Molar Ratio Of Water Research Articles

Rational synthesis of methylsilsesquioxane aerogels addressing thermal load and compression recovery issues in Li-ion batteries

Li-ion batteries suffer from two key safety issues: thermal overload and compression recovery, which may lead to flammability and mechanical failure. Silica aerogels are promising solutions to both these issues owing to their excellent thermal stability and tailored mechanical properties. However, finding the optimum sol composition in sol-gel-based aerogel synthesis is needed to address these issues at industry-relevant scales. Here, we propose an innovative approach to determine the optimum sol composition for methylsilsesquioxane (MSQ) aerogel sheets, which is based on the mechanisms of the effects of molar ratios of hydrolysis water and isopropyl alcohol (IPA) to methyltrimethoxysilane (MTMS) on the physical properties of MSQ aerogel sheets and according to the ternary contour distribution of their properties. The synthesized MSQ aerogels exhibited a soft, light, and powderless texture and featured superhydrophobic properties (150.2°), low thermal conductivity of 33.6 mW/(m·K), high thermal stability temperature in nitrogen atmosphere at 479.3 °C and moderate short-term (<6 h) service temperature of 120.0 °C. Significantly, the structural stability and elasticity of the aerogels surpassed the current state-of-the-art, showing recovery to 81.3 % of the original thickness and 85.2 % of the original stress after being subjected to 400 cycles of high-speed and high-strain consecutive compression, respectively. These excellent properties make the MSQ aerogel sheets promising for applications in thermal load and compression recovery management of diverse energy storage devices, including batteries for next-generation electric vehicles

Polyol synthesis of cobalt doped zinc oxide green nano-pigments: Colorimetry assessments and chemical synthesis parameters optimization

Cobalt-doped zinc oxide nanoparticles were synthesized as inorganic nano-pigments by the Polyol chemical preparation method, which is a simple and cost-effective method. Results showed that ethylene glycol (EG) should be utilized for synthesis of nanoparticles with smaller average crystallite size and better crystallinity. Other factors such as molar ratio of cobalt nitrate(Co(No3)2) to zinc acetate(Zn(Ac)2, reaction time, molar ratio of water and sodium hydroxide(NaOH) to the zinc acetate, surfactant and its molar ratio to the zinc were optimized via Taguchi design. The optimum sample was prepared under conditions such as the cobalt nitrate to zinc molar ratio of 0.01, reaction time of 5h, and Triton X100 (molar ratio of 0.2). X-Ray diffraction analysis demonstrated that average crystallite size of the optimum sample was 11 nm. FESEM revealed the uniformity of the powders having nearly a rod-like structure with low aspect ratios. Besides, the impacts of the effective synthesis factors on the colorimetric properties were optimized. Accordingly, the optimum sample revealed a green region with brightness of 58.89(L*), color purity (a* = −22.82), and color hue of 166.89(h°). Average crystallite size, amorphous phase percentage and colorimetric properties correlations have been investigated for the first time. Placement of more cobalt atoms in the ZnO structure raises the brightness coordinate and results more greenness in the color and increase of the crystal size does not directly affect the brightness coordinate.

Temperature Effects on Physiochemical Characteristics of Sugar-Based Natural Deep Eutectic Solvents

Phase behavior, density, viscosity, conductivity, pH, and surface tension were measured, and FTIR was performed for a series of mixtures of sugar (glucose, fructose, xylose, and sucrose), water, and choline chloride (ChCl) at specific molar ratios. These mixtures, called sugar-based natural deep eutectic solvents (NADESs), were investigated as a function of temperature. Contact angle measurements indicated that NADES exhibited slightly lower wettability but higher surface tension than water. Temperature was found to greatly impact density, viscosity, and conductivity. The optimum water molar ratio for lower viscosity was found at ratios higher than those reported in the literature, indicating that the NADES investigated may have industrial process applications.

