Ethanol-water Solution Research Articles

Extraction of phenolic compounds from apple pomace, process modeling and antioxidant potential evaluation of extracts

Abstract Apple pomace, a byproduct of juice and cider production, is rich in phenolic compounds with antioxidant activity. This work studies the kinetics of solid–liquid extraction of phenolic compounds from apple pomace. Extraction kinetics were determined using a 50% water–ethanol solution and fitted to a phenomenological model. Equilibrium isotherms were also modeled. Effective diffusion coefficient values between 1.85x10−11 and 7.37x10−11 m2/s were found. External mass transfer resistance showed negligible results. The best yields (43.94%) were obtained at 60 °C with a solid–liquid ratio of 1:10 g/mL. Those conditions resulted in a total phenolic content of 9.95 mg gallic acid equivalents (GAE)/g apple pomace d.b., antioxidant FRAP activity of 5.07 mmol ascorbic acid equivalents (AAE)/100 g apple pomace d.b. and 3.74 mmol trolox equivalents (TRE)/100 g apple pomace d.b. based on a DPPH assay. Apple pomace extract efficiently stabilized sunflower oil and may represent a natural alternative to synthetic antioxidants.

Study of Water and Water–Ethanol Solutions of Potassium Salts Through Ultrasonic and Spectroscopic Approach

Study of Water and Water–Ethanol Solutions of Potassium Salts Through Ultrasonic and Spectroscopic Approach

Hollow Silica Microparticles Based on Amphiphilic Polyphosphazenes.

Hollow microparticles are important materials, offering a larger surface area and lower density than their solid counterparts. Furthermore, their inner void space can be exploited for the encapsulation and release of guest species in a variety of applications. Herein, we present phosphazene-based silica hollow microparticles prepared via a surfactant-free sol-gel process through self-assembly of the alkoxysilyl-containing polymer in water–ethanol solution. Solely, a silane-derived polyphosphazene was used as the precursor for the microparticle formation, without additional classical silica sources. These novel hollow silica-based microparticles were prepared without surfactant, using a designed amphiphilic polyphosphazene for the particle formation made by two components, a hydrophilic unit consisting of 3-mercaptopropyl(trimethoxysilane), and a hydrophobic unit (dodecanethiol) attached to the double bonds from the poly(allylamine)phosphazene backbone via a thiol-ene photoreaction. Due to these two functionalities, a “vesicle”-like self-assembled structure was formed in the reaction medium, which could be then utilized for the microparticle preparation. The influence of NaOH during the synthesis was shown to affect the size and the wall thickness of the microparticles. This effect may enhance the possibilities to tailor such microparticles for drug delivery purposes or for future controlled release of other substances, such as drugs, fragrances, or anticorrosive pigments.

Ionization Equilibrium of Water Molecule Dominated Ethanol-water Binary Solution Self-assemble

Water and ethanol are conventional solvents, the anomalous physio-chemical properties of water ethanol binary solution have drawn intensive research. The unidirectional impedance evolution of ethanol-water binary solution in time domain was discovered through electrochemical impedance spectroscopy. Binary solution with different volume ratios has various self-assembly rates indicate ionization equilibrium of water molecule dominate the dynamic self-assembly process of water ethanol binary solution. Combined with molecular dynamics simulation and Raman Spectroscopy, we elucidated that this self-assembly behavior was driven by hydrogen bonding between water as proton donor and ethanol as proton receptor under water ionization, the bond length (162 pm). Different electrolytes addition in binary solution were applied to shift ionization equilibrium of water directionally, and subsequent specified self-assembly evolution was observed to prove the above hypothesis. We proposed the self-assembly mechanism of ethanol-water binary solution is relevant to ionization equilibrium of water for the first time, such perspective may provide some insight to understand the dynamic structural organization of ethanol-water and other binary solutions.

Construction of 0D/2D Schottky Heterojunctions of ZnO and Ti3C2 Nanosheets with the Enriched Transfer of Interfacial Charges for Photocatalytic Hydrogen Evolution.

