Search Results (97)

Surfactant flooding is a promising enhanced oil recovery (EOR) method for mobilizing residual oil after primary recovery and conventional waterflooding. Its performance is highly sensitive to reservoir chemistry, particularly in associated gas reservoirs where CO₂, H₂S, and CH₄ may alter aqueous-phase behavior, surfactant stability, adsorption, and chemical transport. This study evaluates salinity-controlled surfactant flooding performance in a synthetic three-dimensional associated gas–oil reservoir using a simulation-guided diagnostic workflow. The model examines surfactant transport, adsorption, oil rate response, and block-level oil saturation across ultralow-, low-, and moderate-to-high-salinity ranges. Performance was evaluated using field oil production rate (FOPR), cumulative field oil production (FOPT), block oil saturation (BOSAT), block total surfactant concentration (BTCNFSUR), and block total adsorbed surfactant (BTADSUR). Because the simulation does not independently vary gas composition, the results should be interpreted as salinity effects under an associated gas reservoir setting rather than as isolated gas composition effects. The strongest sustained production response occurred in the ultralow- to low-salinity cases, especially 400 ppm and 1000 ppm, where surfactant propagation was more stable and late-time FOPR recovery was stronger. The 15,000 ppm case was the best performer only within the moderate-salinity group and should not be interpreted as the global optimum across all salinity cases. Above 25,000 ppm, FOPR declined to approximately 50–60 Sm³/day, while BOSAT remained high in poorly swept layers, indicating channelized flow, localized chemical contact, and greater retention risk. The results show that salinity compatibility is a dominant control on surfactant flood efficiency and that salinity screening is necessary before applying surfactant flooding in gas-rich reservoirs. Full article

This study presents a sodium alginate/chitosan/activated carbon (SA/CS/AC) gel microspheres loaded with Citrus reticulata peel allelochemicals for continuous inhibition of Microcystis aeruginosa by controlled release. Preparation parameters were optimized via response surface methodology (RSM) for improved algal inhibition, yielding an optimal formulation: 1.97% SA, 0.76% CS, 0.31% AC. The optimized gel microspheres showed a 7-day inhibition rate of 85.17 ± 2.49%, consistent with the predicted 85.29%. Characterization revealed that AC optimized the gel’s porous structure and surface functionality, providing more adsorption sites for allelochemicals. This helps improve the loading capacity of the gel microspheres and enables stable sustained release, with a cumulative release of 70% over 25 days. Algal inhibition declined slightly from day 7 to 30 due to allelochemical depletion but remained 76.27%, versus 30.58% for the blank SA/CS/AC carrier and 52.81% for the allelochemical-loaded SA/CS gel microspheres. AC thus synergistically strengthens algal inhibition by elevating allelochemical loading and prolonging activity, providing a feasible strategy for sustainable cyanobacterial bloom control. Full article

To investigate the influence mechanism of Yellow River silt powder on the hydration process, microstructure, and strength development of shotcrete, and to promote the resource utilization of Yellow River sediment, this study systematically investigated the effects of different silt powder replacement levels (0%, 10%, 30%, and 50%) on a cement–accelerator system. A combination of setting time tests, isothermal calorimetry, and mechanical strength measurements was employed, together with microstructural characterization techniques including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), differential thermal analysis (DTA), and scanning electron microscopy (SEM). The results indicate that the silt powder content exerts a two-stage effect on the setting behavior of shotcrete. At low replacement levels (0–30%), both initial and final setting times are significantly prolonged, whereas at higher replacement levels (>30%), the setting time is anomalously shortened, approaching that of the reference mixture. The incorporation of silt powder delays the onset of the pre-induction period, prolongs the induction stage, and reduces the cumulative heat release, with the reduction exhibiting a staged trend characterized by gradual, pronounced, and then moderate changes as the replacement level increases. With increasing silt powder content, both compressive strength and splitting tensile strength decrease continuously. At a 50% replacement level, the 28-day compressive strength loss reaches 48.35%, while the splitting tensile strength loss reaches 43.30%, with more pronounced deterioration observed at early ages. The tensile-to-compressive strength ratio increases with silt powder content at early ages, while converging to similar values among all mixtures at later ages. Microstructural analysis indicates that silt powder primarily affects hydration through physical dilution and ion adsorption. At low dosages, nucleation effects slightly promote early hydration, whereas at high dosages, the hydration of calcium silicate phases is inhibited, resulting in reduced C–S–H gel formation and increased porosity. Additionally, AFt morphology transitions from dense prismatic crystals to loosely distributed needle-like structures. This study provides a systematic understanding of the role of silt powder in shotcrete and offers theoretical guidance for mix design optimization and the sustainable utilization of Yellow River sediment. Full article

