Water Wettability Research Articles

Thymol incorporation within chitosan/polyethylene oxide nanofibers by concurrent coaxial electrospinning and in-situ crosslinking from core-out for active antibacterial packaging

Active packaging systems that are sustainable and capable of delivering antimicrobial agents are in demand in food industry. In this work, Thymol (Thy) was encapsulated into Polyethylene oxide (PEO)/Chitosan (CS) to form core-shell nanofibers via coaxial electrospinning. Various dose of the crosslinker-genipin (GP) were encapsulated into the core layer to achieve in-situ etching crosslink with the CS of shell layer during the electrospinning process. The core-shell structure of the nanofiber was confirmed by transmission electron microscopy. The microstructures, mechanical properties, water vapor permeability, swelling ratios, wettability, thermal stability, biocompatibility and antibacterial properties of the crosslinked films were characterized. The results showed that the crosslinked films had compact structures, strong water resistance, better mechanical property and thermal stability, the sustained release profiles and antioxidant activity were also improved. More importantly, the antibacterial assays indicated that the Thy loaded nanofiber films could effectively inhibit the growth of two common food spoilage bacteria—E. coli and S. aureus.

Superior solar water purification achieved by the excellent photothermal conversion and thermal management of porous plasmonic TiN nanoparticles

Solar photothermal steam generation promises decentralized water purification, but the lack of materials that have strong sunlight absorption in wide spectral range, superior thermal management, large specific surface area as well as good water wettability limits the overall solar water purification efficiency. Herein, porous TiN nanospheres are prepared for solar water purification. The monodispersed porous TiN nanospheres are prepared through the wet-chemistry synthesis of TiO2 and followed nitridation. The prepared porous TiN nanospheres have relatively large specific surface area and very good hydrophilicity. In comparison with solid TiN nanospheres, the porous counterparts have stronger light absorption and better thermal management. The optimum solar evaporation film prepared with the porous TiN nanospheres and filter membrane (TiN/FM) exhibits a reflectance smaller than ∼ 19% in the entire solar spectrum. All these merits of the porous TiN nanospheres give rise to a water evaporation rate of 1.68 kg m-2 h−1 and a solar-steam conversion efficiency of 93.4% under AM 1.5 irradiation. Both seawater and polluted water can be purified to potable water with TiN/FM. Our work not only provides a preparation approach for monodispersed porous TiN nanospheres but also demonstrates the great potential of porous plasmonic nanoparticles for the future development of solar water purification.

Preparation of gallic acid functionalized polyvinyl alcohol/β‐cyclodextrin‐silver nanoparticles cast film as an antimicrobial and antioxidant agent

AbstractIn recent studies, researchers have been dedicated to the synthesis of silver nanoparticles (AgNPs) that can be adjusted in size, owing to their unique physical and chemical properties. In this study, AgNPs with well‐defined and stable characteristics are successfully functionalized with Gallic acid (GA) within a polymer matrix consisting of polyvinyl alcohol/β‐cyclodextrin polymeric biofilms (BFs) using a casting approach. To evaluate the particle size, functional groups, and crystallinity of the AgNPs, various techniques including UV, FT‐IR, TEM, and XRD are employed. The prepared BF films (BFs) are comprehensively analyzed for mechanical strength, color ratio, swelling ratio, surface morphology, elemental ratio, thermal behavior, and water wettability using stress–strain analysis, spectrophotometer color lab, SEM, EDAX, TGA, and contact angle techniques. Furthermore, the antimicrobial properties of the BFs are also investigated, along with their antioxidant activity assessed through the DPPH radical assay. The multifunctional BFs exhibited promising potential as antimicrobial agents for food preservation.

