Search Results (1,040)

In this study, a composite adsorbent (CS-ABnt) based on activated bentonite and chitosan was prepared using a simple coating method in the form of beads designed to combine high adsorption performance with the ease of solid–liquid separation typical of bead-type materials, serving as a low-cost tetracycline adsorbent. The composite was characterized by FTIR, EDX, and zeta potential measurements, which confirmed successful chitosan coating of the bentonite surface and a marked shift in the point of zero charge (from pH 5.54 for chitosan to pH 7.32 for CS-ABnt). Batch adsorption experiments showed that tetracycline removal was strongly pH-dependent, with an optimum near pH 6, and that the CS-ABnt composite consistently outperformed its individual components (chitosan and activated bentonite) across all tested doses, contact times, and temperatures. Equilibrium data were best described by the Langmuir isotherm, yielding a maximum adsorption capacity of 49.11 mg·g⁻¹, while kinetic data followed the pseudo-second-order model, revealing that the rate-limiting step is chemisorption. The thermodynamic parameters (ΔG° < 0, ΔH° > 0, ΔS° > 0) indicated a spontaneous, endothermic adsorption process. Taken together, these results enabled a 95% removal efficiency of tetracycline to be achieved. Full article

Diffusion against a concentration gradient, also called uphill transport, has been reported for magnesium and sulfate ions in solutions of NaCl and Mg${\mathrm{SO}}_4$ in reverse electrodialysis (RED). Here we derive transport equations for such systems and explain the observed uphill transport using non-equilibrium thermodynamics (NET). A set of Nernst–Planck equations was reformulated into a set of flux equations with neutral salt driving forces. By applying the condition of entropy production invariance to the sets of variables, we show how an ideal ion selectivity model provides Onsager coupling coefficients for the ion transport. These coupling coefficients can predict and explain the observed uphill transport of magnesium and sulfate. A linear fitting scheme is developed to fit the transport coefficients to experimental data for the ideal ion selectivity model and for a more general model. The results show that even the simplest ideal ion selectivity model captures the uphill transport, and the phenomenon occurs due to diffusional ion exchange, as in Donnan dialysis. Under open-circuit conditions, deviations are large, and the simplest model is no longer sufficient; co-ion leakage corrections are essential. The results provide a basis for future modelling of RED processes; in particular, one can determine and optimise the process efficiency, as the model gives direct access to the process’s local entropy production. Osmosis is identified as a potential source of error. Full article

This study investigates the possibility of using aluminosilicochrome (ASC) produced from technogenic raw materials as a potential alternative to FSC-48 ferrosilicochrome in refined ferrochrome smelting. Laboratory smelting tests were carried out in an induction furnace using alumina crucibles with a charge mass of 50 g. The two variants were compared based on the material balance, SEM-EDS analysis of the metallic and slag phases, a conditional estimate of chromium transfer to the metal, and the results of thermodynamic modeling in FactSage 8.4. It was established that a Cr–Fe metallic phase is formed when both FSC-48 and ASC are used. The average metal mass was 13.8 g for FSC-48 and 13.3 g for ASC. According to SEM-EDS data, the Cr content in the metallic phase was 70.53 and 68.64 wt. %, respectively. Aluminum introduced with ASC predominantly transfers into the slag, increasing its Al content to 20.81 wt. %. The conditional estimate of total chromium transfer from the charge to the metallic phase was 91.9% for FSC-48 and 91.6% for ASC. FactSage modeling showed higher calculated ore-derived Cr recovery for ASC under equilibrium conditions; however, excessive ASC addition increased the Si content in the metal. The obtained results confirm the fundamental possibility of using ASC as a complex reductant in refined ferrochrome smelting. Full article

The spontaneous emergence of macroscopic order in driven, far-from-equilibrium complex fluids lacks a generalized framework capable of bridging continuous and discrete symmetry-breaking transitions. In this study, we propose a non-equilibrium phenomenological framework that synthesizes irreversible thermodynamics, coupled Landau–de Gennes potential expansions, and active hydrodynamics. The formulation employs a single tensorial order parameter, a nonlinear state-dependent jamming mobility closure, and a generalized set of dimensionless groups to map the non-equilibrium phase space. The model predicts a sequential symmetry-breaking cascade and reproduces the emergence of polar heliconical smectic and antiferroelectric phases in driven liquid crystals, as well as the transition from isotropic active gases to macroscopic fluid flocks and active Wigner crystals in purely repulsive Janus colloids. Across these systems, a dimensionless active torque number acts as the principal bifurcation parameter, suggesting that their macroscopic structural transitions are governed by a common balance between thermodynamic and kinematic effects rather than by the details of their microscopic interactions. Full article

