Effect Of Solvent Composition Research Articles

SC crystals of porous PLA via thermally–induced phase separation: Effects of process conditions, solvent composition and nucleating agent

The formation of stereo-complex crystals (SC) in porous poly (lactic acid) (PLA) material is intricately linked with improving its comprehensive properties. In this work, the effects of process conditions, solvent composition and additional nucleating agent on SC crystals during the fabrication of porous PLA through thermally-induced phase separation method were studied. Crystallization behavior of SC crystals during the pore-forming process is systematically investigated, revealing that higher quenching temperature and longer quenching period facilitate the formation of SC crystals. Additionally, the addition of deionized water to the solvent effectively enhances SC crystals formation by reducing solution viscosity and prolonging the phase separation time. The highest crystallinity of SC crystals (XSC) can be achieved, reaching 30.6%, when the water content is controlled at 1.6%. Furthermore, the introduction of carbon nanotubes (CNTs) as a nucleating agent exhibits a pronounced effect on the formation of SC crystals. When incorporating a 3 wt% content of CNTs, XSC reaches its peak value at 37.7%. This work is helpful to provide reference for improving mechanical properties and heat resistance of porous PLA, thereby expanding its potential outdoor applications.

Effects of solvent composition on agglomerate structure in catalyst ink for polymer electrolyte fuel cells

The solvent composition of the catalyst ink profoundly impacts both the porous structure and the efficiency of the mass-production process of the catalyst layer for polymer electrolyte fuel cells. However, the underlying mechanism remains far from elucidated. Here, we present the size of aggregate and the fractal dimension of the agglomerate structure as determined by ultra-small X-ray scattering (USAXS) of the catalyst inks with varied solvent composition. By examining the correlations between the structural properties provided by USAXS, rheological properties, and the quantity of ionomer adsorbed on the Pt/C, we elucidate the solvent's influence on the agglomerate structure. In highly polar solvents, akin to water, a considerable number of amphiphilic ionomers adsorb to the Pt/C particles, resulting in the formation of dispersed Pt/C aggregate particles approximately 200 nm in size that cannot be subdivided further into smaller particles even with the use of a homogenizer. As the polarity diminishes with the addition of alcohol content, ionomers desorb, and the affinity between the aggregates and the solvent decreases, leading to the evolution of agglomerates. The observed solvent effect can be rationally characterized by one of Hansen's solubility parameters, which specifies the polar interaction.

CO gas-sensing properties and DFT investigation of pure and Co-modified MoO3 nanostructures: effect of solvent composition, deposition time, and cobalt concentration

CO gas-sensing properties and DFT investigation of pure and Co-modified MoO3 nanostructures: effect of solvent composition, deposition time, and cobalt concentration

Tetraselmis chuii Edible Microalga as a New Source of Neuroprotective Compounds Obtained Using Fast Biosolvent Extraction.

Tetraselmis chuii is an EFSA-approved novel food and dietary supplement with increasing use in nutraceutical production worldwide. This study investigated the neuroprotective potential of bioactive compounds extracted from T. chuii using green biobased solvents (ethyl acetate, AcOEt, and cyclopentyl methyl ether, CPME) under pressurized liquid extraction (PLE) conditions and supercritical fluid extraction (SFE). Response surface optimization was used to study the effect of temperature and solvent composition on the neuroprotective properties of the PLE extracts, including anticholinergic activity, reactive oxygen/nitrogen species (ROS/RNS) scavenging capacity, and anti-inflammatory activity. Optimized extraction conditions of 40 °C and 34.9% AcOEt in CPME resulted in extracts with high anticholinergic and ROS/RNS scavenging capacity, while operation at 180 °C and 54.1% AcOEt in CPME yielded extracts with potent anti-inflammatory properties using only 20 min. Chemical characterization revealed the presence of carotenoids (neoxanthin, violaxanthin, zeaxanthin, α- and β-carotene) known for their anti-cholinesterase, antioxidant, and anti-inflammatory potential. The extracts also exhibited high levels of omega-3 polyunsaturated fatty acids (PUFAs) with a favorable ω-3/ω-6 ratio (>7), contributing to their neuroprotective and anti-inflammatory effects. Furthermore, the extracts were found to be safe to use, as cytotoxicity assays showed no observed toxicity in HK-2 and THP-1 cell lines at or below a concentration of 40 μg mL-1. These results highlight the neuroprotective potential of Tetraselmis chuii extracts, making them valuable in the field of nutraceutical production and emphasize the interest of studying new green solvents as alternatives to conventional toxic solvents.

