Aqueous Phase Properties Research Articles

Physical properties and oxidative stability of mayonnaises fortified with natural deep eutectic solvent, either alone or enriched with pigmented rice bran

This article explores the novel use of natural deep eutectic solvents (NaDES) in real food by incorporating them into mayonnaise, either alone or with pigmented rice bran (RB). Results showed that NaDES-fortified mayonnaises could prevent lipid oxidation. Notably, mayonnaises with NaDES2 (betaine:sucrose:water) significantly reduced the production of lipid hydroperoxides, which was maintained to an average of 2.6 mmol LOOH/kg oil, which is 2.9 times lower than the control (7.5 mmol LOOH/kg oil), or 7.4 times lower than mayonnaise with citric acid (19.1 mmol LOOH/kg oil). NaDES2-fortified mayonnaises maintained high tocopherols levels (0.97 g/Kg oil) and reduced volatile compounds from secondary lipid oxidation. This effect may result from NaDES altering the aqueous phase properties of mayonnaise, notably by reducing water activity by ∼0.1. Finally, pre-enrichment of the NaDES phase with bioactive molecules (e.g. from pigmented RB) represents an innovative perspective to promote the health benefits of formulated foods.

Hydrothermal carbonization of combined food waste: A critical evaluation of emergent products

Hydrothermal carbonization (HTC) increasingly appears as an eco-friendly method for managing food waste (FW). In this work, a combination of FW was subjected to HTC, and products were critically evaluated. This involved a lab-scale pressure reactor and optimization of HTC conditions: temperature (220–340 °C) and residence time (90–260 min) via central composite design type of response surface methodology (CCD-RSM). Results showed varying temperatures and residence time to impact the hydrochar (HC) and hydrothermal carbonization aqueous phase (HTC-AP) properties. Although HC produced through HTC exhibited lower ash content (<2%) despite higher fixed carbon (>55 %) with respect to the raw FW, the heating value of HC ranged from 19.2 to 32.5 MJ/kg. Temperature primarily influenced FW conversion, affecting carbonaceous properties. Saturated fatty acids (SFA) were found to be predominant in the HTC-AP under all tested operating conditions (77.3, 48.4, and 37.1 wt% for HTC at 340, 280, and 220 °C in 180 min, respectively). Total phosphorus recovery in HC and HTC-AP respectively peaked at 340 °C and 220 °C in 180 min. The study concludes that HTC holds promise for energy-dense biofuel production, nutrient recovery, and fostering a circular economy.

Preventing emulsification during rare earths solvent extraction by the addition of Span 80 to enhance the interfacial stability of the P507 oil droplets

The demand for rare earth elements is increasing daily with rapid economic development, thereby increasing the requirements for its separation and purification technologies. The major method for purification and separation of rare earth elements in the industry is currently solvent extraction. In the actual production process, emulsification often occurs because of improper control of the organic phase, aqueous phase properties or operating conditions, and resulting in resource wastage and environmental pollution. This has become an issue that restricts the development of the rare earths industry. To prevent emulsification during rare earths solvent extraction, the organic structure of the P507-kerosene solution was regulated by the addition of Span 80 as a regulator. This study investigated the effects of Span 80 content, P507 concentration, saponification degree and the amount of pre-loading rare earth elements in the organic phase after adding Span 80 on the extraction efficiency of Er3+ and oil content in the raffinates. The results demonstrated that when the content of Span 80 was 6 %, the saponification degree of P507 in the organic phase was 10 %, the concentration of Er3+ in the aqueous phase was 0.5 g /L, the pH value in the aqueous phase was 3, the phase ratio (VO: VA) was 1:2, the extraction efficiency could still reach more than 99 %, and the oil content in the raffinates was 13.9 mg/L. The results demonstrated that the final extraction efficiency did not decrease; however, the extraction rate of rare earth elements did. Further, the oil content in the raffinates decreased greatly after the addition of Span 80. The mechanism was investigated using Fourier-transform infrared (FTIR) spectroscopy and atomic force microscopy (AFM). The interfacial stability of P507 oil droplets was enhanced by the addition of Span 80. Emulsification was, thus, effectively prevented and the dissolution loss of the organic phase was greatly reduced. The results provide a novel method for preventing emulsification during rare earths extraction at the source, and a novel idea for preventing resource loss and protecting the ecological environment.