Prolonged and Controllable Release of Doxorubicin Hydrochloride from the Composite Electrospun Poly(ε-Caprolactone)/Polyvinylpyrrolidone Scaffolds

Burst release, typical for the drug-loaded electrospun poly(ε-caprolactone) (PCL) scaffolds is unfavorable in case of cytostatics due to the toxic levels reached during the initial implantation period. In the present short communication, we report an unexpected ability of the composite scaffolds made of PCL and water-soluble polyvinylpyrrolidone (PVP) to provide long-term release of widely used anti-cancer drug doxorubicin hydrochloride (DOX-HCl). That effect was observed for electrospun DOX-HCl-loaded composite scaffolds based on PCL and PVP with various mass ratios (100/0, 95/5, 90/10, 75/25 and 50/50). After the morphology and water contact angle studies, it was concluded that PVP content has no effect on the average fiber diameter, while PVP content higher 10 wt. % changes the hydrophobic character of the scaffolds surface (water contact angle of 123.9 ± 3.5°) to superhydrophilic (water contact angle of 0°). Despite the dramatic change in water wettability, by high performance liquid chromatography (HPLC), it was revealed that the PVP content in the scaffolds reduces the DOX-HCl release rate under short (first hours) and long-term (during 1 month) exposure to phosphate buffer saline (PBS). These results are in good agreement with in vitro studies, in which the viability of HeLa cervical cancer cells was higher after 24 h of culture with scaffolds with high PVP content.

Physical, reconstitution and phenolic properties of instant drink mix prepared with Moringa oleifera leaf, raw banana and whey protein concentrate

The formulation of instant drink mix with nutritional enhancement and optimum physical properties is a challenging task. The present study was undertaken to formulate instant drink formulation (IDF) mix using the ingredients green unripe mature banana powder (GMBP), Moringa oleifera leaf powder (MLP) and whey protein concentrate powder (WPCP) as main ingredients. Different combinations of these ingredients were mixed to formulate nine different variants (treatments) of composition mixes. The developed treatments were evaluated for physical and reconstitution properties of color characteristics, water activity, bulk density, tapped density, flowability, angle of repose, foaming capacity, swelling index, hygroscopicity, water absorption capacity (WAC), water solubility index (WSI), dispersibility, and wettability. The samples were evaluated for phenolic composition and antioxidant potential. Water activity, bulk and tapped density among the samples was ranging between 0.245–0.254 aw, 0.35–0.43 g/cm3 and 0.67–0.77 g/cm3, respectively. The flowability characteristics of Carr index (CI), Hausner ratio (HR) and angle of repose were ranging between 26.20–55.51, 1.36–2.34 and 27.51–48.33, respectively, with T1 treatment having the highest values for these characteristics. Foaming capacity, swelling index and hygroscopicity was found to be 21.83–51.17 %, 3.55–10.16 % and 24.53–36.67 %, respectively. The WAC and WSI was observed to be highest in the T1 treatment with 2.55 and 76.27, respectively. Whereas, the dispersibility and wettability was found to be between 49.75–87.93 (%) and 14.15–22.46 (s), respectively. Total phenolic content (TPC), total flavonoid content (TFC) and total anthocyanin content (TAC) in the analyzed samples were ranging between 26.86 and 1740.00 mg GAE/100 g, 12.33–1880.50 mg RE/100 g and 0.27–448.83 μg C3G/g, respectively. For the antioxidant assays, the DPPH, ABTS and FRAP assay were recorded with 10.30–8.36 % inhibition, 11.85–88.07 % inhibition and 0.36–22.72 μM Fe2+/100g, respectively. Polyphenol profile and enzyme inhibition activity was analyzed among the formulated compositions.

Effect of Irrigation Water Quality and Wetting and Drying Cycles on the Release of Calcium and Magnesium in Two Soils of Different Textures

Abstract
 The study included two sites for two soils of different textures (Al-Mazara and Bashiqa) within Nineveh Governorate - Iraq. Soil samples were taken from the surface depth (30 cm) naturally by means of columns. The experiment was carried out by adding two types of water (river water and well water) to each column with a volume equivalent to The pore size, and alternating wetting and drying were done for ten cycles, and the period between one cycle and another was 10 days. Soil samples were analyzed after the first cycle, the fifth cycle, and the tenth cycle to find out the effect of the number of humidification cycles on the exchanged ions, the relative effectiveness, and the Gapon constant. The results indicated that the released amount of exchanged calcium ions in the soil of Bashiqa was higher than the amount released in the soil of the Al-Mazara, while the amount of magnesium ions released in the soil of Al-Mazara was higher than the amount released in the soil of Bashiqa and when using both types of water, while the relative effectiveness values for calcium, the values ​​were higher when wetting with well water, except for the first cycle in the soil of Al-Mazara and the tenth cycle in the soil of Al-Mazara and Bashiqa, while the relative effectiveness of magnesium in the two study soils, the values ​​were higher when wetting with well water and for all cycles except the fifth cycle in Bashiqa soil, while the Gapon constant for calcium in the two study soils had higher values ​​when wetting with river water in the fifth cycles, while in the first and tenth cycles the values ​​were higher when wetting with well water, except for the first cycle in Bashiqa soil, while the Gapon constant for magnesium in the two study soils, the values ​​were higher when wetting with well water and for all cycles except for the first and fifth cycle in Al-Mazara soil. Then the following kinetic equations were applied: zero order equation, first order equation, diffusion equation, Eluvich equation and power function equation, the power function equation was the best equation that describes the process of release calcium and magnesium ions in the study soil.

