Changes In Wettability Research Articles

Adsorption mechanism study of viscoelastic surfactants with various molecular structures on oil and gas reservoir rocks

As clean thickeners used in fracturing fluids or self-diverting acids, viscoelastic surfactants (VESs) have garnered increased attention for their unique properties. While VESs leave little residue, their adsorption on rocks can lead to adverse effects on oil and gas seepage. Herein, sandstone and limestone were utilized as adsorbents to examine a series of VESs with diverse molecular structures. The relationship between adsorption capacity and molecular structure was investigated, along with the impact of salinity and temperature on adsorption capacity through static and dynamic adsorption tests. Experiments were conducted at various temperatures (25 °C–100 °C) and different salinity levels (0–4 wt%) using sandstone and limestone as adsorbents. The wettability alteration caused by each VES solution was assessed to confirm the adsorption capacity of these VESs on sandstone and limestone. Scanning electron microscopy was employed to visually study the microscopic morphologies of rock surfaces after adsorption in VES solutions to investigate the adsorption characteristics. Owing to the differing charges between sandstone and limestone, the adsorption capacity of each VES varied. Cationic VESs tend to be absorbed by sandstone, while zwitterionic VESs are easily adsorbed by limestone. The increase in salinity considerably enhances the adsorption capacity of rocks, with a greater amplification on sandstone compared to limestone. Additionally, the adsorption capacity of cationic VESs on sandstone is highly sensitive to salinity owing to the ease with which their head groups are disrupted by ions. Rising temperatures can weaken adsorption capacity due to the breakdown of hydrogen bonding or van der Waals forces. The wettability changes caused by VES solutions on sandstone are more pronounced than on limestone. By combining experimental results, the mineral content of rocks, molecular structure characteristics of VESs, and adsorption-free energy, the adsorption mechanisms of various VESs with different molecular structures on rocks were examined. This research lays a theoretical foundation for optimizing VES molecular structures for the preparation of fracturing fluids or self-diverting acid.

Photopolymerization enabled in-air highly oleophobic and hydrophilic SiC membranes with improved antifouling performance in oil-in-water emulsion separation

Ceramic membranes with tailored surface wettability have gained increasing attention for improving their separation efficiency and antifouling ability, while most of the previous work focused on the underwater oleophobic behavior. In this work, in-air highly oleophobic and hydrophilic SiC membranes were achieved through the UV irradiation triggered polymerization and controlled crosslinking between oleophobic perfluorodecyl acrylate (TFOA) and hydrophilic methacrylic acid (MAA). These key processing parameters including MAA content, soaking time and irradiation duration were systematically studied through examining the changes in porous microstructure, surface wettability and separation performance in oil-in-water emulsion. Results showed that the flux attenuation rate of SiC membranes can be effectively reduced by regulating the content of hydrophilic components. Due to the alternation of the surface wettability to highly oleophobic in air, the oil droplets can hardly attach on the surface of modified SiC membranes at the beginning of filtration process, and the membrane fouling was significantly slow down yet dominated by the intermediate blocking. Correspondingly, a combined cleaning procedure was proposed to regenerate the fouled SiC membranes. Further, the antifouling ability of modified and original SiC membranes was comparatively studied under the conditions of a fixed permeate volume (15 ml) and various oil concentrations (200 ∼ 1000 ppm) in the separation of oil-in-water emulsion. The advantages of modified SiC membranes become more notable when used for highly concentrated oil–water emulsion as reflected by the slower flux decline and higher stable flux. This work provides a feasible pathway to realize the in-air highly oleophobic and hydrophilic surface on ceramic membranes, and primarily demonstrates the advantages of antifouling ability in oil-in-water emulsion separation.

