Search Results (210)

Dental restorative resins available today still have limitations that may affect their durability. This study explores reinforcing a universal microhybrid dental composite resin with organomodified nanoclay at low filler loadings (0, 0.5, 1, 3, and 5 wt%). The morphology, structural features, and light transmittance of the composites were analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD), attenuated total reflection–Fourier transform infrared (ATR–FTIR), and UV–Vis spectroscopy. The degree of conversion and polymerization shrinkage were measured with ATR–FTIR and a linear variable displacement transducer (LVDT). Water sorption and solubility parameters and flexural properties were assessed gravimetrically and with a dynamometer, respectively. The composites mainly showed exfoliated structures and an improved degree of conversion. Polymerization shrinkage and solubility were lower than those of unmodified dental resin. The highest degree of conversion was observed in composites with 0.5–1 wt% nanoclay. The incorporation of 1 wt% nanoclay resulted in the lowest shrinkage and sorption, along with the highest flexural modulus and strength. Overall, the results suggest that low nanoclay concentrations can improve the physicochemical and mechanical properties of dental composites, highlighting their potential to develop advanced restorative materials that can address current clinical challenges. Full article

This study describes the development of an electrochemical sensor for quantitatively measuring acetaminophen (ACOP) in drug tablets. The sensor design is based on the modification of glassy carbon electrode (GCE) using zinc oxide nanoparticles (ZnONPs) embedded in a naturally occurring clay matrix (Sa) functionalized with phenylalanine (Phe). To ensure that the ZnONPs are homogeneously dispersed on the clay surface, the nanocomposite was synthesized using an impregnation approach and low-temperature heat treatment. The amino acid promotes specific interactions with ACOP through hydrogen bonding and π-π stacking, acting as both a stabilizing agent and a molecular recognition moiety. FTIR, UV-Vis, XRD, and FESEM/EDX mapping were employed to fully characterize the developed material (ZnONPs-Sa/Phe). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used for the electrochemical determination of ACOP using the modified electrode GCE/ZnONPs-Sa/Phe. Parameters susceptible to affecting the sensitivity of the developed sensor were optimized, revealing that 5 µL of the suspension ZnONPs-Sa/Phe immobilized on GCE was ideal for the sensing of ACOP in a phosphate buffer solution at pH 2.0. The calibration curve obtained by plotting peak current intensity against ACOP concentration exhibited linear behavior within the concentration range between 0.02 µM and 0.28 µM, enabling determination of the limits of detection (LOD) and quantitation (LOQ) at 8.54 × 10⁻⁹ M and 2.84 × 10⁻⁸ M, respectively. The reproducibility, stability, and selectivity of the sensor were evaluated, followed by its application to the nano-sensing of ACOP in Africure and Doliprane tablets, yielding satisfactory results. The simplicity, affordability, and high analytical sensitivity of the developed sensor make this sensing platform a promising tool for pharmaceutical quality control applications. Full article

By examining a novel nanomaterial that has been modified for use in sustainable construction, this study primarily responds to the growing need for environmentally acceptable materials. The primary goal was to improve the functional and aesthetic qualities of building materials by synthesizing and characterizing environmentally friendly clay-based nanomaterials doped with cobalt pyrophosphate (Co₂P₂O₄). The authors employed contemporary experimental methods, such as scanning electron microscopy (SEM) for morphological characterisation, Fourier transform infrared spectroscopy (FT-IR) for molecular bonding assessment, and X-ray diffraction (XRD) for crystal structure research. The published findings show the doped nanomaterials’ potential durability as well as their structural integrity. An economic assessment is part of the investigation. The study is noteworthy for emphasizing the potential of cobalt-doped pyrophosphate nanoparticles as eco-friendly colour pigments for construction materials made of clay. Full article