Micro-scale wettability of carbonate rocks via high-resolution ESEM imaging

The wettability of several materials has been traditionally quantified using macro-scale contact angles. However, precise identification of the three-phase contact (TPC) line is often difficult due to the resolution limit of macro-scale setups. Moreover, micro-level surface chemical heterogeneities can have a notable impact on the predicted wetting behavior which limits macro-scale contact angles. Thus, here, we investigate the micro-scale water wettability of condensed micro-droplets on carbonate rock surfaces via a high-resolution Environmental Scanning Electron Microscopy (ESEM). Macro- and micro-scale contact angles were evaluated under three conditions: 1) natural carbonate surfaces, 2) surfaces aged in crude oil, and 3) surfaces aged in cationic surfactant to allow for a broader insight of the impact of rock composition and surface morphology on wettability.At the macro-scale, carbonate rocks were preferentially oil-wet to intermediate-wet. However, a profound variability was observed in wetting behavior at the micro-scale where a weakly water-wet state (50° ≥ θ ≥ 80°) was prevalent with evidence of minor oil-wet patches too. At the micro-scale, for the 100% dolomite sample, the contact angle (θ) varied from ∼66° to 76° under natural conditions, while the same sample aged in crude oil depicted a remarkable variability, i.e., θ ranged from 58° to 132° with the majority of micro-droplets having θ of ∼85° – thus suggesting a mixed-wet behavior. For the same sample aged in surfactant, θ was <5° at micro and macro-scales, with few micro-droplets having θ of ∼89°. However, the macro-scale θ values were 105° (natural) and 90° (oil-aged) – suggesting notable variability at macro- and micro-scales.These findings reflect: a) significant differences among macro- and micro-scale contact angles, and b) surface wetting at the micro-scale captures physical and chemical properties of the rock, i.e., surface roughness, pore size and distribution, and chemical composition. The study herein presents qualitative and semi-quantitative analyses of the non-uniform wetting behavior of carbonate rocks and the associated rock/fluid interactions through a multi-scale perspective and thus have broader implications for flow in porous medium.

Direct measurement of hydrogen relative permeability hysteresis for underground hydrogen storage

Underground Hydrogen Storage (UHS) is a long-term storage solution which utilises hydrogen as an energy carrier to store large-scale excess renewable energy in the subsurface. Key petrophysical properties, such as wettability and interfacial tension of hydrogen and water have been discovered which provide a practical basis for simulation models. Our work directly measures relative permeability hysteresis during co-injection core floods of hydrogen and water with a capillary number of Nc=2.92×10−7. Segmented micro-CT images are used to determine saturation in the Bentheimer sandstone. Our results demonstrate that hydrogen relative permeability in sandstones is very low, with an end-point relative permeability of krg0=0.049 at Swi= 0.24. Capillary trapping results in residual gas saturation of Sgr= 0.4. Wettability analysis confirms the system is water-wet, with contact angles of 57° at Sgr and 44° at Swi. These results improve the reliability of numerical simulations and demonstrate the possible challenges involved with the commercial application of UHS.

