Dynamic role of polystyrene microplastics in fouling evolution and structure-performance relationships among floc characteristics, cake layer structure and filtration performance of pre-coagulated low-pressure membrane processes

Electrodeposition of Ni-Zn-S films from zinc plant filter cakes: A waste-derived electrocatalyst for alkaline hydrogen evolution

This study proposed a new bentonite slurry modification method through enzyme-induced carbonate precipitation (EICP) for the filter cake formation in high-permeability sand during slurry shield tunneling. The properties of pure bentonite slurry, bentonite-CMC slurry and EICP-modified slurries were measured. The micro-evolution process of EICP-modified slurries was evaluated through glass slide experiments, and slurry infiltration tests were conducted to explore the effects of slurry properties on filter cake formation. The results show that CaCO<sub>3</sub> precipitations generated during the EICP reaction densely coat and bond bentonite particle, promoting dispersed particles to aggregate into large bentonite particle-CaCO<sub>3</sub> clusters. With the reaction progresses, these clusters further interconnect to form a network structure in slurry. Compared with pure bentonite slurry and bentonite-CMC slurry, EICP-modified slurries exhibit significantly higher density, particle size and viscosity. Meanwhile, the 24h bleeding rates of all EICP-modified slurries are below 5%. In infiltrate tests, the pure bentonite slurry and bentonite-CMC slurry fail to form a filter cake, whereas the EICP-modified slurries rapidly form a low-permeability filter cake. Increasing CaCl<sub>2</sub>-CO(NH<sub>2</sub>)<sub>2</sub> concentration further accelerate filter cake formation and reduce internal filter cake thickness. The EICP-modified slurry with a CaCl<sub>2</sub>-CO(NH<sub>2</sub>)<sub>2</sub> concentration greater than 1mol/L is recommended for slurry shield tunneling in high-permeability strata.

Picolinic acid enhances ultrafiltration performance in surface water treatment by promoting the Mo(IV)/peroxymonosulfate system.

Quantifying cake uniformity and filtration performance: Effects of disk geometries and operation conditions on dynamic filtration

Summary Organic salt-based drilling fluids are recognized for their superior shale inhibition, wellbore stability, environmental compatibility, and thermal resistance. However, the mechanism by which organic salts enhance the high-temperature performance of drilling fluids and their influence on fluid properties under extreme conditions is not well understood. Investigating the role of organic salts in improving the thermal resistance of additives and drilling fluid systems is crucial for advancing thermal stability and facilitating drilling operations in deeper, high-temperature formations. In this study, the effects of organic salts on water-based drilling fluid additives and low-solids organic salt drilling fluid systems were systematically examined before and after thermal aging through rheological, filtration, and sedimentation stability tests. The microstructural characteristics were further analyzed using zeta potential measurements, particle-size distribution (PSD), and scanning electron microscopy (SEM). The results indicate that the addition of organic salts increases the absolute value of zeta potential, enhances particle size uniformity, reduces size fluctuation, and significantly improves the dispersion stability of colloidal particles, leading to denser filter cakes. At a concentration of only 5.0 wt% organic salt, the rheological properties were notably improved, and the fluid-loss control performance of filtrate reducers was enhanced. At higher concentrations (40.0 wt%), corresponding to a fluid density of 2.0 g/cm³, the system maintained stable rheological, filtration, and sedimentation properties before and after aging at 230°C. These findings demonstrate that organic salts significantly enhance the thermal stability of both drilling fluid additives and systems. Based on these results, a high-temperature-resistant, high-density organic saltwater-based drilling fluid system was formulated and successfully applied in the Gaitan-X well. Field results confirmed its excellent thermal stability and operational reliability, effectively addressing challenges of hole cleaning, lost circulation, and wellbore stability in high-temperature deep formations.

Characterization of pressure filtration behavior and filter cake properties in excavated sand-containing shield slurry: A CFD-DEM study

Optimizing baghouse performance through analysis of pulse cleaning and filter cake structure

Filter cake behaviors in sandy strata: From macro-parameters to pore structure

Filter cake formation and particle invasion: A comparative study of OBM and WBM in wellbore applications