Impact of CO2-Brine-Shale Interaction on Wettability Change at Reservoir Temperature and Pressure via AFM Characterization

Impact of CO₂-Brine-Shale Interaction on Wettability Change at Reservoir Temperature and Pressure via AFM Characterization

Study on interfacial tension, wettability and viscosity in different salinities of synthesized a new polymeric surfactant for improving oil recovery

Over 50% of the original oil in place (OOIP) is immobile or trapped in the reservoir. Therefore, today, more efficient methods have been introduced in the tertiary oil recovery sector as a scheme of enhanced oil recovery (EOR). Due to the decline of conventional hydrocarbon reserves, polymers are increasingly used in EOR methods, such as surfactant-polymer (SP) and alkaline-surfactant-polymer (ASP) flooding. SP flooding has a complex formulation and design, leading to undesirable phase separation if improperly mixed. Polymeric surfactants are a promising alternative to SP flooding. They consist of hydrophobic groups attached to hydrophilic polymers, which help to improve the mobility ratio and reduce interfacial tension (IFT). This paper examines the rheological and synthesis properties of a new polymeric surfactant produced through bond co-polymerization reaction using different hydrolyzed polyacrylamide (HPAM) ratios and a zwitterion hydrophobic group. The synthesized hydrophobically modified zwitterionic polyacrylamide (HMZPAM) was characterized by FTIR and HMNR analysis. HMZPAM performed better than other substances in IFT, viscosity, wettability, oil recovery, and resistance to different one and two-valence cations. The results indicate that HPAM reduced the IFT to 13.65, while HMZPAM reduced it to 0.441 mN/m. Wettability change evaluated on a rock carbonate/crude oil/HMZPAM system that changed the water-wet state of the primary oil-wet rock carbonate to strongly water-wet state as wettability change measurements showed a decrease in contact angle from 62.76 to 21.23 degree. Comparative studies on the effectiveness of HPAM and HMZPAM were also conducted according to the measurement of viscosity and shear rate in the presence of salt, which indicates the higher shear rate and viscosity of HMZPAM. Core flooding tests revealed that HMZPAM resulted in better additional recovery due to microscopic displacement, resulting in a total oil recovery of 84%, compared to 48% of residual oil saturation for HPAM. Also, salts decreased oil recovery in HPAM injection but increased oil recovery in HMZPAM injection.

Analyzing the wettability changes of rocks in various states of core plugs

Current core plugs preparation standards for laboratory studies are developed for water-wet reservoirs and do not consider other types of wettability. Researching how different core preparation methods affect laboratory studies and wettability changes is relevant and important for petrophysical reserve estimation. Preconditions of doing this work was the question how core plugs impacts wettability changes in carbonate formations from several Eastern Siberian fields. The article describes the SCAL results of measuring the USBM wettability on core plugs at various states: a core plug with preserved saturation (before extraction), a core plug after extraction, and a core plug after wettability restoration. The authors showed how each of the stages of core plugs preparation affects wettability changes in rocks, the study of which is complicated by strong diagenetic changes: uneven salinization, bituminization, and anhydritization. The most accurate results were obtained from core plugs with preserved saturation. Overall, wettability of core plugs shifted towards a more hydrophilic state after extraction, but extraction did not fully change wettability from hydrophobic to hydrophilic.

Effects of chemical etching on surface structure and tribological behavior of silicate substrates

Abstract This study investigated the effect of chemical etching on the surface structure and tribological behavior of silicate substrates. Silicate surfaces were etched using a mixture of nitric acid (HNO3) and ammonium bifluoride (NH4HF2) for durations ranging from 1 to 60 min. The etched surfaces were characterized using optical microscopy, scanning electron microscopy, surface profilometry, water contact angle measurements, and UV–vis spectroscopy to evaluate the changes in surface morphology, roughness, wettability, and optical properties. Tribological performance was assessed using reciprocating ball-on-plate friction tests. The results showed that increasing the etching time resulted in the formation of microscale surface features, increased surface roughness, enhanced hydrophilicity, and reduced optical transmittance. The average friction coefficient decreased with an increase in the etching time up to 30 min, beyond which a slight increase was observed. The 1-minute etched specimen exhibited the best wear resistance with the narrowest wear track and the least material removal. The improved tribological performance was attributed to the formation of a stable transfer film, reduced real contact area, and entrapment of wear debris. This study highlights the potential of chemical etching as a technique to tailor the surface structure and tribological properties of silicate materials for various applications.