Organic acid-assisted organosolv fractionation of sawdust and using the fractionated lignin to prepare activated carbon pellets for high-temperature applications

In present, activated carbon (AC) pellets that are commonly prepared by petroleum-based binders have been used to control NOx, SOx, and volatile organic compounds (VOCs) emissions in the iron/steel industry. However, the use of petroleum-based binders leads to great challenges toward sustainability and environment. Alternatively, lignin as a natural bio-binder derived from biomass and organic waste can act as a potential additive for preparing AC pellets. Therefore, in this study, pinewood sawdust was initially fractionated into crude cellulose and lignin by organosolv fractionation method at 90–120 °C for 180 min in an acetic acid/formic acid/water mixed solvent of 3/5/2, 3/6/1, and 5/4/1, vol%/vol%/vol%. Afterward, the fractionated crude lignin was used as bio-additive to substitute 50 wt% of petroleum-derived phenol to synthesize phenol-formaldehyde resole resins (PLPF) and compared with those prepared using 100% petroleum-derived phenol resole resins (PF). PLPF and PF resins were further fabricated to AC pellets by thermal treatment/curing at 150 °C and different loadings of resins (i.e., 10–50 wt%), followed by carbonization at 400 and 700 °C. In the fractionation, it was found that temperature played a role in determining the yield and purity of crude cellulose and lignin, while the effect of solvent composition was insignificant. PLPF resins (loading of 50 wt%)-based AC pellets obtained from thermal treatment at 150 °C followed by carbonization at 400 °C showed a relatively higher compressive strength, which meets the national standard and could ensure their uses as an emission control method in the iron/steel industry. Overall, it can be concluded that lignin-derived from woody biomass by organosolv fractionation in acetic acid/formic acid/water mixture is an alternative bio-binder to prepare AC pellets for emission control at high temperatures.

Cationic micelles in deep eutectic solvents: effects of solvent composition.

Deep eutectic solvents (DES) are mixtures of hydrogen bond donors and acceptors that form strongly hydrogen-bonded room temperature liquids. Changing the H-bonding components and their ratios can alter the physicochemical properties of deep eutectic solvents. Recent studies have shown p-toluenesulfonic acid (pTSA) forms room temperature liquids with choline chloride (ChCl) at different molar ratios: 1 : 1, 1 : 2 and 2 : 1 [Rodriguez Rodriguez et al., ACS Sustain. Chem. Eng., 2019, 7(4), 3940]. They also showed that the composition affects the physical properties of these liquids and their ability to dissolve metal oxides. In this work we evaluate the solubility and self-assembly of cationic surfactants alkyltrimethyl ammonium bromides (CnTAB) in these pTSA/ChCl based liquids. CnTABs are insoluble in 1pTSA : 2ChCl, whereas in 1pTSA : 1ChCl and 2pTSA : 1ChCl they form micelles. We characterise CnTAB (n = 12, 14, 16) micelles using small angle neutron scattering and also look at interaction of water with the micelles. These studies help determine the interaction of DES components with the surfactant and the influence of varying pTSA and water ratios on these interactions. This provides potential for controlled surfactant templating and for tuning rheology modification in such systems.

