Enhanced Water Resistance Research Articles

Enhancing water resistance in magnesium oxychloride cement modified with sodium dihydrogen phosphate at low MgO concentrations

Phosphate ions significantly enhance the water resistance of magnesium oxychloride cement (MOC). In this study, MOC was prepared with a MgO/MgCl2 molar ratio of 7 and a H2O/MgCl2 molar ratio of 12, while varying the dosage of sodium dihydrogen phosphate. The aim was to observe the microstructural changes in 5Mg(OH)2·MgCl2·8H2O (Phase 5) crystals and the macroscopic mechanical properties before and after immersion. The research found that phosphate ions increase the content of air-cured Phase 5 and reduce the formation of Mg(OH)2 by lowering the required Mg2+ concentration for Phase 5 production. However, excessive phosphate ions can damage the crystal structure of Phase 5, leading to a decrease in MOC strength. An appropriate amount of phosphate ions increases the output of Phase 5, resulting in a highly dense microstructure, which significantly improves the water resistance of MOC. Additionally, this enhances the pore structure of MOC, making the overall structure more compact and resistant to water penetration. This research offers valuable theoretical insights into Phase 5 crystal variations during air curing and water-immersion damage under low Mg2+ concentrations.

Activated Carbon from Coconut Shells as a Modifier of Urea–Formaldehyde Resin in Particleboard Production

Various methods for the effective modification of urea–formaldehyde (UF) adhesives, aimed at enhancing the performance of wood-based materials, have been continually explored worldwide. The aim of this work was to investigate and evaluate the effect of introducing small amounts (0.25–1.5%) of activated carbon from coconut shells (ACCS) in UF adhesive on the properties of particleboard. The performed investigations of the adhesive mixture’s properties showed an increase in both viscosity and reactivity. Moreover, the use of loadings of 0.75% and 1% had a positive effect on mechanical properties such as bending strength, modulus of elasticity, and internal bond. In these variants, a delay in the degradation of the adhesive bonds by water was also observed, as indicated by the lower thickness swelling values measured after 2 h. However, under long-term exposure to water, the modification had no considerable effect on the dimensional stability of the boards. Markedly, the addition of 1 and 1.5% of ACCS resulted in a reduction in formaldehyde content, which can be attributed to the excellent adsorption capacity of activated carbon. Overall, a loading of 1% was found to be optimal, resulting in improved strength, enhanced water resistance, and reduced formaldehyde content.

Study on hydrophobic modification of starch‐based foam with fumigating and spraying

AbstractTo enhance water resistance of starch‐based foam, based on the porous and irregular surface feature of foam, fumigating hexamethyldisilazane (HMDS) and spraying nano‐SiO2/ethanol solution were utilized to enhance hydrophobic properties of the starch‐based foam. Homemade starch‐molded foams were used for hydrophobic modification studies, the results showed that fumigating HMDS can lead to the formation of “Si‐O‐C” bonds between HMDS and starch. Additionally, it can form more stable “Si‐O‐Si” bonds with nano‐SiO2 in the original composites, which can better adhere to the surface of the starch foam to effectively create a waterproof barrier layer. On the basis of HMDS fumigation modification, hydrophobicity was significantly enhanced by further spraying of nano‐SiO2/ethanol solution. When the mass ratio of nano‐SiO2 to ethanol was 6:100, the combination of HMDS and nano‐SiO2 was optimal, while making the roughness of the foam surface suitable, at which time, the contact angle reached 155°, the maximum value under this system, indicating that the hydrophobicity was optimal. The fumigation and spraying method can evenly and comprehensively act on the surface of the porous and irregular starch‐based foam, which facilitates the waterproof post‐treatment process of the industrial application process and has strong practical significance.Highlights Fumigated with HMDS, the starch foam's exhibit some hydrophobic effect. Fumigation followed by spraying is effective in enhancing the hydrophobicity of starch foams. Both the fumigation method and the spray method are suitable for the post‐treatment of hydrophobic of starch foams.