Severe foaming and a significant decrease in desulfurization performance were noted in a novel UDS solvent applied in a natural gas field in western Sichuan, China. The effects of hydrocarbon and ionic impurities on foaming behavior and the purification performance of candidate adsorbents were investigated. An extraction-gas chromatography method was established and validated for determining total hydrocarbons in amine solutions, enabling quantitative evaluation of hydrocarbon contamination. Controlled contamination experiments revealed that hydrocarbons had the strongest effect on foaming, while sulfate and chloride strongly promoted foam formation; organic acid anions showed only minor effects. Fixed-bed screening identified A-98FM anion-exchange resin as the most effective for anionic impurity removal and AC-02 activated carbon as the best candidate for hydrocarbon purification, with a cumulative adsorption capacity q_0–12 of 14.86 mg/g over 12 h. Pore-structure and thermal-release analyses suggested that conventional pore descriptors alone could not fully explain the dynamic purification performance, while hydrocarbon-related loadings in spent AC-02 occupied accessible pore space and contributed to performance decay. Treatment of a field-aged UDS lean solvent further showed that reductions in target impurities were accompanied by lower foam height and shorter defoaming time. This work provides experimental support for impurity monitoring, foaming-risk identification, and adsorptive purification of UDS desulfurization solvent under flowback-contamination conditions. Full article

The polymer–filler interphase in filled elastomers is often represented by a single thickness, obscuring internal heterogeneity. Coupling coarse-grained molecular dynamics with dynamic mechanical analysis of EPDM/carbon-black compounds, we resolve a bimodal bound-rubber layer with a dense inner zone set by surface adsorption and a looser outer zone sustained by chain connectivity. Heating contracts the outer zone about twice as strongly as the inner zone (outer: 26.5%, 95% confidence interval 17.4–34.8%; inner: 13.3%). Per-layer mean-squared displacement analysis shows a modest mobility gradient between the 1–2 nm outer zone and the bulk. Dynamic mechanical analysis at 120–140 °C shows a flatter reinforcement factor at higher temperature, consistent with interphase-linked thermal contraction. Lengthening the chain at fixed filler loading markedly enlarges the bridging fraction and the cumulative excess thickness, signaling a transition from adsorption-limited to connectivity-limited reinforcement. These results show that a single interphase boundary can miss a dynamically active outer zone relevant to reinforcement and thermal aging in filled elastomers. Full article

Heavy rare earth elements (HREEs) are widely used in permanent magnets, phosphors, catalysts, and advanced electronic devices because of their unique optical, electrical, and magnetic properties. However, their efficient separation remains a major challenge in hydrometallurgy because neighboring rare earths have highly similar ionic radii and chemical behavior. In this work, a silane-grafted aminophosphonate resin, D152-AMPA, was used to systematically investigate the adsorption behavior, adjacent-pair separation, impurity effects, and dynamic column performance of a mixed rare-earth system under different pH conditions. In the presence of Al, Fe, Ca, and Mg, the Er/Ho separation factor increased from 1.031 at pH 2 to 2.298 at pH 4, indicating that the partitioning advantage of Er over Ho was retained and further strengthened despite the presence of impurities. During elution, the purities of the Er-rich and Ho-rich fractions reached 92.79% and 94.34%, with cumulative recoveries of 88.32% and 83.05%, respectively. XPS and FT-IR analyses further indicated that Lu(III) adsorption mainly involved the oxygen donor sites of the aminophosphonate groups. These results demonstrate that D152-AMPA is capable of selective adsorption and dynamic fractionated separation in mixed and impurity-containing rare-earth systems, providing an experimental basis for greener separation and enrichment of complex rare-earth solutions. Full article