Ultrasound assisted choline chloride-based deep eutectic solvent extraction of bioactive compounds from salsify (Tragopogon buphthalmoides (DC.) boiss. Var. Latifolius Boiss.): A Box–Behnken design approach for optimization

This study aimed to investigate the ultrasound-assisted extraction of bioactive compounds from salsify using deep eutectic solvents (DESs) with different molar ratios. For this reason, total phenolic (TPC), total flavonoid (TFC) compounds, and antioxidant activities (1,1-diphenyl-2-picrilhydrazyl radical scavenging activity (DPPH•), and ferric reducing antioxidant power (FRAP)) of extracts prepared with DES were investigated with an experimental design and optimization study conducted for this purpose. An extraction time of 40.15 min was determined as the optimal condition. Under these conditions, a molar ratio of 3:1 (acetic acid:choline chloride) and a water ratio of 42.17 % provided the highest phenolic/flavonoid compounds and antioxidant activity. Correlations between water ratio, molar ratio, and sonication extraction time were determined using principal component analysis (PCA). In conditions where TPC, FRAP, and DPPH• were high according to PCA, it can be concluded that the extraction time, water ratio, and molar ratio are at high levels; contrarily, TFC is at a low level. In conclusion, ultrasound-assisted extraction using DES proved effective for salsify. Therefore, choline chloride-based DESs, can be recommended as environmentally friendly green solvents and an alternative to organic solvents for the extraction of bioactive compounds from salsify.

Ultrasound-assisted deep eutectic solvent extraction of bioactive compounds from persimmon calyx.

This study aimed to investigate the ultrasound-assisted extraction of bioactive compounds from persimmon (Diospyros kaki) calyx by deep eutectic solvents (DES) with different molar ratios. For this reason, the prepared DES extracts' total phenolic-flavonoid compounds and antioxidant activities (1,1-diphenyl-2-picrilhydrazyl radical scavenging activity [DPPH•], Cupric Reducing Antioxidant Capacity (CUPRAC), and ferric reducing antioxidant power [FRAP]) were investigated as a result of the experimental design and optimization study conducted for this purpose. A sonication time of 20min was determined as the optimal condition. Under these conditions, a molar ratio of 1.9:1 (lactic acid:choline chloride) and a water ratio of 70% provided the highest phenolic/flavonoid compounds and antioxidative activity. Correlations among water ratio, molar ratio, and sonication time were determined using principal component analysis (PCA). In conditions where total flavonoid compound, FRAP, and DPPH• are high due to PCA, it can be concluded that the sonication time is at high level; on the contrary, the water and molar ratios are at low level. In conclusion, ultrasound-assisted extraction using DES proved effective in persimmon calyx. Therefore, it can be recommended to use these environmentally friendly green solvents as an alternative to organic solvents in preparing extracts in various fields. PRACTICAL APPLICATION: This study shows the effectiveness of the ultrasound-assisted green extraction method using persimmon calyx specified as waste. These findings are compelling in the food industry in terms of consumers being now aware of green technology and the discovery that calyx is a good source of bioactive compounds.

Study of the Effect of Water Content in Deep Eutectic Phases on the Extraction of Fatty Acids from Microalgae Biomass

Microalgae, as some of the oldest life forms on Earth, are of significant interest to industry and in terms of environmental policies, due to their ability to perform photosynthesis and consume atmospheric carbon dioxide. Moreover, they contain a wide variety of value-added compounds such as amino acids and proteins, carbohydrates, and fatty acids, which can be exploited in multiple fields like medicine, cosmetics, nutritional supplements, and for the production of biodiesel. In this article, Nannochloropsis gaditana, a type of microalgae that inhabits both fresh and salt water, is studied for fatty acid recovery using deep eutectic solvents (DES). This microalgae species is a natural source of eicosapentaenoic acid (EPA), an omega-3 compound that is commonly used in the nutritional industry. There are numerous extraction techniques and pretreatments to obtain these compounds. In this work, DES are studied as extractive agents due to their advantages as neoteric solvents. Specifically, this work focuses on an assessment of the effect of the composition of DES on the extraction yield of fatty acids from microalgae. Several DES compositions based on choline chloride, ethylene glycol, and fructose are studied to analyze the influence of water content in these phases. The results show that water content significantly influences recovery yields. The DES with higher extractive capacity were those based on choline chloride, ethylene glycol, and water at a molar ratio of 1:2:2. This composition offered 48.7% of the yield obtained with a conventional solvent like methanol for the recovery of EPA (11.2 mg/g microalgae). Furthermore, the choline chloride-fructose-based DES shows the capability of selective extractions of fatty acids with low carbon content—choline chloride:fructose:water (molar ratio 2:1:2) can extract 0.14 mg of decanoic acid/g of microalgae, indicating that this DES composition can recover 35.7% more decanoic acid in comparison to methanol.