Biodegradable Plastics from Mango Seed Starch for Sustainable Food Packaging‐Effect of Citric Acid and Fillers

AbstractStarch based bioplastics were prepared and characterized with fillers carboxy methyl cellulose (CMC), chitosan (CS) and nanochitosan (NCS); plasticizer sorbitol and cross‐linking agent citric acid (CA) at different loading levels. Structural, water resistance, water vapor permeability, solubility, mechanical, antimicrobial and biodegradation properties of the bioplastics were investigated. FTIR confirmed bonding of starch with cross‐linking agent, fillers and plasticizer. The water uptake of the CMC bioplastics was decreased up to 70 % with 20 % CA addition. Bioplastics with CS and NCS showed lesser water uptake, only 12.5 % for CS bioplastic. The water vapour permeability (WVP) of all bioplastics was low in the range 2.16×10−7–6.29×10−7 gday−1 m−1 Pa−1. The CA addition increased water resistance and lowered WVP of the bioplastics by restricting the hydrophilic functional groups and forming more tight structures. The fillers CS and NCS additions enhanced the mechanical strength attributing to more hydrogen bonding between NH3+ of chitosan and OH− of starch. All bioplastics demonstrated good antimicrobial activities. These bioplastics offer an attractive alternative to non‐biodegradable plastics used in food packaging due to its enhanced water resistance, antibacterial properties and biodegradability.

Investigation of the effects of different needle hole covering techniques on seam characteristics of waterproof breathable fabric

PurposeStitching is the traditional method of creating seams using needles and threads. However, this is not useful for waterproof breathable garments as needle holes allow water to penetrate inside the garment, compromising its functionality. This study aims to investigate different techniques for covering the needle holes formed during stitching to achieve a seam that is waterproof, durable and functionally effective.Design/methodology/approachThis study investigates different methods to cover needle holes formed during stitching with the help of seam tape, seam grip adhesive and fuser thread. The emphasis is on evaluating the seam characteristics, including seam strength, seam efficiency, puckering, bending stiffness and resistance to water penetration. Statistical analysis involves the use of the Shapiro–Wilk test, Levene statistic, one-way ANOVA and Tukey’s HSD and Tamhane post-hoc tests.FindingsThe experimental results suggest that seam tape is effective in enhancing water resistance, seam strength and seam efficiency, but it contributes to stiffness and aesthetically degrades seams due to increased puckering. Meanwhile, the use of fuser thread presents an alternative, exhibiting improved waterproof properties compared to regular stitching. It offers more flexibility and less puckering compared to seam tape.Originality/valueThis study contributes novel insights by shifting the focus from alternative seaming methods such as bonding and welding, to enhancing traditional stitching for waterproof seam construction. While prior research primarily explored alternatives to stitching, this study uniquely addresses the effectiveness of different techniques in covering needle holes to achieve waterproof seams. The findings provide valuable information for enhancing the functionality of stitched seams in the production of waterproof breathable garments.

Improving hydrophobicity of asphalt surfaces using pulverized recycled polyethylene terephthalate: Towards efficient roofing/waterproofing

Hydrophobic surfaces exhibit low wettability, low water and ice adhesion, etc. with an enhanced water resistance overall. Asphalt binder is popularly employed for roofing and waterproofing due to its intrinsic hydrophobicity. Yet, both unmodified and conventionally polymer-modified asphalt binders exhibit water contact angle (WCA) within the lower hydrophobic range (≤ 121°). Recent studies have shown that the hydrophobicity of asphalt binder can be enhanced via surface treatment using carefully selected materials. In this current study, the use of recycled polyethylene terephthalate (rPET) to improve the hydrophobicity of asphalt-binder was explored. The rPET was processed into micro-sizes and utilized to thermally treat the asphalt-binder at 100 °C. The morphology of the processed rPET and the treated-asphalt surfaces was examined using scanning electron microscopy (SEM). An optical surface profilometer was employed to quantify the roughness of the treated-asphalts. A video contact angle measurement system was used to measure the WCA of the unprocessed/untreated materials and the treated asphalt surfaces. The treated-asphalt showed average and maximum WCA of up to 144° and 148° respectively. This indicates that the rPET-treated asphalt surface could exhibit super-hydrophobicity (WCA ≥ 145°). The improvement in the WCA was due to the increase in surface roughness as a result of the embedment of rPET-particles onto the asphalt surface. The embedment resulted in the stretching of the asphalt surface, forming micro-valleys and -ridges of multiple hierarchies. Higher curing duration was found to yield treated-asphalts with hydrophobicity that last longer. It is found that micronized rPET with sizes smaller than 149 µm can be employed to successfully improve the hydrophobicity of asphalt binder surfaces.

