Ethanol-water Mixtures Research Articles

Pressurized Liquid Extraction of Antioxidant and α-Amylase-Inhibitory Compounds from Red Seaweed Using Water–Ethanol Mixtures

Pressurized Liquid Extraction of Antioxidant and α-Amylase-Inhibitory Compounds from Red Seaweed Using Water–Ethanol Mixtures

Brush-Like Polymeric Gels Enabled Photonic Crystals toward Ultrasensitive Cosolvent Chromism.

Responsive photonic crystals (RPCs) exhibit dynamic chromism upon trigger by various solvents, showing potential applications in qualitative identification and quantitative analysis of multicomponent solvents. However, distinguishing similar solvents, especially traces of cosolvents, remains challenging due to the limited sensitivity of RPCs. To address this, we herein introduce brush-like polymeric gels inside photonic crystals, forming a brush-like polymeric photonic gel (BPPG) that can trace tiny component changes. In this BPPG system, the acrylate backbones and polyethylene glycol (PEG) side-chains stretch incrementally due to the cosolvency of ethanol-water mixtures, resulting in highly sensitive chromatic responses within ethanol-rich concentrations. With water content varying slightly from 0 to 1 vol %, the reflection wavelength of BPPG can sharply redshift over 30 nm, leading to very noticeable changes in structural color. This enhanced sensitivity makes BPPG suitable for real-time, in situ purity monitoring of absolute ethanol during storage, transportation, and other applications.

Effect of solvent and temperature on the micellization and thermophysical properties of cetyltrimethylammonium bromide

The Micellization is the fundamental phenomenon in colloid and surface chemistry which plays a pivotal role in a multitude of industrial processes, biological systems, and everyday applications. In this study, we investigate the micellization behavior of the cationic surfactant, cetyltrimethylammonium bromide (CTAB) within aqueous and ethanol–water mixtures across a temperature range. The electrical conductivity measurements unveil insights into the critical micelle concentration (CMC) and the degree of counterion dissociation (β) at each temperature. Notably, as ethanol content increases in the solvent, both CMC and β values exhibit a corresponding uptick. These findings enable the assessment of standard Gibbs free energy (ΔGmic0). Furthermore, our investigation extends to find out the thermophysical properties (viz., density, dynamic viscosity, and kinematic viscosity) assessments across varying ethanol compositions and temperatures. These metrics facilitate the calculation of activation energy for mixed systems. The implications of these results (data) could be useful for both the fundamental as well applied research, and promise valuable insights for future endeavors.

Implementation of multiobjective decision-making algorithms and image analysis in HPTLC-guided extraction optimization of natural products

A new, efficient, and low-cost approach for monitoring extraction optimization was proposed based on high-performance thin-layer chromatography (HPTLC) coupled with digital image analysis. Since HPTLC produces rich chromatographic signals corresponding to various analytes which may be differently affected by extraction conditions, four multicriteria decision-making (MCDM) techniques were compared for their ability to aggregate multiple chromatographic responses: Derringer's desirability approach, Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS), Preference Ranking Organization Method for Enrichment Evaluations (PROMETHEE-2), and the Sum of ranking differences (SRD). Ultrasound-assisted extraction (UAE) of green tea leaves with ethanol-water mixtures was used as a model system. The amount of ethanol and extraction time were varied according to the central composite design. Ranking eleven extracts by Derringer's desirability approach, TOPSIS, and PROMETHEE-2 showed the same results. SRD analysis yielded slightly different results from previous methods. Response surface models based on the previous three MCDM approaches demonstrated that extraction conditions with moderate amounts of ethanol (73%) and extraction times (46 min) lead to optimal chromatographic profiles. Optimization performed on individual peaks tentatively corresponding to rutin, chlorophyll, and gallic acid may lead to different results. Aside from natural products, the proposed approach has the potential to be implemented in various extraction optimizations.

Chemically Pretreated Densification of Juniper Wood for Potential Use in Osteosynthesis Bone Implants.

The aim of the study was to perform treatment of juniper wood to obtain wood material with a density and mechanical properties comparable to bone, thus producing a potential material for use in osteosynthesis bone implants. In the first step, partial delignification of wood sample was obtained by Kraft cooking. The second step was extraction with ethanol, ethanol-water mixture, saline, and water to prevent the release of soluble compounds and increase biocompatibility. In the last step, the thermal densification at 100 °C for 24 h was implemented. The results obtained in the dry state are equivalent to the properties of bone. The swelling of chemically pre-treated densified wood was reduced compared to chemically untreated densified wood. Samples showed no cytotoxicity by in vitro cell assays. The results of the study showed that it is possible to obtain noncytotoxic wood samples with mechanical properties equivalent to bones by partial delignification, extraction, and densification. However, further research is needed to ensure the material's shape stability, water resistance, and reduced swelling.