A combined CALPHAD-guided thermodynamic and experimental approach was employed to investigate the influence of boron on phase evolution and microstructural development in the Fe–Ni–Cr–Cu–Si–B–C alloy system. Thermodynamic calculations were performed using Thermo-Calc (FE13-2025b) and the TTFe thermodynamic database. Vertical phase-diagram sections and response surface analysis were used to evaluate phase stability over the temperature range of 400–1500 °C and to identify temperature–composition domains favorable for the formation of strengthening phases. The calculations predicted complex multiphase equilibrium behavior involving boride-, carbide-, and silicide-containing phases. Within the investigated composition range, approximately 4 wt.% B provided a favorable balance between the metallic matrix and strengthening phases, while 638 °C corresponded to a thermodynamically favorable equilibrium phase constitution. Response surface analysis further demonstrated that temperature governs phase evolution, whereas boron primarily controls phase redistribution. The optimized alloy composition was characterized experimentally using scanning electron microscopy (SEM), wavelength dispersion spectroscopy (WDS), elemental mapping, and X-ray diffraction (XRD). The experimentally observed heterogeneous multiphase microstructure showed good agreement with the CALPHAD-predicted phase evolution at a qualitative level, demonstrating the usefulness of thermodynamic modeling for guiding alloy design. The proposed CALPHAD-guided workflow integrates thermodynamic modeling with targeted experimental characterization and provides a transferable framework for the accelerated design and optimization of complex Fe-based multicomponent alloys. Full article

One of the consequences of driving a plasma discharge away from the thermodynamic equilibrium is the appearance of one or more fireballs in front of the anode. The formation of this self-organized space charge structure marks the transformation of part of the thermal energy of the electrical charges into the electric potential energy of the structure. The self-assembly of the fireball as well as its existence in a stable stationary state prove to be good candidates for testing the validity/selection of the proposed extremal (maximum or minimum) entropy production principles in the case of systems driven far from the thermodynamical equilibrium. The use of experimental results and of a basic mathematical model shows that the emergence of a fireball in a plasma diode maximizes the entropy production rate, while its subsequent existence minimizes the entropy production rate. Full article

Accurate vapor–liquid equilibrium (VLE) modeling of CO₂ in polar aprotic solvents (PASs) is critical for solvent screening and the design of carbon-capture processes. This study systematically evaluates three SAFT-type equations of state (EoSs), namely CPA, PC-SAFT, and SAFT-VR Mie, under a unified parameter optimization framework. For pure-component saturation properties, SAFT-VR Mie yielded the lowest mean deviations across all investigated substances, with average AARD values of 0.066% for Psat and 0.127% for ${\mathsf{\rho }}_{\mathrm{s}\mathrm{a}\mathrm{t}}$. However, the most accurate EoS for an individual substance depended on the property evaluated, and PC-SAFT produced lower deviations for several substance–property combinations. For binary CO₂ + PAS systems, all three EoSs exhibited substantial pressure deviations when the binary interaction parameter (k_ij) was set to zero. Optimizing k_ij reduced the pressure AARD for every model–solvent combination, indicating that the default combining rules did not adequately represent the CO₂–solvent cross-interactions. Notably, the specific improvement in pressure AARD% after introducing k_ij for each model revealed CPA’s superior sensitivity (e.g., for the CO₂ + MEK system, pressure AARD% decreased from 14.43% to 4.07%, a reduction of over 70%). Furthermore, a comparative analysis of single-temperature (ST) and multi-temperature (MT) optimization strategies reveals that the ST optimization reduces the average pressure AARD% from 4.34% (MT) to 3.05%, whereas the MT-optimized kij values offer superior transferability across a broader temperature range. These findings elucidate the different applicable scenarios of model architecture and k_ij optimization strategies, providing actionable guidance for selecting appropriate thermodynamic models to support the simulation and optimization of carbon-capture systems. Full article

Steam-assisted gravity drainage (SAGD) makes a significant contribution to Canada’s heavy oil production. Yet, it faces notable efficiency challenges during late-life stages, characterized by increased Steam–Oil Ratios and environmental concerns. Non-condensable gas (NCG) injection has emerged as a promising strategy to address these issues, particularly in late-life and post-steam SAGD phases. This review systematically examines the mechanisms, phase behavior, thermochemical interactions, field applications, and operational impacts of injecting NCGs such as methane, nitrogen, and carbon dioxide. This work exclusively synthesizes the application of NCG injections in mature SAGD reservoirs while outlining existing challenges. It delivers a unified perspective on this domain, introducing practical insights to improve NCG injection efficiency. Critical analysis of the existing literature reveals key benefits, including reservoir pressure maintenance, steam chamber stabilization, and viscosity reduction. However, literature gaps persist regarding long-term field-scale validation, complex drive mechanisms at the steam chamber flanks, thermochemical reactions, interactions with geological heterogeneity, and detailed thermodynamic modeling under non-equilibrium conditions. Emphasizing these gaps underscores the importance of further research and integrated modeling to optimize NCG utilization, thus enhancing recovery efficiency, reducing environmental footprints, and extending reservoir life. Full article

