Solvent Dilution Research Articles

An Exceptional Broad-Spectrum Nanobiocide for Multimodal and Synergistic Inactivation of Drug-Resistant Bacteria

An Exceptional Broad-Spectrum Nanobiocide for Multimodal and Synergistic Inactivation of Drug-Resistant Bacteria

Selective separation of α-tocopherol using eco-friendly choline chloride – Based deep eutectic solvents (DESs) via liquid-liquid extraction

In this work, the extraction of α-tocopherol was studied using some recently introduced novel, simple and green deep eutectic solvents (DESs). Liquid – liquid extraction measurements were conducted on ternary mixtures of {n-hexane + (α-, β-, γ-, δ-) tocopherol + DESs}. The recently studied DESs including (mono-, di- and tri-) ethylene glycol, (mono-, di- and tri-) ethanolamine, and sucrose in combination with ChCl for the first time were used for this extraction. The various parameters affected on extraction efficiency including kind of DESs, temperature (298.15–308.15 K) and extraction time (12, 24 and 48 h) were evaluated. The calculated selectivity (S) and solute distribution coefficient (β) showed good performance of the selected DESs for α-tocopherol. The non-random liquid equation (NTRL) was utilized to correlate measured experimental LLE results, prediction of activity coefficient at infinite dilution (γ∞) and capacity of solvent for solute (C∞). Moreover, higher selectivity, lower contamination of extracted α-tocopherol (with solvents) and immiscibility of eutectic solvents in vitamin E were other advantages of this extraction.

Dynamic control analysis of eco-efficient double side-stream ternary extractive distillation process

The novel contribution of this paper is to implement the dynamic control investigation for the energy-saving double side-stream ternary extractive distillation configuration with constructing the practical and workable plumbing arrangement taking the representative example of separating a ternary benzene/isopropanol/water mixture. The new proposed control scheme achieves the stable regulatory control at rejecting the large disturbances of throughput and feed composition, wherein the particularly key control loops are controlling the product isopropanol composition by adjusting the extractant flow rate into extractive column C2 with simultaneously regulating the reflux ratio in extractive column C1 to abate the solvent dilution effect through composition cascade temperature control loops.

Synthesis and properties of ion-exchange materials based on hydrolysis lignins

Hydrolytic lignin is a large-tonnage waste product of ethyl alcohol production and is a renewable resource. The structure of lignin is characterized by the presence of a large number of hydroxyl groups, which provides the value of lignin as a raw material for synthesis in polymer chemistry. But due to their low chemical stability in dilute alkalis, acids and solvents, lignins are of little use for wide practical use. The introduction of additional functional groups into the lignin maromolecule by oxidative modification with the use of resource-saving technologies makes it possible to obtain new products for the synthesis of composite materials. On the basis of electrochemically modified lignin in polycondensation reactions with phthalic acid, ion-exchange materials have been obtained: weakly acidic cation exchangers with a exchange capacity of 0.1 mol/l NaOH 3.5-3.8 mmol/cm3, capable of sorbing cations in a wide range of pH values, and ampholyte (exchange capacity for sodium cation 6.4-6.6 mmol/cm3, for chlorine anion - 1.1-1.3 mmol/cm3). Ion exchangers synthesized on the basis of chlorine and nitro-containing lignins have been investigated in comparison with generally known industrial ion exchangers; they have high exchange and physic-mechanical characteristics and chemical resistance.

(Invited) Defective Hierarchical Porous Copper-Based Metal-Organic Frameworks Synthesised Via Facile Acid Etching Strategy

Introducing hierarchical pore structure to microporous materials such as metal-organic frameworks (MOFs) can be beneficial for reactions where the rate of reaction is limited by low rates of diffusion or high pressure drop. This advantageous pore structure can be obtained by defect formation, mostly via post-synthetic acid etching, which has been studied extensively on water-stable MOFs. Here we show that a water-unstable HKUST-1 MOF can also be modified in a corresponding manner by using phosphoric acid as a size-selective etching agent and a mixture of dimethyl sulfoxide and methanol as a dilute solvent. Interestingly, we demonstrate that the etching process which is time- and acidity- dependent, can result in formation of defective HKUST-1 with extra interconnected hexagonal macropores without compromising on the bulk crystallinity. These findings suggest an intelligent scalable synthetic method for formation of hierarchical porosity in MOFs that are prone to hydrolysis, for improved molecular accessibility and diffusion for catalysis. Figure 1