Effects of solvent composition and test temperature on the stability of water-in-model waxy crude oil emulsions

In this article, we investigated the influence of solvent composition and test temperature on the stability of the water-in-oil model emulsions through asphaltene dispersion stability, wax precipitation characteristics, rheology, interfacial film characteristics measurements of diluted model oil-simulated formation water, emulsion stability, microscopic observations, and molecular dynamics simulation. Specifically, we examined the stability of crude oil emulsions at 15° below and 30 above WAT using model oils containing 0.5 wt% asphaltenes and 10 wt% paraffin wax having varying solvent compositions. We observed that increasing the amount of liquid paraffin in the solvents led to smaller changes in the WAT, a reduction in the cumulative wax crystal at −20 °C, and a change in the form of wax crystals from fine particles to larger agglomerated wax crystals. However, the asphaltenes dispersion stability decreased along with it, rheology continued to improve. Meanwhile, we innovatively validated this experimental result using molecular dynamics simulations. Test temperature significantly affects emulsion stability. At 30 °C, increasing the percentage of liquid paraffin reduces interfacial tension, increases the dilatational modulus, and enhances the durability of the interfacial film. This contributes to form small droplets and increases emulsion stability. At 15 °C, increasing the liquid paraffin percentage promoted the development of a more structured wax crystals network, which significantly enhances emulsion stability by binding water droplets. Additionally, we observed that a wax crystal interfacial film could be developed from the wax crystals on the surface of emulsified drops, which improves the emulsion stability and interfacial film strength. Based on our findings, we innovatively present an influencing mechanism model of solvent composition on the synergistic stabilization of model oil emulsion using asphaltenes and paraffin wax.

Effects of ultrasonication time and solvent composition on physico–chemical properties of the pollen extract

Effects of ultrasonication time and solvent composition on physico–chemical properties of the pollen extract

Tailoring surface and bulk morphologies to control transport properties of sulfonated block copolymer films

We examine the effects of solvent composition and solution-casting protocol on the structure of a lamellar sulfonated pentablock copolymer (SPC) membrane. Films are prepared by a layering process, wherein the film is built up through sequential bar-coating steps. Process variables include bar gap height, which controls drying time and layer thickness, and solvent selectivity toward each block in the SPC, which controls solution-state structure and biases the domain orientations at the surface. We find that irrespective of solvent selectivity, one-layer films have poorly ordered structures in the bulk with minimal restructuring near the surface. However, when the process involves sequential deposition of two or more layers, then the bulk structure of dry films can be well-predicted by the solution-state structure, and domain orientations at the surface are templated by polymer-solvent interactions. Consequently, processing conditions strongly influence through-plane transport properties of the SPC films. When the casting process generates disordered lamellae in bulk with a perpendicular lamellar orientation at the surface, both water and protons can move across the film. However, when the process generates highly ordered lamellae in bulk and parallel lamellar orientations at the surface, transport of both water and protons is inhibited by limited pathways. Significantly, the methodology outlined in this work can be extended to other ionic block copolymer platforms, allowing researchers to tailor bulk and surface morphologies for optimization of critical transport properties.

Simple Protein Analysis by Droplet Paper Spray Ionization Mass Spectrometry with Polyolefin Silica-Based Paper.

Paper spray ionization mass spectrometry (PSI MS) has emerged as a notable method for the rapid analysis of biological samples. However, the typical cellulose-based paper tip is incompatible with protein detection due to the strong interaction between cellulose hydroxyl groups and proteins. In this study, we utilized a commercially available polyolefin-based synthetic paper, Teslin®, as an alternative PSI substrate for simple protein analysis. We have named this method "droplet PSI" MS, as the aqueous protein solution droplet retains its shape on the Teslin® paper tip. For droplet PSI, no further chemical pretreatment was necessary for the Teslin® substrate; the only required preparation was shaping the Teslin® paper into a triangular tip. In droplet PSI MS, protein ion signals were instantly detected from a protein solution droplet upon applying a spray solvent in situ along with high voltage (HV). When compared with conventional PSI MS, our method demonstrated superior sensitivity. The droplet PSI MS utilizing Teslin® also showcased flexibility in real-time observation of protein alterations induced by an acid additive. Additionally, the effects of spray solvent composition and the application method were discussed.

