Continuous Separation Research Articles

Cobalt/nickel purification by solvent extraction with ionic liquids in millifluidic reactors: From single-channel to numbered-up configuration with solvent recycle

This work describes the continuous separation of cobalt and nickel by solvent extraction in a numbered-up millifluidic system (1 mm ID) using Cyphos IL 101 (C101) as extractant, which is recycled. A dilution of 50 vol% C101 in p-cymene was chosen as the optimal trade-off between extraction performance and hydrodynamic properties of the solvent. The effects of channel length (20–100 cm), flow rate (1–2.5 mL min−1) and temperature (20–70 °C) were investigated on the extraction, scrubbing and stripping performance in a single-channel system. Subsequently, the developed manifold structure (five parallel reactors) was benchmarked against the single-channel system, which displayed a maldistribution of only 1% and performed equally well as the single-channel system. Then, a continuous separation process of one extraction and two countercurrent stripping stages was executed for 6 h with the proven manifold. A cobalt and nickel purity of, respectively, 99.7 and 97.7 % were achieved at a rate of 5 mL min−1. Stable slug flow was observed in the entire system throughout the operating period.

Photo‐Driven Quasi‐Topological Transformation Exposing Highly Active Nitrogen Cation Sites for Enhanced Photocatalytic H2O2 Production

AbstractHerein, the exposure of highly‐active nitrogen cation sites has been accomplished by photo‐driven quasi‐topological transformation of a 1,10‐phenanthroline‐5,6‐dione‐based covalent organic framework (COF), which contributes to hydrogen peroxide (H2O2) synthesis during the 2‐electron O2 photoreduction. The exposed nitrogen cation sites with photo‐enhanced Lewis acidity not only act as the electron‐transfer motor to adjust the inherent charge distribution, powering continuous and stable charge separation, and broadening visible‐light adsorption, but also providing a large number of active sites for O2 adsorption. The optimal catalyst shows a high H2O2 production rate of 11965 μmol g−1 h−1 under visible light irradiation and a remarkable apparent quantum yield of 12.9 % at 400 nm, better than most of the previously reported COF photocatalysts. This work provides new insights for designing photo‐switchable nitrogen cation sites as catalytic centers toward efficient solar to chemical energy conversion.

Photo-Driven Quasi-Topological Transformation Exposing Highly Active Nitrogen Cation Sites for Enhanced Photocatalytic H2 O2 Production.

Herein, the exposure of highly-active nitrogen cation sites has been accomplished by photo-driven quasi-topological transformation of a 1,10-phenanthroline-5,6-dione-based covalent organic framework (COF), which contributes to hydrogen peroxide (H2 O2 ) synthesis during the 2-electron O2 photoreduction. The exposed nitrogen cation sites with photo-enhanced Lewis acidity not only act as the electron-transfer motor to adjust the inherent charge distribution, powering continuous and stable charge separation, and broadening visible-light adsorption, but also providing a large number of active sites for O2 adsorption. The optimal catalyst shows a high H2 O2 production rate of 11965 μmol g-1 h-1 under visible light irradiation and a remarkable apparent quantum yield of 12.9 % at 400 nm, better than most of the previously reported COF photocatalysts. This work provides new insights for designing photo-switchable nitrogen cation sites as catalytic centers toward efficient solar to chemical energy conversion.

Continuous Separation and Purification of Chemical Species by Continuous Liquid–Liquid Partition Chromatography Implemented with Membrane-Based Phase Separators

Continuous Separation and Purification of Chemical Species by Continuous Liquid–Liquid Partition Chromatography Implemented with Membrane-Based Phase Separators

Effect of plateletpheresis on haematological values in voluntary donors: a retrospective data analysis over an eight-month period