The Effect of Carbon Ink Rheology on Ink Separation Mechanisms in Screen-Printing

Screen-printable carbon-based inks are available in a range of carbon morphologies and concentrations, resulting in various rheological profiles. There are challenges in obtaining a good print when high loading and elasticity functional inks are used, with a trade-off often required between functionality and printability. There is a limited understanding of how ink rheology influences the ink deposition mechanism during screen-printing, which then affects the print topography and therefore electrical performance. High speed imaging was used with a screen-printing simulation apparatus to investigate the effect of viscosity of a graphite and carbon-black ink at various levels of solvent dilution on the deposition mechanisms occurring during screen-printing. With little dilution, the greater relative volume of carbon in the ink resulted in a greater tendency towards elastic behavior than at higher dilutions. During the screen-printing process this led to the ink splitting into filaments while remaining in contact with both the mesh and substrate simultaneously over a greater horizonal length. The location of separating filaments corresponded with localized film thickness increases in the print, which led to a higher surface roughness (Sz). This method could be used to make appropriate adjustments to ink rheology to overcome print defects related to poor ink separation.

Chronic toxicity of technical atrazine to the fathead minnow (Pimephales promelas) during a full life-cycle exposure and an evaluation of the consistency of responses

Fathead minnows (Pimephales promelas) were continuously exposed to the herbicide atrazine (0.15, 0.25, 0.46, 0.99, and 2.0 mg a.i./L, plus dilution water and solvent controls) for a complete life cycle (274 days). Concentrations of atrazine up to 2.0 mg a.i./L did not significantly reduce hatching success, larval survival at 30 or 60 days post-hatch, or reproduction (eggs/spawn, total eggs, spawns/female, or eggs/female) in the F0 generation. However, at 60 days of exposure, total length and total survival to study completion were significantly reduced in ≥0.46 mg a.i./L and ≥ 0.99 mg a.i./L treatments, respectively. In the F1 generation, hatchability of embryos at ≥0.25 mg a.i./L (range 74–82%) was significantly less than that of pooled control organisms (86%). Following 30 days' post-hatch exposure, F1 survival was not significantly different from pooled control for any treatment. Finally, tissues representing major life stages had bioconcentration factors ranging from 3.7× (F1 embryos, <24 h) to 8.5× (F0 adults), indicating little to no evidence of bioconcentration. We developed a series of questions to assess the consistency of observed responses in order to place the data in context with the wider available and relevant literature (e.g., Observed between studies? Observed between species? Observed at lower levels of biological organization?). The analysis for consistency supports the conclusion that atrazine does not pose a significant chronic risk to freshwater fish in terms of growth, reproduction, or survivorship at concentrations of up to at least 100 μg/L.

Fabrication of nanostructured antibacterial film derived from oligoglucosamine in ultraviolet nanoimprint lithography using a solvent-permeable template

This study aims to expand the antibacterial activity of the cross-linked film derived from oligoglucosamine by processing sharp protrusion nanostructures on the film surface in ultraviolet nanoimprint lithography using a solvent-permeable template. The solvent-permeable template was able to remove the dilution solvent contained in the flowable liquid derived from oligoglucosamine for life science and medical healthcare, which is the cause of molding failure, resulting in nanostructures of sharp protrusions. The nanostructured cross-linked antibacterial film derived from oligoglucosamine indicated 1.6 times the antibacterial activity compared to that of the flat comparative antibacterial film before the fabrication of the nanostructures.

A Vortex-Assisted Microextraction Based On Deep Eutectic Solvents for Determination of Four Parabens from Cosmetic Baby Oils and Optimization by Box-Behnken Design

This study presents microextraction and determination of four parabens by vortex-assisted microextraction based on deep eutectic solvents (DESs) in cosmetic baby oils. The most suitable DES, ChCl-ethylene glycol mole ratios of DES were determined as 1:2 for use in this study. The effect of DES types has been explored at traditional one factor experiment at a time. The effect of DES volume, dilution solvent volume and vortex time on extraction recovery were examined and optimized by the Box-Behnken design. After optimum conditions were determined, vortex-assisted microextraction based on DES, 0.1-100 µg mL-1 concentration in the range of the calibration curve was plotted for all parabens. The recovery values of parabens in cosmetic baby oil samples were in the range of 82.02-101.95% and the RSDs were varied from 1.64% to 2.91%. This developed method is very suitable and effective method for the extraction of parabens from cosmetic products of similar structure.