A new hydration kinetic model based on boundary nucleation and growth mechanism with time-dependent growth rate: Application to quantitively characterize the influence of alkali on the early hydration of cement

In this study, a boundary nucleation and growth model with a time-dependent growth rate was proposed to quantitively characterize the precipitation of CSH. The newly constructed model was typically applied to quantitively analyse the influence of alkali content on the growth of CSH, and the value-taking equations of the time-dependent growth rate of CSH in various alkali content systems were proposed and verified. The experimental and simulation results proved that a high soluble alkali content stimulated early hydration (within the initial several hours) and inhibited the late growth of CSH (>20 h) in cement paste. The time-varying ion concentrations in cement solutions were the main driving force for the change in the growth rate of CSH with time. Likewise, the variation in the aqueous phase properties of cement pastes also explains the influence of alkali content on the growth rate of CSH, i.e., the high initial pH of the solution with high soluble alkali led to the high supersaturation degree and high growth rate of CSH, consuming large amounts of calcium ions and in turn reducing the later supersaturation degree and growth rate. The newly constructed model is also expected to precisely characterize the factors that have a significant influence on the precipitation of cement hydrates.

Experimental Study of Surface Damage of Stainless Steel Subjected to Cavitation Collapse in Aqueous Environment

With the aim of understanding cavitation damage of stainless steel under the effect of cavitation collapse in an aqueous environment, morphology, phase, chemical state, electrochemical, and other properties after cavitation and erosion are methodically examined. The obtained results indicate that the addition of metal ions in pure water strengthens the dynamic effect of cavitation collapse. When the cavitation collapses, it is capable of releasing a high temperature and transferring it to the surface of the stainless steel in a short time. Then, through the rapid cooling of the pure water environment, the martensitic structure is generated, but the presence of a massive amount of metal ions leads to a decrease in the speed of heat conduction and absorption of some heat. After the collapse of the bubble, the passivation film on the surface of the stainless steel incorporates into the creation of initial micropores. A concentration difference and a growth of the current density at the bottom of the hole, as well as a reduction in the pH value are detectable. Compared with pure water, 3.5% NaCl solution contains more free ions and its local current density is higher, so its corrosion resistance is worse.

Machine-learning-aided thermochemical treatment of biomass: a review

Thermochemical treatment is a promising technique for biomass disposal and valorization. Recently, machine learning (ML) has been extensively used to predict yields, compositions, and properties of biochar, bio-oil, syngas, and aqueous phases produced by the thermochemical treatment of biomass. ML demonstrates great potential to aid the development of thermochemical processes. The present review aims to 1) introduce the ML schemes and strategies as well as descriptors of the input and output features in thermochemical processes; 2) summarize and compare the up-to-date research in both ML-aided wet (hydrothermal carbonization/liquefaction/gasification) and dry (torrefaction/pyrolysis/gasification) thermochemical treatment of biomass (i.e., predicting the yields, compositions, and properties of oil/char/gas/aqueous phases as well as thermal conversion behavior or kinetics); and 3) identify the gaps and provide guidance for future studies concerning how to improve predictive performance, increase generalizability, aid mechanistic and application studies, and effectively share data and models in the community. The development of biomass thermochemical treatment processes is envisaged to be greatly accelerated by ML in the near future.