<p><strong>Aim</strong> <br />To analyse changes in haematological values after plateletpheresis in donor population with regard to donor safety.<br /><strong>Methods</strong> <br />A retrospective study was conducted on first time and repeated healthy donors over a period of eight months in the Blood<br />Transfusion Institute in the Federation of Bosnia and Herzegovina in Sarajevo. A total of 75 plateletpheresis procedures performed using Amicus continuous flow cell separator were evaluated. Various pre- and post-donation haematological values were measured in all donors: haemoglobin concentration (Hb), haematocrit (Hct), red blood cell count (RBC), platelet count (PLT), white blood cell count (WBC), mean platelet volume (MPV), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), and mean corpuscular haemoglobin concentration (MCHC).<br /><strong>Results</strong> <br />A significant decrease in post-donation Hb, Hct, RBC, PLT, MCHC (p<0.000) and WBC (p=0.003), and a significant<br />increase in MPV (p=0.011) and MCV (p<0.000) was found. Percentage reduction of haematological parameters Hb, Hct, RBC, PLT, WBC and MCHC decrease of 6.6%, 6.5%, 5.9%, 24%, 4.6% and 0.3%, respectively, in their respective count was noted postdonation. Eight (11%) donors had a post-procedure platelet count less than 150x10e9/L. Twenty two donors (29%) experienced mild side effects due to hypocalcaemia.<br /><strong>Conclusion </strong><br />Plateletpheresis procedures are generally safe and well tolerated, without evident associated clinical manifestations<br />on healthy donors. </p>

High permeability PEG/MXene@MOF membrane with stable interlayer spacing and efficient fouling resistance for continuous oily wastewater purification

Unstable interlayer spacing of lamellar membranes would be rapidly compressed and narrowed under normal high flowrates and concentration polarization effect contributes to reduced permeation and fouling resistance. Herein, a large permeability PEG/MXene@MOF membrane with stable interlayer spacing and superior antifouling property was created via facile interface self-assembly strategy. Metal-organic framework (MOF, UiO-66-NH2) nanoparticles as supports constructed an intercalation-induced structure with hierarchical Ti3C2Tx (MXene) nanosheets, which effectively regulated the interlayer spacing and improved permeability. Hydrophilic polyethylene glycol (PEG) further enhanced the stability of intercalation structure via hydrogen bonding, so that the PEG/MXene@MOF membrane demonstrated excellent swelling resistance with an average layer spacing expansion of only 0.05 nm even after immersion in water for 8 days. Moreover, MOF particles increased the lamellar roughness and interlayer water retention capacity, resulting in the PEG/MXene@MOF membrane with remarkable separation selectivity and powerful fouling resistance (UWOCA >156°, UWOSA <5.5°). Regarding the purification of oil-in-water emulsions stabilized by surfactants, the PEG/MXene@MOF membrane exhibited extremely stable high permeability (1246 ± 12 L m−2 h−1 bar−1) and excellent efficiency (>99.7 %), even during continuous separation of high-viscosity crude oil emulsions for 60 min. In addition, the PEG/MXene@MOF membrane also exhibited superior chemical durability and mechanical robustness in strong-corrosiveness and high-salty environments (72 h), ultrasonic treatments (120 min), bending experiments (100 times) and abrasion tests (20 times). Therefore, this work provided a promising strategy to construct highly permeable membrane with stable interlayer spacing and efficient fouling resistance for practical oily wastewater purification.

Superelastic bio-based polyimide aerogel with excellent oil/water separation performance and effective visible light photocatalytic activity

Aiming to realize sustainable development and reduce environmental pollution, scientists have been on searching for bio-based materials derived from renewable resources to replace petroleum-based materials. Herein, a bio-based polyimide aerogel derived from 2,5-furandicarboxylic acid was synthesized successfully via supercritical fluid drying. The bio-based polyimide aerogel had mesoporous structure and a large specific surface area (220 m2/g), which were highly advantageous to adsorption and photocatalysis. The bio-based polyimide aerogel possessed fast adsorption behavior (within 1 s), outstanding durability (200 cycles of adsorption and desorption), and a self-cleaning property. The bio-based polyimide aerogel could also realize continuous and rapid separation of organic solvent and water with the aid of a vacuum pump. Importantly, the bio-based polyimide aerogel exhibited superelastic (rapid recovery after 90% strain) and anti-fatigue performance (compressive strength remained 96% after 100 cycles). Moreover, the bio-based polyimide aerogel displayed effective photocatalytic activity under visible light. The possible degradation mechanism was also proposed, and radical quenching tests demonstrated that the generation of h+ and ·O2− was the key to photocatalytic degradation. Considering its environmental friendliness and excellent properties, bio-based polyimide aerogel provides a promising solution for oil/water separation and photocatalysis.