Experimental investigation of the influence of ZnO–CuO nanocomposites on interfacial tension, contact angle, and oil recovery by spontaneous imbibition in carbonate rocks

Researchers have recently focused on applying various nanoparticles/nanocomposites to improve the recovery factor from oil reservoirs. In this study, a new enhanced oil recovery agent, i.e., a ZnO–CuO (ZCO) nanocomposite, was synthesized, and its physicochemical properties are investigated by the scanning electron microscope, Fourier transform infrared spectrometer, Brunauer–Emmett–Teller, X-ray diffraction, and energy diffraction x-rays. The impact of ZCO and ZnO on interfacial tension, wettability change, and zeta potential tests has also been investigated under reservoir conditions. 0.1 weight percent (wt.%) of ZnO and ZCO in injection fluid, which minimizes contact angle and maximizes stability (i.e., minimum zeta potential), has been determined as the optimum concentration. The contact angle and zeta potential at this optimum concentration of ZnO and ZCO are 50.83°, 35.69° and −31.38, −35.65 mV, respectively. Then, the spontaneous imbibition using ZnO- and ZCO-based nanofluids with the optimum concentration is applied to monitor the recovery factor. The 22.5 day-long imbibition operation utilizing base fluid (without nanomaterials), ZnO, and ZCO retrieved 24.95%, 35.74%, and 52.01% of the oil, respectively. Overall, we concluded that injecting the ZCO-based nanofluids in carbonate porous media efficiently improves rocks and fluid parameters and enhances oil recovery.

Dynamic wetting mechanism of coal under different CO2 pressure: A new analytical basis through T2 cutoff

The technology of injecting carbon dioxide into coal seams to reduce greenhouse gas emissions and has brought attraction on the wettability of coal. As a fast and non-destructive method, nuclear magnetic resonance (NMR) is widely used in the evaluation of coal wettability, but the inconsistency of analytical basis makes the quantitative evaluation of coal wettability changes uncertain. In this study, based on NMR combined with centrifugal experiments, a novel analytical basis using irreducible water defined by T2 cutoff value was proposed to quantitatively analyze the dynamic wetting mechanism under different CO2 pressures. The results show that when T2 < 72.32 ms, the water in coal is irreducible water; when T2 > 72.32 ms, the water in coal is movable water. CO2 pressure hindered free water conversion to adsorbed and capillary water, but impacted adsorbed water more. Increased CO2 pressure caused the wetting porosity of coal to decrease from 1.62 % to 1.08 %, and coal gradually changed from water-wet to CO2-wet. The increase in CO2 pressure enlarged the CO2 aggregations in the seepage channel, thus weakening the wetting rate of water to coal. CO2 preferentially occupied small pores, which will hinder the migration of water into small pore spaces. Molecular diffusion controls water to achieve wetting equilibrium more than gravity/pressure difference and capillary force. As CO2 pressure increases, the wetting equilibrium time decreases.

Surface modification and patterning of polymer thin films by plasma and adsorption behavior of proteins

The surface wettability property of hydrophobic polystyrene (PS) and hydrophilic polyethylene glycol (PEG) thin films subjected to modification by direct current plasma glow discharge is studied. The polymer films exhibited change of surface wettability on exposure to air, nitrogen, oxygen or argon plasmas. In PS films a swift modification to hydrophilic surface and subsequent steady recovery following first order kinetics are observed. The rate of modification and recovery are adjustable by adjusting the plasma ambient and parameters and additional wet-chemical treatment using ionic solutions. In PEG films the hydrophobic wettability evolve with ageing following the first order kinetics, and is stable for long period on exposure to air ambient. Moreover, a vapor deposition like process is possible using the PEG films as source to deposit self-assembled molecular layers with hydrophobic wettability on other surfaces. Using these surface modification or molecular deposition processes, the fabrication of wettability patterns in the surface of PS and PEG films and on other surfaces by vapor transport using PEG films, and also the possibility to produce gradient wettability patterns are demonstrated. Moreover, the adsorption behavior of immuno-specific system of proteins on surface modified hydrophilic PS films is studied.