The development of cost-effective co-catalysts of high photocatalytic activity and recyclability is still a challenge in the energy transformation domain. In this study, 0D/2D Schottky heterojunctions, consisting of 0D ZnO and 2D Ti3C2, were successfully synthesized by the electrostatic self-assembling of ZnO nanoparticles on Ti3C2 nanosheets. In constructing these heterojunctions, Ti3C2 nanosheets acted as a co-catalyst for enhancing the transfer of excitons and their separation to support the photocatalytic response of ZnO. The as-prepared ZnO/Ti3C2 composites demonstrate an abbreviated charge transit channel, a huge interfacial contact area and the interfacial electrons’ transport potential. The extended optical response and large reactive area of the ZnO/Ti3C2 composite promoted the formation of excitons and reactive sites on the photocatalyst’s surface. The ZnO/Ti3C2 Schottky heterojunction showed significantly high photocatalytic activity for hydrogen production from a water–ethanol solution under the light illumination in the visible region. The hydrogen evolution overoptimized the ZnO/Ti3C2 composition with 30 wt.% of Ti3C2, which was eight times higher than the pristine ZnO. These findings can be helpful in developing 0D/2D heterojunction systems for photocatalytic applications by utilizing Ti3C2 as a low-cost co-catalyst.

Recovery of phenolic compounds from olive oil washing wastewater by adsorption/desorption process

Agroindustry wastewater represents an opportunity to recover high added value antioxidants such as phenolic compounds. An adsorption/desorption process was investigated to recuperate these compounds using Purolite non-ionic resins (MN200, MN202, PAD900 and PAD950). The study was conducted with a model solution containing 1.1 g∙L-1 of tyrosol and 0.2 g∙L-1 of catechin, which are two of the main phenolic compounds found in olive mill wastewaters, and with a real olive mill wastewater. The main objective was to determine the optimal concentration of resin and the best desorption solvent for the maximum recovery of phenolic compounds. For it, the process kinetics were determined, and the adsorption mechanisms were characterized by means of isotherm models. Results showed that the pseudo-second order kinetic model fitted to the experimental data, while the Langmuir isotherm correctly modelled the adsorption process for the MN resins, whereas the Freundlich isotherm was the model that best described the adsorption process with PAD resins. A resin concentration of 40 g·L-1 and a 50% v/v ethanol–water solution were selected as the best options for recovering the phenolic compounds. The tests with olive oil washing wastewater showed that, for some of the resins, other compounds present, such as sugars, interfered with the adsorption of phenolic compounds, reducing the effectiveness of their recovery. Finally, the MN200 resin was selected as the best adsorbent. It achieved a recovery of 91% of the phenolic compounds present in the initial wastewater, finding only 5% of the sugars measured in the initial OOWW sample, in the final stream.

Reusing ethanol-water and recovering residual gum in hemp degumming

Traditional hemp degumming creates large volumes of effluent. Chemical treatment and discharge of the degumming solution is still a challenging task. In this work, ethanol-water solution was reused for hemp degumming and gum recovery was explored to reduce effluent volume and improve resource recovery. The influences of recycling times on fiber color, morphology, mechanical properties, thermal properties and dimensional properties were investigated. Also, the characterizations of the extracted lignin were conducted. The results indicated that pectin could be removed in every degumming cycle. Above 86% of cellulose could be achieved in the five degumming cycles and fiber tenacity increased with each consecutive cycle from 35.6 to 43.6 cN/tex. Most importantly, spherical lignin particles could be extracted from the solution of the last degumming cycle with an average diameter of 249.7 nm. This work contributes to green degumming of bast fibers, reducing degumming cost and value-adding of the lignin-rich residues.

Relative viscosity evaluation of low-volume samples using capillary flow under differential pressure

In this study, we newly considered the analysis of capillary flow under differential pressure, which extends the previous study and allows the independent measurement of relative viscosity and the product of relative surface tension and contact angle for low-volume samples. The theory of this method is explained, and it is demonstrated that relative viscosity and surface tension with contact angle can be obtained independently by measuring the capillary flow under differential pressure. We conducted capillary flow experiments with a small sample volume (less than 100 μl) using a measurement system comprising a flow measurement unit, capillary chip, and differential pressure mechanism. The relative viscosities of pure water and dilute ethanol solutions obtained in the experiment were in one-to-one correspondence with the values in the Chemical Handbook. This also shows that relative surface tension can be determined using these measurement results and the separately measured contact angle values.

