disposal sites. The isolation particle was composed by salt-resistant bentonite coating material and cement core material (D10 was 10 mm in core diameter and 2 mm in coating thickness; D20 was 20 mm and 4 mm). Upon immersion in artificial seawater, the isolation particles underwent expansion, leading to the formation of the novel isolation particle layers with low hydraulic conductivity less than 1 × 10-7 cm/s and adsorption of heavy metals in bentonite interlayers. Large column tests showed that both D10 and D20 isolation particle layers exhibited remarkable swelling capacity and low hydraulic conductivity (4.3 × 10-9 cm/s and 2.6 × 10-8 cm/s) under 3 m seawater pressure. During one year of observation, water tank test demonstrated that both isolation particle layers displayed remarkable stability and low hydraulic conductivity of 2.73 × 10-10 cm/s and 8.36 × 10-10 cm/s with load. The maximum adsorption capacities of salt-resistant bentonite were 123.55 mg/g for Pb2+, 60.29 mg/g for Cd2+ and 54.22 mg/g for Cu2+. Both isolation particle layers exhibited a high removal rate of over 95 % for heavy metals in water tank tests. The large-scale laboratory tests indicated the significant potential of the novel isolation particle layer for offshore final disposal sites. Subsequently, a testing ocean site will be selected to further investigate its practical engineering performance.

ADDITION OF BENTONITE AND CHITOSAN FILLING TO POLYURETHANE COATING PAINT IN AN EFFORT TO INCREASE RESISTANCE AGAINST HEAT AND ANTIBACTERIA

The increasing market demand for polyurethane is due to its various functions, including being used as a coating material, adhesives, elastomers and hard foams.Polyurethane is a polymeric material that contains a functional group (-NHCOO-) in its main chain. In principle, polyurethane can be produced by reacting two reactive materials, polyol and isocyanate. Various researches are intensively carried out to synthesize polyurethane in order to improve the performance of polyurethane.Bentonite and chitosan are widely used as filler materials in polyurethane matrices to retain heat and improve the mechanical properties of polyurethane. The addition of bentonite and chitosan to polyurethane will affect the mechanical properties, thermal properties, and morphological structures which can be seen based on the FTIR test, TGA test, SEM test and Antibacterial test.In this study, variations of Bentonite and Chitosan 5.7.9% will be used, then the mixing process with Polyurethane will be carried out. The results showed that the results of the FTIR analysis showed that the mixing of Polyurethane and bentonite did not affect the wavelength absorption of the Polyurethane functional groups themselves. This was due to the mixing process which took place only physical bonds without chemical bonds. The results of thermogravimetric analysis (TGA) showed changes in the weight of the material when heated and it could be concluded that the best sample was B:K 9%, because it experienced less weight loss. Based on the results of the Morphological Structure test with a Scanning Electron Microscopy (SEM) chitosan chain dispersed well into the bentonite interlayer, as shown by testing using the SEM tool. The results of the antibacterial test showed that the more chitosan and bentonite added, the better the ability to inhibit the growth of Escherichia coli bacteria. In testing the activity of these bacteria it can be seen that chitosan and bentonite are better at inhibiting the growth of Escherichia coli than Staphylococcus aureus.

Hydro-mechanical modelling of swell behaviour of bentonite buffer

Hydro-mechanical modelling of swell behaviour of bentonite buffer

Preparation of Chitosan-Modified Bentonite and Its Adsorption Performance on Tetracycline.

In this study, chitosan-modified bentonite was synthesized using the coprecipitation method. When the Na2CO3 content was 4% (weight of soil) and the mass ratio of chitosan to bentonite was 1:5, the adsorption performance of the chitosan/bentonite composite was best. The adsorbent was characterized by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and Brunauer-Emmett-Teller measurement. Various characterization results demonstrate that chitosan successfully entered the bentonite interlayer and increased layer spacing but did not modify bentonite's laminar mesoporous structure, and the -CH3 and -CH2 groups of chitosan appeared on chitosan-modified bentonite. Tetracycline was used as the target pollutant in the static adsorption experiment. The adsorption capacity was 19.32 mg/g under optimal conditions. The adsorption process was more consistent with the Freundlich model and the pseudo-second-order kinetic model, indicating that it was a nonmonolayer chemisorption process. The adsorption process is a spontaneous, endothermic, entropy-increasing process, according to thermodynamic characteristics.