Study on the Impact of Microscopic Pore Structure Characteristics in Tight Sandstone on Microscopic Remaining Oil after Polymer Flooding.

As a non-renewable resource, oil faces increasing demand, and the remaining oil recovery rates in existing oil fields still require improvement. The primary objective of this study is to investigate the impact of pore structure parameters on the distribution and recovery of residual oil after polymer flooding by constructing a digital pore network model. Using this model, the study visualizes the post-flooding state of the model with 3DMAX-9.0 software and employs a range of simulation methods, including a detailed analysis of the pore size, coordination number, pore-throat ratio, and wettability, to quantitatively assess how these parameters affect the residual oil distribution and recovery. The research shows that the change in the distribution of pore sizes leads to a decrease in cluster-shaped residual oil and an increase in columnar residual oil. An increase in the coordination number increases the core permeability and reduces the residual oil; for example, when the coordination number increases from 4.3 to 6, the polymer flooding recovery rate increases from 24.57% to 30.44%. An increase in the pore-throat ratio reduces the permeability and causes more residual oil to remain in the throat; for example, when the pore-throat ratio increases from 3.2 to 6.3, the total recovery rate decreases from 74.34% to 63.72%. When the wettability changes from oil-wet to water-wet, the type of residual oil gradually changes from the difficult-to-drive-out columnar and film-shaped to the more easily recoverable cluster-shaped; for example, when the proportion of water-wet throats increases from 0.1:0.9 to 0.6:0.4, the water flooding recovery rate increases from 35.63% to 51.35%. Both qualitative and quantitative results suggest that the digital pore network model developed in this study effectively predicts the residual oil distribution under different pore structures and provides a crucial basis for optimizing residual oil recovery strategies.

Fabrication and in vitro biocompatibility of hierarchical cellulose acetate/polyvinylpyrrolidone@titania nanowire hollow microfibers

In this study, hierarchical cellulose acetate/polyvinylpyrrolidone hollow microfibers (CA/PVP HMFs) were first prepared via a dip coating method using a steel wire as tubular template and then supported a sol-gel deposition of titania nanoparticles (NPs) to derive CA/PVP@titania NP HMFs. After hydrothermally treated in NaOH solution, CA/PVP@titania NP HMFs were transformed to CA/PVP@titania nanowire (NW) HMFs. SEM observation showed that CA/PVP@titania NW HMFs had a hollow structure with diameters of 450–600 μm and exhibited a hierarchical and nanofibrous structure. Their surfaces were constructed by numerous titania NWs with diameters of 10–30 nm and lengths of 1–5 μm. The incorporation of PVP not only caused a significant change in surface wettability from hydrophobic CA HMFs to hydrophilic CA/PVP HMFs, but also promoted the sol-gel deposition of titania NPs on CA/PVP HMFs. CA/PVP@titania NW HMFs exhibited the highest hydrophilicity with water contact angle of 32° and the largest specific surface area of 86.1 m2/g. In vitro biocompatible evaluation indicated that CA/PVP@titania NW HMFs exhibited much higher cell adhesion and proliferation than CA/PVP@titania NP HMFs and CA/PVP HMFs within 7 days due to the presence of nanofibrous surface architecture. Thus, the present CA/PVP titania NW HMFs have potential as biocompatible cell supporting matrices.