Application of the e-NRTL model to electrolytes in mixed solvents methanol-, ethanol- water, and PEG-water

In this work, the e-NRTL binary interaction parameters for the alcohol-water (ethanol-water and methanol-water), electrolyte-alcohol (NaBr-methanol, NaBr-ethanol, NaCl-methanol, NaCl-ethanol, KCl-methanol and KCl-ethanol), PEG (polyethylene glycol)-water (PEG1000-, PEG4000- and PEG6000-water) and electrolyte-PEG (NaCl and KCl-PEG4000-water, KCl-PEG1000-water, LiCl-PEG4000-Water, CsCl-PEG (PEG1000, PEG4000 and PEG 6000)-Water) were evaluated by the non-linear regression of experimental data at different temperatures, reported in the literature. The application used was able to evaluate the impact of the NRTL, Debye-Hückel and Born contributions on the activity coefficients of a salt (or an electrolyte) in different media. In addition, the solubility constants, and the free energy of transfer on the molar scale of NaCl, KCl and NaBr in alcohol-water mixed solvents (methanol-water and ethanol-water at different temperatures) were evaluated by using the e-NRTL model and the binary interaction parameters previously computed. It was reached an excellent correlation of the experimental data of water activity, mean activity coefficient and osmotic pressure data of ethanol-water and methanol-water solutions, electrolyte-alcohol systems, and electrolyte-PEG, respectively. The presence of PEG and alcohol in solution had a great influence on the solubility of the solid phases.

Test tube dedicated microwave liquid dielectric sensor for non-contact properties change monitoring and material characterization with tube exchange capability

The paper presents a novel measurement technique for non-contact properties change monitoring and material characterization which is suitable for in-progress monitoring of processes, especially ones using corrosive reagents or reactive materials. The method relies on sensing of dielectric properties of liquids contained inside a test tube at microwave frequencies by a quasi-parallel-plate transmission line type sensor. The theoretical study is validated with experimental data in terms of extracting complex effective permittivity and response reproducibility on an example of various alcohols. This is followed by measurements of ethanol-water and water-sodium persulfate solutions. The determined concentration-normalized differential reflection coefficient transfer curves for a discrete set of frequencies up to 2 GHz indicated sensitivity up to 14 dB/ml and −172 °/ml with a resolution in the range of 6–7 µl for the former solution and up to −17 dB/g and −31 °/g. The obtained results prove the usability of the developed method.

Ethanol Dehydration in Fixed Bed Column Using Pellet Adsorbent From Natural Zeolite Lampung

This research is motivated by the reduced reserves of fossil fuels in Indonesia, so that fossil fuel substitutes are needed, one of which is ethanol. It's just that to make ethanol as a fuel substitute for fossil fuels, a 99% concentration is required, while the ethanol on the market only has a concentration of 96%. One of the processes that can be used to purify ethanol is the adsorption process. In this study, activation of Natural Zeolite Lampung (ZAL) was carried out to increase its adsorption ability to water contained in an ethanol-water solution. This zeolite modification process begins with ZAL pre-treatment, formation of ZAL in the form of pellets, then ZAL activation by calcination, the results of this modification are characterized through the FTIR, XRD, XRF, SEM, and BET mechanisms. ZAL has been successfully formed into pellets, this can be seen when ZAL is immersed and the ethanol-water solution is flowed, it does not change shape. The highest R2 value was obtained in the Adam Bohart equation model at a flow rate of 10 ml/minute with an R2 value of 0.9742 with the highest concentration achieved at a concentration of 98.797%.

Purification of menthone and menthol from Mentha haplocalyx by suspension particle assisted solvent sublation, neuroprotective effect in vitro and molecular docking of menthol on amyloid-β

Suspension particle assisted solvent sublation was designed for the first time. The volatile monoterpenes in Mentha haplocalyx Briq were extracted using this method from a solution containing plant solid particles as the lower phase of solvent sublation. Under the optimum conditions of the solvent sublation (n-hexane/plant solid particles 20% ethanol–water solution system, pH 4, flotation time 30 min and air flow rate 30 mL/min), the extraction yields were 2.0 × 102 mg/kg, 9.5 × 101 mg/kg and 1.2 × 103 mg/kg for menthone, isomenthone and menthol, respectively. Compared with the traditional methods, the established suspension particle assisted solvent sublation might be an economical and efficient extraction method in some aspects. Through a cellular antioxidant activity experiment, menthol could alleviate H2O2-induced oxidative stress. Molecular docking was applied to simulate the molecular recognition process between amyloid-β and menthol. The affinity energy of menthol was −12.59 kJ/mol, indicating that menthol might have neuroprotective activity and the potential to be an amyloid-β inhibitor.