ASSESSMENT AND IDENTIFICATION OF POLYOL BASED ON PALM OIL AND NATURAL FILLING MATERIALS FOR RENEWABLE COATING PAINT APPLICATION

Chitosan/clay hybrid nanoparticles have been prepared as natural antibacterial and anticorrosion agents to enhance the protective function of polyurethane-based coating paints. Chitosan is a material with antibacterial properties because it contains acetamide group which is widely used for hygiene purposes in the medical field. Clay is a natural clay particle with a hollow structure that allows loading and release of active substances such as surfactant ions that can contribute to improving the properties of the material. The polyurethane in this study was obtained from palm oil oleic acid, which was processed into polyol, toluene diisocyanate was added to produce polyurethane. Coating paint is efficiently loaded with chitosan and clay active substances which are combined to form a hybrid composite. Based on the FTIR data of polyurethane showing the formation of a hydroxyl group on the palm oil epoxide compound, the reaction lasted for 2 hours at 60oC as evidenced by the absorption of the OH wave number which widened at 3305.99 cm-1. The value of the wavelength of the OH group in the bentonite sample before and after purification has decreased, proving that the intercalation of surfactants into the bentonite interlayer causes the hydrophilic nature of bentonite to change to hydrophobicity. The d-spacing layer of raw bentonite has a maximum reflection angle peak of 7.26o with a d-spacing value of 1.132 nm, and the d-spacing size increases to 1.631 nm at the peak of the maximum reflection angle of 4.49o after purification. The presence of absorption at 1064.71 cm-1 in shrimp shell chitosan indicates COC vibration.

Synthesis of a Low-Molecular-Weight Filtrate Reducer and Its Mechanism for Improving High Temperature Resistance of Water-Based Drilling Fluid Gel System.

During the exploitation of deep and ultradeep oil and gas resources, the high-temperature problem of deep reservoirs has become a major challenge for water-based drilling fluids. In this study, a novel high-temperature-resistant filtrate reducer (LDMS) with low molecular weight was synthesized using N, N-dimethylacrylamide; sodium p-styrene sulfonate; and maleic anhydride, which can maintain the performance of a drilling fluid gel system under high temperature. Unlike the conventional high-temperature-resistant polymer filtrate reducer, LDMS does not significantly increase the viscosity and yield point of the drilling fluid gel systems. After aging at 210 °C, the filtrate volume of a drilling fluid with 2 wt% LDMS was only 8.0 mL. The mechanism of LDMS was studied by particle size distribution of a drilling fluid gel system, Zeta potential change, adsorption experiment, change of bentonite interlayer spacing, filter cake scanning electron microscope, and related theoretical analysis. The mechanism study revealed that LDMS could be adsorbed on the surface of bentonite particles in large quantities and intercalated into the interlayer of bentonite. Thus, it can improve the hydration degree of bentonite particles and the colloidal stability of the drilling fluid gel system, maintain the content of fine particles in the drilling fluid gel system, form a compact mud cake, and significantly reduce the filtrate volume of the drilling fluid gel system. Therefore, this work will promote the application of a low-molecular-weight polymer filtrate reducer in high-temperature-resistant water-based drilling fluid gel systems.

Stable dispersibility of bentonite-type additive with gemini ionic liquid intercalation structure for oil-based drilling

In this study, the direct intercalation of gemini ionic liquids (ILs) with different alkyl chains into the bentonite (BT) interlayer as a high-performance lubricating additive for base oil 500SN was investigated. The purpose of modifying BT with an IL is to improve the dispersion stability and lubricity of BT in lubricating oil. The dispersibility and tribological properties of IL—BT as oil-based additives for 500SN depend on the increase in interlamellar space in BT and improve as the chain length is increased. More importantly, the IL—BT nanomaterial outperforms individual BT in improving wear resistance, owing to its sheet layers were deformed and sprawled in furrows along the metal surface, thereby resulting in low surface adhesion. Because of its excellent lubrication performance, IL-modified BT is a potential candidate for the main component of drilling fluid. It can be used as a lubricating additive in oil drilling and oil well construction to reduce equipment damage and ensure the normal operation of equipments.