Enhancing water resistance and flame retardancy of wood through phytic acid catalyzed in-situ polyesterification

The treatment of wood using in-situ polyesterification with citric acid and D-sorbitol (SCA) is a novel method for enhancing wood properties. This method can effectively improve the dimensional stability and biological durability of wood. However, achieving effective fixation of polyester in wood at lower curing temperatures has not been achieved. In this study, phytic acid was used to catalyze in-situ polyesterification of SCA. The autocatalytic reaction pattern of SCA polyesterification was elucidated through an investigation of the kinetics of the curing reaction. It was also confirmed that phytic acid reduces the curing temperature and activation energy of SCA. The investigation of polyesters revealed that phytic acid catalysis enhances the esterification degree and thermal stability of the polyester. Wood treated with SCA and 2%wt phytic acid exhibited a 44% reduction in polyester leaching. Moreover, it demonstrated high water resistance and dimensional stability, with water repellency efficiency of up to 33.8% and anti-swelling efficiency of up to 46.2%. Remarkably, it exhibited excellent flame retardancy, with an oxygen index of 33.1% and a 47.5% reduction in total heat release. The outstanding flame retardancy is attributed to the dual action of phytic acid in both the solid phase and gas phase.

Preparation and performance research of ecological concrete using waste wood

To mitigate environmental damage from mineral aggregate extraction, bio-based materials have garnered research interest as potential replacements for natural mineral aggregates. This work utilized waste wood as filler to prepare lightweight foam concrete with thermal insulation, low-temperature and corrosion resistance properties. The feasibility of using wood aggregate-based foam concrete (WFC) was explored in terms of dry density, softening coefficient, compressive strength, thermal conductivity, chloride ion permeability, freezing resistance, and sulfate attack resistance. Results showed that simultaneous addition of waste wood aggregate (WA) and foam effectively reduced WFC bulk weight and thermal conductivity while enhancing water resistance. However, the porous morphology of WA and foam caused the reduction of mechanical properties. In terms of durability, the addition of WA can increase the energy absorption capacity when WFC is subjected to expansion stress, reduce the damage to the structure, and have an inhibiting effect on the cracking of WFC caused by sulfate attack and freeze-thaw cycles. Nevertheless, WA's high water absorption loosened the matrix in WFC's interfacial transition zone (ITZ), increasing harmful pores and negatively affecting durability. In addition, in order to predict the mechanical properties of WFC and the resistance to sulfate attack, this study established a function model for the relationship between the compressive strength (Maintenance specimens of the same age and Specimen of sulfate attack) and the WA dosage. In conclusion, The use of waste wood for the preparation of WFC is more advantageous and sustainable than conventional foam concrete for the insulation of precast walls and coastal structures.

Confined-immigration enhances water resistance and weatherability of highly transparent coatings for cultural heritage preservation

Ultra-transparent polyacrylic (PA) coatings are widely used in cultural heritage conservation but often face issues like whitening from phase separation due to poor water resistance and weatherability. This leads to frequent need for replacement, complicating the preservation of cultural artifacts. In this study, we propose a core/shell polyacrylic emulsion coating (PA-DFMA) with enhanced water resistance and weatherability by confining fluorinated polymers within the shell section. The core/shell structure of PA-DFMA is designed to prevent phase-separation-induced whitening and improve transparency, thanks to the strategic confinement of fluorinated polymers which also mitigates fluorine aggregation and enhances film formation at low temperatures. On the other hand, the introduction of fluorine refines the phase domains during the aging process, further ensuring the transparency of coating and greatly prolonging its durability. Chemically, the strong C-F bonds in the coating offer excellent UV aging resistance, and the lack of a chemical bonding network structure allows for the easy and safe removal of the coating, facilitating reversible treatment of artifacts. The performance test showed that PA-DFMA coatings outperform traditional cultural heritage protection products such as Golden and Rustins in transparency, weatherability, hardness, and reversibility. This eco-friendly coating is proven to offer substantial potential for the preservation of cultural heritage and maintenance of archaeological objects, providing new insights into the design of materials for this purpose.

Eco-Friendly Poly (Butylene Adipate-co-Terephthalate) Coated Bi-Layered Films: An Approach to Enhance Mechanical and Barrier Properties.

In this research work, a coated paper was prepared with poly (butylene adipate-co-terephthalate) (PBAT) film to explore its use in eco-friendly food packaging. The paper was coated with PBAT film for packaging using hot pressing, a production method currently employed in the packaging industry. The coated papers were evaluated for their structural, mechanical, thermal, and barrier properties. The structural morphology and chemical analysis of the coated paper confirmed the consistent formation of PBAT bi-layered on paper surfaces. Surface coating with PBAT film increased the water resistance of the paper samples, as demonstrated by tests of barrier characteristics, including the water vapor transmission rate (WVTR), oxygen transmission rate (OTR), and water contact angle (WCA) of water drops. The transmission rate of the clean paper was 2010.40 cc m-2 per 24 h for OTR and 110.24 g m-2 per 24 h for WVTR. If the PBAT-film was coated, the value decreased to 91.79 g m-2 per 24 h and 992.86 cc m-2 per 24 h. The hydrophobic nature of PBAT, confirmed by WCA measurements, contributed to the enhanced water resistance of PBAT-coated paper. This result presents an improved PBAT-coated paper material, eliminating the need for adhesives and allowing for the fabrication of bi-layered packaging.