Unique structure and new thermophysical properties of poly(ethylene oxide) in nanocomposites based on nanoporous polypropylene matrices

AbstractPolypropylene (PP)−poly(ethylene oxide) (PEO) nanocomposites were prepared by tensile drawing of PP films in water–ethanol solutions containing PEO with molecular masses of 4, 20, and 200 kDa via environmental crazing (EC). EC of PP films is accompanied by the development of nanoporous structure, which is loaded with the PEO component. The content of PEO in the PP − PEO nanocomposites can achieve 40%. Crystallization of PEO within the nanoporous PP matrix proceeds under the conditions of the confined space: as a result, the degree of crystallinity and melting temperature of PEO are markedly reduced. This effect appears to be more pronounced as the molecular mass of PEO increases. The direction of orientation of the PEO crystalline lamellae also depends on the molecular mass of PEO. The prepared PP‐PEO composites with new thermophysical properties of PEO can be used as gas‐separation membranes as well as in microelectronics and electrochemical devices.

Swelling Behavior of Bentonite- Sand Mixtures in the Presence of Organic Pore fluids

ABSTRACT In this study, the swelling behavior of bentonite sand mixtures has been investigated using different percentage of ethanol-water and methanol-water solutions in a conventional one-dimensional consolidometer. Both swelling pressure and percent swell are significantly influenced by the different percentages of ethanol-water and methanol-solutions and the respective dielectric constants of the solutions. The swelling pressure and swell percentage seem to decrease with the increase of ethanol and methanol percentage. Good relation was obtained between the swell percentage and swell pressure of the bentonite sand mixtures with different proportions of ethanol-water and methanol-water solutions, as well as with the dielectric constants of the mixture solutions. Correlations were developed to predict the swelling pressure. The study focuses on the significant influence of the different percentages of ethanol-water and methanol-water solutions on the swelling pressure and the swelling percentage.

Keto-enol tautomerism of curcumin in the preparation of nanobiocomposites with fumed silica

The tautomerism of curcumin (Cur) in water–ethanol solutions in the presence of fumed silica was studied by UV–visible spectroscopy. The results showed that the enol tautomer exists at an ethanol concentration in solution >50%, and with an increase in the water content, the tautomeric equilibrium shifts towards the formation of the keto tautomer. Quantum-chemical calculations (solvation model SM 5.42/6-31G (d), GAMESSPLUS) of various curcumin isomers confirmed that the existence of curcumin keto tautomer in aqueous solution is more thermodynamically favorable. The ratio of keto and enol forms also depends on the dielectric constant of water–ethanol solutions: at ε < 45, only the enol form of curcumin exists, while at ε > 45, the relative amount of the keto tautomer increases in proportion to the dielectric constant. Curcumin tautomers adsorb on fumed silica in different ways. At a low curcumin concentration in the initial solutions (<1.5 × 10−4 M), only the enol tautomer forms a monolayer on the sorbent surface, apparently due to its planar structure. The keto tautomer, characterized by a bent structure, begins to adsorb only at a concentration of Cur > 1.5 × 10−4 M, being a component of molecular aggregates with coplanar geometry.

Electrochemical template synthesis of Ni–Cu bilayer hollow microtubes for green hydrogen production through electrocatalytic reforming of ethanol

This article is devoted to the investigation of the processes occurring at the synthesis of Ni–Cu hollow tubes (NC-HT) and their application as an electrocatalyst in the hydrogen evolution reaction from water-ethanol solution. The reactions at the electrochemical reduction of CuO to Cu and during the electrodeposition of nickel were investigated by chronopotentiometry. Depending on the thickness of the nickel layer, morphology (SEM) and chemical composition (EDX-mapping, XRD) of tubes, as well as electrocatalytic activity (CVA, ECSA, TOF, and stability tests) were studied. The synthesized materials have a structure with a high electrochemically active surface area (ECSA) from 1.38 to 3.50 m2g-1, which makes it possible to fulfill low activation overpotential values equal to −86 and −250 mV at 10 and 50 mAcm−2 after 100 cycles. The stability test results demonstrate the overpotential values −160, −183, −265 mV for NC-HT15, NC-HT30, and NC-HT60, respectively, after 24 h examinations.

Identification of 2-furanmethanethiol contributing to roast aroma in honkaku shochu and awamori

Honkaku shochu and awamori are traditional Japanese spirits. 2-Furanmethanethiol (2FM), a volatile thiol, was identified as a roast aroma compound in honkaku shochu and awamori. The detection threshold of 2FM in 25% (v/v) ethanol water solutions was determined as 1.6ng/L. The odor activity values, calculated using the detection threshold suggested that 2FM affects the quality of honkaku shochu and awamori. The odor activity values of 2FM were higher in barley shochu distilled at atmospheric pressure than in sweet potato shochu, rice shochu and awamori; therefore, 2FM is considered to contribute to the characteristics of barley shochu.