Separation of binary and ternary oil/water mixtures from a highly hydrophobic metal mesh.

A highly hydrophobic metal mesh has great potential for its application in oil/water separation due to its special wettability. However, most current oil/water separation devices are simple with limited separation capacity. A separation device based on a highly hydrophobic metal mesh was constructed for different types of oil/water mixtures. Experimental results show that the device not only can be used for the continuous separation of binary oil/water mixtures of any density ratios but also can realize the simultaneous separation of heavy oil/water/light oil ternary mixtures. This achievement is meaningful for practical applications, which will gain great interest in the future.

Sustainable approach to oil recovery from oil spills through superhydrophobic jute fabric

Ecosystems suffer from increased oil exploitation and frequent oil spills, which calls for effective, environment-friendly, and economically viable solutions. To address this, abandoned gunny sacks as the concerned jute fabric were superhydrophobically (water contact angle ∼159°) modified, incorporating titanium dioxide (TiO2) nanoparticles and hexadecyltrimethoxysilane (HDTMS), rendering a facile drop casting procedure. The modified superhydrophobic-superoleophilic jute fabric has been identified as a high-performance filter with superior reusability that can separate oil-water mixtures in challenging environmental conditions (including potent acidic, alkaline, highly saline, aqueous, frigid, and blistering water environments) while maintaining high separation efficiency. In continuation, static conditions indulging a batch and continuous oil separation performance and dynamic conditions stimulating turbulence in the oil-water mixture were proficiently carried out, mimicking real-world circumstances. As a result, the modified jute fabric has the advantages of high separation efficiency, stable recyclable properties, and outstanding durability, highlighting its enormous potential for use in practical applications.

Spontaneous Separation of Immiscible Organic Droplets on Asymmetric Wedge Channels with Hierarchical Microchannels.

Spontaneous separation of immiscible organic droplets has substantial research implications for environmental protection and resource regeneration. Compared to the widely explored separation of oil-water mixtures, there are fewer reports on separating mixed organic droplets on open surfaces due to the low surface tension differences. Efficient separation of mixed organic liquids by exploiting the rapid spontaneous transport of droplets on open surfaces remains a challenge. Here, through the fusion of inspiration from the fast droplet transport capability of Sarracenia trichome and the asymmetric wedge channel structure of shorebird beaks, this work proposes a spine with hierarchical microchannels and wedge channels (SHMW). Due to the synergistic effect of capillary force and asymmetric Laplace force, the SHMW can rapidly separate mixed organic droplets into two pure phases without requiring additional energy. In particular, the self-spreading of the oil solution on the open channel surface is utilized to amplify the surface energy difference between two droplets, and SHMW achieves the pickup of oil droplets floating on the surface of the organic solution. The maximum separation efficiency on 3-SHMW can reach 99.63%, and it can also realize the antigravity separation of mixed organic droplets with a surface tension difference as low as 0.87 mN·m-1. Furthermore, SHMW performs controllable separation, oil droplet pickup, and continuous separation and collection of mixed organic droplets. It is expected that this cooperative structure composed of hierarchical microchannels and wedge channels will be realized in resource recovery or chemical reactions in industrial production processes.

Rapid, Sustainable, and Versatile Strategy Towards Fabricating Superhydrophobic Cotton Textile Membranes for Separation of Emulsified and Stratified Oil/Water Mixtures

Special wettability membranes represent one of the smart, advanced, and energy-efficient solutions for the separation of contaminated oily wastewater as well as the treatment of crude oil spills. To increase sustainability and facilitate the large-scale applications of the superwetting membranes, novel renewable materials combined with rapid fabrication approaches should be explored. This study describes a simple and rapid strategy for fabricating superhydrophobic cotton textile (SCT) membranes via a solution immersion strategy from a few renewable and low-cost materials. The versatile fabrication approach was extended to fabricate other types of porous 2D/3D superhydrophobic substrates including metal mesh and melamine sponge. The fabricated SCT was employed for the gravity-driven continuous separation of immiscible oil/water mixtures with a high flux of 62500 ± 650 L. m−2. h−1 and high separation efficiency of > 99%. The SCT was employed for the demulsification of oil-in-water and water-in-oil emulsions as well as for the cleanup of crude oil spills. The fabricated SCT membranes exhibited high chemical and mechanical durability as well as excellent recyclability. Thus, the presented fabrication strategy offers a versatile, practical, and sustainable pathway toward the rapid construction of superhydrophobic porous membranes for efficient and diverse oil/water separations for the treatment of stratified and emulsified oily wastewater effluents and crude oil spills.