Multicolor photochromic material with dual protection of anti-counterfeiting and waterproofing

Optical information storage materials with dual protectiveness of anti-counterfeiting and waterproofing are critical to store information and improve paper utilization in a safe and accurate way. A novel multifunctional material with efficient photo-responsiveness and hydrophobicity was herein developed. Wherein, a system of silver ion (Ag+)/polyoxometalates/polymer was creatively formed as a photochromic layer, achieving different color variations by different contents of Ag+ and UV irradiation doses. This functional surface can maintain colored state for a long time in indoor environments, which is favorable to long-term information storage. It can be quickly blenched within 20 min under a hydrogen peroxide-containing atmosphere, achieving controllability of fading time. In addition, a multifunctional transparent coating formed by PDMS and fine particles composed of ytterbium compound and silica was applied on photochromic layer. This coating rapidly generates dazzling green light under infrared radiation, laying a foundation for the safe transmission of information. Its microstructures effectively capture air in gaps and low surface energy avoids wetting of water, achieving excellent hydrophobicity with a surface contact angle of 152°. In a word, this elaborately designed strategy for information storage via photochromism and dual protection shows enormous application potentials in optical information storage and encryption.

A Guide for Selection of Aging Time and Temperature for Wettability Alteration in Various Rock-Oil Systems.

Wettability alteration has been identified to be one of the important mechanisms to improve the microscopic recovery in many of the enhanced oil recovery (EOR) methods including polymer flood, surfactant flood, low salinity flood, microbial flood, alkaline flood, etc. Ensuring the oil-wet nature of the formation before flooding in the laboratory is necessary to study the efficiency of the EOR process, which targets microscopic recovery through wettability alteration. Nevertheless, altering the wettability depends on several parameters, such as aging time, aging temperature, core nature, oil properties, etc. Although several researchers investigated the effect of individual parameters on wettability alteration, the literature is scarce, and the question of what is the shortest and yet the most reliable aging time for ensuring wettability alteration for the specific rock-oil system at different temperatures remains unclear. This paper attempts to seek an answer to this question by compiling the relevant literature to find the effect of individual parameters such as different aging times, temperatures, oil compositions, and rock lithologies on wettability alteration. Results observed from data analysis showed different windows for aging conditions depending on the core sample lithology, initial wettability, and type of oil used. It was noticed that the higher the asphaltene content in the crude oil used, the lower the time and temperature that it takes to alter the sample wettability. Aging a sandstone core under 80 °C using crude oil with 11 wt % % asphaltene took 7 days to shift the core from strongly water-wet to neutral-wet. The same wettability alteration was achieved in 14 days when aging the sandstone sample at 90 °C using crude oil with 0.85 wt % asphaltene content. Generally, it was observed that the aging time decreased as the temperature increased. Moreover, as the sample has a lower initial water wettability condition, the time that it needs to be aged becomes higher. Results indicated that carbonates in general require less aging time to alter their wettability condition to oil-wet, around 1-7 days, compared with sandstones, around 14-21 days.

Characterization of the solvent specific evaporation from a carbon nanotube buckypaper doped by goethite nanowires

Non-functionalized carbon nanotube based self-supporting buckypaper doped by goethite nanowire was prepared (characterized by TEM, XRD, FTIR, DLS, electrophoresis, SEM) and studied to determine the wetting and evaporation properties of the composite. The wetting and vaporization of water, methanol, ethanol, 2-propanol, acetone, 1,4-dioxane were monitored at 50 °C parallel by weight and electrical resistance measurements and also by thermography in case of water and ethanol. Based on the weight measurements, the different stages of the evaporation (evaporation of sessile droplet, vaporization of the condensed and adsorbed solvents from the porous system) could be distinguished, which could be characterized by their evaporation rate and the amount of liquid remaining in the porous system at the end of the given stages. The evaporation profiles determined from the electrical resistance measurements are characteristic for the evaporating solvents, similar to the mass measurement results. The details of the wetting process can be analyzed by thermography based on the area and temperature of the wetted region. The relationship between the physical properties of the solvents and the parameters characteristic for the evaporation obtained from the weight and electrical resistance measurements was statistically analyzed using Pearson correlation coefficients method. There is a very high correlation for example between surface tension and tt (PCC = 0.971) or ts (PCC = 0.992), and also between the boiling point and Area(R) (PCC = 0.929). These results allow us to predict the possibility of this setup in a potential future analytical application.