The Overlooked Role of Humin in Dark Hydroxyl Radical Production during Oxygenation.

Humin, endowed with abundant redox functional groups, can be reduced anaerobically under dark. When reduced humin encounters O2, the possibility of ·OH formation arises. However, the exploration of ·OH generation mediated by humin has not been comprehensively conducted. The study found that O2 oxidized the reduced humin, generating 8.61 μmol/g of ·OH. After isolating humin using the methyl isobutyl ketone (MIBK) method, the lipid component was identified as the primary contributor to ·OH generation. Subsequent polar separation revealed that the lipid fraction extracted from the ethanol-water mixture with a volume ratio of 7:3 (LFEW7:3) played the most significant role in ·OH production. Further characterization confirmed that the simultaneous presence of aromatic C═C and C═O were the predominant features contributing to the ·OH generation. The ·OH generation experiments with humin-pyridine analogue compound demonstrated that polycyclic pyridine N (≥3 rings) played a significant role in promoting the ·OH generation. Most importantly, the study compared the ·OH production by humin and homologous humic acid, indicating that ·OH generated by humin was higher than that of humic acid. Overall, these affirmative findings manifested the overlooked role of humin in ·OH production and offered valuable insights into the mechanism of ·OH generation by humin in the dark.

Physicochemical characterization of Dillenia indica fruits and exploration of extraction methods to obtain reducing compounds and pectin

Dillenia indica Linn. is an unconventional edible plant with numerous health benefits, including anti-diabetic, anti-inflammatory, and anticancer properties. Dillenia indica fruit, known as elephant apple, is rich in nutrients and bioactive compounds and is an excellent source of pectin, a polysaccharide extensively used in the food industry. Despite the potential of this plant, it has been little studied and is still under-explored for commercial purposes. This study aimed to explore methods for extracting total reducing compounds and pectin from Dillenia indica fruit. First, the extraction of reducing compounds was optimized by ultrasound-assisted method within an experimental design considering three variables: solvent-to-feed (S/F) ratio (10:1 – 30:1), ethanol-to-water ratio (0:100 – 100:0) and ultrasound amplitude (24 – 40 %). In the following step, kinetic curves at the optimized conditions were obtained for up to 16 min. The ultrasound-assisted method was then compared to mechanical stirring (100 rpm). In the last step, pectin was extracted, maintaining the same S/F ratio (30:1) and ethanol-to-water ratio (20:80), but using magnetic stirring, pH 2.0, and 80 ºC. Pure water at pH 2.0 was used as a solvent for comparison. In the ultrasound-assisted extraction, the optimal yield was achieved with an S/F ratio of 30:1, an ethanol-to-water ratio of 20:80, and an ultrasound amplitude of 24 %. In the kinetic curves, a higher reducing capacity was obtained at 8 min through mechanical stirring. The pectin extraction was more effective with pure water (12.1 %). However, the ethanol-water mixture promoted a similar amount of pectin (10.3 %) but with a considerably higher total reducing capacity (25.82 mg GAE/g for ethanol-water and 14.5 mg GAE/g for pure water). These results demonstrated that reducing compounds and pectin can be effectively extracted from Dillenia indica fruit, highlighting the potential of this fruit to produce valuable ingredients.

Improving the solar ethanol distillation system by combining the heat pipe and parabolic trough collector

This research examines the advantages of utilizing heat pipe technology with parabolic trough collectors in solar ethanol distillation systems. The goal of this work is to optimize the ethanol yield and concentration generated from the distillation of the ethanol–water mixtures from various types of feedstock. Laboratory experiments were conducted to analyze the effect of charged concentrations (2 % to 10 % v/v) and the properties of feedstock (pineapple, sticky rice, and molasses) on the distillation. The results indicate the feedstock types and charged concentration significantly affected the rate of output and ethanol yield. The amount and concentration of distilled ethanol from molasses (385 ml, 70 % v/v) was higher than that of sticky rice (375 ml, 68 % v/v) but highest from pineapple (395 ml, 72 % v/v). Even though pineapple resulted in the highest overall distillated ethanol, pineapple and sticky rice are costly feedstock, as well as increasing complexity in the ethanol production process, which could result in a reduction of value added investments. Implementing renewable solar energy yield ethanol for reduced operating cost or better benefit overall production to underpin a sustainability aspect of agriculture compared to standard conventional distillation. This research contribution to the solar ethanol distilling process, production of biofuels, and interest in renewable fuel sources.

