Search Results (645)

The adsorption of aromatic hydrocarbons from liquid paraffin is essential because of their harmful nature, long-lasting presence, and detrimental effects on the quality of the product. In this study, we investigated the adsorption of naphthalene from liquid paraffin by using a nanoclay-based adsorbent prepared from boron enrichment process waste. The characterization of the prepared adsorbent was carried out by using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS) and N₂ adsorption–desorption techniques, which confirmed the development of a layered nanostructure containing boron that possesses a porous and high-surface-area format appropriate for the adsorption. The hydrothermal treatment significantly increased the BET surface area from 35.42 to 112.15 m²/g, indicating the successful formation of a porous nanostructure. The kinetic and isotherm parameters of the adsorption process were calculated from experimental data. The adsorption of naphthalene followed pseudo-second-order kinetics and the isotherm fit well to the Langmuir model. Adsorption experiments revealed that the optimum adsorption performance was achieved at pH 4.0, and equilibrium was reached within 90 min. The adsorption kinetics were best described by the pseudo-second-order model (R² > 0.99), while the equilibrium data showed excellent agreement with the Langmuir isotherm model (R² = 0.995), suggesting monolayer adsorption. The maximum adsorption capacity of BNC was determined as 365.20 mg/g, which was more than twice that of the raw BEW (247.59 mg/g). Thermodynamic analysis indicated that the adsorption process was spontaneous at lower temperatures and exothermic, with a ΔH° value of −15.42 kJ/mol for BNC. The results suggest that the adsorption occurs through a multi-step process, beginning with external film diffusion, followed by pore diffusion and surface interaction. Based on the kinetic, isotherm, and spectroscopic data, a supramolecular adsorption mechanism is suggested, which encompasses π-π interactions, van der Waals forces, and surface complexation between naphthalene and the nanoclay structure. These results indicate that boron enrichment process waste-derived nanoclay is a sustainable, economical, and efficient adsorbent for removing naphthalene from liquid paraffin. Full article

This study addresses the early-age brittleness and performance limitations of sustainable cement soil. While prior works optimized the baseline compressive strength using recycled sand and nanoclay, the multi-scale synergistic effects of fibers and nanomaterials on the post-peak deformation remain underexplored. To address this gap, a composite modification system incorporating recycled sand, nanoclay, polypropylene fibers, and graphene derivatives was developed. The experimental program comprised standard specimen fabrication, early-age curing, and unconfined compressive strength (UCS) testing, supplemented by RBF neural network curve fitting and quantitative ArcGIS digital image processing of scanning electron microscopy (SEM) micrographs. The results demonstrate that optimizing the fiber parameters (0.6% content with 6 mm length) successfully increases the early UCS to 2263.2 kPa, which is further elevated to a peak of 2755.0 kPa upon co-incorporation with 0.05% small-sized graphene oxide. Correspondingly, a newly introduced ductility index quantitatively confirms that the single-fiber reinforcement yields an index of 1.93, which is further enhanced to 2.02 by the graphene composite system. Microstructure tracking and digital image extraction revealed that the SEM-derived surface porosity decreased significantly, exhibiting a clear inverse relationship with the macroscopic mechanical strength. These quantitative microstructural shifts confirm that graphene effectively filled micropores and reinforced the fiber–matrix interface, establishing a dense matrix network with enhanced interfacial bonding. This multi-scale approach offers a sustainable strategy for green geotechnical applications. Full article

Polyvinylidene fluoride (PVDF)/clay nanocomposite membranes with different nanoclay loadings (0–5 wt%) were prepared via the non-solvent induced phase inversion method. Effects of organo-montmorillonite (OMMT) content on the morphology and performance were systematically investigated. Results showed that OMMT was uniformly exfoliated and dispersed in the PVDF matrix, while the nanocomposite membranes consistently maintained the β-crystalline phase of PVDF. The incorporation of nano-clay significantly enhanced membrane hydrophilicity, porosity, pure water flux, and protein rejection performance: when clay content increased to 5 wt%, the pure water flux improved from 89.8 L·m⁻²·h⁻¹ to 216.3 L·m⁻²·h⁻¹, with rejection rates of 98.6% for bovine serum albumin (BSA) and 95.1% for pepsin. Mechanical tests showed that 3 wt% was the optimal clay loading, at which the storage modulus of the membrane increased by 59.8% compared to neat PVDF membranes. Antifouling experiments revealed that the nanocomposite membranes exhibited significantly lower irreversible fouling resistance, substantially improved hydraulic cleaning flux recovery rates, and markedly enhanced antifouling properties. Furthermore, long-term stability, economic analysis, and environmental safety assessments confirmed the practical application potential of these nanocomposite membranes in water treatment. These findings provide theoretical support and technical references for the preparation and application of high-performance PVDF ultrafiltration membranes. Full article

