Binary Composite System Research Articles

Binary composite depolymerization system targeting polymer injection wells: A fusion of experiment and mechanism

With the continuous development and application of polymer flooding technology, the problem of polymer injection well blockage has become increasingly severe, and various plugging removal technologies have emerged. This paper studies the depolymerization agent system, aiming at the blockage problem caused by the injection of polymer HLCHEM-P01 in the mine. The depolymerization agent system is evaluated through gel chromatography analysis, corrosion evaluation, pH sensitivity evaluation, and core displacement experiment. Finally, an efficient, safe, low corrosion and reliable binary compound depolymerization agent system was obtained. It can almost wholly degrade the polymer solution after 90 min. Analyze the mechanism of action of the binary compound depolymerization agent system, which involves specific antagonistic or synergistic interactions. The overall oxidation performance of mixed chemical agents is not just a simple superposition of the oxidation performance of individual chemical agents. The application effect of the depolymerization agent system is significant, and the core permeability recovery reaches over 90%. Effectively solving blockage problems can help improve oilfield efficiency and increase crude oil recovery.

Highly efficient lithium leaching from α-spodumene via binary composite salts low-temperature roasting process

With the rapid development and widespread application of lithium-ion batteries, the demand for lithium has surged dramatically, drawing increasing attention to its extraction from spodumene deposits. However, the sustainable development of the lithium industry faces challenges, as traditional processes are hindered by high conversion temperatures, excessive acid consumption, and difficulties in purifying the leachate. Hence, we propose a binary composite additive system based on sodium sulfate‑calcium oxide (Na2SO4-CaO) for roasting α-spodumene at comparative low temperatures. The optimal roasting conditions entailed a mass ratio of spodumene/CaO/Na2SO4 at 1:0.1:0.8, a roasting temperature of 900 °C, a holding time of 2 h, a liquid-to-solid ratio of 5 mL/g, and leaching at 60 °C for 30 min, resulting in an impressive lithium leaching efficiency of 95.45 %. Thermodynamic and kinetic analyses reveal that the roasting formed the product of water-soluble LiNaSO4, which was then dissolved into water, with the leaching process being governed by internal diffusion.

Simultaneous photocatalytic removal of tetracycline and hexavalent chromium by BiVO4/0.6CdS photocatalyst: Insights into the performance, evaluation, calculation and mechanism

In this study, a novel Z-scheme heterojunction on bismuth vanadium/cadmium sulfide (BiVO4/0.6CdS) was developed and evaluated for simultaneous photocatalytic removal of combined tetracycline (TC) and hexavalent chromium Cr(Ⅵ) pollution under visible light. Based on the analysis of intermediate products and theoretical calculation, the property of the intermediate products of TC degradation and the effect of built-in electric field (IEF) of composite materials on photo-generated carrier separation were illustrated. According to the experiments and evaluation results, the performance of BiVO4/0.6CdS is higher than CdS 2.83 times and 4.82 times under the visible light conditions, with the aspect of simultaneous oxidizing TC and reducing Cr(Ⅵ), respectively. The catalyst has a faster removal rate in the binary composite pollution system than the single one. Therefore, the photocatalytic degradation of TC using BiVO4/0.6CdS can reduce the toxic effect of TC on the environment. The aforementioned evaluation provides a new design strategy for Z-scheme heterojunction to simultaneous photocatalytic degradation of composite organic and inorganic pollutants.

The effect of multi-component Inhibitor systems on hydrate formation

Based on the existing components of drilling fluids, the construction of a multi-component hydrate inhibitor system is essential for building a high-performance hydrate drilling fluid system and reducing production costs. The constant rate cooling method are performed to investigate the effect of different inhibitor systems on hydrate formation. The results indicate that thermodynamic inhibitors exhibit enhanced effectiveness in inhibiting hydrate formation at higher mass concentrations. In contrast, kinetic inhibitors demonstrate superior performance at lower mass concentrations, and their inhibitory efficacy does not scale up with concentration. Kinetic inhibitors can synergize with other components of the drilling fluid that have thermodynamic inhibitor effects. In particular, the ternary composite system has better synergistic effects compared to the binary composite system. It is of great significance for the construction of efficient hydrate drilling fluid systems in the future.