This study presents an analytical investigation of the dynamic behavior of concrete beams reinforced with different types of nano-clay (NC) particles and resting on a Winkler–Pasternak elastic foundation. The equivalent elastic properties of the nanocomposite were determined using an Eshelby-based homogenization model. An improved quasi-three-dimensional beam theory was applied to formulate the governing equations of motion, which were subsequently then analytically solved using Navier’s method. The analysis shows that NC reinforcement systematically elevates the natural frequencies of the beam, with the magnitude of improvement varying by particle type and concentration. Increasing the NC volume fraction to 30% leads to a significant rise in the fundamental frequency, reaching about 30% for hectorite (SHca-1) compared with the unreinforced beam, whereas montmorillonite (SWy-1) produces a more moderate increase of approximately 13%. This reinforcing effect remains consistent across different span-to-depth ratios, indicating that the influence of nano-clay content on the dynamic response is largely independent of beam slenderness. Furthermore, increasing the Winkler foundation stiffness results in an almost linear rise in frequency of approximately 18–22%, whereas the Pasternak shear parameter produces a stronger effect, reaching around 25% enhancement depending on the reinforcement type. These results indicate that incorporating nano-clay platelets can be an effective strategy for enhancing the vibrational stiffness of concrete beams and improving their dynamic performance when interacting with supporting soil media. Full article

This study addresses the challenges posed by weakly cemented strata in mine tunnels, where surrounding rock softens and deforms upon water exposure, which promotes the development of seepage pathways, and exhibits insufficient stability in bolt (cable) support systems. This study conducts laboratory grouting tests using silica sol on typical weakly cemented sandstone from Xinjiang mining areas. The mineral composition and pore structure were characterized using XRD, SEM, and mercury porosimetry. The injectable mixing ratio parameters for silica sol and the catalyst were determined through viscosity-time evolution tests. Grouting was performed using a custom-built constant-pressure grouting apparatus. After curing, unconfined compressive strength (UCS) and porosity-permeability tests were conducted to evaluate the micro-mechanism of grouting effects on the mechanical and permeability properties of weakly cemented sandstone. The results indicate: (1) The sandstone exhibits a high clay mineral content of 39.8%, dominated by illite. Its pores are primarily small-scale (10–100 nm), accounting for 79.31% of the total pore volume. This scale matches that of silica sol nanoparticles (approximately 9–20 nm), facilitating slurry penetration into micro-pores; (2) microscopic analyses reveal that silica sol effectively reconstructs pore structures through permeation filling and surface coating. Compared to KCl-induced gelation (with approximately 8% gel coverage), NaCl-induced gelation forms a more continuous gel film with more complete pore filling, achieving coverage of around 22%. Furthermore, the larger surface area of the gel aggregates indicates a more thorough filling of micro- and nano-pores, effectively enhancing rock mass compactness. (3) Permeability decreased from 6.91 mD to 3.55 mD, a reduction of 48.6%, while porosity decreased from 16.94% to 13.55%, showing a phased reduction during the grouting process; (4) following pressure grouting stabilization, the uniaxial compressive strength of sandstone increased appropriately by approximately 7–14%, while the elastic modulus rose by about 18–28%. The failure mechanism shifted from shear brittleness to a shear-tension composite state, with enhanced post-peak bearing capacity. These findings provide support for optimizing silica sol grouting parameters in weakly cemented strata tunnels and for the synergistic reinforcement of rock mass permeability and strength. Full article

This study aimed to investigate the effect of time and different disinfecting agents on nanocomposite filler composed of natural clay nanoparticles (modified and non-modified) added to maxillofacial silicone elastomers and readymade pigment additives. A total of 360 disk-shaped samples were divided into nine pigment-based groups, each with four subgroups (n = 10) exposed to different disinfectants: distilled water, 1% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), and effervescent tablets. Color changes (ΔE) were measured before and after disinfection using a colorimeter. The ΔE values were assessed against perceptibility (ΔE = 1.1) and acceptability (ΔE = 3) thresholds. Nanoclay additives were also characterized using FTIR, XRD and EDX. Statistical analysis, including ANOVA and post hoc HSD tests, revealed that while all samples exhibited some color change, most remained below the acceptability threshold. Colorless silicone showed minimal, non-significant change according to perceptibility threshold (ΔE = 1.1). Blue pigments displayed significant change only with effervescent tablets. Red and mixed pigments showed perceptible changes with NaOCl, CHX, and effervescent tablets. However, nanoclay-containing specimens showed no significant perceptible alterations. Overall, despite minor perceptible changes in some pigments, all disinfecting agents tested resulted in color differences below the acceptability threshold, indicating their safe use for disinfecting maxillofacial silicone materials without compromising esthetics. Nevertheless, nanoclays are more reliable agents for the pigmentation of maxillofacial silicone as they show non-significant chromatic alteration. Full article