Maize‐derived zein/acrylic hybrid emulsion for superior skin adhesion and water resistance in cosmetic adhesives

AbstractWaterborne acrylic emulsions are considered suitable materials for cosmetic skin adhesives because of their positive attributes, such as their safe water‐based polymerization process and low volatile‐organic‐compound emissions. The significant challenge of inadequate water resistance in emulsion adhesives, which is primarily caused by the excess surfactants retained at the interface of emulsion particles upon film formation, necessitates urgent resolution for their viable application as cosmetic adhesives. Zein, a corn‐derived protein, possesses hydrophobic amino acids that provide exceptional water‐repellent characteristics. Therefore, zein is expected to exhibit a remarkable skin‐adhesion attribute. This paper presents the introduction of a pioneering zein/acrylic hybrid emulsion exhibiting remarkable skin adhesion and water resistance, which was achieved through the use of zein, a corn‐derived protein. After formation, the zein/ sodium dodecyl sulfate (SDS) complex can unfold the zein chain, thereby enhancing skin adhesion, while concurrently inhibiting surfactant migration to enhance water resistance. The zein/SDS complex was introduced into the Pre‐emulsion (PE) manufacturing process during emulsion polymerization. As expected, the zein/acrylic hybrid emulsion demonstrated favorable skin adhesion and a notable improvement in water resistance. This approach presents a promising avenue for the practical application of emulsion nanoparticles as eco‐friendly cosmetic adhesives, offering excellent durability and skin adhesion through the utilization of naturally derived proteins.

Enhancing Water Resistance and Mechanical Properties of Cemented Soil with Graphene Oxide.

Although cemented soil as a subgrade fill material can meet certain performance requirements, it is susceptible to capillary erosion caused by groundwater. In order to eliminate the hazards caused by capillary water rise and to summarize the relevant laws of water transport properties, graphene oxide (GO) was used to improve cemented soil. This paper conducted capillary water absorption tests, unconfined compressive strength (UCS) tests, softening coefficient tests, and scanning electron microscope (SEM) tests on cemented soil using various contents of GO. The results showed that the capillary water absorption capacity and capillary water absorption rate exhibited a decreasing and then increasing trend with increasing GO content, while the UCS demonstrated an increasing and then decreasing trend. The improvement effect is most obvious when the content is 0.09%. At this content, the capillary absorption and capillary water absorption rate were reduced by 25.8% and 33.9%, respectively, and the UCS at 7d, 14d, and 28d was increased by 70.32%, 57.94%, and 61.97%, respectively. SEM testing results demonstrated that GO reduces the apparent void ratio of cemented soil by stimulating cement hydration and promoting ion exchange, thereby optimizing the microstructure and improving water resistance and mechanical properties. This research serves as a foundation for further investigating water migration and the appropriate treatment of GO-modified cemented soil subgrade.

Improved resistance to water poisoning of Pd/CeO2 monolithic catalysts by heat treatment for ozone decomposition

Durability is a crucial requirement in heterogeneous catalysis; however, many catalysts suffer from severe deactivation in humid conditions due to water poisoning. Ozone, as a significant air pollutant, should be efficiently removed through catalytic decomposition, making it imperative to develop a water-tolerant monolithic catalyst for practical air purification. In this study, we present highly durable Pd/CeO2 monolithic catalysts resistant to water poisoning achieved through a simple heat treatment of the ceria support. The heat treatment controlled the ceria surface properties, including oxygen vacancy defects, surface oxygen, and basicity, thereby improving resistance to water poisoning. When Pd/CeO2 monolithic catalysts were used in bench-scale ozone decomposition under humid conditions, the catalyst heat-treated at 900 °C exhibited superior performance without experiencing deactivation due to water poisoning. Modulating the ceria surface properties plays a pivotal role in enhancing water resistance, and heat-treated Pd/CeO2 monolithic catalysts stand as a promising candidate for practical ozone decomposition in air purification applications.