A novel method for continuous chromatographic separation of monoclonal antibody charge variants by combining displacement mode chromatography and step elution.

Charge heterogeneity of monoclonal antibodies is considered a critical quality attribute and hence needs to be monitored and controlled by the manufacturer. Typically, this is accomplished via separation of charge variants on cation exchange chromatography (CEX) using a pH or conductivity based linear gradient elution. Although an effective approach, this is challenging particularly during continuous processing as creation of linear gradient during continuous processing adds to process complexity and can lead to deviations in product quality upon slightest changes in gradient formation. Moreover, the long length of elution gradient along with the required peak fractionation makes process integration difficult. In this study, we propose a novel approach for separation of charge variants during continuous CEX chromatography by utilizing a combination of displacement mode chromatography and salt-based step elution. It has been demonstrated that while the displacement mode of chromatography enables control of acidic variants ≤26% in the CEX eluate, salt-based step gradient elution manages basic charge variant ≤25% in the CEX eluate. The proposed approach has been successfully demonstrated using feed materials with varying compositions. On comparing the designed strategy with 2-column concurrent (CC) chromatography, the resin specific productivity increased by 95% and resin utilization increased by 183% with recovery of main species >99%. Further, in order to showcase the amenability of the designed CEX method in continuous operation, the method was examined in our in-house continuous mAb platform.

Tune wastepaper to hydrophobic membranes through metal-ion-induced lignocellulose nanofibril crosslinking for oil-water separation

Herein, we proposed a metal-ion-induced surface nano-engineering technology for transforming hydrophilic waste newspaper (WNP) into a hydrophobic material suitable for oil-water separation, without using hydrophobic chemicals/materials. WNPs were swelled in a dilute ferric ion solution (i.e., 50 mM FeCl3) followed by oven-drying to induce the coordination between ferric ions and hydroxyls of lignocellulose nanofibrils of the paper. This resulted in the crosslinking of lignocellulose nanofibrils and converted the hydrophilic WNP to the hydrophobic membrane (HM). The HM exhibited remarkable oil sorption capacity for various oils, up to 3.4 times its weight, and demonstrated good recyclability after undergoing 10 cycles of absorption-desorption-drying. Additionally, HM demonstrated the ability to effectively separate both immiscible oil-water mixtures and surfactant-stabilized water-in-oil emulsions in continuous gravity-driven oil-water separation processes. With the modification method and advantages in oil-water separation, the as-prepared HM exhibits great potential for application in oil spill treatment and environmental remediation.

Rational Design of Porous Ionic Liquids for Coupling Natural Gas Purification with Waste Gas Conversion

AbstractRemoval of trace impurities for natural gas purification coupled with waste gas conversion is highly desired in industry. We here report a type of porous ionic liquids (PILs) that can realize the continuous flow separation of CH4/CO2/H2S and the conversion of the captured H2S to useful products. The PILs are synthesized through a step‐by‐step surface modification of ionic liquids (ILs) onto UiO‐66‐OH nanocrystals. The introduction of free tertiary amine groups on the nanocrystal surface endows these PILs with an exceptional ability to enrich H2S from CO2 and CH4 with impressive selectivity, while the permanent pores of UiO‐66‐OH act as containers to store an exceptionally higher amount of the selectively captured H2S than the corresponding nonporous ILs. Simultaneously, the tertiary amines as dual functional moieties offer effective catalytic sites for the conversion of the H2S stored in PILs into 3‐mercaptoisobutyric acid, a key intermediate required for the synthesis of Captopril (an antihypertensive drug). Molecular dynamics, density functional theory calculations and Grand Canonical Monte Carlo simulations help understand both the mechanisms of separation and catalysis performance, confirming that the tertiary amines as well as the permanent pores in UiO‐66‐OH play vital roles in the whole procedure.

