The demulsification by microwaves of liquid-liquid systems for metal recycling was experimentally and numerically investigated. Strongly ionic aqueous phases with high conductivities and typical ...organic phases, both representative of industrial ones, were used. Experimental microwave demulsification was achieved in both the W/O and O/W systems at the laboratory scale showing the rapidity and the efficiency of the process. The dielectric properties of these representative emulsions were measured and modeled using the permittivities measured in the separate phases and the phase fractions. Taking into account the direction of the emulsion, permittivities were predicted over a wide range of frequencies, along with microwave penetration depths in the whole range of phase fractions. Numerical simulations of the electric field distribution and penetration depths calculations at several frequencies demonstrated that microwave heating is relevant and possible in both W/O and O/W dense packed emulsions, which should rapidly lead to demulsification, including on a large industrial scale.
•Microwaves promote the demulsification of liquid-liquid systems in metal recycling.•Very fast microwave demulsification is achieved in both W/O and O/W emulsions.•Despite the high conductivity of ionic aqueous phases, scale up is possible.•Hanai’s model accurately fits the measured permittivities with phase fractions.•Demonstration that efficient large microwave demulsifiers can be designed is made.
Mechanomorphogenic Films
In article number 2104223, Scott H. Medina and co‐workers exploit fluorous–air–water interfaces to template the assembly of fluorinated amino acids into mechanomorphogenic ...thin films. These adaptive, crystalline materials change their macroscopic state in response to various mechanical and chemical signals, can self‐heal when damaged, and show selective permeability, capturing fluorous compounds from contaminated water samples.
•A compact axial separator with conical tube was studied.•The droplet trajectory comparison in the conical tube and equal-diameter tube was observed.•The effect of inlet oil fraction and liquid flow ...on separation efficiency was investigated.•The split ratio has considerable effect on separation performance.
Centrifugal technology for two-phase flow separation is widely used in industrial fields. However, the liquid-liquid separation is more difficult than solid-liquid and gas-liquid separation due to its relative small density difference and emulsion caused by droplets breakup. And the current hydrocyclones for liquid-liquid separation have some shortcomings limiting further improvement of separation efficiency. Axial separators with static swirler emerged as an effective alternative method. In this paper, a compact axial separator with conical tube was introduced and investigated experimentally using oil as the dispersed phase and tap water as the continuous phase. A high-speed camera was used to verify the advantages of conical tube compared to a cylindric tube by oil droplets trajectories. Additionally, the separation performance and pressure drop on different inlet flow rate and oil fraction was studied. In the experiment, the split ratio was changed by controlling the valve in HPO pipe, and the results show that separation efficiency can be improved by increasing the split ratio to ensure the drain of oil core.
•Air injection shifts oil droplets to the central region and enhances the separation efficiency.•The migration velocity of oil droplets toward the center is increased using air injection.•The length ...of the reverse flow region is increased by the air injection.•Air injection with the small diameter of air bubbles enhances the separation efficiency.
The need to have an efficient oil-water separator leads to improve and optimize the hydrocyclones. One way to improve the efficiency of a deoiling hydrocyclone is using air injection. In the present study, the effects of air injection on the three-phase flow field, oil droplet distribution, separation efficiency, and the working principles of deoiling hydrocyclones are investigated using the Eulerian-Eulerian multi-fluid model. The numerical results of two and three-phase flow are in good agreement against the experimental data. The oil core which is formed at the center of the deoiling hydrocyclones disappeared due to the air injection. The injected air creates an air-core inside the deoiling hydrocyclone and flows out through the overflow. The results show that the air injection increases the migration velocity of oil droplets and the length of the reverse flow region, leading to the enhancement of the separation efficiency. The air injection also increases the turbulence level and consequently increases the breakup rate of the oil droplets inside the deoiling hydrocyclone with air injection. Therefore, the air-liquid ratio and the injected bubble diameter should be regulated to increase the efficiency of the air-injected deoiling hydrocyclone. The results of different air injection diameters show that the small injection diameter is preferable due to the more penetration inside the deoiling hydrocyclone and increase the reverse flow region. The simulation results show that the air injection with bubble diameter of 42 μm increases the hydrocyclone efficiency up to 95.6%.
Carbon dioxide solubility {(vapor
+
liquid) equilibria: VLE} in ionic liquid, 1-butyl-3-methylimidazolium acetate (bmimAc), has been measured with a gravimetric microbalance at four isotherms about ...(283, 298, 323, and 348)
K up to about 2
MPa. (Vapor
+
liquid
+
liquid) equilibria (VLLE: or liquid–liquid separations) have also been investigated with a volumetric method used in our previous works, since the present analysis of the VLE data using our equation-of-state model has predicted the VLLE at CO
2-rich side solutions. The prediction for the VLLE has been confirmed experimentally. CO
2 solubilities at the ionic liquid-rich side show extremely unusual behaviors; CO
2 dissolves in the ionic liquid to a great degree, but there is hardly any vapor pressure above these mixtures up to about 20
mol% of CO
2. It indicates that CO
2 may have formed a non-volatile or very low vapor pressure molecular complex with the ionic liquid. The thermodynamic excess properties (enthalpy, entropy, and Gibbs free energy) of the present system do support such a complex formation. We have conducted several other experiments to investigate the complex formation (or chemical reactions), and conclude that a minor chemical reaction occurs but the complex formation is reversible without much degradation of the ionic liquid.
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•Liquid-liquid separation of PGMs’ from HCl medium using Cyphos IL 101 was studied.•Increasing acid and total Cl– ion concentration inhibited the extraction efficiency.•Poorly ...extracted Rh(III) efficiently scrubbed from organic phase in high acid solution.•Outer sphere complexation of PtCl62− and PdCl42− with ionic liquid was observed.•Quantitative stripping of Pt(IV) with NaSCN and Pd(II) with CH4N2S was achieved.