The influence of key reactions during hydrothermal carbonization of sewage sludge on aqueous phase properties: A review

Hydrothermal carbonization (HTC) emerges as a promising technology to reduce the volume of activated sewage sludge (SS) and generate solid products as fuels. During HTC, extracellular polymeric substance and cell wall degrade to form low molecular compounds, which can further carry out hydrolysis, dehydration, polymerization, etc. The temperature has a notable impact on the HTC, which ultimately changes the composition of the aqueous phase. A large amount of the aqueous phase remains a by-product containing high amounts of organic and inorganic compounds. Herein, the HTC of SS process and aqueous phase treatment were discussed, especially in industrial applications within China. This review depicts the influence of aqueous phase properties on the hydrochar properties of SS, especially using the aqueous phase recirculation process. The mechanism during HTC of SS has been discussed, especially Maillard reaction, which would significantly influence the aqueous phase and hydrochar. The systematic information on the current research, new applications and new perspectives in this field to promote its further development were provided.

Effect of agave fructans on xanthan rheology: Impact on sodium caseinate emulsion properties.

The influence of agave fructans (AF) (1-10%) and xanthan (from 0.03% to 0.25%) in combination with sodium caseinate (SC) at 1% on the rheological and physicochemical properties of aqueous phases and emulsions was evaluated. Steady-state flow behavior, particle size distribution, and stability studies were used to characterize the systems. The aqueous systems displayed the shear-thinning behavior characteristic of xanthan solutions; however, this behavior was modified by the presence of SC and AF due to interactions between AF-SC and AF-xanthan based on predominant hydrogen bonding because of the hydroxyl groups on AF. In emulsions, an increase in viscosity due to the effect of the AF concentration reflects a probable association of fructan aggregates on the surface of SC particles that reinforce the interfacial layer of SC, while xanthan contributes to an increase in the viscosity of the continuous phase, which effectively prevents coalescence and floc formation even at higher concentrations, despite the possible existence of a depletion flocculation effect attenuated by the interaction between AF-SC and AF-xanthan. PRACTICAL APPLICATION: These results can be of use, in an important way, in the design of stable functional emulsions in which there is an application for agave fructans recognized as dietary fiber, also considering their peculiar way of interacting with xanthan favoring its stabilizing functionality.

Machine learning predicting wastewater properties of the aqueous phase derived from hydrothermal treatment of biomass

Hydrothermal treatment (HTT) is a potential technology for producing biofuel from wet biomass. However, the aqueous phase (AP) is generated inevitably in the process of HTT, and studies are lacking on the detailed exploration of AP properties. Therefore, machine learning (ML) models were built for predicting the pH, total nitrogen (TN), total organic carbon (TOC), and total phosphorus (TP) of the AP based on biomass feedstock and HTT parameters. Results showed that the gradient boosting decision tree (average testing R2 0.85–0.96) can accurately predict the above wastewater properties for both single- and multi-target models. ML-based feature importance indicated that nitrogen content of biomass, solid content, and temperature were the top three critical features for pH, TN, and TP, while those for TOC were reaction time, lipid, and temperature. This ML approach provides new insights to understand the formation and properties of the HTT AP by ML rather than time-consuming experiments.

Investigation of Anaerobic Digestion of the Aqueous Phase from Hydrothermal Carbonization of Mixed Municipal Solid Waste

In 2017, the United States Environmental Protection Agency (EPA) reported that Americans generated over 268 million tons of municipal solid waste (MSW). The majority (52%) of this waste ends up in landfills, which are the third largest source of anthropogenic methane emissions. Improvements in terms of waste management and energy production could be solved by integrating MSW processing with hydrothermal carbonization (HTC) and anaerobic digestion (AD) for converting organic carbon of MSW to fuels. The objectives of this study were to (a) investigate HTC experiments at varying temperatures and residence times (b) evaluate aqueous phase and solids properties, and (c) perform AD bench scale bottle test on the aqueous phase. A mixture of different feedstock representing MSW was used. HTC at 280 °C and 10 min yielded the highest total organic carbon (TOC) of 8.16 g/L with biogas yields of 222 mL biogas/g TOC. Results showed that AD of the aqueous phase from a mixed MSW feedstock is feasible. The integrated approach shows organic carbon recovery of 58% (hydrochar and biogas). This study is the first of its kind to investigate varying temperature and times for a heterogeneous feedstock (mixed MSW), and specifically evaluating HTC MSW aqueous phase anaerobic biodegradability.