Wettability alteration and dynamic wetting behavior of coal during geologic CO2 sequestration using LF-NMR technology

As CO2 has a strong affinity to coal surface, coal seams are considered as an attractive geological formation for CO2 sequestration. Naturally occurring coal seams are often saturated with free water in the cleats as well as moisture. Hence, the wetting behavior of coal by water is an important aspect in the study of coal properties. However, carbon dioxide, which replaces methane on the surface of coal, interacts with water and coal for a long time. Geochemical reactions of CO2-H2O-coal system can change the surface properties and pore structure of coal. Studies on wettability of coal altered by CO2-H2O-coal interaction are rare. This paper explored the wettability alteration and wetting dynamic behavior of two bituminous coals in Huainan and Huaibei coalfield using low-field nuclear magnetic resonance (LF-NMR) combined with CO2-H2O-coal interaction experiments. The results show that dynamic wetting of water in the coal mainly depends on the pores structure. The geochemical reaction changed the pore structure of coal reservoir, further promoted the hydrophobicity of coal surface, and thereby affected the dynamic wetting process of water. Moreover, the wetting of large pores in coal is not significantly affected by the weakening of hydrophilicity, whereas wetting in small pores is obviously affected by the enhanced hydrophobicity, which may be beneficial to the adsorption and storage of CO2 in the coal.

Evaluation of paper coated with cationic starch and carnauba wax mixtures regarding barrier properties

Studies of single-use packaging have aimed to replace materials obtained from non-renewable sources with biodegradable materials from renewable sources in response to environmental concerns. Their barrier properties maximize shelf life and product safety. To provide such green packaging, this work aimed to describe the chemical, physical, morphological, and barrier properties of bilayer coatings made from mixtures of cationic starch (S) and carnauba wax (W) on kraftliner paper (86 ± 1 g/m²). Two coating layers (15.0 ± 0.5 g/m²) of both materials in different proportions were compared to uncoated paper and doublewet-and-dry paper. The addition of cationic starch to carnauba wax raised the melting point of the wax, preventing it from completely entering the paper's pores but instead producing a layer on top of them. The hydroxyl groups present in coated paper S contributed to its hydrophilicity, showing a high Cobb value, absorbing 153 g/m² more water than control samples. Further, the mixtures showed higher hydrophobicity than the cationic starch-treated samples, with a high-water contact angle (100 ± 4°), similarly found for the W treatment. In addition, mixtures showed 0.35°/s less wettability than the W treatment. In terms of mechanical strength, the lower tensile strength and Young's modulus of the coated sheets brought on by hornification appear to have been predominantly caused by water in the suspensions. The addition of carnauba wax to the cationic starch decreased the resistance of coated papers to oil. However, there was an improvement in the water barrier by decreased water absorption and wettability and an increase in water contact angle.

Thermodynamic expression of surface reconstruction impact on surface wettability

In this work we demonstrated noticeable change in the surface wettability in response to environmental changes for self-assembled monolayers (SAM) of functional alkanethiols as a result of the orientation of surface polar groups as well as the permeation of the environmental phase into the SAM surface region with the aid of sum frequency generation spectroscopy and quartz microcrystal balance. Yet the revealed surface reconstruction caused unexpectedly subtle change in SAM surface energy (within ± 8 %) due to checks and balances of the dispersive and polar components of surface energy. By introducing the work of wetting as the difference between the work of adhesion of a fluid on a solid and its surface tension, here we managed to consistently express surface reconstruction impact in SAM surface wettability as an exponential function of the relative change in work of wetting for the wetting fluid. Furthermore, we also succeeded in harnessing the relative change ratio of the work of wetting of water to that of oil to demarcate surface polar groups, which are > 1 for weakly polar groups (e.g., Br and pyrrole), <1 for small, highly polar groups (e.g., OH, NH2 and COOH), and environmentally sensitive for large, highly polar groups (e.g., H2PO3).

Poly(2-hydroxyethyl methacrylate) hydrogels containing graphene-based materials for blood-contact applications: from soft inert to strong degradable material.