The present study dealt with liquid–liquid separation of PGMs (Pt, Pd, and Rh) from a model chloride-based leach solution using an undiluted phosphonium-based ionic liquid, Cyphos IL 101. Based on the parametric optimization studies, 30 min equilibration of both phases at an organic-to-aqueous volume ratio of 1 showed the highest PGMs’ extraction of > 99% Pt(IV) and Pd(II), and ~ 22% Rh(III). Depending upon the HCl and total Cl− ions concentrations, species like PtCl62− and PdCl42− exhibited remarkable ability for ion-pairing with Cyphos IL 101 unlike the higher charge density of RhCl63− which significantly lowered down to be < 5% at an aqueous feed of 0.1 mol.L−1 HCl. Thermodynamic properties with negative changes in enthalpy and entropy indicated that the PGMs’ extraction process exhibit exothermic behaviour with the formation of outer-sphere complexes in the ionic liquid phase. With the supports of experimental results and spectral analysis, the possible structure of Pt(IV)-Pd(II)-loaded ionic liquid could also be revealed. The poorly extracted Rh(III) was efficiently scrubbed by contacting with 5.0 mol.L−1 HCl solution, leaving the organic phase free from Rh(III). The selectivity in back-extraction of Pt(IV) and Pd(II) was achieved by first contacting the loaded ionic liquid with 1 × 10−1 mol.L−1 NaSCN in two stages, which exhibiting ~ 99% efficacy of Pt(II) stripping. Subsequently, Pt(IV)-depleted organic phase was stripped with 1 × 10−2 mol.L−1 CH4N2S that yielded > 99% Pd(II) recovery in a single contact. Results of extraction-stripping cycles that were showing similar efficiency of PGMs extractability clearly indicated the stability and reusability of ionic liquid.
Presented here is the design and performance of a coalescing liquid–liquid filter, based on low-cost and readily available meltblown nonwoven substrates for separation of immiscible phases. The ...performance of the coalescer was determined across three broad classes of fluid mixtures: (i) immiscible organic/aqueous systems, (ii) a surfactant laden organic/aqueous system with modification of the type of emulsion and interfacial surface tension through the addition of sodium chloride, and (iii) a water–acetone/toluene system. The first two classes demonstrated good performance of the equipment in effecting separation, including the separation of a complex emulsion system for which a membrane separator, operating through transport of a preferentially wetting fluid through the membrane, failed entirely. The third system was used to demonstrate the performance of the separator within a multistage liquid–liquid counterflow extraction system. The performance, robust nature, and scalability of coalescing filters should mean that this approach is routinely considered for liquid–liquid separations and extractions within the fine chemical and pharmaceutical industry.
We report crystals are ubiquitous and play an important role in our daily life. Recent studies on properties and formation of crystals have proven the attachment of particle ranging from ion pairs to ...well-crystallized nanocrystal is one of the most important ways for crystallization. Compared with the monomer-by-monomer (i.e., atoms, ions, or molecules) addition described in longstanding classical theories, so-called nonclassical crystallization pathways are more complex as the non-specific interaction of variation in system free energy and reaction kinetics. In view of the detailed insights into nonclassical crystallization pathways has broadened the scope of research across various disciplines such as geological events, biomineralization mechanisms, environmental remediation, and the development of functional materials, this paper reviews the current state of the art in nonclassical nucleation (the prenucleation clusters pathway, aggregation pathway, etc.) and growth pathways (oriented attachment and random attachment) based on several spotlights. In addition, the observed specific phenomena on crystallization in the last 10 years as well as recent advancements and achievements made on the synthesis of mesocrystals are also elucidated. With implications and perspectives of nonclassical crystallization researches proposed in this paper, this review aims to summarize research advancement regarding crystallizing systems. Emphasis will be placed on novel insights into nonclassical crystallization of materials, which are expected to provide completely new perspectives on the underlying crystallization mechanisms.
Halogenated organic solvents are the most commonly detected pollutants in groundwater and are particularly toxic and harmful. How to separate these dense nonaqueous phase liquid (DNAPL) pollutants ...efficiently from groundwater has become an important research question. Here, a novel hydrocyclone with annular overflow structure was designed, which eliminated the short-circuit flow of the traditional hydrocyclone and solved the problem of overflow entrainment caused by the enrichment of droplets near the locus of zero vertical velocities (LZVV) into turbulence. The flow field characteristics of this novel hydrocyclone were studied using Computational Fluid Dynamics (CFD) simulation and compared with the traditional hydrocyclone. It was found that the annular gap structure of the novel hydrocyclone increased the tangential velocity of the outer vortex. Moreover, the radius of the LZVV was expanded outward by 0.17 mm, which reduced the possibility of droplets with small particle sizes in the second phase escaping from the overflow pipe. The collective effect was to eliminate the short-circuit flow. This novel hydrocyclone was able to separate DNAPL pollutants with low consumption and high efficiency, across a range of inlet velocity from 4 to 6 m/s. The maximum separation efficiency was 99.91 %. In addition, with trichloroethylene (TCE) as the target pollutant, the maximum volume fraction of the dispersed phase in the hydrocyclone was located on the side wall of the hydrocyclone. Taken together, we believe that this work will provide a low-cost, efficient separation method for the separation of groundwater- contaminated liquid mixtures. Furthermore, it has broad application prospects in the field of heterotopic remediation of groundwater.
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•A novel hydrocyclone was designed to separate DNAPL contaminants in groundwater.•The annular gap structure can reduce the short-circuit flow rate of the hydrocyclone.•Lower-consumption and higher-efficiency separation were achieved simultaneously.
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