The influence of technological conditions and molecular weight of PEG on basal spacing of Vietnamese bentonite

AbstractThe unique expansion properties of the interlayer space of montmorillonites allow for surface modification of bentonite. PEG is a nonionic polymer that can adsorb and intercalate into the interlayers of bentonite. The results of FTIR and TGA spectra allow confirming that PEG has not only covered bentonite but also inserted into the interlayers of bentonite. Therefore, the modified product can be applied not only as a dispersant in polymer composites, but also as an adsorbent. Moreover, a variety of technological factors affecting modification have been studied and the most suitable conditions have been proposed. In which, temperature, stirring speed, time and suspension concentration were selected at 25°C, 800 rpm, 8 h and 2 wt.%, respectively. The influence of the component ratio (Ben/PEG) on the modification process was also studied. The most suitable Ben/PEG ratio for each PEG type was also given. The results show that the interlayer spacing in modified bentonite depends not only on the technological conditions, the composition ratio but also on the molecular weight of PEG. Thus, the choice of PEG for bentonite modification will determine the d001 basal spacing of modified product.

Removal of elemental mercury from coal combustion flue gas using bentonite modified with Ce-Fe binary oxides

Mercury removal from coal combustion flue gas remains a great challenge for environmental protection because of the lack of cost-effective sorbents. This study prepared a series of bentonites modified with Ce-Fe binary oxides (CeXFe4-X/Ben) for elemental mercury (Hg0) capture from flue gas. The textural properties, crystal structure, magnetic properties, redox properties, and surface chemistry of CeXFe4-X/Ben were characterized. The results testified that modification procedure had little effect on the pore shape and pore size of bentonite. During modification process, a synergistic effect occurred between iron oxide and cerium oxide and Ce-Fe binary oxides entered the interlayer of bentonite. The CeXFe4-X/Ben samples presented far better Hg0 removal performance compared with raw, Fe-modified, and Ce-modified bentonite. The optimum Ce/Fe molar ratio and adsorption temperature were 2:2 and 150–200 °C, respectively. O2, NO, and HCl promoted Hg0 removal whereas SO2 and H2O inhabited Hg0 removal. The Hg0 removal process was dominated by heterogeneous adsorption and CeXFe4-X/Ben was used as a sorbent. Furthermore, the Hg0 removal mechanism was revealed, where CeO2 and Fe2O3 served as active sites for Hg0 removal. Multiple adsorption-regeneration cycles demonstrated that the deactivated CeXFe4-X/Ben could be effectively regenerated after thermal treatment at 400 °C for 1 h under air atmosphere.

Curcumin functionalized TiO2 modified bentonite clay nanostructure for colorimetric Aflatoxin B1 detection in peanut and corn

This work reports an analytical technique to determine Aflatoxin B1 (AFB1) in food samples using electrostatic interaction with curcumin (Cur) functionalized TiO2 NPs supported on layered structured bentoniteclay(Ti(Cur)O2Bent). TiO2Bent synthesized by thermal decomposition method, obtained crystallite size of 32.4 nm by XRD and SEM uniform morphology of TiO2NPs on the bentonite surface. The optical band gap decreased with intercalation of TiO2 NPs in the interlayers of bentonite than bare TiO2 NPs and showed presence of alumina-silicate in composite by FT-IR for improved ion-exchange properties. Cur form a chelated complex with TiO2Bent due to extended conjugation of the dye at 1,3 diketone moiety as shown by C13 NMR studies. TiO2Bent improved Cur capability to form electrostatic bond with unsaturated aldehyde electrophiles of AFB1 at pH 9.54. This was evidenced by FT-IR at 1647 cm−1 and sp. hybridization by C13 NMR studies for CO bond in AFs. The hypsochromic modification in color of the dye from red (505 nm) to yellow (403 nm) was recorded by UV–Vis in AFB1 spiked peanut (1–5 ppb) and corn (1–20 ppb). Absorption at maximum intensity of ~434 nm in the linear concentration of AFB1 obtained limit of detection (LOD) (3σ) as 1.4 ppb and 0.38 ppb for peanut and corn respectively. Hence, this rapid sensing developed by the green chemicals synthesis of NPs reagent could be developed into paper-based sensor for onsite detection of AFB1 in food sector.

