Search Results (385)

The discharge of synthetic dyes in industrial wastewaters poses a serious environmental threat as they are difficult to degrade naturally and are harmful to aquatic organisms. This study aimed to evaluate the feasibility of using clean untreated rice husk (CRH) as a sustainable and low-cost adsorbent for the removal of methylene blue (MB) from synthetic wastewater. This approach effectively avoids the energy-intensive grinding process by directly using whole unprocessed rice husk, highlighting its potential as a sustainable and cost-effective alternative to activated carbon. A series of batch adsorption experiments were conducted to evaluate the effects of key operating parameters such as initial dye concentration, contact time, pH, ionic strength, and temperature on the adsorption performance. Adsorption kinetics, isotherm models, and thermodynamic analysis were applied to elucidate the adsorption mechanism and behavior. The results showed that the maximum adsorption capacity of CRH for MB was 5.72 mg/g. The adsorption capacity was stable and efficient between pH 4 and 10, and reached the highest value at pH 12. The presence of sodium ions (Na⁺) and calcium ions (Ca²⁺) inhibited the adsorption efficiency, with calcium ions having a more significant effect. Kinetic analysis confirmed that the adsorption process mainly followed a pseudo-second-order model, suggesting the involvement of a chemisorption mechanism; notably, in the presence of ions, the Elovich model provided better predictions of the data. Thermodynamic evaluation showed that the adsorption was endothermic (ΔH° > 0) and spontaneous (ΔG° < 0), accompanied by an increase in the disorder of the solid–liquid interface (ΔS° > 0). The calculated activation energy (Ea) was 17.42 kJ/mol, further supporting the involvement of chemisorption. The equilibrium adsorption data were well matched to the Langmuir model at high concentrations (monolayer adsorption), while they were accurately described by the Freundlich model at lower concentrations (surface heterogeneity). The dimensionless separation factor (RL) confirmed that the adsorption process was favorable at all initial MB concentrations. The results of this study provide insights into the application of agricultural waste in environmental remediation and highlight the potential of untreated whole rice husk as a sustainable and economically viable alternative to activated carbon, which can help promote resource recovery and pollution control. Full article

Under the accelerating global energy restructuring and the deepening carbon neutrality strategy, hydrogen energy has emerged with increasing strategic value as a zero-carbon secondary energy carrier. Water electrolysis technology based on renewable energy is regarded as an ideal pathway for large-scale green hydrogen production. However, polymer electrolyte membrane (PEM) conventional water electrolysis faces dual constraints in economic feasibility and scalability due to its high electrical energy consumption and reliance on noble metal catalysts. The mixed ionic-electronic conducting oxygen transport membrane (MIEC–OTM) reactor technology offers an innovative solution to this energy efficiency-cost paradox due to its thermo-electrochemical synergistic energy conversion mechanism and process integration. This not only overcomes the thermodynamic equilibrium limitations in traditional electrolysis but also reduces electrical energy demand by effectively coupling with medium- to high-temperature heat sources such as industrial waste heat and solar thermal energy. Therefore, this review, grounded in the physicochemical mechanisms of oxygen transport membrane reactors, systematically examines the influence of key factors, including membrane material design, catalytic interface optimization, and parameter synergy, on hydrogen production efficiency. Furthermore, it proposes a roadmap and breakthrough directions for industrial applications, focusing on enhancing intrinsic material stability, designing multi-field coupled reactors, and optimizing system energy efficiency. Full article