Antibacterial and Healing Efficacy of Mangiferin-Loaded Silver Nanoparticle and Chitosan-Alginate Membrane Dressings

Mangiferin, a bioactive constituent of Mangifera indica (family Anacardiaceae), has an impressive therapeutic profile, having antioxidant, anti-inflammatory, analgesic, antibacterial, and immunomodulatory properties capable of possessing wound healing potential. Our investigation aims to isolate and characterize mangiferin, green synthesis of silver nanoparticles (Ag-NPs) and production of chitosan alginate (Cs/Alg) film dressing loaded with mangiferin Ag-NPs and assess antibacterial and wound-healing properties against infected excision and burn wounds. The isolated mangiferin was authenticated by estimating melting point, thin layer chromatography (TLC), fourier-transform infrared spectroscopy (FTIR), and high-performance liquid chromatography (HPLC). Ag-NPs were green synthesized and characterized by UV-visible, particle size, zeta potential (ZP), entrapment efficiency (%EE), scanning electron microscope (SEM), transmission electron microscope (TEM), and stability study. Chitosan alginate membrane dressing was prepared by incorporating mangiferin Ag-NPs, and film thickness, pH, film weight, water intake capacity, and in-vitro drug release parameters were estimated. Among the four mangiferin Ag-NP batches, MN3 formed stable polydispersity spherical Ag-NPs with smaller particle size and high %EE. Mangiferin-loaded Cs/Alg film MN-CM4 showed significantly higher (p &lt; 0.001) drug content, wettability, release profile, and favorable pH changes. The mangiferin Ag-NPs embedded Cs/Alg film dressing showed a significantly high antimicrobial effect against the gram-positive bacterial strain of S. aureus, commonly found in wounds. MN3 and MN-CM4 treatment showed the shortest epithelialization period and enhanced wound closure. The hydroxyproline content has significantly (p &lt; 0.001) increased, and myeloperoxidase content was reduced by MN3 and MN-CM4 treatment. MN-CM4 treatment showed complete re-epithelialization reduced inflammatory cells with thicker and denser collagen fiber deposition. The effectiveness of the Cs/Alg film of mangiferin Ag-NPs dressing has a synergistic effect on promoting speedy wound healing. The Cs/Alg film of mangiferin Ag-NPs showed rapid wound healing against infected and burned wounds, enhanced collagen synthesis, and anti-inflammatory and antibacterial efficacy.

Asphaltene deposition effects on reservoir rock wettability and modification strategies

Asphaltene deposition, a widespread challenge in the petroleum industry, detrimentally affects oil production, transport, and processing. Our study investigates asphaltene's impact on sandstone and carbonate reservoir rock wettability using ASTM-D6560 extraction and heptol solutions. A significant part of our focus was to examine wettability change due to asphaltene damage and the use of nanoparticles to improve this situation. Qualitatively, advanced techniques reveal altered rock composition, and contact angle measurements, along with zeta potential assessments, highlight significant wettability changes. Quantitatively, asphaltene-infused solutions induce a quantifiable increase in contact angles. Specifically, with gamma alumina nanoparticle addition, contact angles rise from 68° to 87° for sandstone and 110°–142° for carbonate rocks. Temperature variations within our experimental range also induce notable wettability changes. These findings establish a clear link between asphaltene deposition and quantifiable wettability modifications, providing crucial insights for optimizing oil recovery processes and enhancing well performance in the petroleum industry. The study's results suggest that nano-gamma alumina can be an effective solution for improving wettability and mitigating asphaltene deposition issues in carbonate rocks, offering promising prospects for the oil and gas industry.

Photo-induced time-dependent controllable wettability of dual-responsive multi-functional electrospun MXene/polymer fibers