Construction and properties of curdlan gum/gellan gum binary composite gel system

In the present study, the synergetic gelation of curdlan gum (CG) and gellan gum (CG) at different biopolymer ratios were investigated. The optimal gelation of CG and GG was determined at total biopolymer concentration of 0.6% and a mass ratio of 1:1 according to visual observation and viscoelastic properties. The gelation behavior of the CG/GG binary composite gel exhibited ratio-dependent behavior at different biopolymer mixing ratios (2:8–8:2). With the increase in the CG/GG ratio from 2:8 to 8:2, the gel strength and transition temperature of the CG/GG gel showed an increasing trend followed by a decrease, reaching a peak at 5:5, with corresponding G′, melting and gelling temperatures of 335.8 Pa, 82.5 °C and 33.7 °C, respectively. The improved gel properties could be ascribed to hydrogen bonds between CG and GG, as reflected by the blueshift of the O–H vibration peaks and water associated regional variation. Moreover, the CG/GG binary composite gel exhibited a significantly increasing water holding capacity (WHC) as the ratio of CG/GG decreased from 8:2 to 4:6, while the excess involvement of GG had no effect on the WHC improvement. Furthermore, the CG/GG binary composite gel exhibited denser and more homogeneous microstructures in comparison to individual CG and GG and performed the most compact gel network at ratio of 5:5, supporting the stronger gel rigidity and WHC. Therefore, these novel CG/GG hydrogels showed considerable gel strength and microstructures, which would provide a better mechanistic understanding of the polysaccharide complex in practical applications as a hydrogel base material.

Mechanical and thermal characterization of coir/hemp/polyester hybrid composite for lightweight applications

Individual applications of coir and hemp as reinforcement in composites have been exhaustively studied; however, their hybridization must also be investigated. In this context, this research investigates the utilization of coir and hemp fibers as reinforcements in a polyester-based hybrid composite system. The primary objective is to find out how these reinforcements affect the hybrid composites' mechanical (tensile, flexural, and impact) and thermo-gravimetric properties. To accomplish this, composite samples with varying weight proportions of coir and hemp fibers were fabricated, and extensive mechanical testing was performed. The findings from the tensile, flexural, and impact tests revealed an enhancement in the mechanical characteristics of the fabricated composites as the proportion of coir fiber grew and the proportion of hemp fiber reduced. The hybrid composite, containing 15% coir and 5% hemp fibers, had superior mechanical properties to the binary composite system. In addition, thermogravimetric analysis was performed to determine the thermal stability of the hybrid composites. Within a temperature range of 30 °C–800 °C, weight loss was observed, confirming the overall thermal resistance of the materials. Fourier Transform InfraRed Spectroscopy (FTIR) was used to determine the composite's chemical composition, revealing the presence of functional groups that contribute to the composite's performance. Utilizing Scanning Electron Microscopy (SEM), the surface morphology of hybrid composites was investigated, yielding valuable insights into the fiber-matrix interaction and composite structure. The results of this study demonstrate the potential of the coir/hemp/polyester hybrid composite as a lightweight material in a variety of industries.

Spalling mitigation techniques for high-performance concrete at elevated temperature

High-performance concrete (HPC) is highly susceptible to temperature-induced spalling, which unveils severe damage of HPC structural members. Therefore, this research work is aimed at developing spalling mitigation techniques for HPC and experimentally assessing spalling behaviour at transient heating conditions up to 1000 °C for a 4-hour fire resistance rating. A total of four HPC mixes were comprised for spalling behaviour evaluation, in which Mix H1 was designed only using main binder ordinary Portland cement (OPC), whereas Mix-H2, Mix-H3, and Mix-H4 were designed by partial replacement of OPC with three different supplementary cementitious materials (SCMs), i.e., fly ash (FA), silica fume (SF), ground granulated blast furnace slag (GGBS) one at a time as a binary composite system. Polypropylene (PP) fibres and steel (ST) fibres one at a time from a range of 0.00, 0.62, 1.24, 1.86, and 2.48 kg/m3 and ST fibres range of 0.00,12.43, 24.87, 37.30, and 49.74 kg/m3 were incorporated into HPC mixes for evaluating spalling mitigation behaviour at elevated temperature. For each HPC mix, a total of three standard cylindrical specimens (100 mm diameter × 200 mm height) were exposed to transit temperature 1000 °C for up to 4 h to assess spalling behaviour. It is observed that Mix-H1 content only OPC does not reveal any severe damage and spalling behaviour, whereas Mix-H2, Mix-H3, and Mix-H4 comprising SCMs revealed very severe damage and spalling behaviour. This result indicates that the highly dense microstructure with a highly durable HPC matrix using SCMs does not allow any moisture movement/migration from the inherent concrete binding matrix to the outer exposed surface of cylinder specimens and resulting in explosive-type spalling of HPC. However, using 1.86 kg/m3 of PP fibres and 37.30 kg/m3 of ST fibres in HPC binary systems has a positive impact on mitigating spalling of HPC at elevated temperatures.