Sustainable Asphalt Mixtures with Enhanced Water Resistance for Flood-Prone Regions Using Recycled LDPE and Carnauba-Soybean Oil Additive.

This manuscript presents a comprehensive study on the sustainable optimization of asphalt mixtures tailored for regions prone to flooding. The research addresses the challenges associated with water damage to asphalt pavements by incorporating innovative additives. The study centers on incorporating recycled Low-Density Polyethylene (LDPE) and a tailored Carnauba-Soybean Oil Additive, advancing asphalt mixtures with a Control mix, LDPE (5%) + Control, and LDPE (5%) + 3% Oil + Control. A critical aspect of the research involves subjecting these mixtures to 30 wetting and drying cycles, simulating the conditions prevalent in tropical flood-prone areas. The incorporation of innovative additives in asphalt mixtures has demonstrated significant improvements across various performance parameters. Tensile Strength Ratio (TSR) tests revealed enhanced tensile strength, with the LDPE (5%) + 3% Oil-modified mixture exhibiting an impressive TSR of 85.7%. Dynamic Modulus tests highlighted improved rutting resistance, showcasing a remarkable increase to 214 MPa in the LDPE (5%) with a 3% Oil-modified mixture. The Semi-Circular Bending (SCB) test demonstrated increased fracture resistance and energy absorption, particularly in the LDPE (5%) with 3% Oil-modified mixture. Hamburg Wheel-Tracking (HWT) tests indicated enhanced moisture resistance and superior rutting resistance at 20,000 cycles for the same mixture. Cantabro tests underscored improved aggregate shatter resistance, with the LDPE (5%) + 3% Oil-modified mixture exhibiting the lowest weight loss rate at 9.820%. Field tests provided real-world insights, with the LDPE (5%) + 3% Oil mixture displaying superior stability, a 61% reduction in deflection, and a 256% improvement in surface modulus over the control mixture. This research lays the groundwork for advancing the development of sustainable, high-performance road pavement materials, marking a significant stride towards resilient infrastructure in flood-prone areas.

Fabrication and characterization electrospun nanofibers of vitamin E-loaded poly(vinyl alcohol) and hydroxy-beta-cyclodextrin crosslinked by citric acid

Electrospun fibers were developed using different ratios of PVA/CD crosslinked with citric acid to enhance their water resistance properties. The diameter of the fibers increased as the amount of CD increased. PVA/CD fibers loaded with vitamin E (VE) were successfully prepared in 9-1PVA/CD and 7-3PVA/CD ratios, with VE loadings of 24% and 33% respectively. The release of VE from 7-3PVA/CD fibers was faster compared to that from 9-1PVA/CD fibers. Skin permeation studies demonstrated deeper penetration of FITC-incorporated VE in 9-1PVA/CD-CL fibers into the dermis. These promising results have potential for various applications involving enhanced water resistance and topical drug delivery.

Synthesis and characterization of a bio-aldehyde-based lignin adhesive with desirable water resistance

Wood-based panels find widespread application in the furniture and construction industries. However, over 90 % of adhesives used are synthesized with formaldehyde, leading to formaldehyde emission and associated health risks. In this study, an entirely bio-based adhesive (OSL) was innovatively proposed through the condensation of multi-aldehyde derived from the oxidization of sucrose (OS) with sodium lignosulfonate (L). This approach positioned oxidized sucrose (OS) as a viable substitute for formaldehyde, ensuring safety, simplicity, and enhance water resistance upon reaction with L. The optimization of the OSL adhesive preparation process involved determining the oxidant level for high sucrose conversion to aldehyde (13 % based on sucrose), the mass ratio of OS to L (0.8), and hot-pressing temperature (200 °C). Notably, the shear strength of 3-plywood bonded with the developed adhesive (1.04 MPa) increased to 1.42 MPa after being immersed in hot water at 63 ± 3 °C for 3 h. Additionally, the plywood specimens exhibited excellent performance after soaking in boiling water for 3 h, resulting in a shear strength of 1.03 MPa. Chemical analysis using Fourier-transform infrared spectroscopy (FTIR), 1H nuclear magnetic resonance (NMR), and X-ray photoelectron spectroscopy (XPS) confirmed an addition reaction between L and OS, forming a dense network structure, effectively enhanceing the water resistance of OSL adhesives. Furthermore, compared with lignin-formaldehyde resin adhesive (LF), the OSL adhesive exhibited superior wet shear strength. This study offered an innovative approach for developing lignin-based adhesives utilizing a biomass aldehyde (OS), as a promising substitute for formaldehyde in the wood industry. The findings indicated that this approach may advance lignin-based adhesives, ensuring resistance to strength deterioration under highly humid environmental conditions.