Hydraulic flushing is an effective permeability enhancement technology for coal seams in underground coal mines and has been widely applied in several mining areas in China. However, in low-permeability coal seams, gas drainage from hydraulic flushing boreholes often enters a rapid depletion phase, and achieving secondary enhanced drainage remains a critical challenge. To address this issue, this study investigates a synergistic gas drainage technology that combines gas injection displacement with hydraulic flushing. Taking the No. 3 coal seam in the Lu’an mining area of China as the research object, the optimal process parameters of this synergistic technology are systematically determined through numerical simulation and validated by underground field tests. A fully coupled numerical model incorporating the adsorption–desorption–seepage processes of the CH₄/N₂/O₂ ternary gas system is established. The influences of injection spacing and injection pressure on drainage performance are systematically analyzed. Simulation results identify the optimal process parameters as an injection spacing of 3.5 m and an injection pressure of 1.4 MPa. Under these conditions, the relative coal permeability reaches a maximum of 1.06, the permeability enhancement zone fully covers the region between the injection and drainage boreholes, and the coal seam gas content decreases to the critical threshold of 8 m³/t in approximately 235 days. The model is quantitatively validated using 82-day field monitoring data from the synergistic module, with a relative error of approximately 1.1% between the simulated and field-derived recovery ratios. Subsequently, four sets of underground engineering trials—conventional drainage, gas injection displacement alone, hydraulic flushing alone, and the synergistic technology—are conducted in the target coal seam based on the optimized parameters. Statistical analysis of the 82-day field data shows that the synergistic technology achieves a cumulative pure methane volume of 4.83 m³, outperforming conventional drainage by 85.8% (4.83 m³ compared with 2.60 m³), gas injection alone by 23.5% (4.83 m³ compared with 3.91 m³), and hydraulic flushing alone by 52.4% (4.83 m³ compared with 3.17 m³). The mean flow rate of the synergistic module during the injection phase reaches 0.070 ± 0.012 L/min, significantly higher than that of gas injection alone (0.044 ± 0.011 L/min). This study provides economically feasible theoretical and technical support for efficient gas drainage in low-permeability coal seams in underground mines. Full article

Background/Objectives: The growing prevalence of obesity necessitates innovative gut-targeted material strategies to modulate diet-associated metabolic dysfunction. This study investigates a spray-dried konjac glucomannan–montmorillonite (KGM-MMT) hybrid designed to integrate fermentable polysaccharide properties with luminal lipid-adsorptive clay functions within a single micro-engineered formulation. Methods: In HFD-fed mice treated for 42 days with 2% w/w KGM-MMT, cumulative body weight gain was attenuated by 7.6%, with an AUC of 5094 ± 52.95, compared to 5513 ± 81.35 in HFD controls (p < 0.0001). Results: Serum IL-6 concentrations were reduced by 97% (p = 0.0002), while blood glucose decreased by 46% (p < 0.0001); these effects were greater than those observed with MMT (24%, p = 0.0271) and KGM (16%, ns). Gut microbiota profiling demonstrated a significant 6.2-log₂-fold increase in Lactobacillaceae (p = 0.023) and a 2.4-log₂-fold increase in Enterococcaceae (p = 0.015) following KGM-MMT treatment. Functional shifts inferred from 16S rRNA gene-based prediction indicated a 1.9-fold increase in short-chain fatty acid-related pathways and a 5.4-fold increase in bile acid deconjugation pathways. Conclusions: Although the KGM-MMT hybrid did not consistently outperform its individual components across all endpoints, it consolidated complementary KGM- and MMT-associated effects within a single dosage form. These findings support spray-dried KGM-MMT as a gut-targeted biomaterial strategy that integrates multiple luminal and microbiota-associated functions within a single formulation. Future studies should define dose–response relationships, validate microbiota-derived functional predictions using higher-resolution approaches, and assess durability and safety under longer-term exposure. Full article

Volatile organic compounds (VOCs) pose significant health risks. Photocatalytic oxidation offers a promising route for VOC purification under ambient conditions. Based on a review of over 80 studies, this article critically evaluates research progress on four semiconductor photocatalyst systems (TiO₂-based, g-C₃N₄-based, bismuth-based oxides, and MOFs) for VOC degradation. Unlike traditional descriptive reviews, this work establishes a quality-based filtering framework to distinguish studies reporting standardized photochemical parameters from those that do not. The analysis reveals a fundamental problem: the vast majority of reviewed studies lack essential parameters (incident photon flux, apparent quantum yield, or rigorous dark adsorption equilibrium), rendering cross-study comparisons invalid. Most literature relies on non-standardized metrics such as conversion percentages or rate constants per catalyst mass. While some high-quality studies report AQY, these remain a small fraction of the literature. Within individual studies under identical conditions, modification strategies enhance activity relative to controls, but relative efficiency (ζr) values are meaningful only within the same study and cannot be compared across setups. This review thus serves a dual purpose: to summarize modification strategies and to critically expose the lack of standardization. Future research must adopt unified reporting standards (photon flux, AQY, benchmarks under identical conditions) to transform the field into a reproducible, cumulative science. Full article