Combined determination analysis of surface properties evolution towards bentonite by pH treatments

Bentonite possesses multiple physicochemical properties because of a large number of charges on the surface. Understanding charges-related surface characteristics at various aqueous solution conditions is critical for bentonite application in various fields, including material modification and environmental restoration. In this study, the evolution of surface properties (surface potential, surface electric field strength, specific surface area, and surface charge numbers) for bentonite samples was investigated using simple ion-exchange experiments and extended combined determination method at different pH conditions. Zeta potential, X-ray diffraction (XRD), and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) techniques were used to examine changes in bentonite structure and surface functional groups. The results demonstrated that surface potential was considerably negative (larger in absolute value) and more sensitive to pH variation than the zeta potential of bentonite under identical conditions. At multiple pH settings, the surface electric field strength and the numbers of bentonite’s surface charges were inversely proportional to hydrogen ion concentrations. Cations covalently bonded to clay’s surface might reduce negative surface charges and diminish surface electric field strength, particularly as ionic strength increased. Although moderate pH variation has no discernible effect on bentonite interlayer structural alterations, moderate clay dissolution and changes in mineralogical properties may increase the specific surface area of bentonite, particularly when the solvent chemical conditions are acidic. This study comprehensively sheds light on the evolution of surface properties of bentonite clay under acidic, neutral and alkaline conditions, which is helpful in understanding and optimizing its surface performance for material and environmental applications.

Intercalated organo-bentonite as efficient biosorbent for aromatic carboxylic acids from wastewater

This study aims to prepare intercalated organo-bentonite using cetylbenzyldimethylammoniumbromide (CBDAB) and investigate its ability for the removal of benzoic (BA) and salicylic (SA) acids from wastewater. The obtained results confirm the intercalation of CBDA into the bentonite interlayer. Several important parameters of SA and BA adsorption onto sodium bentonite (Na-bent) and intercalated bentonite (CBDA-bent) including the adsorbent dosage, contact time, pH, ionic strength, and temperature are investigated in batch mode. Overall, CBDA-bent, which possesses a high specific surface (32 m2/g) area and a pore volume (0.14 cm3/g) demonstrates promising prospects for SA and BA adsorption, reaching 55.2 mg/g and 64.5 mg/g, respectively. The SA and BA are found to primarily interact well through both surface and interlayer processes in basic media. The equilibrium experimental data have been analyzed by Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich isotherms; nonetheless the adsorption is well described by the Langmuir model. The influence of contact time on SA and BA uptake is modeled using pseudo second-order, pseudo first-order, intraparticle diffusion, and Boyd kinetic models. An intraparticle diffusion mechanism is found to control the adsorption process, where the internal mass transfer is higher than the external mass transfer. A thermodynamic study shows that the adsorption of both acids is not spontaneous and endothermic. Desorption of SA and BA acids from both Na-bent and CBDA-bent has been performed and the possibilities for reuse investigated.

Stabilization of dissolvable biochar by soil minerals: Release reduction and organo-mineral complexes formation

Biochar has two existing forms in the moist soil environment, free dissolvable biochar (particle size < 0.45 μm) and undissolvable particles (particle size > 0.45 μm). The release and decomposition of dissolvable biochar from bulk biochar particles is a primary C loss pathway in biochar-amended soils, which would be reduced by their interactions with soil minerals. Most previous studies focused on the effect of feedstock types and pyrolysis conditions on dissolvable biochar stability, while few studies researched the interaction between dissolvable biochar and soil components, for instance the soil minerals, and its effect on the stability of dissolvable biochar. In this study, bentonite and goethite were selected as model soil minerals because of their differences in structure and surface types: negatively charged 2:1 type phyllosilicate (bentonite) and positively charged crystalline mineral (goethite). Dry-wet cycling was conducted to determine the effect of these two minerals on the release of dissolvable biochar from walnut shell-derived biochar particles. The stability of dissolvable biochar was measured by chemical oxidation and biodegradation. Both soil minerals reduced the release of dissolvable biochar by over 34% with the presence of Ca2+. Mechanisms of “Ca2+ bridging”, “ligand exchange” and “van der Waals attraction” contributed to the formation of dissolvable biochar-bentonite complexes, and Ca2+ promoted dissolvable biochar inserting into bentonite interlayer space, expanding d-spacing from 1.25 nm to 1.55 nm. However, “Ca2+ bridging” barely formed on goethite because of charge repulsion, indicating that the dissolvable biochar was bound with goethite mainly by “van der Waals attraction” and “ligand exchange”. Due to organo-mineral complexes formation, the chemical oxidation extent of dissolvable biochar was reduced by 22.8–36.5%, and the biodegradation extent was reduced by 72.7–85.0%, since the soil minerals are more effective to prevent the dissolvable biochar from being biodegraded. This study proved soil minerals and Ca2+ were beneficial for enhancing biochar stability, these observations assisted in assessing the biochar ability for long-term carbon sequestration.