Investigating the amount of water on reducing Lix(OH)yClz hydroxide phases in the synthesis of Li3OCl anti-perovskite as a solid electrolyte in Li-ion batteries

ABSTRACT The Li3OCl solid electrolyte was synthesized in the present study via the hydrothermal method. In order to investigate the effect of water on the stability of the Li3OCl phase and reduce the amount of secondary hydroxide phases, different molar ratios of water were added to the precursors during the synthesis procedures. Employing XRD, DSC, FE-SEM, EIS, and CV techniques revealed that the LiCl: LiOH: H2O (1:2:10) molar ratio has better phase stability and fewer undesired hydroxide phases. The DSC results also showed that during the first heat treatment cycle, the Lix(OH)yClz phases were converted to the Li3OCl phase. After heat treatment, the final structure was characterized as a glass-ceramic structure. At 60°C and 110°C, respectively, the synthesized Li3OCl reached an ionic conductivity of 5.0 × 10−2 mS cm−1 and 0.76 mS cm−1. Also, the activation energy of 0.27 eV in the 60–110°C temperature range was recorded for the synthesized Li3OCl. The chemical stability of the synthesized Li3OCl was confirmed during lithiation/delithiation from −1.5 to 4 V at 130°C.

Nanostructure of aqueous ternary amino-acid-based natural deep eutectic solvents by water bridging

Natural deep eutectic solvents (NADESs) have drawn significant attention as green solvents for their special properties like biodegradability and biocompatibility. Nevertheless, the high viscosity of NADESs tends to prevent their implementation in industry. Even though dilution with water will lower the viscosity of NADESs effectively, fundamental knowledge of the intermolecular network in NADESs as well as the effect of water on the cooperative hydrogen-bonding network has not been evaluated systematically. Herein, solutions spanning a range of molar ratios of DL-Malic acid, L-Serine and water were synthesized. The experimental results demonstrate that it takes at least three moles of water to achieve a stable NADES. Besides, density functional theory (DFT) calculations indicate that water molecules connect DL-Malic acid and L-Serine by a water bridge framework. Furthermore, the progressive addition of water facilitates the proton transfer, making the hydrogen atom of the carboxyl group gradually ionize and approach the amino group. We hope the findings would provide a better understanding of the structural characteristics of NADESs and shed light on the applications.

Tomato performance and changes in soil chemistry in response to salinity and Na/Ca ratio of irrigation water

Although unconventional water can be applied as an alternative for agricultural production, inappropriate irrigation water quality may adversely affect the soil crop system. Thus, field experiments under mulched drip irrigation were performed over three years (2017–2019) to investigate the impacts of three salinity (1, 2 and 3 g·L−1) with five Na:Ca molar ratios (1, 3, 5, 7 and 9) of irrigation water on tomato plant growth, fruit development, soil salt accumulation and soil sodium adsorption ratio. The results showed that, with irrigation water salinity of 1 g·L−1, the critical value of irrigation water Na:Ca molar ratio for the high yield and dry matter accumulation was 3 and 5, respectively, while the threshold for high concentration of vitamin C and lycopene was 7. With the irrigation water salinity of 2 g·L−1 and 3 g·L−1, the Na:Ca molar ratio threshold for a high concentration of soluble solids, vitamin C and lycopene was 5. Moreover, considering the increase of plant nitrogen and phosphorus accumulation, the decrease of sodium adsorption ratio at 40–100 cm soil layer inside the film, and the diminution of soil salt accumulation at 0–100 cm layer, irrigation water with higher salinity and lower Na:Ca molar ratio was more proper than that with lower salinity and higher Na:Ca molar ratio. Based on the multi-objective optimization with entropy-weight TOPSIS method, irrigation water with a salinity level at 2 g·L−1 and the Na:Ca molar ratio at 5 was suggested for tomato planting in the Yinbei Yellow River Irrigation District, China.