Electromagnetic interference (EMI) shielding materials are essential for ensuring the reliable operation of electronic devices and safeguarding human health, yet conventional metal-polymer materials are non-biodegradable, energy-intensive, and difficult to recycle. This study prepared a biodegradable paper-based shielding material; renewable cellulose filter paper was employed as the sole substrate, and graphene was integrated to construct an electromagnetic shielding network. A low-cost paper-based electromagnetic shielding preparation method was developed, and the performance of the material was analyzed in electromagnetic shielding applications. Samples were fabricated through a simple impregnation-evaporation-lamination process. It has a thickness of 1 mm for single layers and a maximum conductivity of 21.3 S/m. The influence of sample thickness on electromagnetic shielding in the X-band (8.2–12.4 GHz) was investigated, when the graphene filter cake loading reached 20 wt%, the SET values for triple-layer electromagnetic shielding papers reach 36 dB at 8.2 GHz and 33 dB at 12.4 GHz. A phone box for indoor environments and a card holder with anti-radio-frequency identification (RFID) functionality were designed. Furthermore, achievable design solutions for an EMI shielding wallpaper in medical and artistic installations were proposed.

This study addresses the persistent issue of membrane fouling in filtration systems, a phenomenon that disrupts flow dynamics and reduces efficiency across various membrane types. To overcome the limitations of traditional models, a novel generalized framework, characterized by its fractional order (α), clogging indicator (n), and clogging rate constant (k), is proposed as a flexible and unified alternative to traditional models. This fractional formulation inherently allows the model to generalize effectively across various fouling behaviors: cake filtration, intermediate clogging, and standard blocking. Comparative analysis with classical models showed that the new framework consistently achieved higher accuracy, with normalized RMSE values ranging from 0.93% to 1.73% and R2 values exceeding 0.995. Due to its fractional formulation, the model demonstrates strong generalization across various fouling behaviors, without requiring separate calibration for each scenario. It also enables one-step identification and characterization of the prevailing fouling mechanism while maintaining computational simplicity. Overall, this study introduces a scalable, accurate, and robust modeling framework that enhances membrane performance in fluid and mechanical engineering applications.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-33755-4.

This paper aims to address the difficulty in membrane formation of slurries in highly permeable formations during slurry shield tunnelling by using wheat straw powder (WSP) as an environmentally friendly slurry viscosity enhancer. The viscosity-enhancing mechanism is revealed through scanning electron microscopy (SEM). Rheological property tests show that WSP-Slurry conforms to the Herschel-Bulkley model, maintaining shear-thinning properties and balancing cuttings-carrying capacity. The yield stress of WSP-Slurry first decreases and then increases with higher straw content, exhibiting a “vulnerable interval”. In infiltration experiments, sodium fluorescein is added as a tracer to enable real-time observation of the slurry movement front. Three slurry infiltration patterns are identified: filter cake type, filter cake with infiltration zone type, and non-filter cake type. The critical cumulative filtration flow rate for judging filter cake formation is found to be 40×10-3 m3/m2. The smaller the variation trend of filtration flow rate and infiltration distance with infiltration pressure, the higher the compactness of the filter cake. Wheat straw can improve the membrane-forming performance of the slurry, reduce bentonite use by 40%, and decrease dependence on traditional additives.

Mullite ceramics were synthesized from filter cake waste following the diphasic gel method. Filter cake waste, with over 65% silica content, and aluminum nitrate nonahydrate were utilized as the sources of silica and alumina, respectively. The prepared samples were sintered at various temperatures of 1150, 1250, and 1350°C. The sintered bodies were then evaluated for porosity, density, compressive strength, and dielectric strength. Differential Thermal Analysis (DTA) revealed exothermic peaks at 970°C and 1147°C, corresponding to spinel and mullite formation, which was also confirmed by X-ray diffraction (XRD) analysis. The XRD result also showed single-phase mullite crystallization at 1250°C. Field Emission-Scanning Electron Microscopy (FESEM) and Energy Dispersive Spectroscopy (EDS) demonstrated morphological changes, grain growth, and uniform elemental distribution in sintered mullite ceramics. The mullite ceramics sintered at 1350°C exhibited a density of 2.615g/cm3, compressive strength of 420MPa, and dielectric strength of 10.2kV/mm. These findings highlight the potential of the diphasic gel method to produce high-quality mullite ceramics from industrial waste, contributing to cost-effective, eco-friendly materials with promising applications, including electronic devices, electrical power transmission systems, and other structural and functional advanced ceramics.