This mini-review presents the major research trends in the synthesis, performance, and mechanisms of clay-supported magnetic iron oxide nanocomposites for the adsorption of heavy metals in water and wastewater treatment applications. The immobilization of iron oxide nanoparticles onto the hydrophilic natural or synthetic nanoclay matrices not only minimized the magnetic nanoparticles’ tendency to aggregate in aquatic solutions but also facilitated their recovery from the solutions via magnetic separation after adsorption. For these reasons, research on such materials emerged in the early 2010s, leading to the development of highly efficient nanocomposite adsorbents. At optimum conditions, including solution pH values between 5 and 7, rapid equilibrium times ranging from 30 to 180 min, and ambient or moderately elevated temperatures (up to 60 °C), maximum adsorption values of up to 225 mg/g were reported for certain heavy metals. Moreover, the nanocomposites demonstrated reusability, maintaining adsorption performance towards heavy metals for up to five adsorption–desorption cycles when common acids (such as HNO₃ and HCl) were used as regenerating agents. However, the current findings are all based on batch-scale laboratory experiments. To move toward industrial-scale applications, further research is necessary to address scale-up challenges and evaluate the performance of the clay-supported magnetic iron oxide nanocomposites under real-world conditions. All the critical limitations are highlighted in the context of this mini review to support future efforts toward achieving their economic and environmentally sustainable application for the adsorption of heavy metals from water/wastewater streams. Full article

The characterization and biomedical modification of bentonite clays from the Kalzhat deposit (Kzh), which is situated in Kazakhstan’s Zhetysu region, are the main objectives of this work. In order to improve the raw material’s structural qualities, the montmorillonite fraction was enriched, and coarse impurities were eliminated using the Salo method. The presence of meso- and micropores that guarantee high dispersity and specific surface area, as well as the prevalence of montmorillonite and kaolinite, was all confirmed by physicochemical analysis. Particle size measurements indicated finely dispersed structures with a propensity to aggregate, whereas thermal analysis demonstrated resilience under heating. After effective functionalization with silver nanoparticles, a porous hybrid system with improved surface reactivity was produced. These enhancements demonstrate the modified bentonite’s usefulness as a multifunctional carrier for the immobilization and controlled release of pharmaceuticals, with potential uses in drug delivery systems, antimicrobial coatings, and wound-healing materials. The material has potential use in sorption and environmental protection technologies in addition to its biomedical application. Overall, Kzh’s structural and functional performance is greatly improved by the combination of purification and functionalization with silver nanoparticles, highlighting its promise as a useful element in the development of next-generation polymer–composite systems. Full article

Nanocomposites composed of compatibilized polyolefin blends and organically modified montmorillonite (OMMT) nanoparticles were produced through melt mixing using a twin-screw extruder. High-density polyethylene (HDPE) and polypropylene (PP) blends were compatibilized with maleic anhydride-grafted PE compatibilizer (COMP). Blends with a 10/25 (w/w) HDPE/PP content were prepared and were reinforced with 1, 2, and 3 phr OMMT. Characterization of nanocomposites was performed using X-ray diffraction (XRD), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Tensile Testing, and Melt Flow Index (MFI) measurements. Preparation of polyolefin blend/OMMT nanocomposites with a twin-screw extruder was successful at low clay levels (1 phr). These nanocomposites presented increased onset temperature of thermal degradation, crystallinity, and stiffness, whereas their MFI values were lower than those of the pure matrix. Full article