Analysis of Pesticide Residues on Fruit Using Swab Spray Ionization Mass Spectrometry.

The vast quantity and high variety of pesticides globally used in agriculture entails considerable risks for the environment and requires ensuring the safety of food products. Therefore, powerful analytical tools are needed to acquire qualitative and quantitative data for monitoring pesticide residues. The development of ambient ionization mass spectrometry methods in the past two decades has demonstrated numerous ways to generate ions under atmospheric conditions and simultaneously to reduce the need for extended sample preparation and circumvent chromatographic separation prior to mass analysis. Swab spray ionization enables the generation of ions directly from swabs via the application of high voltage and solvent flow. In this study, swab sampling of fruit surfaces and subsequent ionization directly from the swab in a modified electrospray ion source was employed for the screening and quantitation of pesticide residues. Aspects regarding sample collection, sampling efficacy on different surfaces, and swab background are discussed. The effect of solvent composition on pesticide-sodium adduct formation and the suppression of ionization by the background matrix have been investigated. Furthermore, a novel approach for the quantitation of pesticide residues based on depletion curve areas is presented. It is demonstrated that swab spray ionization is an effective and quick method for spectral library-based identification and the quantitative analysis of polar contact pesticide residues on food.

Investigation of the effects of ternary deep eutectic solvent composition on pretreatment of sorghum stover

AbstractBiomass‐derived deep eutectic solvents (DESs) have been introduced as promising pretreatment and fractionation solvents because of their mild processing conditions, easy synthesis, and green solvent components from biomass. In recent DES studies, solvent‐based third constituents like water, ethanol, and others improve the processibility of typical binary DESs. However, the impacts of these components are not well understood. Here, two solvent‐based constituents, including water and ethylene glycol, were applied to 3,4‐dihydroxybenzoic acid (DHBA)‐based DES system for improving the conversion efficiency of cellulose‐rich fraction and the properties of lignin fraction. Chemical composition, enzymatic digestibility, degree of polymerization of cellulose and physicochemical properties of lignin were used to evaluate the impact of each third constituent on biomass processing. Ternary ChCl‐DHBA DESs exhibited better performances in delignification, fermentable sugar production, and preservation of β‐O‐4 ether linkage in lignin compared with binary ChCl‐DHBA DES.

Effect of Organic Carbonate Solvent Composition on the Volumetric and Viscometric Behavior of Linear Ethers

Effect of Organic Carbonate Solvent Composition on the Volumetric and Viscometric Behavior of Linear Ethers

Electrospun Poly (Vinylidene Fluoride-Co-Hexafluoropropylene) Nanofiber Membranes for Brine Treatment via Membrane Distillation.

The major challenge for membrane distillation (MD) is the membrane wetting resistance induced by pollutants in the feed solution. The proposed solution for this issue was to fabricate membranes with hydrophobic properties. Hydrophobic electrospun poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) nanofiber membranes were produced for brine treatment using the direct-contact membrane distillation (DCMD) technique. These nanofiber membranes were prepared from three different polymeric solution compositions to study the effect of solvent composition on the electrospinning process. Furthermore, the effect of the polymer concentration was investigated by preparing polymeric solutions with three different polymer percentages: 6, 8, and 10%. All of the nanofiber membranes obtained from electrospinning were post-treated at varying temperatures. The effects of thickness, porosity, pore size, and liquid entry pressure (LEP) were studied. The hydrophobicity was determined using contact angle measurements, which were investigated using optical contact angle goniometry. The crystallinity and thermal properties were studied using DSC and XRD, while the functional groups were studied using FTIR. The morphological study was performed with AMF and described the roughness of nanofiber membranes. Finally, all of the nanofiber membranes had enough of a hydrophobic nature to be used in DCMD. A PVDF membrane filter disc and all nanofiber membranes were applied in DCMD to treat brine water. The resulting water flux and permeate water quality were compared, and it was discovered that all of the produced nanofiber membranes showed good behavior with varying water flux, but the salt rejection was greater than 90%. A membrane prepared from DMF/acetone 5-5 with 10% PVDF-HFP provided the perfect performance, with an average water flux of 44 kg.m-2.h-1 and salt rejection of 99.8%.