A Sol-gel Membrane Utilized Cellulose Paper Doped with α-furil Dioxime for Colorimetric Determination of Nickel.

A simple and sensitive colorimetric sensor for nickel(II) ions has been successfully prepared by immobilizing α-furil dioxime reagent in the sol-gel matrix with a solid supporting filter paper medium. The sensor was developed using tetraethyl orthosilicate (TEOS) precursors with 4 days aging time, the mole ratio of water: precursor was 4:1, and reagent concentration at 0.10%. The sensor was quantified by utilizing the Red (R), Green (G), and Blue (B) values ​​of the colors that were successfully displayed after the detection process. The RGB value is confirmed by the Euclidean Distance (ED) equation to determine the optimum conditions. There was no observed degree of leaching in plain sight, and the result of leaching investigation by the double dyeing method did not show any significant change. The linear range was ​​0.10 to 2.8 ppm with an R2 of 0.9964. The values of LOD and LOQ were 0.1 ppm and 0.4 ppm, respectively. In addition, the sensor was free from interfering species and had a percent recovery around 90 to 110%.

Field experiments for evaluating the effects of water management and phosphate application on inorganic arsenic accumulation in water spinach (Ipomoea aquatica Forssk.)

Water spinach (Ipomoea aquatica Forssk.) is a commonly planted vegetable in the Southeast Asia; it is a semi-aquatic leafy vegetable with high inorganic arsenic (As) accumulation capability and can be planted under both upland and flooding cultivation conditions. To date, a limited number of field studies have investigated the effect of soil management on As phytotoxicity and accumulation of water spinach. Therefore, in this study, a field experiment was conducted to investigate the effects of water management and phosphate (P) application on the As phytotoxicity and accumulation of water spinach grown in As-contaminated fields (121 mg As kg−1). Water spinach was planted in the study field with two water management (flooding and upland cultivation) and two P application rates (90 and 180 kg P2O5 ha−1), and continuously harvested three times. Results reveal that the concentration and estimated daily intake (EDI) of inorganic As in the edible parts of water spinach under flooding cultivation were approximately twofold higher than those under upland cultivation. It was also found that the accumulation of As in the shoot of water spinach was strongly related to the As concentrations, rather than P/As molar ratio in pore water due to that P application rates were lower than the maximum capacity for P retention of the tested soil. Moreover, the As phytotoxicity and accumulation of water spinach were reduced at the third harvest relative to the first two harvests because of the increase in iron plaque formation on the root surface and the decrease in the growing temperature during the experimental period. Our results suggest that upland cultivation is the better practice than flooding cultivation for reducing inorganic As accumulation in the edible parts of water spinach grown in As-contaminated soils. Further, ratooning may be a feasible cultivation approach to reducing inorganic As accumulation in water spinach.

Synthesis and characterizations of sugar-glass nanoparticles mediated protein delivery system for tissue engineering application