Structural (monomer and dimer), wavefunctional, NCI analysis in aqueous phase, electronic and excited state properties in different solvent atmosphere of 3-{(E)-[(3,4-dichlorophenyl)imino]methyl} benzene-1,2-diol

In this present work, structural, wave functional and electronic properties of 3-{(E)-[-(3,4-dichlorophenyl)imino]methyl}benzene-1,2-diol are investigated by utilizing Gaussian 16W density functional theory tool. Optimized geometrical properties, wave functional properties like, localized orbital locators, electron localization functions and reduced density gradient are examined in aqueous phase. Band gap energies with solvation effect are calculated from HOMO-LUMO orbital’s with different solvent molecules. Reactive sites are identified from MEP analysis in various solutions. Excited energies are calculated using TD-DFT method in different polar and non polar liquids. Intra molecular and intermolecular interactions are studied by NBO method to explain the charge transfer within the molecules. Spectroscopic (IR and Raman) wave numbers for headline compound are predicted computationally in monomer and dimer form. Moreover, adsorption, metabolism, excretion, distribution with toxicity are computed. Finally, to find biological and anticancer activities of title compound molecular docking study is performed.

Hydrothermal carbonization of anaerobic digestate and manure from a dairy farm on energy recovery and the fate of nutrients

Hydrothermal carbonization (HTC) of raw and anaerobically digested (AD) manure with either water or whey was studied, with the goal of recovering energy and nutrients. Specifically, the impacts of HTC reaction temperature (180–240 °C), solid feedstock, and type of liquid on hydrochar quality and aqueous phase properties were tested. Of the hydrochars produced, the calorific value of whey-based hydrochar was the highest, (19.4 and 16.0 MJ/kg for manure and digestate, respectively). Overall, the net energy gain was higher for HTC of manure with whey (7.4–8.3 MJ/kg dry feedstock) and water (4.4–5.1 MJ/kg) compared to the combined AD-HTC process with whey (4.4–5.3 MJ/kg) and water (2.3–2.9 MJ/kg). Digestate-derived hydrochar contained up to 1.8% P, higher than manure-derived hydrochar (≤1.5%). Using whey as a liquid for HTC increased the aqueous-phase N-P-K concentrations up to 3,200, 410, and 7,900 mg/L, respectively, suggesting its potential use as a liquid fertilizer.

Transferable interactions of Li+ and Mg2+ ions in polarizable models.

Therapeutic implications of Li+, in many cases, stem from its ability to inhibit certain Mg2+-dependent enzymes, where it interacts with or substitutes for Mg2+. The underlying details of its action are, however, unknown. Molecular simulations can provide insights, but their reliability depends on how well they describe relative interactions of Li+ and Mg2+ with water and other biochemical groups. Here, we explore, benchmark, and recommend improvements to two simulation approaches: the one that employs an all-atom polarizable molecular mechanics (MM) model and the other that uses a hybrid quantum and MM implementation of the quasi-chemical theory (QCT). The strength of the former is that it describes thermal motions explicitly and that of the latter is that it derives local contributions from electron densities. Reference data are taken from the experiment, and also obtained systematically from CCSD(T) theory, followed by a benchmarked vdW-inclusive density functional theory. We find that the QCT model predicts relative hydration energies and structures in agreement with the experiment and without the need for additional parameterization. This implies that accurate descriptions of local interactions are essential. Consistent with this observation, recalibration of local interactions in the MM model, which reduces errors from 10.0 kcal/mol to 1.4 kcal/mol, also fixes aqueous phase properties. Finally, we show that ion-ligand transferability errors in the MM model can be reduced significantly from 10.3 kcal/mol to 1.2 kcal/mol by correcting the ligand's polarization term and by introducing Lennard-Jones cross-terms. In general, this work sets up systematic approaches to evaluate and improve molecular models of ions binding to proteins.