Investigating the effect of solvent composition on ink structure and crack formation in polymer electrolyte membrane fuel cell catalyst layers

To improve the performance of polymer electrolyte membrane fuel cells (PEMFCs), controlling the microstructure of the membrane electrode assembly (MEA) catalyst layer is crucial. Ink design, which includes a catalyst, an ionomer, and a solvent, serves as the starting point for controlling the microstructure of the catalyst layer. However, there is a significant lack of understanding of the ink structure required for this purpose. In this study, we investigated the effect of the solvent, a key component that determines the ink structure. The ink comprises 20 wt% Pt/C, short-side-chain (SSC) Aquivion ionomer, and a solvent mixture of 1-propanol (NPA) and water. Three types of inks with different compositions of NPA and water are manufactured, and their stability and rheological properties were measured to infer and compare the ink structures. Furthermore, the crack characteristics of the catalyst layer were compared by directly coating the ink onto the electrolyte membrane using the doctor-blade method. In the ink with a high water content, we observed a gel-like elastic behavior dominated by network structures formed by ionomers adsorbed between catalyst particles. In contrast, the ink with a high NPA content exhibited a liquid-like viscous behavior dominated by well-dispersed catalyst particles and ionomers. These properties of the inks directly influence the crack formation characteristics after coating. Specifically, the strong liquid properties of the NPA-rich ink were found to suppress crack formation in the catalyst layer. These findings provide important insights into how the solvent composition affects ink structure and how it, in turn, influences crack formation in the catalyst layer, which can help optimize the ink design to improve the performance of PEMFCs.

Purification of synthetic oils using liquefied gases of reduced flammability

In this work we evaluate the technical feasibility of using liquefied CO2 + propane as a solvent for the purification of lubricant oils. A model lubricant made of a silicone oil (polydimethylsiloxane, MW ≈6000) and Decamethylcyclopentasiloxane (D5, MW: ≈371) is prepared to study the extraction process. The phase behavior of the CO2 +propane+silicone oil system is evaluated in a high-pressure view cell to set the window of operating conditions where the system exhibits partial liquid miscibility (298–323 K). Then, we add D5 monomer (2 mass % in the silicone oil) to the previous ternary mixture, and we assess the effect of solvent composition (CO2/propane: 60/40–90/10) over the fractionation process by means of new equilibrium measurements. The solvent-free distribution coefficient of D5 between the liquid phases is determined from experimental determinations. Results evidence that liquefied gases with propane concentrations between 10 and 26 mass % are suitable to remove the monomers from the raw lubricant oils with good selectivity and extraction yields. Conceptual engineering designs of the liquid-liquid fractionation process are performed to determine the suitable solvent composition that completely removes the monomer present in the lubricant oil and to assess the recovery of the lubricant oil.

High-intensity ultrasound-based process strategies for obtaining edible sunflower (Helianthus annuus L.) flour with low-phenolic and high-protein content

The sunflower Helianthus annuus L. represents the 4th largest oilseed cultivated area worldwide. Its balanced amino acid content and low content of antinutrient factors give sunflower protein a good nutritional value. However, it is underexploited as a supplement to human nutrition due to the high content of phenolic compounds that reduce the sensory quality of the product. Thus, this study aimed at obtaining a high protein and low phenolic compound sunflower flour for use in the food industry by designing separation processes with high intensity ultrasound technology. First, sunflower meal, a residue of cold-press oil extraction processing, was defatted using supercritical CO2 technology. Subsequently, sunflower meal was subjected to different conditions for ultrasound-assisted extraction of phenolic compounds. The effects of solvent composition (water: ethanol) and pH (4 to 12) were investigated using different acoustic energies and continuous and pulsed process approaches. The employed process strategies reduced the oil content of sunflower meal by up to 90% and reduced 83% of the phenolic content. Furthermore, the protein content of sunflower flour was increased up to approximately 72% with respect to sunflower meal. The acoustic cavitation-based processes using the optimized solvent composition were efficient in breaking down the cellular structure of the plant matrix and facilitated the separation of proteins and phenolic compounds, while preserving the functional groups of the product. Therefore, a new ingredient with high protein content and potential application for human food was obtained from the residue of sunflower oil processing using green technologies.