In this contribution, the classical Cauchy first-gradient elastic theory is used to solve the equilibrium problem of a bidimensional (2D) reinforced elastic structure under small displacements and strains. Such a 2D first-gradient continuum is embedded with a reinforcement, which is modeled as a zero-thickness interface endowed with the elastic properties of an extensional Euler–Bernoulli 1D beam. Modeling the reinforcement as an interface eliminates the need for a full geometric representation of the reinforcing bar with finite thickness in the 2D model, and the associated mesh discretization for numerical analysis. Thus, the effects of the 1D beam-like reinforcements are described through proper and generalized boundary conditions prescribed to contiguous continuum regions, deduced from a standard variational approach. The novelty of this work lies in the formulation of an interface model coupling 1D and 2D continua, based on weak formulation and variational derivation, capable of accurately capturing stress distributions without requiring full geometric resolution of the reinforcement. The proposed framework is therefore illustrated by computing, with finite element simulations, the response of the reinforced structural element under uniform bending. Numerical results reveal the presence of jumps for some stress components in the vicinity of the reinforcement tips and demonstrate convergence under mesh refinement. Although the reinforcement beams possess only axial stiffness, they significantly influence the equilibrium configuration by causing a redistribution of stress and enhancing stress transfer throughout the structure. These findings offer a new perspective on the effective modeling of fiber-reinforced structures, which are of significant interest in engineering applications such as micropiles in foundations, fiber-reinforced concrete, and advanced composite materials. In these systems, stress localization and stability play a critical role. Full article

A method for generally predicting interface chemical bonding at the metal–oxide interface with the interface reaction considered is reported. So far, the interface between pure metal or alloy and 11 oxides—MgO, Al₂O₃, SiO₂, Cr₂O₃, ZnO, Ga₂O₃, Y₂O₃, ZrO₂, CdO, La₂O₃, and HfO₂—without considering the interface reaction, has been discussed and implemented in the free web-based software product InterChemBond (v2022). Now, the number of oxides available for prediction is 83 in total. Among them, 29 oxides are in one stable valence, and the others are multi-valence. The newly developed prediction method considering the interface reaction is additionally implemented in InterChemBond. The principles and formula for predicting interface bonding while considering interface reactions are provided as well as some screenshots of the software. Full article

This review offers an in-depth analysis of soil contamination, discussing the origins, impacts, and remediation strategies, as well as the complex connections with interfacial chemistry. Interfacial chemistry plays a critical role in addressing soil contamination by governing the interactions between pollutants, soil particles, water, and remediation agents at phase boundaries (solid–liquid, solid–gas). Some key aspects include adsorption/desorption that controls pollutants binding to soil surfaces; chemical transformation which facilitates redox, hydrolysis, or catalytic reactions at interfaces to degrade contaminants; colloidal transport that affects the movement of nanoparticle-bound contaminants through soil pores; and techniques like soil washing, phytoremediation and permeable reactive barriers that can neutralize soil pollutants. The combination of interfacial chemistry and soil remediation techniques offers rich opportunities for improving predictive models of contaminant fate. Such approaches represent a paradigm shift from equilibrium-based remediation to dynamic process management. The review demonstrates how heterogeneous interfaces and molecular-scale dynamics dictate contaminant behavior. Furthermore, in addition to consolidating existing knowledge, the review also pioneers new directions by revealing how interfacial processes can optimize soil decontamination, offering actionable insights for researchers and policy makers. By understanding and manipulating interfacial chemical processes, scientists can develop more precise and sustainable cleanup methods. Full article

Considering the implications for the environment and human health, oil-contaminated soil generated in the petroleum industry requires treatment. Chemical cleaning represents an effective treatment approach for oil-contaminated soil and has attracted considerable attention. In this study, sodium d-gluconate (C₆H₁₁NaO₇), trisodium citrate (C₆H₅Na₃O₇), and L-arginine (C₆H₁₄N₄O₂) were employed as detergents to remove oil from oily sludge. The impacts of sludge (solid) concentration (C_S), types of detergents, temperature (T), and pH value on the deoiling efficiency (D_e) were systematically investigated. The results indicated that at a given detergent concentration (C_DG) and C_S, D_e followed the order C₆H₁₁NaO₇ > C₆H₅Na₃O₇ > C₆H₁₄N₄O₂. When C_S was 3.86 g·L⁻¹ and C_DG was 10.0 g·L⁻¹, sodium d-gluconate achieved a maximum D_e of approximately 85%. Additionally, at a fixed C_S, D_e decreased as the pH value increased, while it increased with increasing temperature. Interestingly, during the deoiling equilibrium, an obvious “solid effect” (or C_S−effect) was observed. The “solid effect” refers to the phenomenon where the oil distribution coefficient (K_D) changes with an increase in C_S. The observed C_S effect was described using the surface component activity (SCA) model. The values of the intrinsic distribution coefficient ($K_D^0$) and C_S−effect constant (γ), which are the model parameters of the SCA model, were derived from three detergent−sludge systems under different temperatures (T) and pH values. The strength of the C_S effect (or γ value) was found to be independent of detergent type and increased as T and pH value increased. This study broadens the application range of the SCA model and contributes to a deeper understanding of the adsorption and desorption behavior of oil droplets at the solid−liquid interface. Full article