Constructing outstanding 1D/2D Co3O4/NiMnO3 heterostructure to promote the PEC efficiency for water pollution remediation

The structural design and morphology control of materials is a very attractive topic because the structure and morphology of materials usually play a key role for their performance and application. In this work, we report a facile two-step hydrothermal process for construction of the binary composite oxide system (i.e., 1D/2D Co3O4/NiMnO3 core-shell heterostructure) based on Ostwald ripening effect. Interestingly, Co3O4 nanowire will expand only when it is fully covered with NiMnO3 nanosheets to form a core-shell structure in sequential hydrothermal process. In binary composite oxide system, the formation of continuous and uniform interface between core (Co3O4) and shell (NiMnO3) based on Ostwald ripening effect is the key factor in the heterogeneous nucleation process, which can be proved by the homogeneous diffusion of Co element in the Ti/Co3O4-NiMnO3 sample. As a result, the optimized Ti/Co3O4-NiMnO3-1.5 exhibited superior PEC performance (degradation rates are ∼ 91.2% for 120 min and 80.5% after 5 cycles) for degrading reactive brilliant blue KN-R solution, which can be attributed to the construction of the hollow Co3O4/NiMnO3 core-shell heterostructure. Furthermore, the identification experiments of active species showed that the h+ and •O2- radicals are the dominant reactive species, indicating the induced charge transfer is based on the type II semiconductor heterostructure.

Designing Bioinspired Composite Structures via Genetic Algorithm and Conditional Variational Autoencoder

Designing composite materials with tailored stiffness and toughness is challenging due to the massive number of possible material and geometry combinations. Although various studies have applied machine learning techniques and optimization methods to tackle this problem, we still lack a complete understanding of the material effects at different positions and a systematic experimental procedure to validate the results. Here we study a two-dimensional (2D) binary composite system with an edge crack and grid-like structure using a Genetic Algorithm (GA) and Conditional Variational Autoencoder (CVAE), which can design a composite with desired stiffness and toughness. The fitness of each design is evaluated using the negative mean square error of their predicted stiffness and toughness and the target values. We use finite element simulations to generate a machine-learning dataset and perform tensile tests on 3D-printed specimens to validate our results. We show that adding soft material behind the crack tip, instead of ahead of the tip, tremendously increases the overall toughness of the composite. We also show that while GA generates composite designs with slightly better accuracy (both methods perform well, with errors below 20%), CVAE takes considerably less time (~1/7500) to generate designs. Our findings may provide insights into the effect of adding soft material at different locations of a composite system and may also provide guidelines for conducting experiments and Explainable Artificial Intelligence (XAI) to validate the results.

Adsorption behavior of UV aged microplastics on the heavy metals Pb(II) and Cu(II) in aqueous solutions

As the “vector” of heavy metals in the aquatic environment, microplastics (MPs) have a great influence on the migration and transformation of heavy metals. In this study, the adsorption of polypropylene (PP), polyethylene (PE) and polystyrene (PS) on two models of heavy metals after UV aging and environmental variables (ionic coexistence, pH, salinity, and fulvic acid) were comprehensively explored on adsorption. The results show that new oxidation functional groups are formed and their hydrophilicity is enhanced after MPs aging. As a result, the adsorption experiments showed that the adsorption of contaminants by UV aged MPs exceeds that of pristine MPs. The adsorption amounts of Pb(II) and Cu(II) by PP, PE and PS increased by 1.45, 1.46, 1.25 and 1.63, 1.39, 1.22 times, respectively. Adsorption kinetic data were more consistent with the pseudo-second-order kinetic model, proving chemisorption to be the mechanism governing the interaction between metal ions and MPs. The Freundlich model could accurately predict the heavy metal adsorption isotherms on MPs, showing that non-homogeneous multilayer adsorption dominates the process. In Pb(II)–Cu(II) binary composite system, metal ion adsorption capacity on MPs is less than that of the single system adsorption capacity, which proves that there is a specific inhibitory effect between coexisting ions. Additionally, external factors like pH, salinity, and fulvic acid content have a big impact on adsorption behavior. According to mechanism analysis, the adsorption process mainly relies on electrostatic interaction, surface complexation, and van der Waals force.