Direct air capture (DAC) of CO₂ via temperature-swing adsorption (TSA) can support sustainable carbon dioxide removal, but only if sorbents regenerate with low energy demand and maintain performance under humid ambient air. In this paper, we evaluate three commercial molecular sieves (JLPM3, 13X, and 4A) in packed-bed tests using humid ambient air. We compared 40 g samples as received with 200 g samples conditioned for 12 days at 100 °C to emulate prolonged exposure to regeneration temperature (the cumulative effect of many heating/desorption cycles); all cycle-stabilized uptake values are reported from the conditioned materials. JLPM3 delivered the highest stabilized CO₂ uptake (0.24 ± 0.01 mmol·g⁻¹), consistent with a combined physisorption/chemisorption mechanism. Its higher total porosity (26.190%) and smaller mesopores (7.569 nm width) promoted rapid mass transfer and site accessibility, while slightly greater micropore area (710.285 m²·g⁻¹) and volume (0.267 cm³·g⁻¹) than 13X supported its marginally higher capacity. Evidence of partial structural degradation under mechanical and thermal stress indicates that minimizing strain during cycling will be important for scale-up and for reducing sorbent replacement. Conditioning at 100 °C activated additional chemisorption sites across all sieves but reduced physisorption capacity. Importantly, a ~100 °C desorption step fully regenerated physisorbed CO₂ while purging moisture from zeolite pores, indicating that low-temperature TSA (compatible with low-grade or waste heat) can replace harsher 300 °C regeneration and lower energy demand. CO₂–H₂O competition experiments confirmed substantial site occupancy by water vapor, which limits capture under humid conditions and motivates water management strategies. Overall, maximizing DAC performance requires tailoring pore structure and operating conditions while preserving sorbent integrity; JLPM3 emerges as a promising candidate for more energy- and resource-efficient DAC. Full article

Atmospheric water harvesting (AWH) has been recognized as a promising technology to address global freshwater scarcity in a decentralized manner. Nevertheless, conventional AWH sorbents are often associated with high energy consumption, toxic synthesis procedures, and short operational lifetimes. To address such limitations, a comprehensive review paper develops a unified framework to bridge the gap between nanoscale material properties, such as synthesis routes, structural architecture, and adsorption thermodynamics, and macro-scale environmental and economic performance. This review paper rigorously examines emerging nanomaterials such as metal–organic frameworks (MOFs), covalent organic frameworks (COFs), mesoporous metal oxides, and graphene oxide derivatives. By highlighting benchmark materials such as MOF-303 and passive solar-regenerated COF-ok, the review paper emphasizes the advantages of bio-assisted “green” synthesis routes. Crucially, this review extends beyond traditional water uptake figures and incorporates comprehensive Techno-Economic Assessments (TEA) and Life-Cycle Assessments (LCA). It examines various real-world influences, such as cumulative energy demand, levelized costs of water, and ton-scale manufacturing viability, to name a few. This report bridges atomic-level mechanics with industrial economics, and by so doing, offers design criteria to guide researchers in crafting a new generation of sustainable AWH infrastructure, with a focus on hierarchical pores, surface chemistry, and photothermal design. Full article

Poly(vinyl alcohol) (PVA)/montmorillonite (MMT)/Ti₃C₂T_x (MXene) nanocomposite membranes (PVA/MMT/MXene) were developed and evaluated in terms of their mechanical properties, mesoporosity, and adsorption performance toward Pb²⁺ ions and methylene blue (MB). The incorporation of MMT and MXene resulted in a strong synergistic reinforcement, increasing the ultimate tensile strength from 10 to 20 MPa, the Young’s modulus from 14.7 to 29.5 MPa, and reducing the swelling ratio from 2.0 to 1.1 g·g⁻¹. BJH porosimetry revealed a refined and interconnected mesoporous structure, with the cumulative pore volume increasing from 0.134 to 0.448 cm³·g⁻¹. In adsorption experiments (mono-solute systems, 25 °C), the ternary membrane achieved high uptake capacities of 55 mg·g⁻¹ for Pb²⁺ and 80 mg·g⁻¹ for MB, outperforming binary PVA/MMT and neat PVA. Statistical–physics modeling provided microscopic descriptors consistent with the experimental isotherms: Pb²⁺ adsorption follows a monolayer regime (n ≈ 1), whereas MB exhibits multilayer behavior (n > 1) with a higher site density (Nm ≈ 1.6 mmol·g⁻¹). These results demonstrate that the hybrid 2D–2D architecture of MMT and MXene significantly enhances the structural robustness, pore accessibility, and adsorption efficiency of PVA-based membranes, highlighting their potential for efficient removal of metal ions and dyes from aqueous media. Full article