Advances in gluten detection: A rapid colorimetric approach using core-satellite magnetic particles

Monitoring gluten levels in foods labelled as gluten-free or low-gluten — i.e. containing less than 20 ppm and 100 ppm of gluten, respectively — is crucial for preventing celiac disease-related disorders. Due to their inherent complexity, the standard analytical techniques to assess the gluten content in food are not suitable for on-site measurements, whose need is widely recognized. In this context, we developed a rapid and cost-effective biosensor based on core-satellite magnetic particles (CSMPs) — magnetic cores coated with gold nanoparticles (AuNPs) — further functionalized with anti-gliadin antibodies. The study demonstrates that a 0.016% concentration of the surfactant Tween-20 can induce the spontaneous formation of stable CSMP clusters in dispersion. These clusters, composed of weakly interacting functionalized CSMPs, undergo fragmentation in the presence of gliadin, which specifically binds to the antibodies on the CSMPs. This process results in a colour change, which is measurable by a UV–VIS spectrophotometer. Gliadin extraction was achieved by treating the sample with a non-toxic ethanol-water mixture (60%), sufficient to induce a measurable colour change in the presence of gluten contamination, with a limit of detection (LOD) of 8 ppm, which is lower than low limit established for gluten-free food.

Efficient anti-frosting enabled by femtosecond laser-induced salt-philic and superhydrophobic surface

Frost formation is a normal phase transition phenomenon in cold climates, while it usually brings certain troubles to human lives and production. Therefore, it is of great significance to develop frost resistant materials and key technologies. Here, a salt-philic and superhydrophobic surface is designed on a PDMS substrate by femtosecond laser direct writing technology in combination with salt–ethanol–water mixtures droplet treatment. The laser-treated PDMS embedded salt (LTP-S) surface exhibits superhydrophobicity, which alone is a property that can resist the formation of frost and enables a self-cleaning effect. Meanwhile, the salt coating further enhances the frost resistance of the surface by reducing the freezing point temperature. The LTP-S surface is revealed to perform well in frosting-defrosting cycles, washing resistance, chemical corrosion resistance, heating resistance, and long-term air exposure tests as a highly efficient and stable anti-frosting surface. This work demonstrates a facile strategy to fabricate a salt-philic and superhydrophobic surface for efficient anti-frosting.

Nanoscale Surface Tension, Adsorption Isotherms and Separation of Water–Ethanol Mixtures Confined between Graphene-Based Slit Pores

Nanoscale Surface Tension, Adsorption Isotherms and Separation of Water–Ethanol Mixtures Confined between Graphene-Based Slit Pores

Effect of Water on Wear of DLC Coatings in High Temperature and Pressurized Ethanol

The friction and wear characteristics of a-C:H:Si and a-C:H coatings in an ethanol environment at 120 °C and 10 MPa focusing on the effects of water and dissolved oxygen in ethanol were investigated. The friction tests were conducted using an autoclave chamber, with gases (oxygen or nitrogen) and ethanol–water mixtures (0 and 6 vol.%). The wear acceleration of a-C:H:Si took place when it slid in ethanol with 6 vol.% water and pressurized by oxygen, thus the specific wear rate was the highest, approximately 1.8 × 10−7 mm3/Nm. The reason of this wear acceleration was assumed the effect of hardness reduction due to oxidation of the a-C:H:Si, so the O/C ratio by AES and the hardness of topmost surface by AFM nano-scratch were investigated. As a result, the higher O/C ratio showed higher specific wear rate due to the hardness reduction from 13.3 to 6.0 GPa. These findings highlight the role of water and dissolved oxygen in accelerating wear of a-C:H:Si coatings.Graphical abstract

Evaluation of a prototype variable frequency mode soil moisture and EC probe for its final development

AbstractA prototype dielectric probe developed by the Daiki Rika Kogyo Co., Ltd, Japan, was evaluated by controlled laboratory experiments. The probe simultaneously measures the real and imaginary parts of the dielectric permittivity, which are comparable to the measurements obtained with a vector network analyser (VNA) at frequencies ranging from 10 to 160 MHz. The probe accurately (±2% error) measures the real parts of the dielectric permittivity of oil–ethanol and ethanol–water mixtures over a wide range of real permittivities (3.26 ~ 79) at frequencies ranging from 70 to 90 MHz. The imaginary parts of the dielectric permittivity of aqueous solutions are related to the electrical conductivity (EC) through a unique rational model (±2.5% error) over 80–90 MHz. Dielectric measurements by probes at the desired frequencies can eliminate/reduce the limitations of fixed‐frequency measurements, such as the effects of EC, clay composition, porosity, and organic matter, of currently available probes.