Degradable biomaterials for blood-contacting devices (BCDs) are associated with weak mechanical properties, high molecular weight of the degradation products and poor hemocompatibility. Herein, the inert and biocompatible FDA approved poly(2-hydroxyethyl methacrylate) (pHEMA) hydrogel was turned into a degradable material by incorporation of different amounts of a hydrolytically labile crosslinking agent, pentaerythritol tetrakis(3-mercaptopropionate). In situ addition of 1wt.% of oxidized graphene-based materials (GBMs) with different lateral sizes/thicknesses (single-layer graphene oxide, and oxidized forms of few-layer graphene materials) was performed to enhance the mechanical properties of hydrogels. An ultimate tensile strength increases up to 0.2 MPa (293% higher than degradable pHEMA) was obtained using oxidized few-layer graphene with 5 μm lateral size. Moreover, the incorporation of GBMs has demonstrated to simultaneously tune the degradation time, which ranged from 2 to 4 months. Notably, these features were achieved keeping not only the intrinsic properties of inert pHEMA regarding water uptake, wettability and cytocompatibility (short and long term), but also the non-fouling behavior towards human cells, platelets and bacteria. This new pHEMA hydrogel with degradation and biomechanical performance tuned by GBMs, can therefore be envisioned for different applications in tissue engineering, particularly for BCDs where non-fouling character is essential. STATEMENT OF SIGNIFICANCE: Suitable mechanical properties, low molecular weight of the degradation products and hemocompatibility are key features in degradable blood contacting devices (BCDs), and pave the way for significant improvement in the field. In here, a hydrogel with outstanding anti-adhesiveness (pHEMA) provides hemocompatibility, the presence of a degradable crosslinker provides degradability, and incorporation of graphene oxide reestablishes its strength, allowing tuning of both degradation and mechanical properties. Notably, these hydrogels simultaneously provide suitable water uptake, wettability, cytocompatibility (short and long term), no acute inflammatory response, and non-fouling behavior towards endothelial cells, platelets and bacteria. Such results highlight the potential of these hydrogels to be envisioned for applications in tissue engineered BCDs, namely as small diameter vascular grafts.

Effect of the Chemical Composition of Coals on Surface Wettability and Filtration Properties

The method of liquid filtration through a layer of coal powder was used for a comprehensive characterization of surface wettability in conjunction with the determination of the contact angle. The effect of the degree of chemical maturity (metamorphism) of coal on the filtration characteristics of a layer with fractured porous properties was evaluated. Different activity of coal surfaces to water wettability upon a change from the native state to the surface-oxidized one was established. It was shown that the wetting and filtration properties of the coal surfaces increased from native to surface-oxidized coals and decreased as the degree of metamorphism increased from low to medium metamorphosed coals.

Influence of surface characteristics of cement pavement on ice-concrete adhesion

Breaking the adhesion between ice- and pavement is crucial for road de-icing. This study investigates the impact of concrete pavement surface characteristics on ice-pavement adhesion. To achieve this, 20 cement concrete specimens with different combinations of 10 surface textures and 2 wettability surface characteristics were prepared. The water contact angle (WCA) and six texture parameters were determined using the sessile drop and tangent line methods, as well as the sand patch and laser texture scanner techniques. To evaluate the ice–concrete adhesion, shear strength measurements obtained through interlayer shear instrument testing were utilized. In our analysis, we examined the relationship between ice adhesion strength and several factors, including the freezing temperature (T), water wettability, and surface texture parameters. A partial least squares (PLS) model was built to comprehensively analyze the effects of different factors on ice-concrete adhesion. The results indicate that improving hydrophobicity, as demonstrated by an increase in WCA from 20.4° to 119.4°, and raising the freezing temperature were both effective approaches for significantly reducing ice-concrete adhesion. The effects of different texture parameters on hydrophilic and hydrophobic concrete were significantly different. Specifically, for ordinary concrete, the ratio of the surface area (Sr) and the mean texture depth (MTD) demonstrated a positive correlation with ice adhesion strength. For hydrophobic surfaces, the MTD exhibited the greatest correlation with adhesion, followed by Sr. However, skewness (Rsk) also had a significant effect on the ice adhesion of hydrophobic concrete, and ice adhesion preferred valley-texture concrete. Finally, the PLS model results showed that the order of influence on ice-concrete adhesion was: Sr > WCA > MTD > T > Rsk. Based on our findings, we suggest three approaches for reducing ice adhesion to concrete surfaces: implementing semicircular or trapezoidal groove textures, reducing the surface energy of the concrete, and introducing the valley texture surfaces. This study focuses on the influence of surface characteristics of concrete pavements on ice adhesion and provides guidance on designing concrete surfaces for effective road de-icing.