Switchable wettability potential in smart fibers is of paramount importance in various applications. Light-induced controllable changes in surface wettability have a significant role in this area. Herein, smart waterborne homopolymer, functional copolymer with different polarity and flexibility, and multi-functional terpolymer particles containing a time-dependent dual-responsive acrylated spiropyran, as a polymerizable monomer, were successfully synthesized through eco-friendly single-step emulsifier-free emulsion polymerization. Presence of 10 wt% of butyl acrylate and dimethylaminoethyl methacrylate relative to methylmethacrylate as functional comonomers decreased the Tg of the samples almost 20 ℃ and increased their polarity. The optical properties of the particles were investigated, and the UV–vis and fluorescence spectroscopy results showed that not only polarity and flexibility of the polymer chains may have a positive effect on improving the optical properties, but also the simultaneous presence of functional groups has a synergistic effect. The smart polymer particles with flexibility and polarity features exhibited higher absorption and emission compared to other samples. Inspired by these findings, multi-functional smart polymer fibers were prepared using the electrospinning method. The smart multi-functional electrospun fibers containing few-layer Ti3C2 MXenes were synthesized to improve the fibers’ properties and change the surface wettability due to the hydrophilic functional groups of MXene. Field-emission scanning electron microscopy images displayed the successful preparation of few-layer MXenes. Smooth and bead-free fibers with bright red fluorescence emission under UV irradiation were shown using fluorescence microscopy. The study on the surface wettability of fibers revealed that UV and visible light irradiation induced reversible time-dependent changes in the wettability of the smart multi-functional MXene/polymer electrospun fibers from hydrophobic to hydrophilic, reaching a water contact angle of 10° from an initial water contact angle of 100° under UV light and also changing to superhydrophilic state with passing time. Upon visible light exposure, the fibers returned to their original state. Furthermore, the fibers demonstrated a high stability over five alternating cycles of UV and visible light irradiation. This study shows that the fabrication of time-dependent smart fibers, utilizing the flexibility and polarity in the presence of MXenes, significantly improves and controls surface wettability changes. The outstanding dynamically photo-switchable wettability of these fibers may offer exciting opportunities in various applications, especially in the separation of oil from water contaminants.

Influence of TiO2-MWCNTs nanohybrid material on the corrosion resistance of epoxy low-zinc coatings

Aiming to improve the corrosion resistance of epoxy low-zinc coatings in marine environments, TiO2-MWCNTs nano-hybridized materials were prepared by sol-gel method in this study, and different contents of reinforcing phases were implanted as to improve the anticorrosive properties of epoxy low-zinc coatings. Characterization of the microscopic morphology, physical phase composition and chemical structure of the TiO2-MWCNTs materials demonstrated that the TiO2 hybridization was successful and the loading of TiO2 improved the dispersion of MWCNTs. To investigate the effect of the additive reinforcing phase on the mechanical and corrosion resistance of the coatings by characterizing the coating microscopic morphology, surface wettability, substrate adhesion, and impedance changes at different immersion times. The above results demonstrated that the epoxy composite coating had lower surface energy and 16 % larger surface contact angle compared with the pure epoxy low-zinc coating; the 0.4 wt% TiO2-MWCNTs/epoxy composite coating had the highest adhesion of 6.52 MPa. The electrochemical test results indicated that the TiO2-MWCNTs/epoxy low-zinc composite coating had the largest self-corrosion potential, the smallest self-corrosion current density of 4.538 μA/cm2, and the largest impedance of 242.3 KΩ/cm2. The addition of TiO2-MWCNTs reinforcing phase significantly extended the barrier protection time of the epoxy low zinc coating and maintained good corrosion resistance throughout the immersion cycle.

Structure-rheological relationship of capillary protein oleogels: The role of particle wettability

The design of well-structured food colloids and functional interfaces provides new perspectives for developing healthy and sustainable foods in the future. In this study, we show how particle wettability affects the structural features and rheological properties of capillary oleogels, which are formed using colloidal zein particles with varying wettability from 77.8° to 106.7° as building blocks, creating a space-spanning network in oil via capillary attraction. Confocal microscopy was utilized to image the structural heterogeneities in the oleogels caused by variations in particle wettability, while rheological scaling analysis was used to describe the multiscale structural contributions of protein particles within the network. These changes in particle wettability led to large-scale structural heterogeneity and differences in the mechanical strength of the oleogels. As particle wettability increases, both structural homogeneity and mechanical strength improve, forming adjustable network structures from the capillary state (θ > 90°) to the pendular state (θ < 90°). The fractal dimensions of these oleogels also increases, suggesting that the fractal structural features within both inter- and intra-floc clusters become more densely packed. The results indicate that the structural features and mechanical properties of capillary oleogels can be tailored by modifying the wettability of protein particles to suit specific applications.