Flexible PET/(PET-TiO2) core/shell nanofibrous mats as potential photoanode layer for dye-sensitized solar cells, DSSCs

In this detailed study, high porous flexible structures composed of polyethylene terephthalate (PET) and a PET composite comprised of titanium dioxide (PET-TiO2) core/shell nanofibrous mats were developed using coaxial electrospinning technique. Two different TiO2 shapes (nanobars and nanorhombics) were developed, using the solvothermal synthesis method, then incorporated at various contents (0–20 wt%) in the shell layer of the nanofiber to improve the optical, thermal, and mechanical properties of their corresponding fibrous mats to use them as alternative porous structures to the brittle porous TiO2 based photoelectrode presently used. The surface morphology, porosity, specific surface area, thermal stability, dye adsorption, optical and mechanical properties of the so developed nanofibrous mats were investigated. Emphasis was to the effect of solvent miscibility and solvent composition on fibrous mats' morphology. The successful incorporation of TiO2 nanoparticles inside the nanofibers’ shell was confirmed by various characterizations techniques. It was observed that addition of up to 15 wt% TiO2 shifted the UV–Visible absorption of the of the so developed nanofibrous mats to larger wavelength. Moreover, PET/(PET-TiO2) core/shell nanofibrous mats obtained with nanobars TiO2 showed higher thermal stability due to a better TiO2/PET interfacial interaction. Photoluminescence results confirmed the efficient charge transfer between TiO2 nanoparticles and PET with a minimum recombination of the photogenerated charges.

CONDUCTIVITY STUDY OF SODIUM BROMIDE AND SODIUM CHLORIDE SALTS IN BINARY MIXTURES OFAQUEOUS AND ORGANIC SOLVENTS

The effect of solvent composition on the conductivity behaviour of sodium bromide (NaBr) and sodium chloride (NaCl) salts in binary mixed aqueous and organic solvents was evaluated using conductivity measurement. The specific conductivities of the salts in methanol-water, ethylene glycol-water and ethylene glycol-methanol mixtures were determined at different solvent compositions (0, 0.1, 0.4, 0.7 and 1) and concentrations (0.01, 0.02, 0.03, 0.04 and 0.05 M) of the salts with JENWAY 4510 conductivity meter at room temperature. The results show that the conductivities of the solutions of both salts in the mixed solvent systems were higher at lower organic solvent compositions and gradually decreased with increasing composition of the solvents. It was also observed that conductivity decreased as the hydrocarbon character of the organic solvent increased in all the binary mixtures. These results have been discussed on the basis of free-ion and ion-pair interactions as well as other chemical and physical properties of the single component solvents.

Purification of monoethylene glycol by melt crystallization

Separation of glycols with close boiling points and relatively high viscosity at their melting point is a challenge in the production of high purity products downstream of biorefinery processes. In this work, the efficiency of the layer melt crystallization process with acetone as the assisting solvent was evaluated for a mixture of monoethylene glycol and 1,2-pentanediol. Solid-liquid equilibrium was measured and modelled with the NRTL and modified UNIFAC group-contribution models to evaluate the thermodynamic driving force of crystallization. Layer melt crystallization was conducted to determine the effect of solvent composition on purity, distribution coefficient of impurity, crystal growth rate, and yield at different operating conditions. Addition of the solvent altered the thermodynamics and kinetics of crystallization, thereby altering the purity level of the final product. An effective distribution coefficient of impurity between 0.1 and 0.6 in one-step crystallization was obtained, depending on the solvent composition and the applied operating conditions.