Static permittivity of environmentally relevant low-concentration aqueous solutions of NaCl, NaNO3, and Na2SO4.

In this paper, the result of a systematic study and molecular mechanisms governing the dielectric spectra of aqueous solutions of NaCl, NaNO3, and Na2SO4 with environmentally relevant concentrations (∼mmol/l) are presented, for frequencies from 200 MHz up to 20 GHz and at temperature 25.00 ± 0.01 °C. The measured spectra were fitted with a Debye relaxation model using a non-linear, weighted, least-squares analysis. Conductivity was measured independently to reduce uncertainty in obtaining other parameters by spectral fitting. Careful experimentation provided dielectric data of sufficiently low uncertainty to enable observation of polarization mechanisms that emerge only in the low-concentration regime. The data were fitted by a concentration-dependent parametric model that includes terms accounting for internal depolarizing fields and the solvent dilution effect (mixture relation), the kinetic depolarization effect, the dielectric saturation effect, and the Debye-Falkenhagen effect that accounts for the contribution of ionic atmosphere polarization. It has been shown that, in NaCl and NaNO3 solutions at sufficiently low concentrations, the static permittivity increases due to the Debye-Falkenhagen effect. It has also been shown that, to calculate the number of irrotationally bound water molecules ZIB, the measured static permittivity values should be corrected to account for the contributions of kinetic depolarization and Debye-Falkenhagen effects. Otherwise, unrealistic values of ZIB are obtained. An explanation for the different strengths of the Debye-Falkenhagen effect observed for the different electrolyte solutions, essentially due to the electrophoretic effect and coordination number, is also presented.

Viscosity Mixing Rules for Bitumen at 1–10 wt % Solvent Dilution When Only Viscosity and Density Are Known

Viscosity is an important parameter to assess heavy oil and bitumen upgrading operations, such as bitumen dilution to meet pipeline viscosity specification limits. In conceptual design studies that...

Expanding the applicability of magnetic ionic liquids for multiclass determination in biological matrices based on dispersive liquid-liquid microextraction and HPLC with diode array detector analysis.

Monitoring biological samples at trace levels of chemicals from anthropogenic actions such as pesticides, pharmaceuticals, and hormones has become a very important subject. This work describes a method for the determination of eight compounds of different chemical classes in human urine samples. Dispersive liquid-liquid microextraction based on magnetic ionic liquids was used as the sample preparation procedure. The main parameters of the method, such as sample dilution, type, and volume of disperser solvent, amount of magnetic ionic liquids, extraction time, and pH were optimized by univariate and multivariate procedures. Validation was performed using a urine sample of a male volunteer in order to obtain a calibration curve and the main analytical parameters of merit such as limits of detection and quantification. Values varied from 3.0 to 7.5µg/L and from 10 to 25µg/L, respectively. Satisfactory precisions of 21% for intraday (n = 3) and 16% for interday (n = 9) were achieved. Accuracy was evaluated by relative recovery assays using different urine samples and ranged from 75 to 130%. Robustness was assured by the Lenth method. The validated procedure was applied to five urine samples from different volunteers and the hormone estrone was found in one sample.

Ultrasound-assisted deep eutectic solvent extraction of echinacoside and oleuropein from Syringa pubescens Turcz.

In this work, deep eutectic solvents (DESs) were synthesized using ultrasound-assisted and stirring heating methods. DES combined with ultrasonic-assisted extraction (UAE) was proposed for the efficient extraction of glycosides from Syringa pubescens Turcz. A series of DES systems were used to evaluate the extraction efficiency of glycosides in S. pubescens. The DES composed of choline chloride/glycerol extracted higher than those of conventional solvents and other DESs. The extraction procedure of DES-UAE was optimized using response surface methodology. The extraction solvent was choline chloride-glycerol formed a DES with the mole ratio of 1:2 with 20 % of water content. The optimum conditions for echinacoside (ECH) and oleuropein (OLE) were ultrasound power of 200 W, extraction temperature of 68 °C, solvent to solid ratio of 20:1 mL/g and the extraction time of 45 min. Furthermore, the DES with 30 % water content can be used as dilution solvent before HPLC analysis of DES extract. In addition, the enrichment of ECH and OLE from DES extract was achieved using HPD-450 macroporous resin, with the recoveries of 80.04 % and 86.21 %, respectively.