Alkyl sulfobetaine shows a strong advantage in the compounding of surfactants due to the defects in the size matching of hydrophilic and hydrophobic groups. The interfacial tensions (IFTs) of alkyl sulfobetaine (ASB) and xylene-substituted alkyl sulfobetaine (XSB) with oil-soluble (Span80) and water-soluble (Tween80) nonionic surfactants on a series of n-alkanes were studied using a spinning drop tensiometer to investigate the mechanism of IFT between nonionic and betaine surfactants. The two betaine surfactants’ IFTs are considerably impacted differently by Span80 and Tween80. The results demonstrate that Span80, through mixed adsorption with ASB and XSB, can create a relatively compacted interfacial film at the n-alkanes–water interface. The equilibrium IFT can be reduced to ultra-low values of 5.7 × 10⁻³ mN/m at ideal concentrations by tuning the fit between the size of the nonionic surfactant and the size of the oil-side vacancies of the betaine surfactant. Nevertheless, Tween80 has minimal effect on the IFT of betaine surfactants, and the betaine surfactant has no vacancies on the aqueous side. The present study provides significant research implications for screening betaine surfactants and their potential application in enhanced oil recovery (EOR) processes. Full article

Slope failures in overconsolidated hard clays present significant geotechnical challenges, particularly in stratified formations prone to pre-existing discontinuities. Despite extensive research on residual shear strength and fissuring in stiff clays, the role of undetected tension cracks and their interaction with hydrogeological conditions in temporary excavations remains underexplored. This study addresses this research gap through a detailed case study of a slope failure during an unsupported residential excavation on Corfu Island, Greece. The investigation aimed to identify the failure mechanism, assess the influence of geological discontinuities and groundwater conditions, and evaluate the contribution of residual shear strength to slope stability. The methodology combined field observations, laboratory testing (including unconfined compression and ring shear tests), and numerical modelling using both finite element (FEM) and limit equilibrium (LEM) approaches. The results revealed that a nearly vertical, pre-existing fissure—acting as a tension crack—and water infiltration along the clay–sandstone interface significantly reduced the factor of safety, triggering a planar slide. Both FEM and LEM analyses indicated that critical conditions for failure were reached with a residual friction angle of 19°, inclined sandstone layers at 15–17°, and hydrostatic pressure from groundwater accumulation. This study demonstrates the compounded destabilizing effects of undetected discontinuities and water pressures in stratified hard clays and underscores the necessity of comprehensive geotechnical assessments for temporary excavations, even in seemingly stable formations. Full article

By combining density functional theory with the non-equilibrium Green’s function method, we conducted a first-principles investigation of spin-dependent transport properties in a molecular device featuring a dynamic covalent chemical bridge connected to zigzag graphene nanoribbon electrodes. The effects of spin-filtering and spin-rectifying on the I–V characteristics are revealed and explained for the proposed molecular device. Interestingly, our results demonstrate that all three devices exhibit significant single-spin-filtering behavior in parallel (P) magnetization and dual-spin-filtering effects in antiparallel (AP) configurations, achieving nearly 100% spin-filtering efficiency. At the same time, from the I–V curves, we find that there is a weak negative differential resistance effect. Moreover, a high rectifying ratio is found for spin-up electron transport in AP magnetization, which is explained by the transmission spectrum and local density of state. The fundamental mechanisms governing these phenomena have been elucidated through a systematic analysis of spin-resolved transmission spectra and spin-polarized electron transport pathways. These results extend the design principles of spin-controlled molecular electronics beyond graphene-based systems, offering a universal strategy for manipulating spin-polarized currents through dynamic covalent interfaces. The nearly ideal spin-filtering efficiency and tunable rectification suggest potential applications in energy-efficient spintronic logic gates and non-volatile memory devices, while the methodology provides a framework for optimizing spin-dependent transport in hybrid organic–inorganic nanoarchitectures. Our findings suggest that such systems are promising candidates for future spintronic applications. Full article