The present work focuses on the synthesis and characterization of a sugar-glass nanoparticle (SGnP) based reservoir type protein delivery system pertinent to tissue engineering applications. The SGnP nanocarriers were prepared via inverse micelle of sodium bis(2-ethylhexyl) sulfosuccinate based on an anionic surfactant and subsequent flash-freezing technique. Initially, a total of five different grades of protein-free SGnPs have been prepared to examine the effects of systematic changes in starting concentrations of the aqueous phase, organic solvent, the molar ratio of water, and surfactant in controlling the size, shape, and uniformity of micelles. Evidently, the Fourier transform infrared (FTIR) and scanning electron microscope (SEM) results confirmed that the SGnP can be successfully prepared. Subsequently, SGnP based protein depot has been validated using bovine serum albumin (BSA), horseradish peroxidase (HRP) and growth and differentiation factor-5 (GDF-5). The particle size, morphology, protein encapsulation efficiency and in vitro release kinetics were assessed using SEM, FTIR, UV–visible spectroscopy and Bradford protein assays. Excellent encapsulation efficiency (93%–94%) and sustained release behaviour of BSA (∼22% protein release after 14 d) and GDF-5 proteins (∼29% protein release after 30 d) were exhibited by the optimal grades of SGnP constructs with an average particle size of 266 nm and 93 nm, respectively. Furthermore, FTIR, differential scanning calorimeter (DSC), polyacrylamide gel electrophoresis (PAGE) and NATIVE-PAGE studies results confirm successful encapsulation, stability and preserving the structural integrity of proteins placed into the core of the SGnP constructs. Evidently, a very high (93%) residual HRP enzyme activity signifies the capability of our SGnP system to protect the encapsulated proteins from process-related stresses. In vitro cytotoxicity and fluorescence cell morphology analyses using human adipose-derived mesenchymal stem cells affirmed good cytocompatibility of protein encapsulated SGnP. Overall, the study findings indicate SGnP nanocarrier-mediated protein delivery systems as a promising approach complementary to conventional techniques in tissue engineering and therapeutic applications.

Synthesis optimization of phase-singularized UZM-5 zeolite under hydrothermal conditions: The critical control points of its crystalline phase and crystallinity

Pure UZM-5 zeolite with either nanosheet or rosette-shaped morphology have been successfully synthesized by a charge density mismatch (CDM) method under a corresponding tumbling or static conditions. The synthesis parameters were fully investigated to abstain from commonly accompanying by-products, including SOD or amorphous phase which greatly interfered with the use of UZM-5. The crystalline phases and relative crystallinity of resultant products were carefully substantiated by using scanning electron microscope and X-ray diffraction. As a result, the molar ratios of water and structure directing agents thereof were deemed to be two vital parameters which had significant effects on the well-defined pure-phase UZM-5 zeolite production. Trace ethanol added in the reagent solution was found to play a role in zeolite purification. There is an urgent need in electrocatalytic reduction of nitrate to ammonia. In this work, pure UZM-5 zeolite with Lewis acid sites served as catalyst matrix for the application to produce this valuable chemical. Excellent ammonia production rate with high faradaic efficiency was achieved by using the obtained novel UZM-5-based catalyst for the reduction reaction, strongly proving the great potential of this young zeolite in catalysis applications.

Kinetics of ethanol steam reforming over Ni/Olivine catalyst

Olivine, a natural mineral consisting of different metal oxides (mainly Mg, Si and Fe oxides) was used as a support for nickel catalyst used in steam reforming of ethanol. Catalyst containing different wt% of Ni on olivine were prepared by conventional wet-impregnation method and characterized by BET, XRD, SEM (coupled with EDS) and H2-TPR. The reaction was carried out in a tubular fixed bed reactor. Among all the catalysts, 5% Ni on olivine catalyst gave highest hydrogen yield as well as ethanol conversion through ethanol steam reforming reaction. The catalyst activity was analyzed by varying three important process parameters (temperature, ethanol to water molar ratio and space-time). The reaction was performed in the temperature range of 450 °C to 550 °C with 1:6 to 1:12 M feed ratio of ethanol to water at a space-time range 7.21–15.87 kg cat h/kmol ethanol. A maximum yield of 4.62 mol of hydrogen per mole of ethanol reacted was obtained at 550 °C with ethanol to steam molar ratio of 1:10 and space-time of 7.94 kg cat h/kmol ethanol with the ethanol conversion level of 97%. CHNS analysis of the spent catalyst was performed to find the coke deposited over the catalyst surface during the reaction. The power law and LHHW type kinetic models were developed. The power law model predicts the activation energy as 29.07 kJ/mol, whereas the LHHW type model gives the activation energy as 27.4 kJ/mol.