Direct Nanoimprint Lithography of Polyethersulfone Using Cellulose‐Based Mold

AbstractPolyethersulfone (PES) with a glass transition temperature of 224 °C is a class of high‐performance super engineering plastics with excellent heat resistance, as well as mechanical, electrical, and optical properties. However, the nanopatterning of PES using thermal nanoimprint lithography at a high temperature can induce technical difficulties. High‐accuracy 900‐nm line patterning of PES is fabricated 50 times using both a solvent‐permeable cellulose‐based mold and dimethylformamide as a dilution solvent in direct thermal nanoimprint lithography. The use of dilution solvents in PES has yet been limited in the nanoimprint lithography, and the developed processes expand the surface patterning of super engineering plastic.

A deep eutectic solvent based liquid phase microextraction for the determination of caffeine in Turkish coffee samples by HPLC-UV

ABSTRACTA novel liquid-phase microextraction procedure for the determination and extraction of caffeine using a deep eutectic solvent based liquid-phase microextraction method (DES-LPME) was developed. A deep eutectic solvent consisting of choline chloride-phenol (1:3) and tetrahydrofuran as a dilution solvent were used for the extraction of caffeine from Turkish coffee samples. The quantitative recoveries were obtained when the DES volume was 400 µL, and the volume of tetrahydrofuran that was used as an emulsifier solvent was 800 µL. The limit of detection and the limit of quantification were found to be 0.12 and 0.40 µg mL−1, respectively. Linear dynamic range was 0.5–100 µg mL−1, and coefficient of determination (R2) was 0.9998. The relative standard deviation (RSD) was 2.20% when the standard solution concentration was 1.0 µg mL−1. The fact that the determination coefficient obtained from the calibration curve was greater than 0.9998 gives information about the accuracy of the method. Also, in order to determine the accuracy of the developed method, selected coffee samples were spiked with 25 and 50 µg mL−1 caffeine.

Hydrometallurgical separation of zinc and copper from waste brass ashes using solvent extraction with D2EHPA

A blend of brass ashes containing 48.0% of zinc and 16.6% of copper was processed through selective leaching with dilute H2SO4 and solvent extraction, using D2EHPA as the extracting agent in order to separate zinc and copper. Solvent extraction tests performed in bench and pilot scales were designed to evaluate the following operating parameters: time, pH, D2EHPA concentration, A/O ratio in the extraction step, and O/A ratio in the stripping step. Zinc present in the brass ashes was efficiently leached by H2SO4 (recovery of 91.9%), whereas only 8.6% of copper was leached, producing a liquor containing zinc (28.6g/L), copper (1.5g/L), calcium (0.45g/L), iron (0.43g/L), and chloride (0.22g/L), as well as fluoride, lead, nickel and cadmium, at levels below 0.01g/L. Zinc was selectively extracted over copper by solvent extraction with D2EHPA. A continuous solvent extraction run in pilot scale was carried out using 4 extraction stages (pH=2, A/O ratio=1) and 2 stripping stages (O/A ratio=2), where 91.8% of zinc extraction and 96.9% of zinc stripping were achieved. Iron extraction efficiency reached 85.9%, thus illustrating the need for its prior removal if required. The fluorine extraction was 29.9%, as compared to 10.4% for chlorine, whose respective extractions are related to the presence of iron and zinc in the liquor, as evidenced by species speciation analysis. A copper concentrate containing 42.2% was obtained in the leaching step.