Direct contact heat transfer as an efficient heat recovery method. It is used in the fields of waste heat recovery, nuclear engineering, desalination, and metallurgy. This study examined two key issues of the direct contact heat transfer process: difficulty in accurately characterizing the dynamics of the flow field–phase interface; and difficulty in coupling the complex multiphysics fields involved in direct contact heat transfer. This paper systematically reviews the spatio-temporal evolution characteristics and quantitative characterization methods of bubble dynamics in direct contact heat transfer processes, with an in-depth discussion on theoretical modeling approaches and experimental validation strategies for coupled heat and mass transfer mechanisms within multiphase flow systems. An interesting phenomenon was found in this study. Many scholars have focused their research on optimizing the working conditions and structure of direct contact heat transfer in order to improve heat transfer efficiency. The non-equilibrium phenomenon between the two phases of direct contact heat transfer has not been thoroughly studied. The non-equilibrium phase transition model can deepen the understanding of the microscopic mechanism of interfacial energy exchange and phase transition dynamics in direct contact heat transfer by revealing the transient characteristics and non-equilibrium effects of heat and mass transfer at dynamic interfaces. Based on the findings above, three key directions are proposed to guide future research to inform the exploration of direct contact heat transfer mechanisms in future work: 1 dynamic analysis of multi-scale spatio-temporal coupling mechanisms, 2 accurate quantification of unsteady interfacial heat transfer processes, and 3 synergistic integration of intelligent optimization algorithms with experimental datasets. Full article

Interfaces between two fluids exhibit an excess free-energy cost per unit area that is manifested as surface tension. This equilibrium property generally depends on temperature, which enables the phenomenon of thermocapillary flow, wherein application of a temperature gradient having a component parallel to the surface generates a net in-plane effective body force on the fluid and thereby causes flow. Here, we study the thermocapillary flow in fluid smectic liquid crystal films freely suspended in air and stabilized in thickness by the smectic layering. If such films are a single layer (~3 nm) or a few layers thick, they have the largest surface to volume ratio of any fluid preparation, making them particularly interesting in the context of thermocapillary flow, which is two-dimensional (2D) in the film plane. Five-layer thick films in the form of spherical bubbles were subjected to a north–south temperature gradient field along a polar axis, with flow fields mapped using inclusions on the film surface as tracers, where the inclusions were “islands”, small circular stacks of extra layers. These experiments were carried out on the International Space Station to avoid interference from thermal convention of the air. The flow field as a function of latitude on the bubble can be successfully modeled using Navier–Stokes hydrodynamics, modified to include permeative flow out of the background fluid into the islands. Full article

A typical head–disk interface of hard drives can feature pressures exceeding 50 atmospheres, where the non-ideal gas effects can play an important role. One possible consequence is a change in the rate of water evaporation from the disk. This report describes a semi-analytical procedure that employs the concept of fugacity to investigate the non-ideal gas effects on the saturation pressure of water at an elevated temperature and pressure. A vapor–liquid equilibrium equation is solved to derive the saturation pressure. The results show a deviation from the ideal gas law, which is further examined through saturation pressure isotherms. At areas of low temperature and high pressure, lighter gases such as helium show about a 10% deviation from the ideal gas law, whereas heavier gases such as nitrogen deviate by up to 100%. As temperature increases, the differences between the gases decrease. Full article