Hybrid organic–inorganic composites based on biopolymers and nanoclays are attracting increasing interest for the development of functional materials in biomedical and agricultural applications. In this work, elongated alginate/halloysite nanotube (Alg/HNT) composite filaments were fabricated through a wet-spinning process assisted by syringe-based extrusion. Alg/HNT dispersions with different inorganic/organic ratios were first screened in terms of colloidal stability and injectability in order to identify suitable formulations for extrusion. The influence of key processing parameters, including the extrusion flow rate and calcium chloride concentration in the coagulation bath, was then systematically investigated to elucidate their effect on filament morphology and structure. Optical and scanning electron microscopy revealed that filament diameter can be tuned by varying the CaCl₂ concentration, while partial alignment of alginate chains along the extrusion direction was observed. Halloysite nanotubes were homogeneously distributed within the polymer matrix, mainly as micro-sized aggregates. Finally, the nanotubes were chemically functionalized with caffeine, as a model molecule, and incorporated into the alginate filaments, demonstrating the feasibility of introducing specific functionalities into wet-spun Alg/HNT composite fibers. These results establish a reproducible strategy for the fabrication of alginate/HNT filaments with tunable morphology and functionalizable nanotube interfaces, providing a versatile platform for the development of sustainable hybrid biopolymer materials. Full article

The development of sustainable, high-performance construction materials is essential for enhancing the resilience and economic efficiency of infrastructure in seismically active regions. Although nanomaterials can improve concrete performance, the combined influence of hybrid nanomaterial systems—particularly those sourced from agricultural and industrial waste streams—on early-age behavior, building-scale seismic response, and cost efficiency remains insufficiently quantified. This study presents an integrated experimental and numerical assessment of high early-strength concrete (HESC) incorporating nano-silica (NS), nano-clay (NCl), and cellulose nanofibers (NCels). Experimental results indicate that the optimized mixture (HESC-O) achieved a 3.15-fold increase in 28-day compressive strength, a 93.3% reduction in water penetration depth, and an 88.7% decrease in corrosion rate compared with conventional concrete. Finite element analyses of low-, mid-, and high-rise building models showed that HESC-O increased lateral stiffness and reduced story drift by up to 30% compared to normal concrete (NC); improvements over reference HESC (HESC-R) were of 5–10% and lateral displacement differed by 25–40%, with the most pronounced improvements observed in taller structures. Despite a higher unit material cost, the cost–benefit analysis demonstrated substantial net savings, particularly for high-rise buildings, primarily due to a 52% reduction in column cross-sectional areas and the associated increase in usable floor space. The findings support the performance-based selection of nano-engineered concrete that balances structural performance, economic value, and sustainability. Full article

Conventional epoxy polymers and their composites are increasingly challenged by environmental concerns, high manufacturing costs, and limited recyclability, necessitating the exploration of sustainable alternatives. Many research groups have sought to develop alternate polymers from various renewable resources, such as lignin, polyphenols, natural resins, saccharides, and plant oils. This new type of polymer has led to the emergence of bio-based polymers, which are often used with different reinforcements as bio-based composites. In this review, the synthesis of different bio-epoxy resins is discussed in detail along with their chemical structures. Subsequently, the enhancements in the properties of these bio-composites with the addition of different nanomaterials such as carbonaceous nanofillers (carbon nanotubes, graphene nanoplatelets, graphene oxide, etc.), cellulose-based nanomaterials, inorganic nano-silica (spherical and mesoporous), and nano-clay is explained. Lastly, the properties of these bio-composites and their applications in civil engineering are highlighted. This review has provided a detailed overview of the developments in bio-composites that can be used as a guide for the development of a new class of bio-composites using other alternate resources. Full article