CuO-bentonite-gold nanocomposites: Facile green preparation and their characterization

In this work, we design a facile green preparation of CuO-bentonite-gold nanocomposites by a pillarization-immobilization method. Bentonite has been successfully pillared with CuO (CuO-Bentonite) by using Tinospora crispa leaf extract. Gold nanoparticle (AuNPs) has immobilized in the interlayer of CuO-Bentonite. The presence of an amine group acts as a source of nitrogen bases for a hydrolyzing agent in the formation of CuO-bentonite. Meanwhile, the flavonoid secondary metabolites play an essential role in reducing Au3+ to Au0 nanoparticles. The dspacing value of CuO-bentonite was greater than dspacing value of Na-bentonite at 2θ of 5.29°, indicating CuO has been pillared in the bentonite interlayer. Moreover, AuNPs was systemically formed in the interlayer of CuO-bentonite confirmed by XRD and EDX. The morphology of CuO-bentonite-gold nanocomposites was in a layered shape with a particle size of approximately 30 nm. Additionally, this work reported a simple, affordable, and less-toxic method to modify bentonite for better performance.

Evaluation of Clay Hydration and Swelling Inhibition Using Quaternary Ammonium Dicationic Surfactant with Phenyl Linker.

Water-based drilling fluids are extensively used for drilling oil and gas wells. However, water-based muds cause clay swelling, which severely affects the stability of wellbore. Due to two adsorption positions, it is expected that cationic gemini surfactants can reduce the clay swelling. In this work, quaternary ammonium dicationic gemini surfactants containing phenyl linkers and different counterions (Cl− and Br−) were synthesized, and the effect of variation in counterions on swelling and hydration properties of shales was studied. Numerous water-based drilling fluid formulations were prepared with different concentrations of surfactants to study the swelling inhibition capacity of surfactants. The performance of surfactant-containing drilling muds was evaluated by comparing them with base drilling mud, and sodium silicate drilling mud. Various experimental techniques were employed to study drilling mud characteristics such as rheology and filtration. The inhibition properties of drilling mud formulations were determined by linear swelling experiment, capillary suction time test, particle size distribution measurement, wettability measurements, and X-ray Diffraction (XRD). Experimental results showed that surfactant-based formulation containing bromide counterion exhibited superior rheological properties as compared to other investigated formulations. The filtration test showed that the gemini surfactant with chloride counterion had higher filtrate loss compared to all other formulations. The bentonite swelling was significantly reduced with increasing the concentration of dicationic surfactants as inhibitors, and maximum reduction in the linear swelling rate was observed by using a formulation containing surfactant with chloride counterion. The lowest capillary suction timer (CST) was obtained in the formulation containing surfactant with chloride counterion as less CST indicated the enhanced inhibition capacity. The particle size measurement showed that average bentonite particle size increased upon the addition of surfactants depicting the inhibition capacity. The increase in basal spacing obtained from XRD analysis showed the intercalation of gemini surfactants in interlayers of bentonite. The contact angle measurements were performed to study the wettability of the bentonite film surface, and the results showed that hydrophobicity increased by incorporating the surfactants to the drilling fluid.

Synthesis and characterization of nylon 6 polymer nanocomposite using organically modified Indian bentonite

In this present research work two different organic compounds are applied for the modification of Indian origin bentonite. One is with n-hexadecyltrimethylammonium bromide (CTAB), intercalated with an interlayer of bentonite via cation exchange mechanism. Whereas, another with 3-Aminopropyl trimethoxysilane (APTES) interlayer functionalization with bentonite –OH group. APTES and CTAB–intercalated bentonites samples were further cross modified with CTAB and APTES to obtain novel co-surfactant locked organo bentonite modeling (CLOM) like matrices. Original and modified bentonite samples were comparatively evaluated by advanced characterization techniques such as, powder X-ray diffraction, Fourier-transform infrared spectroscopy, thermal gravimetric analysis (TGA). Moreover, the applicability of the developed CLOM like materials were investigated in nylon 6 nanocomposite preparation by melt compounding method using a micro twin co-rotated extruder. Additionally, CLOM-nylon-6 polymer nanocomposites were characterized by wide angle X-ray diffraction, TGA, differential scanning calorimetry, atomic force microscopy and tensile strength measurement. The observed thermograph results confirmed no significant difference in the thermal properties of the developed composites. Whereas, the significant variation observed in the tensile strength results particularly for developed composite 5% of N6-OAMSB and N6 AMOSB 5 showed 111.5 and 76.6% respective enhancement in tensile strength results when compared with a bare nylon-6 polymer.