Threatening environmental resources such as water, air and soil, and thus indirectly threatening biodiversity, through rapid, uncontrolled and non-ecological industrial production systems must be prevented through appropriate purification methods. In this research, the sorption of Reactive blue 19 anthraquinone dye from aqueous solution was carried out in a batch system using nano zinc–manganese ferrite carbonate (ZnMn–Fe₂O₄–CO₃) synthesized by the co-precipitation method. Various factors affecting the sorption activity of the material were examined, and the most suitable conditions were determined to be pH 2 and ZnMn–Fe₂O₄–CO₃ concentration of 0.25 g/L, whereby an equilibrium sorption capacity of 1463.10 mg/g was achieved. The ZnMn–Fe₂O₄–CO₃ removal efficiency was found to be 88.48% in effluent from a textile manufacturing industry. Utilizing FTIR, SEM, EDS, XRD, TGA and BET methods, the material’s morphological and structural characteristics were thoroughly investigated and reported. Regarding the kinetic and isotherm models that were analyzed, the Langmuir and pseudo-second-order (PSO) models provided the best fit to the aforementioned sorption system. Thermodynamic data confirmed the spontaneity of the sorption reaction and the exothermic nature of the process. An extensive study of ZnMn–Fe₂O₄–CO₃ demonstrated its high efficiency in removing RB19 dye, as well as the safety and simplicity of the synthesis, the cost-effectiveness of the sorption process, and the possibility of regeneration and reuse over multiple cycles. These findings highlight the potential of ZnMn–Fe₂O₄–CO₃ for advanced water and wastewater purification technologies targeting anthraquinone dyes. Full article

The concurrent disposal of industrial lithium slag (LS) and the remediation of heavy-metal-contaminated water remain critical environmental imperatives. Herein, industrial lithium slag was successfully upcycled into a high-capacity geopolymer via alkali activation to systematically evaluate its Pb(II) removal mechanisms. Synthesized under optimal conditions (11 mol/L alkali concentration, 0.616 solid-to-liquid ratio), the geopolymer showed exceptional Pb(II) capture, achieving ~99% removal efficiency within 120 min for a 100 mg/L Pb(II) solution at pH 6.0. The adsorption kinetics obeyed the pseudo-first-order model, yielding a remarkable theoretical equilibrium capacity of 284 mg/g. Thermodynamic results reveal a spontaneous (ΔG < 0), endothermic (ΔH = 17.66 kJ/mol) process with increased interfacial randomness (ΔS > 0). Integrating macroscopic performance with characterizations and density functional theory (DFT) computations elucidated a site-specific chemisorption mechanism and the precipitation of PbSO₄ caused by Pb(II) and SO₄²⁻ in LS. Ultimately, this work provides a sustainable paradigm for the value-added upcycling of industrial solid waste. Full article

Vanadium–titanium-bearing direct reduced iron (V-Ti DRI) is a promising feedstock for the full-value utilization of V-Ti magnetite. Selective partition of V and Cr into the metal phase, with Ti retained in the slag, requires quantitative thermodynamic guidance. We investigate this slag–metal distribution using the ion and molecule coexistence theory (IMCT). An eight-component slag model with 33 complex-molecule equilibria is coupled to reduction thermodynamics through an iterative mass-balance procedure; the metal-phaseWagner activity is temperature-scaled by Chipman’s rule, and the dissolved oxygen concentration is closed through the C-CO-O equilibrium. The equilibrium V and Cr recovery ceilings (metal side) rise from 89%/96% at 1400 °C to approximately 99.4% at 1500 °C and exceed 99.8% at 1550 °C. Ti-in-slag retention (slag side) drops steadily from 99.998% at 1400 °C to 99.4% at 1700 °C, giving a V/Ti separation factor above 104. Fe recovery to the metal phase exceeds 97% at 1600 °C and above, driven by the strong reduction of FeO, which constitutes approximately 32 wt.% of the initial slag. Carbon activity exerts a cubic power-law effect: at 1450 °C, the V recovery ceiling collapses from 97.4% at a_C = 1 to 6.5% at a_C = 0.05, identifying imperfect carbon saturation as a primary thermodynamic mechanism behind the ceiling-to-pilot gap. Once temperature and oxygen closure are enforced, the ceilings are only weakly sensitive to metallization, basicity, coke ratio, and TiO₂ content. Comparison with pilot data shows the ceilings exceed reported yields by 16–29 percentage points (pp), quantifying the kinetic/mass-transfer deficit and providing a benchmark for scale-up. Full article