Molecular engineering of an inverse hexacopper(II) coordination complex with a photoactive metallacyclophane centroligand as prototype of a magnetic photoswitch

A primary goal of molecular spintronics is detecting the response of the spins from a single magnetic molecule to an external stimulus and, eventually, being able to implement logic quantum memory capabilities for information data storage and processing applications in quantum computation. Having this in mind, a novel hexanuclear oxamatocopper(II) complex of formula {[Cu2(naba)2][Cu(pmdien)]4}(ClO4)4·8H2O (2) [naba = N,N'-1,5-naphthalenebis(oxamate) and pmdien = N,N,N’,N”,N”-pentamethyldiethylenetriamine] has been prepared by the reaction of stoichiometric amounts of (nBu4N)4[Cu2(naba)2] · 4H2O (1) (nBu4N+ = tetra-n-butylammonium cation) and [Cu(pmdien)](ClO4)2 (1:4 molar ratio) in water. 2 exhibits a ladder-like “dimer-of-trinuclears” structure featuring a photoactive dicopper(II) naphthalenophane core acting as inverse coordination centre (centroligand) towards four peripheral [Cu(pmdien)]2+ groups through the outer amidate/carboxylate oxygen atoms of the oxamato fragments. 2 undergoes a unique magnetic photoswitching ON/OFF behaviour upon UV light irradiation because of an intramolecular (“pseudo-bimolecular”) photocycloaddition of the two facing naphthalene spacers through the more reactive carbon atoms at the 1,4 and 1’,4’ positions of the benzene rings to afford the putative [4 + 4] cycloaddition product c-2. Hence, the two oxamato-bridged S = 1/2 CuII3 linear units antiferromagnetically coupled within the CuII6 precursor (2, ON state) become magnetically uncoupled in the corresponding [4 + 4] photocycloaddition product (c-2, OFF state) [jeff = –2.13 (2) and 0 cm−1 (c-2); H = – jeffSA.SB with SA = SB = 1/2]. This new example of inverse coordination complex constitutes thus a potential candidate to molecular magnetic photoswitch in the “bottom-up” approach to nanometer-scale spintronic and quantum computing devices.

Synthesis and characterization of mesoporous gamma-alumina by glucose as soft-template for molybdenum-99 adsorption: high and low molar ratio of water to aluminium isopropoxide effect

The mesoporous gamma-alumina is a good material for metal adsorption. Its textural properties are excellent, mainly for molybdenum-99 radioisotopes adsorption as part of 99Mo/99mTc generator in nuclear medicine. In this work, we have prepared mesoporous gamma-alumina by sol-gel treatment in the presence of glucose as a soft template. The molar ratio of reactant (water: aluminium isopropoxide(AIP)) was applied in the high and low ratios (150:1 and 25:1). The resulted mesoporous gamma-alumina was investigated using characterization analysis of X-ray diffraction, Nitrogen adsorption-desorption, and FTIR. The results indicate that the mesoporous gamma-alumina in the high molar ratio of water to AIP had a higher surface area and better crystallinity than the low molar ratio of reactants. Furthermore, in the Mo adsorption test, the mesoporous gamma-alumina with the high molar ratio posed a higher Mo adsorption capacity up to 55.69 mg Mo g−1 adsorbent. In the future, the molar ratio of reactants should be tuned in the range of around 150:1 to obtain the optimal Mo adsorption capacities of the resulted mesoporous gamma-alumina using the glucose template.