Rational Design of Porous Ionic Liquids for Coupling Natural Gas Purification with Waste Gas Conversion.

Removal of trace impurities for natural gas purification coupled with waste gas conversion is highly desired in industry. We here report a type of porous ionic liquids (PILs) that can realize the continuous flow separation of CH4 /CO2 /H2 S and the conversion of the captured H2 S to useful products. The PILs are synthesized through a step-by-step surface modification of ionic liquids (ILs) onto UiO-66-OH nanocrystals. The introduction of free tertiary amine groups on the nanocrystal surface endows these PILs with an exceptional ability to enrich H2 S from CO2 and CH4 with impressive selectivity, while the permanent pores of UiO-66-OH act as containers to store an exceptionally higher amount of the selectively captured H2 S than the corresponding nonporous ILs. Simultaneously, the tertiary amines as dual functional moieties offer effective catalytic sites for the conversion of the H2 S stored in PILs into 3-mercaptoisobutyric acid, a key intermediate required for the synthesis of Captopril (an antihypertensive drug). Molecular dynamics, density functional theory calculations and Grand Canonical Monte Carlo simulations help understand both the mechanisms of separation and catalysis performance, confirming that the tertiary amines as well as the permanent pores in UiO-66-OH play vital roles in the whole procedure.

Signal-Free Corridor Development and Their Impact on Pedestrians: Insights from Expert and Public Surveys

Increasing vehicular demand has compelled decision makers to turn urban roads into signal-free corridors (SFCs) in Lahore. These corridors aim at prioritizing car flow over other modes and consist of various car-centric projects (CCPs), such as continuous flow intersections, grade separation, and continuous through movement. These projects often ignore pedestrian requirements and, thus reduce pedestrian safety. Considering the ongoing development projects in Lahore, this study aimed at evaluating the concept of SFCs. A total of 6 existing SFCs were identified in Lahore, which lacked basic pedestrian infrastructure. An expert survey was then conducted to understand the purpose of creating these SFCs, their effects on pedestrians, and the way forward. The thematic analysis regarding the purpose of creating these SFCs and their effect on pedestrians indicated the prioritization of private cars and pedestrian safety issues as the two underlying themes. A questionnaire survey was conducted to evaluate the perceptions of pedestrians on these two themes, i.e., pedestrian safety and car priority. Principle component analysis extracted two components labeled as pedestrian safety and car priority. Component scores were computed, and the three CCPs were then compared using non-parametrical tests in terms of both these components. According to the results, continuous flow intersections were declared to be significantly safer than continuous through movement and grade separation, whereas continuous flow intersection was found to be prioritizing cars over pedestrians significantly more than continuous through movement and grade separation. Finally, policy implications were presented for practitioners.

AI aided microfluidic auto continuous separation and sorting of microspheres simultaneously based on their morphological and optical properties

We report a novel method of continuous online microsphere/particle separation and sorting that integrated techniques of microsphere-imaging, microfluidic chip, moving micro-object super-resolution analysis, and AI image recognition into a simple system. It is the first method with the ability to determine the size of moving micro-objects with nanoscale resolution and separate/sort them simultaneously according to their size, shape, and refractive index. In the experiment, the separation and sorting of polystyrene, silica, and PMMA microspheres from the mixture solutions of several different microspheres using a microfluidic device demonstrated that the sorting was accurate and highly efficient and could classify micro-objects with a nanoscale size difference of ∼ 10 nm and a refractive index difference of 10−5. The method is suitable for coupling with various micro-object separation/sorting instruments for different micro-object separations. It can also divide micro-objects either with or without coating.

Separation of CTCs from WBCs using DEP-assisted inertial manipulation: A numerical study.