Combined cooling, heating, and power (CCHP) tri-generation systems can greatly improve comprehensive energy utilization efficiency thanks to their energy-cascade utilization concept. However, traditional fossil-fuel-based CCHP systems still suffer from intensive carbon emissions, hindering their further development in the current low-carbon scenario. To solve this issue, a new low-carbon CCHP system (LC-CCHP) integrating a calcium-looping, sorption-enhanced steam methane reforming (CL-SE-SMR) unit, a lithium bromide absorption chiller, and a hydrogen gas turbine is proposed in this work, and the corresponding system model is built to evaluate its performance. The proposed system features an innovative architecture that integrates carbon capture directly into the reforming process, which simultaneously enables a high hydrogen yield and low carbon-capture penalty. Moreover, instead of the widely used thermodynamic equilibrium assumption, a detailed kinetic model is employed for the CL-SE-SMR unit, which provides more realistic predictions and greater reference value for practical engineering applications. Then, multi-objective optimization is conducted using a particle swarm optimization algorithm to identify the optimal operating conditions. It is found that the proposed system performs best at a steam-to-carbon molar ratio of 4.37, a calcium-to-carbon mass ratio of 6.23, an air-equivalency molar ratio of 1.39 for a hydrogen gas turbine and a reaction temperature of 600 °C for SE-SMR. Under these operating conditions, the system can achieve a carbon-capture rate of 89.2%, an exergy efficiency of 45.7%, an energy efficiency of 95.4%, and a levelized cost of exergy of 0.109 $/kWh. Full article

Inorganic scale deposition in crude oil–water transport trunklines is a formidable flow assurance challenge, uniquely exacerbated in extensive gathering networks where multiple production flowlines commingle multiphase fluids. As some fields experience progressively higher water cuts, the mixing of incompatible waters, characterized by diverse thermodynamic profiles and varying concentrations of scaling ions (Ca²⁺, Ba²⁺, Sr²⁺, ${\mathrm{SO}}_4^{2-}$, ${\mathrm{CO}}_3^{2-}$, etc.) triggers severe precipitation. This comprehensive literature review synthesizes seminal and contemporary studies to critically evaluate the state-of-the-art methodologies for assessing scaling risks in these intricate systems. Progressing chronologically and thematically, the analysis details the transition from static, bulk-fluid thermodynamic equilibrium calculations to dynamic, high-fidelity deterministic and probabilistic approaches. These advanced frameworks include Reactive Transport Modeling (RTM), Computational Fluid Dynamics (CFD), and Machine Learning (ML) architectures. Special emphasis is placed on the mathematical governing equations that dictate trunkline-specific phenomena: multi-stream commingling, non-isothermal gradients, probabilistic kinetic induction, and the profound impact of turbulent transport (turbophoresis) on crystal attachment and wall shear detachment. Finally, an integrated, multi-tier flow assurance workflow is proposed to guide future field-scale risk management and digital twin deployment. Full article

Thermophysical properties of thermal plasmas are essential input data for computational models. The required data are usually taken from the literature without examination of their reliability. Cross-code verifications of properties are rare in the thermal plasma literature, partly due to the complexity of the calculation methods, which require a systematic treatment of large datasets, multiple computations and the adoption of different models. Here, a detailed comparison of two computational codes that use different workflows but very similar underlying methods is presented, using the example of thermophysical properties of argon, krypton, and xenon plasmas in local thermodynamic equilibrium at pressures from 1 to 100 atm. The comparison considers plasma composition, collision integrals, thermodynamic properties and, in particular, transport coefficients. The comparison allowed inconsistencies and errors to be identified and corrected, resulting in improved thermophysical properties of argon, krypton, and xenon. Furthermore, transport coefficients obtained from state-of-the-art intermolecular potentials were compared with those obtained from the simpler phenomenological potential, demonstrating good agreement, including at high pressures. Full article

The CaO-Al₂O₃-Fe₂O₃ system is widely encountered in cement production, iron ore sintering, metallurgical slags, and refractory materials. A thermodynamic assessment of the CaO-Fe₂O₃ and CaO-Al₂O₃-Fe₂O₃ systems was carried out in this study based on the CALculation of PHAse Diagrams (CALPHAD) method. The liquid was modeled using the ionic two-sublattice model, expressed as (Ca⁺², Al⁺³, Fe⁺²) _P (O⁻², AlO_1.5, FeO_1.5, Va, O) _Q. The Compound Energy Formalism (CEF) was adopted to describe compounds and solid solutions. A self-consistent thermodynamic assessment of the CaO-Fe₂O₃ and CaO-Al₂O₃-Fe₂O₃ systems was achieved, enabling accurate reproduction of phase equilibrium and thermodynamic data. The obtained thermodynamic description provides a useful foundation for the design, optimization, and processing of refractory materials. Full article