In this study, the effects of electric-field intensity on N transformation during aerobic composting of biochar/pig manure were investigated. Four experimental groups were established under different applied voltages: 0 V (Group CK); 2 V (Group L); 4 V (Group M); and 5 V (Group H). The physicochemical properties of compost, as well as the nitrogen content and its existing forms in the compost, were systematically analyzed. The underlying mechanisms were further explored from the microscopic perspective by analyzing the pore structure of biochar and the microbial diversity in compost. The results showed that the total nitrogen content in compost increased by 5.66–20.87% with the application of the electric field. Cumulative NH₃ emissions decreased by 37.43%, 31.35%, and 40.95% in groups L, M, and H, respectively, while the NO₂ content decreased by 40.73%, 87.93%, and 94.44%, respectively, reducing the N losses during composting. The electric field significantly promoted the migration of nutrients from the compost to the surface of cotton stalk biochar. It also enhanced the microporous structure and adsorption capacity of cotton stalk biochar, thereby facilitating interfacial deposition and N immobilization. The amplification and sequencing of 16S rRNA gene further revealed that Ruminofilibacter, norank_f_MWH-CFBk5, and HN-HF0106 were the key bacterial genera affecting the gas emissions during aerobic composting. Among them, Ruminofilibacter and HN-HF0106 promoted the emission of N₂O, while norank_f_MWH-CFBk5 and Planktosalinus reduced NH₃ emission. This finding indicates that the electric field regulated N transformation and promoted N retention in compost by inhibiting the reproduction of denitrifying bacteria and increasing the abundance of nitrifying and nitrogen-fixing bacteria. This study confirms that electric field and biochar synergistically affect the nitrogen immobilization and waste resource utilization by optimizing the metabolic pathways of microorganisms and the structural characteristics of biochar. Full article

Hydrogen-based energy systems require large amounts of high-purity water, motivating thermally driven desalination that can recover low-grade heat. This study evaluates a silica gel–water adsorption chiller–desalination unit as a coupled source of cooling and pre-treated water for electrolysers. A laboratory two-bed system was tested on saline feed using 300 s valve-switching periods at an 80 °C driving temperature and 20–30 °C cooling water. Dynamic vapour sorption measurements provided Dubinin–Astakhov equilibrium and linear driving force kinetic parameters, implemented in a CFD porous bed model via user-defined source terms. Experiments yielded COP values of 0.29–0.41, an SCP of 165 W·kg⁻¹ of adsorbent, and an average distillate production of 1.68–1.82 kg·h⁻¹, while distillate conductivity remained ≈2.3 μS·cm⁻¹. The model reproduced the mean condensate production with a ≈6% underprediction. It was then used to compare six alternative fin geometries with a constant heat-transfer area. Fin-shape modifications changed inter-fin heating by <2 K and cumulative desorbed mass by <0.05%, indicating limited sensitivity to subtle local refinements. Performance gains are more likely to arise from operating conditions and exchanger-scale architecture than from minor fin-shape changes. Full article

The surface chemistry of biochar plays a pivotal role in the adsorption and stabilization of soil organic carbon (SOC); however, sorption-mediated mechanisms remain insufficiently understood for biochars derived from invasive plants. In this study, Solanum rostratum biomass, an aggressive invasive weed in northern China, was pyrolyzed at 400–600 °C in 2023 to produce biochars with varying surface functionalities and structural features. FTIR, Raman, XPS, and SEM analyses revealed that increasing pyrolysis temperature led to decreased oxygen-containing functional groups and enhanced aromatic condensation, reflecting a transition from hydrogen bonding to π–π and hydrophobic sorption mechanisms. Soil incubation experiments using sandy loam soil showed that biochar produced at 500 °C significantly increased the stable carbon pool (SCP) to 52.4%, compared to 30.6% in unamended soils. It also reduced cumulative CO₂ release from 1.74 mg g⁻¹ to 1.21 mg g⁻¹ soil, indicating improved carbon retention. Bacterial 16S rRNA gene sequencing revealed that biochar amendments significantly altered community composition and increased deterministic assembly, particularly under 500 °C biochar, suggesting a sorption-driven niche filtering effect. These findings demonstrate that S. rostratum-derived biochar, especially at intermediate pyrolysis temperatures, enhances both carbon sequestration and microbial habitat structure. This has direct implications for improving degraded soils in arid farming regions, offering a dual strategy for invasive biomass management and climate-resilient agriculture. Full article