Fabrication, characterization, and performance of antimicrobial alginate-based films containing thymol-loaded lipid nanoparticles: Comparison of nanoemulsions and nanostructured lipid carriers

Antimicrobial biopolymer films were prepared by incorporating thymol-loaded nanostructured lipid carriers (NLC) or nanoemulsions (NE) into Ca-alginate solutions. Thymol-loaded-NLCs with thymol/lipid mass ratios of 0.1 and 0.2 were prepared and then used to fabricate NLC/alginate films containing either 20% (NLC20 film) or 10% (NLC10 film) of NLCs. Consequently, these two films had the same total thymol mass fraction: R thymol/alginate = 0.02. A nanoemulsion-loaded film (NE film) containing the same amount of thymol and a neat alginate film (control) were also prepared. Incorporation of the NLCs increased the porosity and surface roughness, thickness, water vapor permeability, and yellowness of the films, but decreased their water contact angle, mechanical strength, and swelling ratio. The release of thymol into the air and into water-ethanol solutions was slower for NLC-loaded than NE-loaded films, moreover being slower for the NLC20 than NLC10 films. The antimicrobial activity of the active films was tested on ground beef samples. Their antimicrobial activity was correlated to their release rates, with the NLC20 film giving the longest protection against the enumerated microorganisms. Our results show that encapsulating antimicrobial essential oils within NLCs was more effective at creating antimicrobial films with sustained release properties than encapsulating them within NEs.

Evaluating two nanosilica dimensional range for the consolidation of degraded silicate stones

The application of silica nanoparticles strengthening agents in conservation of monumental and architectural heritage field is currently a challenge of particular interest. Some commercial products are already on the market and several studies highlighted the related strength and weakness. In order to contribute to the knowledge of the interaction between nanoparticles and stone materials as well as to provide key elements to improve the approach to conservative treatments, two silica nanoparticles products for the consolidation of silicate stones were developed in the laboratory. Bianco Sardo granite, Firenzuola and Muggia sandstones were selected as substrates for the experimentation after a laboratory investigation of their open porosity. Silica nanoparticles having two different particles size, both compatible with the porosimetric features of the selected stones, were synthesized and dispersed in an ethanol–water solution. The carrier was specifically studied for avoiding the agglomeration of silica nanoparticles and facilitating the penetration of the products in the stone substrates. Sound and artificially aged specimens were impregnated by capillary absorption method and the effectiveness of the treatment was evaluated through morphological and physical analyses. Microscopic observations, colorimetric analyses, sponge tests, ultrasound velocity determinations and porosimetric measurements showed positive results, which encourage, on one hand, the use of silica nanoparticles for consolidating silicate stones, on the other hand, further researches aimed to improve the synthesized products by reaching a deeper penetration and the reduction of water absorption.

Algae: Study of Edible and Biologically Active Fractions, Their Properties and Applications

The beneficial properties of algae make them perfect functional ingredients for food products. Algae have a high energy value and are a source of biologically active substances, proteins, fats, carbohydrates, vitamins, and macro- and microelements. They are also rich in polyunsaturated fatty acids, proteins, mycosporine-like amino acids, polysaccharides, polyphenols, carotenoids, sterols, steroids, lectins, halogenated compounds, polyketides, alkaloids, and carrageenans. Different extraction parameters are used depending on the purpose and the substances to be isolated. In this study, the following parameters were used: hydromodule 1:10 and an extraction duration of 1–2 h at the extraction temperature of 25–40 °C. A 30–50% solution of ethanol in water was used as an extractant. Algae extracts can be considered as potential natural sources of biologically active compounds with antimicrobial activity and antiviral properties. The content of crude protein, crude fat, and carbohydrates in U. Prolifera, C. racemosa var. peltata (Chlorophyta), S. oligocystum and S. fusiforme (SF-1) was studied. It was found that C. muelleri (Bacillariophyta), I. galbana (Haptophyta), and T. weissflogii (Bacillariophyta) contain about 1.9 times more omega-3 than omega-6 fatty acids. N. gaditana (Ochrophyta), D. salina (Chlorophyta), P. tricornutum (Bacillaryophyta) and I. galbana (Haptophyta) extracts showed inhibitory activity of varying intensities against E. coli or P. aeruginosa. In addition, algae and algae-derived compounds have been proposed to offer attractive possibilities in the food industry, especially in the meat sector, to evolve functional foods with myriad functionalities. Algae can increase the biological activity of food products, while the further study of the structure of compounds found in algae can broaden their future application possibilities.