Testing and Evaluation of the Emulsifying Properties of Compound Oil Displacement Agents.

Aiming at the phenomenon that the emulsification degree of the composite oil displacement agents affects the recovery factor, composite oil displacement agents of the P/S binary system and the A/S/P ternary system were taken as research objects. Emulsion particle size and stability were tested and evaluated, and the effects of the surfactant and alkali content on the emulsification degree of emulsion were investigated. The concept of the emulsification stability index and its measuring method were put forward, and a method was used to test and evaluate the emulsification stability of the emulsion. The results showed that the emulsion formed by the ternary system had the smallest average particle size, the best stability, and the best emulsification stability. The binary composite system was second, and the polymer solution did not form an emulsion. The emulsification stability index method could effectively quantify the emulsification degree of the emulsion. Within a certain range, the increase of the surfactant and alkali content in the composite oil displacement agent was beneficial to the improvement of the emulsification degree of the emulsion.

Carbonization‐dominated synergistic behaviors of ammonium hypophosphite/EG composite in improving flame retardancy of flexible polyurethane foam

AbstractDeveloping flexible polyurethane foam (FPUF) with good anti‐ignition and self‐extinguishing performance is the fundamental way to prevent fire hazards in application. A binary composite system containing ammonium hypophosphite (NHP) and expandable graphite (EG) was applied to prepare flame‐retardant FPUF. The co‐action of NHP and EG exhibited high‐efficiency synergistic effect in improving the anti‐ignition, self‐extinguishing, and carbonization performance of FPUF. The analysis of micromorphology, element retention and chemical structure character on charring residue, reveals the physical–chemical synergistic carbonization mechanism of NHP/EG composite. The real‐time tracing on thermal‐decomposition volatiles, discloses the behaviors of NHP/EG composite in suppressing volatile fuel supply and toxic fume production. With an addition of 11 wt.% NHP and 7 wt.% EG, 11NHP/7EG achieved a limited oxygen index value of 30.3%, passed horizontal burning class HF‐1, and retained 55.6 wt.% charring residue. The peak of heat release rate and total heat release of 11NHP/7EG were both reduced by more than 50%, compared with that of pristine FPUF. The synergistic flame‐retardant mechanism of NHP/EG composite provides a valuable reference for high‐performance flame‐retardant FPUF manufacturing.

Synthesis of Sb2S3-Sb4O5Cl2 composite used as a photocatalyst for crystal violet cationic dye degradation

• Sb 2 S 3 -Sb 4 O 5 Cl 2 composite binary system was elaborated by a hydrothermal process. • SEM demonstrated that Sb 2 S 3 -Sb 4 O 5 Cl 2 composite has microtubes morphology. • UV–visible analysis and absorbance measurements confirmed its photocatalytic removal of crystal violet (CV) dye. • The degradation efficiency of CV was up to 96.24% after 270 min of exposure to visible light. In the present paper, a new composite material namely Sb 2 S 3 -Sb 4 O 5 Cl 2 has been prepared using the hydrothermal route and its photocatalytic properties for crystal violet dye removal from water were estimated. The prepared samples were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-Visible measurements. XRD and SEM results confirmed that the desired binary composite system was successfully formed with distinctive morphology. The photocatalytic test proved that the prepared composite material could act as a sustainable photocatalyst for the tested dye removal.