Given the increasing human exposure to electromagnetic radiation of various frequen-cies, mostly in the microwave range, awareness of potential health problems caused by this radiation has begun to grow. New building materials are being developed and tested to prevent or limit the penetration of microwave radiation, especially those frequencies that are used in mobile telephony. In contrast with the majority of the available literature on the investigation of concrete (cement) materials, in this paper, clay composite materials with the addition of nanoparticles of antimony(III)–tin(IV) oxide, zinc ferrite, iron(III) oxide, and two crystal modifications of titanium dioxide (rutile and anatase) were prepared in order to examine their effect on the absorption of electro-magnetic radiation. Nanomaterials are characterized by different physical and chemical methods. Specific surface area (B.E.T.), thermal properties (TGA/DSC), phase composition (PXRD), morphology (SEM), and chemical and mineralogical composition (EDX, and ED–XRF,) were determined. Thermal conductivity of clay composites was tested, and these materials showed a positive effect on the thermal conductivity (λ) of the composite: a reduction of 10–33%. The reflection and transmission coefficients of microwave radiation in the frequency range used in mobile telephony (1.5–4.0 GHz) were determined. From these data, the absolute value of radiation absorption in the materials was calculated. The results showed that the addition of the tested nanomaterials in a mass fraction of 3 to 5 wt.% significantly increases the absorption (reduces the penetration) of microwave radiation. Two nanomaterials, Sb₂O₃·SnO₂ and TiO₂ (rutile), have proven to be particularly effective: the reduction in transmission is 30–50%. The results of the test were correlated with the crystal structures of the examined nanomaterials. The inclusion of titanium dioxide and antimony-doped tin oxide into the clay led to a significant enhancement in microwave electromagnetic radiation absorption, which can be attributed to their interaction with the dielectric and conductive phases present in clay-based building materials. Full article

Historically, clays have been widely used for the treatment of wounds and to stop hemorrhaging. The aim of this study was to combine four natural clay minerals (kaolinite, glauconite, montmorillonite, and bentonite) with magnetite (Fe₃O₄) nanoparticles to produce Fe₃O₄–clay complexes with enhanced antimicrobial properties and chemopreventive activity against melanoma. The magnetite–clay complexes were synthesized by the chemical co-precipitation method and characterized using XRD, TEM, STEM-EDS, SEM, and SQUID magnetometer. Antimicrobial properties were determined by evaluation of MIC values. The most promising materials were also subjected to direct contact antibacterial test according to the OECD standard for porous materials. Cytotoxicity of the complexes towards melanoma cells and normal human skin fibroblasts was assessed by MTT assay. We performed XRD, which confirmed the formation of Fe₃O₄–clay complex materials. It was also proven that complexes exhibited superparamagnetic properties. Microbiological experiments clearly revealed that modification of natural clays with magnetite significantly boosted their antimicrobial properties. Fe₃O₄–montmorillonite and Fe₃O₄–bentonite showed the strongest antimicrobial activity. Moreover, the mentioned complexes had the ability to reduce the viability of melanoma cells by 35–40%, while exhibiting no cytotoxicity against the normal human fibroblast (BJ) cell line, which is an extremely desirable feature. Thus, it may be concluded that Fe₃O₄–montmorillonite and Fe₃O₄–bentonite complexes hold promise for use in the management of infected wounds and wounds after melanoma excision. Full article

This study focused on creating a novel material by integrating ZnO and CuO nanoparticles into the structure of halloysite using a hydrothermal method. The formation of the nanocomposite was validated through X-ray diffraction and Raman analysis, which confirmed the presence of ZnO and CuO phases without compromising the structure of halloysite. Microscopic analysis revealed a well-distributed presence of metallic oxide nanoparticles within the nanotubular structure of halloysite, which adhered to both the outer and inner surfaces of the clay mineral. Optical characterization identified a substantial density of defects, which played a key role in improving the performance of the supported semiconductors. Furthermore, the narrow band gap at 3.02 eV promoted the mobility of photogenerated charges. Photocatalytic tests yielded promising results, demonstrating a synergistic effect between photocatalysis and adsorption processes that positively influenced the removal of ciprofloxacin from solutions. The material achieved up to 76% removal of the antibiotic within 120 min, utilizing a catalyst concentration of 0.5 g L⁻¹ with a pollutant concentration of 20 mg L⁻¹. In reuse experiments, the material exhibited high recyclability even after multiple reaction cycles. Halloysite-based nanocomposites represent a strategic advancement in environmental remediation technologies, contributing to the development of clean, effective, and reusable materials. Full article