From the lanthanide group, part of the rare earth elements (REEs), lanthanum is one of the most important elements given its application potential. Although it does not have severe toxicity to the environment, its increased usage in advanced technologies and medical fields and scarce natural reserves point to the necessity also of recovering lanthanum from diluted solutions. Among the multiple methods for separation and purification, adsorption has been recognized as one of the most promising because of its simplicity, high efficiency, and large-scale availability. In this study, a xerogel based on silicon and iron oxides doped with zinc oxide and polymer (SiO₂@Fe₂O₃@ZnO) (SFZ), obtained by the sol–gel method, was considered as an adsorbent material. Micrography indicates the existence of particles with irregular geometric shapes and sizes between 16 μm and 45 μm. Atomic force microscopy (AFM) reveals the presence of dimples on the top of the material. The specific surface area of the material, calculated by the Brunauer–Emmet–Teller (BET) method, indicates a value of 53 m²/g, with C constant at a value of 48. In addition, the Point of Zero Charge (pH_pZc) of the material was determined to be 6.7. To establish the specific parameters of the La(III) adsorption process, static studies were performed. Based on experimental data, kinetic, thermodynamic, and equilibrium studies, the mechanism of the adsorption process was established. The maximum adsorption capacity was 6.7 mg/g, at a solid/liquid ratio = 0.1 g:25 mL, 4 < pH < 6, 298 K, after a contact time of 90 min. From a thermodynamic point of view, the adsorption process is spontaneous, endothermic, and occurs at the adsorbent–adsorbate interface. The Sips model is the most suitable for describing the observed adsorption process, indicating a complex interaction between La(III) ions and the adsorbent material. The material can be reused as an adsorbent material, having a regeneration capacity of more than 90% after the first cycle of regeneration. The material was reused 3 times with considerable efficiency. Full article

The co-addition of chromium (Cr) and tin (Sn) is known to enhance the wettability between copper (Cu) and graphite (C_gr), but the effect of Sn content remains poorly understood. This study aims to systematically investigate the influence of Sn content a (a = 0, 10, 20, 30, 40, 50, 80, 99 at. %) on the wettability, interfacial structure, surface/interface energy (σ_lv/σ_sl), and adhesion behavior of the Cu–aSn–1Cr/C_gr system at 1100 °C. The experimental results show that as the Sn content increases, the equilibrium contact angle (θ_e) of the metal droplet shows a non-monotonic trend; the thickness of the reaction product layer (RPL, consisting of Cr carbides (Cr_mC_n)) gradually increases, accompanied by a decrease in the calculated adhesion work ($W_{\mathrm{ad}}^{\mathrm{cal}}$). A “sandwich” interface structure is observed, consisting of two interfaces: metal||Cr_mC_n and Cr_mC_n||C_gr. Sn content mainly affects the former. At metal||Cr_mC_n, Sn exists in various forms (e.g., Cu–Sn solid solution, Cu_xSn_y compounds) in contact with Cr_mC_n. To elucidate the wetting and bonding mechanisms of metal||Cr_mC_n, simplified interfacial models are constructed and analyzed based on first-principles calculations of density functional theory (DFT). The trend of theoretically calculated results (σ_metal and W_ad) agrees with the experimental results (σ_lv and $W_{\mathrm{ad}}^{\mathrm{cal}}$). Further analysis of the partial density of state (PDOS) and charge density difference (CDD) reveals that charge distribution and bonding characteristics vary with Sn content, providing the microscopic insight into the nature of wettability and interfacial bonding strength. Full article

This study investigates the mechanisms controlling multiphase landslide reactivation at red soil–sandstone interfaces in subtropical climates, focusing on the Eastern Pearl River Estuary. A significant landslide in September 2022, triggered by intense rainfall and human activities, was analyzed through field investigations, UAV photogrammetry, and geotechnical monitoring. Our results demonstrate that landslide evolution is governed by the interplay of geological, hydrological, and anthropogenic factors. Key findings reveal that landslide boundaries are constrained by fractures at the northern trailing edge and granite outcrops in the south, with deformation progressing from trailing to leading edges, indicative of a creep-traction failure mode. Although the landslide is stabilizing, ongoing deformations suggest disrupted stress equilibrium, emphasizing the risks of future reactivation. This work advances the understanding of progressive landslide dynamics at soil–rock interfaces and provides critical insights for risk mitigation in subtropical regions. Full article