Aqueous phase properties on governing particle coagulation and mechanism nucleation in one-step emulsion polymerization of styrene

As is well known, changing continuous phase properties has a great influence on the nucleation mechanism and particle size, and the addition of electrolytes or alcohol is the main mean to control the properties of solution phase. In this study, a series of experiments about polystyrene emulsion polymerization were produced by adding K2CO3 and alcohols in different types and contents, so as to study the essential reasons for the influence of solution phase properties on the growth process of particles and the synergistic effect between electrolytes and alcohols. In the presence of methanol-water polymerization systems, the particle size of polystyrene latex particles was enlarged obviously with the increase of methanol content when 0.6 wt% K2CO3 was contained, but there are no significant changes for the particle size with 0.1 wt% K2CO3. For the alcohols with different chain lengths, the particle diameters as follows: Dpropanol (212.6 nm) > Dethanol (123.1 nm) > Dmethanol (90.75 nm). They indicate that adding alcohol to the solution could promote particle coagulation by reducing dielectric constant of the continuous phase. As a result, the polystyrene latex particles with large-scale particle size can be acquired using controlling particle coagulation by changing aqueous phase composition.

Influence of the polymer degradation on enhanced oil recovery processes

• A novel 2-D chemical reservoir simulator is proposed using flux limiting functions. • A new polymer degradation model is used to calculate the aqueous phase properties . • The oil desaturation curve is modified to consider the viscoelastic effects. Polymer flooding is one of the most common and technically developed chemical Enhanced Oil Recovery (EOR) processes. Its main function is to increase the carrying phase’s (i.e., water or brine) viscosity in order to mobilize the remaining trapped oil. Many numerical simulators have been developed during the last 30 years considering the influence of the polymer molecules on the viscosity as well as on other physical parameters (e.g., diffusion, adsorption). Nevertheless, there are certain phenomena which were not previously considered, for instance, the interfacial effects of hydrophobically modified polymers. Furthermore, the degradation of the polymer molecules in a harsh environment such as the one found in porous media is well known. This causes a deterioration on the viscosifying properties, diminishing the efficiency of the method. It is important also to consider the effect of the polymer viscoelasticity on the microscopic sweeping efficiency, lowering the residual oil saturation , which has not been properly addressed. A new compositional 2D numerical simulator is presented for polymer flooding in a two-phase, three-component configuration, considering all these physical effects present in porous media and using a fully second-order accurate scheme coupled with total variation diminishing (TVD) functions. Results demonstrated that degradation cannot be considered negligible in any polymer EOR process, since it affected the viscoelastic and viscosifying properties, decreasing the sweeping efficiency at both micro- and macroscopic scales. This simulator will allow setting the desired designing properties for future polymers in relationship with the characteristics of the oil field to be exploited.

Experimental methods in chemical engineering: Preface

AbstractChemical engineering research encompasses a plethora of subjects ranging from nanoscale to climate change, from medicine to hazardous waste management, and from electronics and photonics to process intensification, manufacturing, and modelling. The 2017 AIChE meeting included 8000 oral presentations and posters with all these diverse topics. Here we identify experimental methods and instrumentation that straddle these subjects based on Can. J. Chem. Eng. articles published from 2016–2017. Temperature, pH, pressure, and flow rate are the physical properties most researchers report. We identified over 50 experimental techniques, reactor types, and modelling methodologies and show that articles with an experimental focus are more strongly linked than those that concentrate on hydrodynamic modelling and numerical simulation. Spectroscopy dominates instrumental techniques to characterize solids and catalyst properties and we classify 36 instruments according to what property they measure and the scale, nature of the phase, composition, and morphology. A bibliometric analysis grouped the physicochemical properties into three major research clusters centered around solid properties, liquid phase properties, and gas phase and aqueous phase properties. Articles in this special series describe the basic principles of one experimental method or instrument that appears frequently in the journal. Together with a short background, the articles highlight fields of application, assess the sources of error, detection thresholds, and uncertainty. This series provides chemical engineers with a concise, accessible reference guide to help identify and choose appropriate experimental techniques and instruments.