Membrane gas-solvent contactor pilot plant trials for post-combustion CO2 capture

Membrane gas-solvent contactors are a hybrid technology of solvent absorption with membrane separation that achieves efficient and compact carbon dioxide capture. Here, we report on a successful pilot plant trial of membrane contactor technology undertaking post-combustion carbon dioxide capture from flue gas generated by an Australian black coal fired power station. The pilot plant utilised membrane contactors to undertake CO2 absorption into 30 wt% monoethanolamine (MEA) and the subsequent solvent regeneration stage to produce a pure CO2 product. The pilot plant trials identified a commercially available non-porous poly dimethylsiloxane composite hollow fiber membrane as the most suitable for both CO2 absorption and solvent regeneration. The overall mass transfer coefficient for CO2 absorption across the membrane into the solvent was comparable to laboratory results, enabling a recovery of >90% CO2 from the flue gas. Over time the mass transfer coefficient decreased because of both solvent dilution and some MEA loss, which reduced the enhancement the reaction provides to mass transfer in the solvent boundary layer. The overall mass transfer of CO2 from the solvent into the steam sweep during solvent regeneration was greater than that observed in the laboratory for the same temperature. The energy demand of the pilot plant was higher than for conventional CO2 capture technology, given the pilot nature of the process, lack of energy integration and thermal losses from uninsulated membrane modules. Accounting for these factors, the energy duty of the membrane contactor process was evaluated to be less than 4.2 MJ/kg of CO2 captured. Critically, the pilot plant demonstrated the viability of membrane contactor technology for post-combustion carbon capture on an industrial scale.

Determination of five Alternaria toxins in wolfberry using modified QuEChERS and ultra-high performance liquid chromatography-tandem mass spectrometry

A modified quick, easy, cheap, effective, rugged, and safe method coupled with ultra-high performance liquid chromatography-tandem mass spectrometry was established for the simultaneous detection of five Alternaria toxins (tenuazonic acid, alternariol, alternariol monomethyl ether, altenuene, and tentoxin) in wolfberry. The sample pretreatment conditions including the dilution solvent, the extraction solvent and the QuEChERS purification parameters were optimized. Detection of the five Alternaria toxins was performed in MRM mode under ESI + conditions. The results showed that the five Alternaria toxins exhibitedgood linearity (1–200 μg/L, with correlation coefficients > 0.999). The limits of detection were 0.07–0.24 μg/kg, and the limits of quantification were 0.32–0.77 μg/kg. The trueness was between 73.8% and 111.5%, and the precision was lower than 10%. The established method was effectively used for the determination of five Alternaria toxins in 155 wolfberry samples from Northwest China.

Dilute solvent welding: A quick and scalable approach for enhancing the mechanical properties and narrowing the pore size distribution of electrospun nanofibrous membrane

Major limitations to the practical use of nanofibrous membranes in water filtration are their weak mechanical properties and wide pore size distribution. This study describes a quick and scalable method to improve the mechanical properties and narrow the pore size distribution of nanofibrous membranes by welding the nanofibers at their junction points. The welding process involves a simple dilute solvent spraying step followed by heating, requiring only a few minutes. The polymer's solvent was diluted with a non-solvent to avoid excessive dissolution of the nanofibers. With that, the degree of welding can be controlled by the volume fraction of solvent, the heating temperature and heating temperature. Dilute solvent welding enhanced the mechanical properties of the nanofibrous membrane while slightly changed the fiber crystallinity and fiber size distribution. Furthermore, the membrane pore size distribution narrowed with welding while high porosity (~80%) was retained. In membrane distillation (MD) experiments, the welded nanofibrous membrane exhibited more robust MD performance than the pristine nanofibrous membrane with only slight decreases of vapor flux. This technique can be applied universally to treat both nanofibrous flat sheet and tubular membranes made from soluble polymers with their corresponding diluted solvents.

Solubility of water in n-alkanes: New experimental measurements and molecular dynamics simulations

The solubility of water in n-hexane, n-heptane, n-undecane and n-hexadecane was experimentally determined at atmospheric pressure from 282 K to 318 K, using the Karl-Fischer coulometric method. The standard thermodynamic functions of solution and solvation were estimated from the experimental results and interpreted according to the density and molecular composition of the solvents. The new data provides a coherent, high accuracy set of results, which adds to existing data (n-hexane, n-heptane), while filling an important gap in the literature for much less studied n-alkanes such as n-undecane and n-hexadecane. Atomistic molecular dynamics simulations of water at infinite dilution in the same solvents and in n-tetradecane are presented and analysed, providing molecular level insight into the solvation process and structure of the solutions.