Estimation of the Structure of Hydrophobic Surfaces Using the Cassie-Baxter Equation.

The effect of extreme water repellency, called the lotus effect, is caused by the formation of a Cassie-Baxter state in which only a small portion of the wetting liquid droplet is in contact with the surface. The rest of the bottom of the droplet is in contact with air pockets. Instrumental methods are often used to determine the textural features that cause this effect-scanning electron and atomic force microscopies, profilometry, etc. However, this result provides only an accurate texture model, not the actual information about the part of the surface that is wetted by the liquid. Here, we show a practical method for estimating the surface fraction of texture that has contact with liquid in a Cassie-Baxter wetting state. The method is performed using a set of ethanol-water mixtures to determine the contact angle of the textured and chemically equivalent flat surfaces of AlSI 304 steel, 7500 aluminum, and siloxane elastomer. We showed that the system of Cassie-Baxter equations can be solved graphically by the wetting diagrams introduced in this paper, returning a value for the texture surface fraction in contact with a liquid. We anticipate that the demonstrated method will be useful for a direct evaluation of the ability of textures to repel liquids, particularly superhydrophobic and superoleophobic materials, slippery liquid-infused porous surfaces, etc.

In Vitro Antioxidant, Anti-Inflammatory Activity and Bioaccessibility of Ethanolic Extracts from Mexican Moringa oleifera Leaf.

This study aimed to assess the antioxidant and anti-inflammatory properties, and bioaccessibility of Moringa oleifera ethanolic extracts using pressurized liquid extraction with varying ethanol concentrations (0%, 30%, 50%, 70%, and 100%) in water-ethanol mixtures. Quercetin derivatives and neochlorogenic acid were identified as major compounds via high-performance liquid chromatography with diode array detection. The 70% ethanol extract displayed the highest antioxidant activity and phenolic content, highlighting a strong correlation between phenolics and antioxidant potential. Extracts prepared with 50% and 70% ethanol (30 μg/mL) significantly inhibited TNF-α, IL-1β, and IL-6 cytokine secretion, with the 70% ethanol extract demonstrating robust anti-inflammatory effects. During in vitro digestion (oral, gastric, and intestinal phases), minimal changes were noted in most phenolic compounds' post-oral phase, but reductions occurred after the gastric phase. Substantial decreases in major compounds and antioxidant activity were observed in post-gastric and intestinal phases. Overall, ethanolic extracts of Moringa oleifera, particularly those with 70% ethanol, exhibit promising antioxidant and anti-inflammatory properties, suggesting potential for developing therapeutic agents against oxidative stress and inflammation-related disorders. However, it is essential to protect these compounds to prevent their degradation during digestion.

An efficient green synthesis and in vitro evaluation of novel adamantane-containing 4-thiazolidinone derivatives as anticancer agents

The novel 4-thiazolidinone derivatives incorporating an adamantane moiety were synthesized in high yields through the reaction of N-adamantyl-substituted thioureas and dimethyl acetylenedicarboxylate (DMAD) using an environmentally benign method. These catalyst-free reactions were performed in an ethanol-water mixture at room temperature, with short reaction times of 3–8 minutes. The in vitro anticancer activity of the target compounds was evaluated against the A-549 human non-small cell lung cancer (NSCLC) cell line. Among the target compounds, 2b, 2c, and 2a exhibited promising cytotoxic effects, with IC50 values of 19.07, 32.92, and 63.38 µM, respectively. Additionally, the mechanisms for inhibition of cell growth and induction of apoptotic cell death were assessed using DAPI and Annexin V-FITC staining. The results indicated that the 4-thiazolidinone derivatives incorporating an adamantane moiety have significant potential for the development of anticancer therapeutics.

Towards a sustainable recovery of polyphenols from agrifood waste: Performance of polymeric sorbents with natural deep eutectic solvent extracts

Olive oil production generates large amounts of waste, which contains phenolic compounds at relevant concentrations. In recent years, interest in the recovery of these compounds has grown to take advantage of their natural antioxidant properties. Natural deep eutectic solvents (NaDESs), considered as green solvents, have proved their efficiency to extract phenolic compounds from agri-food waste. The resulting extracts must be purified before being used in pharmaceutical, food, or cosmetic applications. In this study, the performance of several non-functionalized polymeric sorbents (PuroSorb PAD900, PAD950 and PAD610, and Macronet MN202) was evaluated for the purification of NaDES extracts (choline chloride-glycerol (1:5); 30% water) from olive tree leaves. It is important to highlight that these types of characterization studies are common for conventional solvent extracts but are very novel and scarce for their NaDES counterparts. Sorption was investigated at the natural conditions of the extracts (pH 5.3), and ethanol-water mixtures were used in the desorption experiments. Overall, the four sorbents displayed good sorption characteristics, with MN202 being particularly suited to retain 3-hydroxytyrosol. Ethanol levels above 70% were appropriate for desorption of most phenolic compounds, while mixtures with ethanol content below 50% were more efficient for small polar molecules such as 3-hydroxytyrosol.