Fabrication of peppermint essential oil nanoemulsions by spontaneous method: Effect of preparing conditions on droplet size

AbstractPeppermint essential oil is used in food, cosmetics, and pharmaceutical industries. The fabrication of peppermint nanoemulsion can increase its efficiency at lower concentrations. Spontaneous emulsification is a low‐energy method based on the characteristics of the surfactant. Factors affecting the interfacial properties of organic and aqueous phases at the time of mixing can influence the formation and droplet size of emulsions. In this study, nonionic surfactants of Tween 20, Tween 40, and Tween 80 were used to prepare peppermint microemulsions. After selecting an appropriate surfactant, the effect of stirring speed, organic phase temperature, storage for 90 days, and different surfactant‐to‐oil ratios were evaluated to investigate the emulsifying ability of the surfactant under different conditions and concentrations. The results showed that the best microemulsion was formed using Tween 80 with a droplet size of around 50 nm. Varying the surfactant‐to‐oil ratio from 50 to 225%, we found that a nanoemulsion was formed at all concentrations. Moreover, we found that the speed of mixing of organic and aqueous phases and the temperature of the organic phase affects the droplet size. At higher surfactant‐to‐oil ratios, storing the microemulsion for 90 days decreased its droplet size and increased transparency.

Marangoni-driven flower-like patterning of an evaporating drop spreading on a liquid substrate

Drop motility at liquid surfaces is attracting growing interest because of its potential applications in microfluidics and artificial cell design. Here we report the unique highly ordered pattern that sets in when a millimeter-size drop of dichloromethane spreads on an aqueous substrate under the influence of surface tension, both phases containing a surfactant. Evaporation induces a Marangoni flow that forces the development of a marked rim at the periphery of the spreading film. At some point this rim breaks up, giving rise to a ring of droplets, which modifies the aqueous phase properties in such a way that the film recoils. The process repeats itself, yielding regular large-amplitude pulsations. Wrinkles form at the film surface due to an evaporative instability. During the dewetting stage, they emit equally spaced radial strings of droplets which, combined with those previously expelled from the rim, make the top view of the system resemble a flower.

Estimate of dynamic change of fluid saturation during CO2 injection — Case study of a regional aquifer in Croatia

Total carbon dioxide ([Formula: see text]) storage capacities are estimated in numerous studies, but there is a lack of research of possible injection rates at a particular site. We have performed compositional simulation with permeability variation (based on log-normal distribution parameters of the measured data from similar formations in an oil field above the aquifer) to include changes of aqueous and gaseous phase properties (composition, viscosities, density), and heterogeneity of a regional [Formula: see text] storage site. We have performed sensitivity tests on vertical permeability multiplier, different grid block sizes, diffusivity, and capillary pressures to detect the key parameters for injectivity and storage efficiency. In this way, we modeled heterogeneity of a [Formula: see text] storage site and the possible injection rate in this detail for the first time. Based on pressure analysis in simulation cases, we found that it will be hard to avoid fracturing the near-wellbore zone, but fracturing these zones might also increase the injectivity, and this can still be done without damaging the cap rock. Simulation results indicated that maximum pressure will occur in zones above wellbores at the short period after the injection, and almost no change of average pressure in the regional aquifer will be noticeable, which leads to the conclusion that the total (theoretical) storage capacity is not the key issue for [Formula: see text] storage in aquifers and that injectivity for the storage site (expressed as the rate) should be the key parameter for selecting the pilots for [Formula: see text] storage.

A new robust stability algorithm for three phase flash calculations in presence of water

Thermodynamic phase equilibrium calculations for systems containing water are inseparable parts of the compositional hydrocarbon reservoir simulation. In this regard, stability analysis of the phases for distinguishing the existing ones at specific pressures and temperatures is a principal part of such calculations. This study is aimed to develop a new stability algorithm with application to three phase flash calculations in the presence of brine. The developed scheme is capable of doing the phase behavior calculations in a more robust way compared to the other available algorithms. Henry's law is utilized to predict the aqueous phase properties, and a new initial guess is provided for three phase flash calculations that assures the convergence of the scheme. It is shown that the proposed procedure is able to handle the systems with high CO2 content while the available schemes in the literature fail.