Micromechanics-Based Viscoelasticity Predictions of Crumb Rubber Modified Bitumen Considering Polymer Network Effects

Crumb rubber modified bitumen (CRMB) can be regarded as a binary composite system in which swollen rubber particles are embedded in the bitumen matrix. Previous study has successfully implemented the micromechanics models in predicting the complex moduli of CRMB binders using more representative constituent parameters. In the regime of master curves, while the micromechanics models used predicted well in the high-frequency range, they underestimated the complex modulus in the low-frequency range. The current study aims to further improve the prediction accuracy of micromechanics models for CRMB by considering the interparticle interactions. To accomplish this goal, a new reinforcement mechanism called chain entanglement effect was introduced to account for the interparticle interaction effect. Results show that the polymer chain entanglement effect accounts for the underestimation of complex modulus and lack of elasticity (overestimation of phase angle) for CRMB at high temperatures/low frequencies. The mechanical properties of bitumen matrix and entangled polymer network can be determined based on the rubber content. The introduction of the entangled polymer network to the generalized self-consistent model significantly improved the prediction accuracy for both complex modulus and phase angle in the whole frequency range. In summary, by incorporating the physio-chemical interaction mechanism into the currently available models, a new dedicated micromechanics model for predicting the mechanical properties of CRMB has been developed. The predicted viscoelastic behaviors can thereafter be used as inputs for an improved mix design.

Solution Properties of a Composite System Containing Dynamic Borate Ester Bonds Formed by a Guar Gum and Polyboric Acid Compounds

Polymer systems containing dynamic covalent bonds have great application potential in the field of enhanced oil recovery. In this paper a series of polyboric acid compounds were synthesized by using polyamine and formylbenzeneboronic acid as raw materials, and then a binary composite system containing dynamic borate ester bonds was formed by mixing guar gum with the polyboric acid compound. The effects of the polyboric acid compound structure, composite system concentration, temperature, inorganic salt concentration and pH on the apparent viscosity and rheological properties of the composite system solution were investigated. The results showed that the higher the content of boric acid groups in the polyboric acid compound, the greater the solution viscosity of the composite system. The apparent viscosity of the guar gum solution increased from 350 mPa.s to 1854 mPa.s at room temperature, the highest value obtained, when the guar gum was mixed with a polyboric acid compound formed by the reaction of polyethyleneimine (PEI) and 2-formylphenylboric acid (2-FPBA) at a molar ratio of 1:4.5. Temperature and pH had a great influence on the apparent viscosity of the composite system, whereas NaCl addition had little effect on the apparent viscosity of the composite system. In addition, the rheological test results showed that the composite system had good shear resistance and structural elasticity, which meets the basic requirements of a polymer flooding agent used for enhanced oil recovery.

Optimum Calcination Condition of Waste Stabilized Adobe for Alkali Activated High Volume Adobe-Slag Binder Cured at Room Temperature

This study aims to determine the most convenient calcination temperature and calcination duration of waste-stabilized Adobe (AB) to produce a new alkali-activated binder. Waste-stabilized Adobe mainly consists of soil, CaCO3 as a stabilizer, and straw (for strengthening). The availability of raw materials for making Adobe presents the waste-stabilized Adobe as a potential product for a new alkali-activated binder. Waste-stabilized Adobe collected from an abandoned damaged building in the village of Inonu in Northern Cyprus, ground and calcined at the following temperatures: 450, 550, 650, 750, 850, and 950°C. The calcination at each temperature was held for different durations 1, 3, 5, and 7 h. Raw and calcined waste stabilized Adobe structures were investigated using XRF, TGA-DTA, XRD, FTIR, and SEM. Considering technical and environmental views related to energy consumption, waste stabilized Adobe calcined at 750°C for 1 h presented the most promising results regarding the production of a new precursor for alkali-activated binder. This study also presents the effect of ground granulated blast furnace slag (GGBFS) usage on the fresh and hardened properties of optimum calcined AB-based alkali-activated pastes cured at room temperature. GGBFS was used to partially replace AB to form a binary composite raw material system and seven experimental groups were designed according to replacement levels of 0%, 5%, 10%, 15%, 20%, 25% and 30% (by mass). Alkali-activated high volume waste-stabilized Adobe-slag pastes prepared using Na2SiO3-to-NaOH ratio of 2 and 12 M concentration of Sodium Hydroxide. The fresh property as flowability and the hardened property as the compressive strength of the alkali-activated pastes with different GGBFS contents were investigated. The results indicated that the incorporation of GGBFS increased the flowability of fresh alkali-activated pastes. A 28-day compressive strength of 43.75 MPa can be obtained by a 30% replacement level of GGBFS.