The efficient dewatering of high-moisture coal slime, a byproduct of coal washing processes, remains a significant technological challenge in resource recovery operations. This investigation systematically examines how clay minerals (particularly montmorillonite and kaolinite) impede dewatering processes through three key mechanisms: surface hydrophilicity modification, filter cake porosity alteration, and bound water retention enhancement. By employing an innovative multiscale approach combining molecular dynamics simulation with laboratory-scale filtration experiments, the fundamental interactions between mineral components and water molecules under pressure filtration conditions were elucidated. Molecular simulation results revealed distinct adsorption energy hierarchies: montmorillonite exhibited the strongest water affinity (−8750 ± 150 kcal/mol), followed by kaolinite (−5500 ± 90 kcal/mol), with quartz showing minimal adsorption (−1400 ± 50 kcal/mol). These molecular-scale findings were corroborated by macroscopic wettability measurements, where contact angles followed the inverse sequence: montmorillonite (34°±2°) < kaolinite (52°±3°) < quartz (65°±2°), confirming the mineral-dependent hydrophilicity gradient. Filtration performance metrics demonstrated clear mineralogical dependence. Quartz-dominated systems achieved peak initial flow rates (2.05 ± 0.04 mL/s) but experienced rapid flux decay (τ = 8.2 min), ultimately yielding the driest filter cakes (28.1 ± 0.3% moisture). In contrast, montmorillonite-rich samples showed severely constrained dewatering, with initial flow rates limited to 0.87 ± 0.02 mL/s and final moisture contents reaching 40.5 ± 0.4%. The dewatering resistance coefficient (DRC) followed the sequence: montmorillonite (DRC = 1.00) > kaolinite (DRC = 0.68) > quartz (DRC = 0.42), exhibiting strong correlation (R2=0.96) with simulated adsorption energies. Industrial validation tests confirmed these laboratory findings, with quartz-bearing coal slimes demonstrating 35∼40% faster dewatering cycles compared to clay-rich counterparts. The mechanistic understanding developed in this study provides a scientific foundation for process optimization through: (1) feedstock mineral composition control, (2) targeted dewatering aid development, and (3) equipment parameter adjustment based on mineralogical characteristics. Future research directions should address the scaling effects in industrial filter presses and the economic feasibility of mineral-based process modifications.

Influence of Dually Modified Tapioca Starch on Drilling Fluid Filtration and Filter Cake Development on Rock Samples

Impact of disperse populations of non-equant crystals on filter cake resistance: Insights from filtration experiments and simulations

Enhancing bentonite slurry with sodium alginate for subsea tunnelling: rheological behavior, infiltration, and filter cake characteristics

Beyond charge neutralization: Self-skeletization of inorganic coagulants reinforces pore networks for enhanced sludge dewatering.

With increasing challenges in high-pressure high-temperature (HPHT) and saline drilling environments, improving the thermal and filtration stability of water-based drilling fluids (WBDFs) is critical. In this study, a zwitterionic polymer–grafted titanium dioxide (TiO₂) nanocomposite was developed as a multifunctional additive. The nanocomposite was synthesized via aqueous free-radical polymerization of acrylamide (AM), 2-acrylamido-2-methylpropanesulfonic acid (AMPS), N-vinylpyrrolidone (NVP), and dimethyldiallylammonium chloride (DMDAAC), which were covalently bonded to silane-modified TiO₂ nanoparticles. Structural and thermal analyses confirmed successful grafting, uniform dispersion, and stability up to 300 °C. When 0.11–1.00 g per 350 mL of bentonite-based WBDF was incorporated, the rheological performance of the nanocomposite improved, increasing the plastic viscosity from 7 to 15 mPa·s (7–15 cP), the apparent viscosity from 25.5 to 55 mPa·s (25.5–55 cP), and the yield point from 8.86 to 19.15 Pa (18.5–40 lb/100 ft²), while maintaining shear-thinning behavior. Under low-pressure low-temperature conditions, fluid loss decreased by ~ 35%, and filter cake thickness decreased by 75%, whereas HPHT tests (120–180 °C, 3.45 MPa/500 psi) revealed up to 23% lower fluid loss and ~ 62% thinner cakes. Comparative tests with the pure zwitterionic polymer confirmed that TiO₂ functionalization further enhanced the gel strength, filtration control, and salt resistance. The additive also maintained stability up to 30 wt% NaCl, and cyclic HPHT aging tests demonstrated superior long-term performance relative to that of the polymer alone. Zeta potential (–75 mV), DLS, and SEM analyses revealed high colloidal stability and compact, low-permeability filter cakes, driven by synergistic electrostatic–steric stabilization and nanoparticle–polymer reinforcement. Rheological modeling revealed that the Herschel–Bulkley model best captured flow behavior (R² > 0.99). These findings highlight the TiO₂–zwitterionic nanocomposite as a robust thermal stabilizer and filtration controller, offering next-generation performance for WBDFs in HPHT and saline drilling environments.