Gel plugging agents are key drilling fluid additives for maintaining wellbore stability. However, the downhole ultra-high-temperature, high-salinity environments, and developed micro-fractures in deep and ultra-deep wells pose severe challenges to the performance of gel plugging agents. To address this problem, this paper presents the preparation of a nano-micron gel plugging agent with a core–shell structure, denoted as LMS, suitable for high-temperature and high-salinity water-based drilling fluids. LMS was synthesized via emulsion polymerization, using a styrene–sodium p-styrenesulfonate copolymer as the core and 2-acrylamido-2-methylpropanesulfonic acid and methacryloyloxyethyltrimethyl ammonium chloride as the shell-modifying monomers. LMS was characterized by infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, and particle size analysis, confirming that LMS met the design expectations. Experimental results showed that after aging at 220 °C for 16 h under saturated-salt conditions, the filtration loss of the drilling fluid with 3 wt% LMS was 10.4 mL, a reduction of 57.4% compared to the base mud. Meanwhile, LMS exhibited good plugging performance in microporous membrane tests and sand bed tests. After aging at 220 °C for 16 h under saturated-salt conditions, the core plugging rate reached 95.4%. LMS can not only adsorb onto clay surfaces to increase the thickness of the hydration film, enhancing drilling fluid stability, but can also synergistically build a filter cake with clay particles to plug nano-micron pores, preventing drilling fluid infiltration into the formation. This paper provides a preparation method for a high-temperature- and high-salinity-resistant gel plugging agent with excellent plugging effects, which is expected to support safe and efficient drilling in deep and ultra-deep formations. Full article

The upper Permian Dalong Formation in western Hubei Province is a crucial strategic successor for shale gas development in South China. However, the geological controls on reservoir pore development, particularly the influence of organic–inorganic interactions on the pore system, remain poorly understood. This restricts the precise optimization of shale gas exploration targets in this formation. To investigate the pore development characteristics and main controlling factors of the Dalong Formation shale reservoirs, this study takes the DFS from the Shuanghe section in western Hubei as the research object. X-ray diffraction (XRD), argon-ion polishing-scanning electron microscopy (SEM), and N₂/CO₂ gas adsorption–desorption technologies were integrated to achieve qualitative characterization and quantitative assessment of the pore network, with analyses of pore size distribution. The results show that the pores of the DFSs are dominated by interparticle pores and organic matter pores, and the pore structures of organic-rich and organic-lean shales exhibit significant differentiation characteristics. The quartz in the DFSs are mainly of diagenetic origin, and authigenic quartz cementation blocks primary intergranular pores, exerting a significant negative effect on pore development. In contrast, the smectite-to-illite transformation promotes the development of interlayer micropores, leading to a good positive correlation between clay mineral content and micropore volume, as well as specific surface area. Organic matter abundance is the core controlling factor for the construction of micro–nano pore networks. This study clarifies the dominant mechanisms of pore development driven by organic–inorganic interactions in the DFS. Authigenic diagenetic quartz impedes pore development, while smectite-to-illite transformation promotes micropore formation. Organic matter abundance is the dominant control on the micro-nanopore system. This study lays a critical geological theoretical foundation for the exploration evaluation and target selection of shale gas in the Dalong Formation. Full article

Multilayer paper composites have been widely applied in industrial sectors and as sustainable concrete formwork in civil construction. These materials are produced by pressing paper layers bonded with a sodium silicate adhesive; however, their structural performance is often limited by the adhesive’s low mechanical strength. Therefore, in this study, the effects of incorporating 0.5 wt.% nanoclay (NA), nanosilica (NS), and kaolin into sodium silicate on the physical, mechanical, and microstructural properties of the composites were evaluated. The composites were fabricated with 20 layers of recycled kraft paper and a final mass of 65 g/m² of reinforced sodium silicate applied by a glue line. The adhesive was applied using a paper coating machine, followed by pressing at 4.30 MPa. The results showed that the presence of nanomaterials had no measurable effect on the apparent density of the composites; nevertheless, the inclusion of 0.5% NA promoted a 25% increase in toughness. Thus, the use of nanomaterials is efficient at obtaining better-quality composites for numerous technological applications. Full article

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

The swell-shrink behavior of expansive soil strongly affects the long-term stability of subgrades and other geotechnical infrastructures. This study investigated the effects of three nanomaterial additives, namely nano-lime, nano-calcined clay, and hydrophobic nano-silica, on expansive soil. A series of laboratory tests was performed to evaluate the swell-shrink behavior of nanomaterial-treated soils under varying initial water contents and curing durations. Additionally, microstructural analyses were conducted to reveal the underlying stabilization mechanisms. The results showed that all three nanomaterials reduced the swell-shrink potential of the expansive soil, but their improvement effects were strongly dependent on the initial water content. Nano-lime exhibited the strongest overall stabilization effect, especially under relatively high initial water contents, and its performance became more pronounced with curing. Nano-calcined clay provided a moderate but relatively stable improvement. In contrast, hydrophobic nano-silica performed better under relatively low initial water contents, indicating a distinct moisture-dependent behavior. Nano-lime and nano-calcined clay were more effective in refining the pore structure and promoting a denser soil fabric, whereas nano-silica mainly modified particle surface conditions and showed limited pore-refinement capacity under wet conditions. These findings highlight the novelty of the present study in terms of the moisture-dependent stabilization performance and comparative mechanisms of three representative nanomaterials under a unified low dosage, and they provide useful guidance for the improvement of expansive soil subgrades in engineering practice. Full article