Influence of Rock Firing on the Wettability of Clay-Rich Sandstones

Rock firing is a conventional technique of core preparation to prevent clay swelling and fines migration in clay-rich rock; however, the influence of rock firing on the wetting behaviors and alterations of mineralogical compositions of clay-rich sandstones is not yet explicit. Thus, we assessed and compared the impacts of rock burning at two different temperatures (700 and 1100 °C) on the changes in wetting states of Bentheimer (BN) and clay-rich Bandera Gray (BG) sandstones through contact angle measurement, Amott wettability index determination, and thermogravimetric analysis (TGA). Results showed that rock firing makes the rocks more water-wet, but the clay-rich BG sandstone becomes significantly more water-wet than the quartz-dominated BN rock with increasing temperature. There was no change in rock porosity due to firing, but some clay remained, whereas some clays were transformed into other minerals after rock firing. Particularly, there were thermal transformations of clay to quartz and the disappearance of dolomite, chlorite, and clinochlore. Such transformation of these minerals into alkali metal oxide silicates dispersed on the rock matrix makes the surface more polar and enhances the interactions with water molecules, resulting in more water wettability for the BG sandstone. The study suggests that rock firing could change the clay-rich rock-wetting state into a more water-wet condition than the clay-poor or zero-clay sandstone samples; thus, the influence of rock burning on rock-wetting behavior should be considered to ensure an accurate prediction of the rock-wetting state due to rock burning. Moreover, burning at 1100 °C is recommended to achieve effective clay transformation and removal in clay-rich rock to prevent swelling, fines migration, and clay–fluid interactions.

Improving the anti-oxidation and water wettability of graphite through the design of coating structure for the preparation of Al2O3–SiC–C castables

C/SiC composite powders with different SiC morphologies were prepared by various methods, and the effects of composite powders on the microstructure, mechanical properties, oxidation resistance, and slag corrosion resistance of Al2O3–SiC–C castables were studied. The results show that compared with wet mixing and catalytic modification, the modified graphite with nano SiC prepared by the molten salt method has a prominent “coating” structure, which cooperatively improves the water wetting and oxidation resistance of graphite. At the same time, it was found that the dried strength of castables increased significantly with the gradual replacement of graphite by C/SiC composite powder prepared by the molten salt method. After heat treatment, the bending strength, cold crushing strength, residual strength after thermal shock, and refractoriness under load of the sample increase with the additional increase. In addition, the sample that completely replaces graphite has the smallest decarburization area and slag erosion penetration depth.

Tuning the distribution of zinc ions by manganese dioxide ion sieve to realize the uniform deposition of zinc ions on Zn metal anode of aqueous zinc-ion batteries

Zinc (Zn) metal, as a promising anode for aqueous zinc-ion batteries (AZIBs), has attracted much attention owing to its reasonable redox potential and fabulous theoretical capacity. Notwithstanding, Zn dendrites and side reactions generated during charging/discharging seriously inhibit the reversibility of Zn anode of AZIBs. Herein, ultra-long manganese dioxide (MnO2) nanowires with low cost and easy synthesis have been designed as a high-efficiency zinc ion shunt to achieve uniform Zn deposition. The Zn coated with MnO2 protection layer possesses good water wettability, high ionic conductivity (1.3 mS cm−1) and low activation energy (38.2 kJ mol−1). As a result, the Zn@MnO2||Zn@MnO2 symmetric cell exhibits an ultra-long lifespan over 3800 h at 0.5 mA cm−2/0.25 mAh cm−2; for the Zn@MnO2||Zn@MnO2 symmetric cell, the accumulative discharge capacity surpasses 1600 mAh cm−2 and the depth of discharge (DOD) is 34.2% at the harsh conditions of 20 mA cm−2/20 mAh cm−2; and the average coulombic efficiency (CE) of the Zn//Cu@MnO2 asymmetric cell achieves 99.6%. In addition, the Zn@MnO2//NVO full cell possesses an excellent reversible discharge capacity of 176.3 mAh g−1 after 1000 cycles at 2 A g−1. This investigation provides a useful reference for designing high-efficiency zinc ion shunt to realize highly reversible Zn anode for AZIBs.