Isolation and detection of circulating tumor cells (CTCs) hold significant importance for the early diagnosis of cancer and the assessment of therapeutic strategies. However, the scarcity of CTCs among peripheral blood cells presents a major challenge to their detection. Additionally, a similar size range between CTCs and white blood cells (WBCs) makes conventional microfluidic platforms inadequate for the isolation of CTCs. To overcome these challenges, in this study, a novel inertial-dielectrophoretic microfluidic channel for size-independent, single-stage separation of CTCs from WBCs has been presented. The proposed device utilizes a spiral microchannel embedded with interdigitated electrodes. A numerical model is developed and validated to investigate the influence of various parameters related to the channel design, fluid flow, and electrode configuration. It was found that optimal separation of CTCs could be obtained at a relatively low voltage, termed the critical voltage. Furthermore, at the critical voltage of 7.5V, the hybrid microchannel is demonstrated to be capable of separating CTCs from different WBC subtypes including granulocytes, monocytes, T-, and B-lymphocytes. The unique capabilities of the hybrid spiral microchannel allow for this size-independent isolation of CTCs from a mixture of WBCs. Overall, the proposed technique can be readily utilized for continuous and high-throughput separation of cancer cells.

Introducing pyrazole-based MOF to polymer of intrinsic microporosity for mixed matrix membranes with enhanced CO2/CH4 separation performance

The performance of mixed matrix membranes (MMMs) substantively depends on the intrinsic structure and composition of the introduced nanofillers. In this work, pyrazole-based metal-organic frameworks (termed as MOF-303) were introduced into polymer of intrinsic microporosity (PIM-1) through a physical blending approach. Thanks to the well CO2-philic capability, high porosity, and appropriate pore structure of the incorporated MOF-303, the obtained MMMs exhibited remarkable separation performance. The improved CO2 permeability and well-maintained CO2/CH4 selectivity were achieved. Specifically, MMMs introducing 30 wt% MOF-303 loading exhibited a CO2/CH4 selectivity of 27.6 and a high-CO2 permeability of 7528.2 Barrer, which were 2.2 and 1.9 times greater than those of the unfilled PIM-1 membranes, respectively. Furthermore, a 33-h continuous separation test verified the excellent stability of the manufactured MMMs. More importantly, the MMMs showed significant resistance against physical aging, retaining up to 92.8% of their original CO2 permeability after 150 days, compared to just 33.0% for control PIM-1 over the same period. Meanwhile, the plasticization resistance of the MMMs was reinforced compared to the unfilled PIM-1 membrane. This study potentially provides a novel approach for the rational design of MMMs in CO2 separation applications.

Cyclists’ perceived safety on intersections and roundabouts – A qualitative bicycle simulator study

Introduction: Although cycling provides both individual and societal benefits, the mode share in Germany remains at a relatively low level. One reason described in literature is the lack of perceived safety due to the cycling infrastructure, especially at junctions. The study addresses the influence of junction design on cyclists’ perceived safety. Method: Three intersections (BS: Berlin Standard, PI: protected intersection, CbC: cycle lanes between car lanes) and one roundabout were modeled in a virtual environment. Using a bicycle simulator, n = 46 participants cycled through each junction design, followed by a qualitative interview. We conducted a structured content analysis on the interview transcripts. Results: Regarding the quality of statements, PI provides the highest level of perceived safety whereas CbC provides the lowest level. Both roundabout and BS provide medium to low perceived safety. Specific design features, such as continuous cycling infrastructure, physical separation and elements enhancing cyclists’ visibility improve participants’ perceived safety. On the other hand, curbs, bends, and elements obstructing visibility decrease perceived safety. Our findings also point towards a difference between overextending and manageable interactions between cars and cyclists. While manageable interactions raise attention to an appropriate extent, overextending interactions diminish the quality of the cycling experience so that some cyclists rather violate rules instead of using the designated cycling infrastructure. Furthermore, three factors influence participants’ perception of infrastructure design: comprehensibility, comfort, and perceived safety. Conclusions: To provide a cycling friendly infrastructure, planners should consider cyclists’ perceived safety as well as comfort and comprehensibility. Furthermore, in contrast to isolated segments, a continuous high-quality cycling infrastructure network should be implemented. Lastly, infrastructure might focus on manageable interactions rather than cause overextending interactions. Practical Application: The findings should be considered in future cycling infrastructure planning. Planners may test and modify temporary solutions to find appropriate designs for each junction.