In the mining industry, key unit operations such as grinding, flotation, thickening, and tailings transport are negatively affected by the presence of clay minerals, which impart complex rheological behaviors to mineral suspensions by increasing their rheological properties. This deterioration arises from specific physicochemical characteristics of clay minerals such as fine particle size, anisotropic character, laminar morphology, and swelling capacity. This work reviews the effects of various rheology-modifying reagents on clay suspensions including kaolinite, illite, and montmorillonite. The reviewed reagents include inorganic salts, pH modifiers, polymers, surfactants, and nanoparticles. Their mechanisms of interaction with solid particles are analyzed, highlighting their influence on the degree of dispersion or aggregation. Furthermore, this review proposes research opportunities focused on the formulation of hybrid reagents, modified biopolymers, and the development of reagents effective under adverse conditions such as high salinity or elevated temperatures. This review provides a comprehensive basis for optimizing the use of rheological additives through more efficient and sustainable strategies for managing clay-rich suspensions in the mining industry. Full article

The stability of nitrogen gas foam hinders its applicability in petroleum applications. Fly ash nanoparticles and clay improve the N₂ foam stability, and flue gas foams provide a cost-effective solution for carbon capture, utilization, and storage (CCUS). This study examines the stability, volume, and bubble structure of foams formed using two anionic surfactants, sodium dodecyl sulfate (SDS) and sodium dodecylbenzene sulfonate (SDBS), along with the cationic surfactant cetyltrimethylammonium bromide (CTAB), selected for their comparable interfacial tension properties. Analysis of foam stability and volume and bubble structure was conducted under different CO₂/N₂ mixtures, with half-life and initial foam volume serving as the evaluation criteria. The impact of fly ash and clay on SDS-N₂ foam was also evaluated. The results showed that foams created with CTAB, SDBS, and SDS exhibit the greatest stability in pure nitrogen, attributed to low solubility in water and limited gas diffusion. SDS showed the highest foam strength attributable to its comparatively low surface tension. The addition of fly ash and clay significantly improved foam stability by migrating to the gas–liquid interface, creating a protective barrier that reduced drainage. Both nano fly ash and clay improved the half-life of nitrogen foam by 11.25 times and increased the foam volume, with optimal concentrations identified as 5.0 wt% for fly ash and 3.0 wt% for clay. This research emphasizes the importance of fly ash nanoparticles in stabilizing foams, therefore optimizing a foam system for enhanced oil recovery (EOR). Full article

Poly(trimethylene terephthalate) (PTT) is a thermoplastic polyester with a unique structure due to having three methylene groups in the glycol unit. PTT competes with poly(ethylene terephthalate) (PET) and poly(butylene terephthalate) (PBT) in carpets, textiles, and thermoplastic materials, primarily due to the development of economically efficient synthesis methods. PTT is widely utilized in textiles, carpets, and engineering plastics because of its advantageous properties, including quick-drying capabilities and wrinkle resistance. However, its low melting point, resistance to chemicals, and brittleness compared to PET, have limited its applications. To address some of these limitations for targeted applications, PTT nanocomposites incorporating clay, carbon nanotube, silica, and ZnO have been developed. The distribution of nanoparticles within the PTT matrix remains a significant challenge for its potential applications. Several techniques, including sol–gel blending, melt blending, in situ polymerization, and in situ forming methods have been developed to obtain better dispersion. This review discusses advancements in the synthesis of various PTT nanocomposites and the effects of nanoparticles on the isothermal and nonisothermal crystallization of PTT. Full article