Preparation and characterization of anti-freezing conductive organohydrogel based on carboxyl modified polyvinyl alcohol and polypyrrole

Functional hydrogels have many excellent properties and many potential applications. However, hydrogels are easy to lose certain moisture or solvent in open environment, which makes volume shrinkage and hardness enhancement, even failure to possess use value. In addition, hydrogels usually lose their flexibilities at lower temperature due to water freezing. Therefore, the study of gels with low temperature flexibility and water retention are of great significance. In this paper, a kind of anti-freezing conductive organohydrogel was prepared from carboxyl modified polyvinyl alcohol which was dissolved in water and dimethyl sulfoxide (DMSO) (molar ratio = 3:1), pyrrole was added to the solution and polymerized, then gels were obtained by freeze-thawing method. It was found that the mixed solvent shows excellent low temperature freezing resistance, the carboxyl groups give favorable water retention property, polypyrrole makes the gel conductivity. The gels show good flexibility even at −60 °C. In open environment the mass loss of gels is only 30% after 17 days at room temperature. When the pyrrole content is 10%, the gel conductivity reaches the maximum value of 1 S/m. However, the introduction of pyrrole brought two changes, on one hand, when the pyrrole content increased from 0% to 10%, the mass retention dropped from 83% to 70%. On the other hand, with the content of pyrrole increased, the fracture stress of the organohydrogel first increased and then decreased. When the pyrrole content was 2%, the fracture stress reached the maximum value of 0.50 MPa. The gels can be further crosslinked by Fe3+, which was helpful for improving the mechanical properties. It is of great importance for recording intricate deformational signals in advanced flexible sensors.

The dealuminated zeolites via acid leaching and followed calcination method for removal of hydrophobic bisphenol A

The commercial Hβ (25, 50), HY (11) and HZSM-5(50) were dealuminated by acid leaching and subsequent calcination to improve their hydrophobic nature for the removal of bisphenol A (BPA). The structure and properties of the raw zeolites and the modified ones (labelled as T-Hβ (25, 50), T-HY (11), T-HZSM-5(50)) have been investigated comparatively by XRD, BET, SEM, XRF and contact angle test (CA). The results indicated that HY (11) and T-HY (11) had poor adsorption capacity for hydrophobic BPA because of destroyed crystalline phase of T-HY (11) and hydrophilic nature of HY (11). HZSM-5(50) and T-HZSM-5(50) also had poor adsorption ability for BPA molecules because larger BPA molecules cannot enter smaller pores of HZSM-5(50) and T-HZSM-5(50). However, the T-Hβ (25, 50) zeolites exhibited significantly higher adsorption capacity for BPA because their larger pore size remained than molecule size of BPA and larger water contact angles and molar ratios of SiO2/Al2O3 of T-Hβ (25, 50) than Hβ (25, 50), respectively. BPA removal mechanism study showed that hydrophobic interaction force between BPA and T-Hβ (25, 50) should be a main driving force. The adsorption process conformed to pseudo-second order model and the three-parameter Redlich-Peterson model. The adsorption rate of BPA over T-Hβ (50) (0.01050 ​g ​mg−1 ​min−1) was 2.29 times faster than that over Hβ (50) (0.004581 ​g ​mg−1 min−1), and the maximum adsorption capacity of BPA on T-Hβ (50) (117.62 ​mg ​g−1) was 3.5 times than that on Hβ (50) (33.78 ​mg ​g−1). The acid treatment-calcination method is feasible and appropriate for modification of Hβ in order to remove hydrophobic organic pollutants.

Structural properties and stability of the Betaine-Urea natural deep eutectic solvent

This work focuses on the stability and supramolecular structure of the betaine-urea-water (B:U:W) natural deep eutectic solvent. Solutions spanning a range of molar ratios of betaine, urea, and water were prepared, varying the temperature and preparation times, and were analyzed by attenuated total reflection Fourier-transform infrared spectroscopy and Nuclear Magnetic Resonance. Density Functional Theory and the Natural Bond Orbital analysis were employed to obtain the most stable conformations for each mixture. The experimental results show that, in non-anhydrous conditions, betaine:urea (1:1), a minimum of two moles of water are needed to form a metastable transparent liquid, and a minimum of three moles of water is required to have a stable NADES. Comparison of the 13C NMR spectra of B:U:W 1:1:2 and 1:1:3 shows for the latter that the carbonyl groups of betaine and urea form stronger hydrogen bonds with water, and that the CH3 group of betaine becomes more deprotected by the addition of the extra water molecule, making 1:1:3 a more stable solution. Our experimental and computational results show that water is of crucial importance to the NADES supramolecular structure and stability. A better understanding of the structural characteristics of NADES can lead to better envisage applications for these green solvents.