Novel Bioplastic Based on PVA Functionalized with Anthocyanins: Synthesis, Biochemical Properties and Food Applications.

Over the last ten years, researchers' efforts have aimed to replace the classic linear economy model with the circular economy model, favoring green chemical and industrial processes. From this point of view, biologically active molecules, coming from plants, flowers and biomass, are gaining considerable value. In this study, firstly we focus on the development of a green protocol to obtain the purification of anthocyanins from the flower of Callistemon citrinus, based on simulation and on response surface optimization methodology. After that, we utilize them to manufacture and add new properties to bioplastics belonging to class 3, based on modified polyvinyl alcohol (PVA) with increasing amounts from 0.10 to 1.00%. The new polymers are analyzed to monitor morphological changes, optical properties, mechanical properties and antioxidant and antimicrobial activities. Fourier transform infrared spectroscopy (FTIR) spectra of the new materials show the characteristic bands of the PVA alone and a modification of the band at around 1138 cm-1 and 1083 cm-1, showing an influence of the anthocyanins' addition on the sequence with crystalline and amorphous structures of the starting materials, as also shown by the results of the mechanical tests. These last showed an increase in thickening (from 29.92 μm to approx. 37 μm) and hydrophobicity with the concomitant increase in the added anthocyanins (change in wettability with water from 14° to 31°), decreasing the poor water/moisture resistance of PVA that decreases its strength and limits its application in food packaging, which makes the new materials ideal candidates for biodegradable packaging to extend the shelf-life of food. The functionalization also determines an increase in the opacity, from 2.46 to 3.42 T%/mm, the acquisition of antioxidant activity against 2,2-diphenyl-1-picrylhdrazyl and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) radicals and, in the ferric reducing power assay, the antimicrobial (bactericidal) activity against different Staphylococcus aureus strains at the maximum tested concentration (1.00% of anthocyanins). On the whole, functionalization with anthocyanins results in the acquisition of new properties, making it suitable for food packaging purposes, as highlighted by a food fresh-keeping test.

A novel formulation of an eco-friendly calcium nitrate-based heavy completion fluid

Calcium-nitrate-based transparent completion fluids are widely used in the oil and gas industry for well completion and stimulation operations in carbonate reservoirs. These fluids have many advantages, such as medium density, low corrosion, good temperature stability, low clay swelling, and high wettability. However, the density of calcium nitrate brine is limited by its solubility, which can be increased by the addition of alcohols. This study investigated the effects of adding different types of alcohols (G1, G2, and G3) to calcium nitrate brine on the properties and performance of the completion fluid for carbonate reservoirs. The fluid properties and performance were evaluated through a series of laboratory tests, including density measurement, corrosion test, viscosity measurement, rheology test, temperature stability test, clay swelling test, wettability test, and compatibility test. The results showed that the addition of alcohols to brine can improve or reduce the fluid density, viscosity, corrosion, temperature stability, clay swelling, wettability, and compatibility, depending on the type and amount of alcohols. The optimum fluids have been selected based on their highest density, lowest viscosity, lowest corrosion, highest temperature stability, lowest clay swelling, highest wettability change, and highest compatibility with formation fluids. The densities of the fluids CN4, CNG14, CNG24, and CNG34 were respectively 96, 101, 101.5, and 100 pounds per cubic foot (pcf). Their rates of corrosion on L80 steel were respectively 0.829, 0.589, 0.720, and 0.599 mils per year (mpy). Their apparent viscosities at 62.4 °F were respectively around 15, 120, 100, and 60 centipoise (cp). Their apparent viscosities at 176 °F were all around 10 to 25 mpy. The fluids remained clear with no evidence of suspended solid particles at 20 °F, indicating their resilience to low-temperature conditions and suitability for use in cold weather operations. The fluid CNG24 becomes cloudy at 285 °F, and the fluid CNG34 becomes cloudy from 212 °F onward, but the CN4 fluid remains clear and transparent at all temperatures. In the tested high temperatures, the effect on their pH was around the same. The fluids CN4, CNG24, and CNG34 had a lower swelling index than 5 ml per 2 g of bentonite clay. The contact angles of oil and carbonate-type thin sections after their wettabilities were affected by the fluids were also 99.5, 36.54, and 46.03°, respectively. Finally, they’re all relatively compatible with formation fluids. The best completion fluid for carbonate reservoirs was CNG24, which contained calcium nitrate and G2 alcohol. This fluid had the best overall performance and safety of the fluids tested.