Enhancing phase and morphology control of vanadium oxide films for resistive memory applications: A water-assisted chemical approach

This study explores the influence of precursor solution composition and solvent selection on the synthesis of vanadium oxide (VO2) thin films tailored for resistive memory applications. The vanadium pentoxide and oxalic acid molar ratio and the dispersing medium (ethanol, water, and their mixture) were varied. Water content significantly influenced the VO2 phase, morphology, and film thickness. Ethanol yielded mixed vanadium oxide phases VO2 − Tetragonal, V2O5 − Orthorhombic, and Monoclinic) and a film with minor imperfections. Conversely, the active layer prepared using an aqueous medium showed a predominant VO2 − Monoclinic phase, albeit with a non-uniform film. An ethanol–water mixture produced the most uniform morphology and a mixture of vanadium oxide phases (VO2 − Tetragonal, V2O5- Orthorhombic). All devices displayed resistive switching behavior. VO2-containing devices exhibited a more pronounced transition from an ohmic conduction state to a space-charge-limited conduction mechanism. ON-state currents remained consistent, while OFF-state currents varied notably.

Fabrication of dye-sensitised solar cell using dry Ixora extract as sensitiser

ABSTRACT A dye-sensitised solar cell was fabricated using dry Ixora flower extract. The sensitiser was obtained by physical extraction using a mixture of ethanol and distilled water as solvent in the ratio of 7:3. The optical study of the sample was done within wavelength range of 230 nm to 1100 nm using spectrophotometer (UV- 750 series). The outcome shows an optimum absorption in the visible region of the EM spectrum, which shifted to the UV region when adsorbed onto a nano-porous TiO2 surface. An alternative peak of 0.95a.u in the visible region was observed with enhanced optical absorption across the infrared region of the spectrum. The absorption coefficient values suggest the extract absorbs light in the visible region, which was also confirmed with the relatively high extinction coefficient observed in the visible region of the EM spectrum. The extract exhibits a low transmittance in the visible range, which increases to over 99% in the red wavelengths. The extract has low reflectance of about 20% in the visible range, which falls lower as wavelength increases into the infrared region. The energy band gap (for direct transition) of 2.13 eV was obtained for dry Ixora dye extract. The fabricated solar cell performed a fill factor of 0.27, Jsc of 0.1273 mA/cm2, Voc of 0.7001 V, and conversion efficiency of about 0.02%. with these results, the dye extract of dry ixora flower can serve as a good photo-sensitiser for the fabrication of dye-sensitised solar cell.

Unraveling the Surface Activity of Ethanol-Water Mixtures through Experiments and Molecular Dynamics Simulations.

Ethanol's complete miscibility in water makes it a widely used solvent in various applications, such as organic compound synthesis, paint manufacture, chromatography, and cosmetics preservation. Studies suggest that ethanol's concentration at interfaces can be higher than in the bulk due to its amphiphilic nature, especially at lower concentrations, making it a surface-active agent. Accordingly, ethanol plays a crucial role in controlling the emulsion stability, foam formation, heat transfer, and coating adhesion. However, the precise concentration ranges up to which ethanol's surface activity dominates its interfacial properties, and the underlying molecular mechanism is not fully understood in the literature. In this context, our foamability experiments, coupled with film stability experiments conducted via ethanol drop impact on varying concentration ethanol-water mixture pools, indicate that the surface-active nature of ethanol is observed up to a maximum of 10% molar ethanol concentration in water. We next employ all-atom molecular dynamics simulations to reveal that the surface tension and other interfacial properties are most significantly affected only up to the molar concentration in the range of 0-10% of ethanol in water. This observation is further supported by free energy analyses, indicating that the stabilization free energy of an ethanol molecule at the interface becomes comparable to that in the bulk region beyond this concentration range. The transition from surface-active to a behavior resembling a homogeneous solution occurs when the molar concentration of ethanol in water exceeds 10%. This transition is attributed to distinctive alterations in the number and strength of ethanol-water hydrogen bonds. These findings provide valuable insights into the interfacial molecular structure, which can be suitably exploited to modulate interfacial properties and dynamic behavior in a wide array of industrial and scientific applications.