Percolation in metal-insulator composites of randomly packed spherocylindrical nanoparticles

While classical percolation is well understood, percolation effects in randomly packed or jammed structures are much less explored. Here we investigate both experimentally and theoretically the electrical percolation in a binary composite system of disordered spherocylinders, to identify the relation between structural (percolation) and functional properties of nanocomposites. Experimentally, we determine the percolation threshold $p_c$ and the conductivity critical exponent $t$ for composites of conducting (CrO$_2$) and insulating (Cr$_2$O$_3$) rodlike nanoparticles that are nominally geometrically identical, yielding $p_c=0.305 \pm 0.026$ and $t=2.52 \pm 0.03$ respectively. Simulations and modeling are implemented through a combination of the mechanical contraction method and a variant of random walk (de Gennes ant) approach, in which charge diffusion is correlated with the system conductivity via the Nernst-Einstein relation. The percolation threshold and critical exponents identified through finite size scaling are in good agreement with the experimental values. Curiously, the calculated percolation threshold for spherocylinders with an aspect ratio of 6.5, $p_c=0.312 \pm 0.002$, is very close (within numerical errors) to the one found previously in two other distinct systems of disordered jammed spheres and simple cubic lattice, an intriguing and surprising result.

Micromechanics-based complex modulus prediction of crumb rubber modified bitumen considering interparticle interactions

Crumb rubber modified bitumen (CRMB) can be regarded as a binary composite system in which swollen rubber particles are embedded in the bitumen matrix. The current study aims to further improve the prediction accuracy of micromechanical models for CRMB by considering the interparticle interactions. To accomplish this goal, two different strategies were used. Firstly, the (n+1)-phase model was applied to the CRMB system by considering the multilayer properties of swollen rubber particles. Secondly, a new micromechanical scheme called the J-C model was used to account for the interparticle interaction issue. Results show that the (n+1)-phase models slightly increase the prediction accuracy but the underestimation of complex modulus at lower frequencies remains unsolved. The J-C model remedies the underestimation of modulus in the low-frequency range by other models and provides an overall improvement for the relative prediction accuracy by properly addressing the interparticle interactions from the perspective of particle configuration.

Effect of binary admixture of sepiolite and fly ash on carbonation and chloride resistance of modified cement mortar

This study presents the influence of binary admixture of sepiolite and fly ash on the performance of modified cement mortar including hydration heat, mechanical strength, carbonation resistance, chloride diffusion and the interaction between various binders. The experimental results showed that single incorporation of sepiolite can to some extent increase the strength of mortar, while it was even significant if a binary sepiolite-fly ash composite system was adopted. When the sepiolite content was 15%, the carbonation resistance of the modified mortar can be improved and its carbonation depth was decreased by 37.8%. It took place for chloride resistance of the corresponding modified mortar as well. Meanwhile, using binary admixture of sepiolite and fly ash, it can effectively shorten the induction period of cement hydration and reduce the cumulative hydration heat release of the modified system.

Microstructural evolution, mechanical and nanoindentation studies of stir cast binary and ternary aluminium based composites

The superior qualities offered by aluminium matrix composites (AMC) over the years has made it a widely used material for the fabrication of various components in the engineering sector. The effect of silicon carbide and ferrotitanium particles addition on the properties of stir cast aluminium-based composite was investigated. Stir casting technique was employed to ensure homogeneous dispersion of the reinforcement particles within the aluminium matrix. The microstructural, mechanical and tribological properties of the specimens were further assessed to determine the integrity of the fabricated composites. Results from microstructural examination showed a uniform dispersion of the reinforcement particles within the aluminium matrix. The reduced wear rate recorded by the composite reinforced with 5 wt% SiC +2 wt% TiFe resulted from the sliding of the stainless steel counterface over the oxide layers formed on the specimen surface. The specimen reinforced with 5 wt% TiFe +2 wt% SiC exhibited an enhanced tensile and nanomechanical properties, while the binary composite system with 5 wt% TiFe reinforcement had its wear resistance and modulus of elasticity improved.