Investigation of mechanical and wettability properties of commercial pure titanium by surface mechanical attrition treatment

The examination of mechanical and wettability properties of commercial pure titanium (CP-Ti) introduced a novel challenge. The microstructure of samples was analyzed by using OM and SEM micro-images. In this study, the hardness of the surface and cross section of samples was evaluated, and the effect of several surface mechanical attrition treatments (SMATed) on samples was examined. Also, the tensile test was done to compare the effect of SMAT duration on mechanical properties of samples. The contact angle method was then employed to investigate the impact of SAMT duration on the wettability trend. According to results, as the treatment time increases, twins become evident in the deeper layers of the samples. In contrast, the near-surface twins are shorter than those found in the deeper material, signifying the presence of finer grains. Moreover, the elevated hardness in SMATed samples can be attributed to several key factors, including cold work, a rise in defects and twins, and grain refinement. The surface hardness increases across the sample series (up to Ti6) due to the substantial energy input. Nevertheless, it is anticipated that further continuation of the process will result in a constant surface hardness. The increased strength observed in SMATed samples can be attributed to factors such as reduction in grain size and the formation of twins. The wettability results show that the treated surfaces exhibited a significant change in wettability compared to the untreated samples, with a 25% reduction in the contact angle. This is attributed to the surface modifications induced by the treatment process, which introduced more hydrophilic functional groups. The results also show that after 4 h of treatment, the contact angle increases, suggesting that the trend may plateau with additional treatment time.

Superhydrophilic and Underwater Superaerophobic Dual-Function Peony-Shaped Selenide Micro-nano Array Self-Supported Electrodes for High-Efficiency Overall Water Splitting Driven by Renewable Energy.

With the intensification of global environmental pollution and resource scarcity, hydrogen has garnered significant attention as an ideal alternative to fossil fuels due to its high energy density and nonpolluting nature. Consequently, the urgent development of electrocatalytic water-splitting electrodes for hydrogen production is imperative. In this study, a superwetting selenide catalytic electrode with a peony-flower-shaped micronano array (MoS2/Co0.8Fe0.2Se2/NixSey/nickel foam (NF)) was synthesized on NF via a two-step hydrothermal method. The optimal catalytic activity of cobalt-iron selenide was achieved by adjusting the Co/Fe ratio. The intrinsic catalytic activity of the electrodes was enhanced by incorporating transition metal selenides, which then served as a precursor for the subsequent loading of MoS2 nanoflowers on the surface to fully expose the active sites. Furthermore, the superwetting properties of the electrode accelerated electrolyte penetration and electron/mass transfer, while also facilitating bubble detachment from the electrode surface, thereby preventing "bubble shielding effect". This resulted in superior oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) performance, as well as overall water splitting capabilities. In a 1.0 M KOH solution, the electrode required only 166 and 195 mV overpotential to achieve a current density of 10 mA cm-2 for OER and HER, respectively. When functioning as a bifunctional catalytic electrode, only 1.60 V of voltage was necessary to drive the electrolyzer to reach a current density of 10 mA cm-2. Moreover, laboratory simulations of wind and solar energy-driven water splitting validated the feasibility of establishing a sustainable energy-to-hydrogen production chain. This work provides new insights into the preparation of low-overpotential, high-catalytic-activity superhydrophilic and underwater superaerophobic catalytic electrodes by rationally adjusting elemental ratios and exploring changes in electrode surface wettability.