Tunable Electrode Architectures for La0.8Sr0.2Fe1-XTixO3- δ Based Symmetrical Solid Oxide Fuel Cells

The efficiency of SOCF electrodes can be improved by optimizing the microstructure from alternative preparation methods, such as infiltration and nanostructured electrodes deposited at low temperature. Recent studies have demonstrated that spray-pyrolysis deposition is a versatile method to obtain nanostructured electrodes with improved performance in comparison with conventional electrodesprepared at high sintering temperatures. Among the different electrodes studied in the last few year, titanium-doped ferrites are one of the most promising because of their high redox stability and great electrochemical performance in both oxidizing and reducing conditions2,3. In this work, (La0.8Sr0.2)0.95Fe1-xTixO3- δ (x=0.2, 0.4) perovskites, hereafter labelled as LSFT02 and LSFT04, respectively, with different architectures were obtained by spray-pyrolysis deposition and they were tested as symmetrical electrodes for solid oxide fuel cell (SSOFC). The electrodes were deposited on as-prepared YSZ pellets and porous Ce0.9Gd0.1O1.95, preciously fixed on the electrolyte. A nanocomposite electrode was also prepared in a single step onto YSZ. The precursor solution containing the corresponding nitrates and etilendiaminetetraacetic acid (EDTA) as a complexing agent in a 25% molar ratio in Milli-Q water with a concentration of 0.025 M, was sprayed directly onto the electrolyte. The temperature deposition, time and flow rate was optimized to 325 ºC, 1 h and 20 mL min-1, respectively. After the deposition, the samples were calcined at 800 ºC for 1h to achieve crystallization. The structural characterization by XRD revealed that both LSFT02 and LSFT04 are nanocrystalline compounds without any secondary phases after annealing in air and reducing conditions. Figure 1 shows SEM images of the different electrode architectures cross-section at different magnifications. The electrodes deposited into the CGO backbone consists of a porous backbone (10 µm) coated with a layer of LSFT nanoparticles (∼50 nm of diameter) at 800 ºC (Fig. 1a). The HAADF-STEM images of the nanocomposite material showed a high homogeneity and particle size as low as 50 nm at 1000 ºC The electrochemical properties of the symmetrical cells were tested by impedance spectroscopy. The polarization resistance (Rp) in air of LSFT0.2 and LSFT0.4 impregnated CGO backbone by spray pyrolysis (SP) decrease from 1.19 and 8.84 Ω·cm2 to 0.23 and 0.67 Ω·cm2 at 700 ºC, respectively, when compared with the powders obtained by freeze drying precursor method. The similar behavior observed for both compositions confirmed that the increase of the TPB length, highly improves the electrochemical performance. Same results were obtained for the nanocomposite architecture. On the other hand, the Rp values in H2 for LSFT04 are slightly lower when compared with LSFT02, 0.21 and 0.35 Ω·cm2 at 700 ºC, respectively, fact that could be explained by the great efficiency of Ti-doped electrodes in reducing conditions at high temperature. In other to further improving the electrochemical performance, LSFT02 was doped with Ni and Ru, infiltrated into the CGO backbone and tested as SSOFC. The electrochemical performance in H2 improves substantially for the Ni-doped sample, achieving 0.09 Ω·cm2 at 750 ºC, which is one of the lowest ASR values for related materials, mainly attributed to the Ni0 nanoparticle exsolution combined with an advance microstructure configuration. The influence of d.c. bias in a 3-probe configuration was studied under cathodic and anodic polarization in symmetrical cells in both oxidizing and reducing conditions. The results revealed a considerable decrease on the LF process, attributed to surface diffusion and/or charge transfer in the electrode. The study of performance of the different architectures electrodes in real SOFC conditions are currently in process, but high maximum power densities are expected due to the low ASR values achieved.