A porous inorganic material with high water resistance fabricated by sodium silicate and boric acid

A porous inorganic material with enhanced water resistance was fabricated using sodium silicate and boric acid. The influence of boric acid on the functional groups, porosity, compressive strength, water absorption, softening coefficient, leaching concentration, and chemical frameworks was examined. The findings indicate as the boric acid content increases, the porosity, water absorption, and leaching concentrations of silicon and sodium elements decrease, while the compressive strength and softening coefficient increase. Boric acid can decrease the amount of hydroxyl groups, and lead to a transformation in the chemical framework of Si, which protects the low-polymerized silicon structure, thereby enhancing the water resistance.

Enhancing Water Resistance in Foam Cement through MTES-Based Aerogel Impregnation.

The propensity of foamed concrete to absorb water results in a consequential degradation of its performance attributes. Addressing this issue, the integration of aerogels presents a viable solution; however, their direct incorporation has been observed to compromise mechanical properties, attributable to the effects of the interface transition zone. This study explores the incorporation of MTES-based aerogels into foamed cement via an impregnation technique, examining variations in water-cement ratios. A comprehensive analysis was conducted, evaluating the influences of MTES-based aerogels on the thermal conductivity, compressive strength, density, chemical composition, and microstructure of the resultant composites across different water-cement ratios. Our findings elucidate that an increment in the water-cement ratio engenders a gradual regularization of the pore structure in foamed concrete, culminating in augmented porosity and diminished density. Notably, aerogel-enhanced foamed concrete (AEFC) exhibited a significant reduction in water absorption, quantified at 86% lower than its conventional foamed concrete (FC) counterpart. Furthermore, the softening coefficient of AEFC was observed to surpass 0.75, with peak values reaching approximately 0.9. These results substantiate that the impregnation of MTES-based aerogels into cementitious materials not only circumvents the decline in strength but also bolsters their hydrophobicity and water resistance, indirectly enhancing the serviceability and longevity of foamed concrete. In light of these findings, the impregnation method manifests promising potential for broadening the applications of aerogels in cement-based materials.

Ternary wetting modification technology: A remedy for water blockage and prevention sand in unconsolidated sandstone gas reservoirs

In the development of unconsolidated sandstone gas reservoirs, water and sand production pose challenges, reducing gas deliverability and causing reservoir damage. This paper presents a novel ternary water control and gas recovery technology using hydrophobic modification. The technology focuses on reversing capillary forces at the far-well edge of the reservoir to prevent water intrusion and creating a hydrophobic gravel layer around the wellbore to enhance water resistance. Additionally, the slotted liner cavities are treated to improve erosion resistance and maintain smooth gas flow, effectively controlling water and sand. The approach aims to minimize water and particle migration, thereby improving gas phase permeability. Researchers assessed the technology's effectiveness using a sand-gravel-slotted liner model and examined how sand wettability, gravel size, and liner slot width affect water resistance. Results show that the technology significantly reduces water phase permeability and gas sand content, increases water breakthrough pressure, and maintains the original permeability of the gas reservoir. When the formation sand contact angle θsand > 156°, the particle size ratio D50/d50 = 6.5, and the slit width is 0.30 mm, the water-resisting ability is the best. The research results can provide corresponding theoretical construction parameters for the field engineering of high-water cut-off loose sandstone gas reservoirs.

Enhanced water resistance mechanism in Ag-Hollandite for catalytic ozone decomposition

Catalytic ozone (O3) decomposition at ambient temperature is an efficient method to mitigate O3 pollution. However, practical application is hindered by the poor water resistance of catalysts. Herein, Ag-Hollandite (Ag-HMO) with varying Ag+ content was synthesized. Catalysts with more Ag+ exhibited improved efficiency and water-resistance, with the optimal one maintaining 98% O3 conversion at 70% relative humidity (RH) within 8 h. Physicochemical characterizations revealed that Ag+ had entered the tunnel of OMS-2, facilitating oxygen species removal. Notably, enhanced H2O desorption and the complete inhibition of chemisorbed water formation on Ag-HMO were the primary reasons for its high-efficiency O3 conversion across a wide humidity range. The underlying mechanism arises from the charge redistribution induced by the Ag-O interaction within the tunnel, which reduces acidity and modulates hydrophilicity. This study aims to contribute insights for designing catalysts with higher water-resistance.