This work presents a comparative study of micro- and nano-scale fillers in liquid composite molding processes, focusing on how particle size and morphology affect resin rheology, flow behavior, and filler filtration within fiber preforms. Glass microspheres and organo-modified montmorillonite were dispersed in epoxy resin and injected through glass-mat preforms at different fiber volume fractions (ranging from 0.27 to 0.47). Our study integrates rheological characterization, in situ flow-front tracking, unsaturated permeability analysis, thermogravimetric quantification of retained particles, and microstructural observations by SEM. Despite their smaller loading, nanoclay suspensions showed a markedly higher viscosity increase than microsphere systems, yet their permeability remained nearly unchanged. In contrast, microsphere-filled resins exhibited strong filtration at the flow inlet, density-driven settling near the lower tool face, and significant permeability loss. The results demonstrate that nano-fillers, although more viscous, maintain homogeneous distribution and flow continuity, whereas micro-fillers promote cake formation and local compaction. This controlled side-by-side comparison clarifies how filler size and shape govern filtration mechanisms in liquid composite molding (LCM), providing design guidelines for processing filled resin systems without compromising part quality. Full article

Anthropogenic phosphorus (P) release from human activities continues to degrade freshwater systems, underscoring the need for effective and sustainable approaches to P removal and management. This study investigates steel slag–chitosan–nanoclay hydrogel composites as a waste-derived alternative to metal-doped biopolymer hydrogels for P removal from wastewater and stormwater. Steel slag aggregates (SSAs), a by-product of steel manufacturing, were incorporated into chitosan-based hydrogel matrices to produce composite sorbents derived from waste materials with potential for cost-effective application. Two formulations (SSA20 and SSA40) were synthesized and compared with a chitosan–nanoclay–iron (CH/NC/Fe) reference hydrogel. Phosphorus adsorption affinity was evaluated using a standardized 24 h batch protocol at environmentally relevant concentrations representative of municipal wastewater (10 mg P L⁻¹) and stormwater or agricultural runoff (1 mg P L⁻¹). The SSA40 composite exhibited the highest P adsorption affinity (Rd = 2.39 ± 0.22 L g⁻¹), outperforming both standalone SSA and the Fe-based hydrogel reference. Scanning Electron Microscopy and Energy-Dispersive X-Ray Spectroscopy (SEM–EDX) analyses revealed strong polymer–slag interactions and metal–phosphate associations, consistent with coupled adsorption and precipitation mechanisms. The SSA-based hydrogels also exhibited self-induced acidification (pH 3.3–4.2), enhancing phosphate uptake while providing intrinsic pH buffering. This study introduces a stable, waste-derived hydrogel composite and demonstrates a reproducible, environmentally relevant batch-testing approach for comparative evaluation of hydrogel phosphorus sorbents, supporting evidence-based strategies for sustainable phosphorus pollution control. Full article

Bio-based, biodegradable, and renewable polymers offer a promising alternative to traditional synthetic polymers derived from petroleum or other non-renewable resources. However, their use is limited by suboptimal properties and high costs. Incorporating sustainable reinforcements into the polymer matrix significantly improves biopolymer performance while preserving key properties, sustainability, and cost-effectiveness. Bio-based polymeric composites have emerged as a crucial category of biopolymers, playing a key role in advancing a sustainable, circular economy. This review provides an updated overview of bio-based polymer composites and nanocomposites, focusing on reinforcement strategies using natural nanofillers and engineered nanoparticles. We summarize key synthesis and processing methods, discuss structure–property relationships, and highlight recent advances in applications such as food packaging, biomedical devices, energy systems, environmental remediation, 3D printing, and supercapacitors. Polymer nanocomposites are versatile, with their performance depending on the type, size, and interactions between the fillers and the polymer matrix. Progress in metallic, ceramic, carbon-based, natural, and hybrid fillers has improved their properties. Using bio-based polymers and renewable fillers supports sustainability. Natural nanofillers derived from renewable sources and industrial byproducts offer a sustainable approach to developing high-performance, biodegradable nanocomposites. Smart nanocomposites can react to external stimuli by integrating specialized fillers that enhance their mechanical and mobility properties. Shape memory nanocomposites can be remotely activated—using heat, electricity, magnets, or light—enabling advanced applications. Finally, we address major challenges and outline future directions for scalable, circular-material solutions, drawing on perspectives from the circular economy and life cycle assessment (LCA). Full article