Conventional Separation Research Articles

Development of a novel magnetic separator for segregation of minerals of dissimilar electromagnetic properties

This study has been carried out to develop a novel magnetic separator which uses alternating magnetic field to exploit dissimilarities in electromagnetic properties of minerals. The alternating magnetic field imparts rotational movement in a free-falling hematite particle to enhance particle deflocculation and it also produces repulsive force on semiconductive pyrolusite and diamagnetic quartz particles to improve separation efficiency. A mathematical model has been developed using first principal modelling and C++ programming language to simulate trajectories of different mineral (hematite & pyrolusite) particles of diverse sizes (0.5, 1, 3 mm) under variable magnetic field intensities (5–7 K gauss) and at different rotation speed (15, 25, 30 rpm) of magnetic roll. A magnetic separator of 10 kg/h has been designed and fabricated using the modelling results and setup has been tested using different size steel balls to validate the idea. Real time applicability of the system is tested using ferruginous manganese ores (25.6–43% Mn & 1.1–1.6 Mn/Fe) and results are compared with conventional magnetic separators. Experimental studies have been carried out for different feed rates and slurry densities to maximize the effect of particle rotation and repulsion to improve mineral selectivity and separation. Studies revealed that particle shape is an important parameter for axial rotation of particles and magnetic coagulation takes place to segregate the magnetic and nonmagnetic particles. The results revealed that new design rotating magnetic field separator has achieved 5 to 10.2% increment in Mn % & 0.4-to-0.7-unit increment in Mn/Fe ratio to produce a concentrate (nonmagnetic product) of 35.8–48% Mn & 1.6–3.3 Mn/Fe. It was found that developed equipment can attain higher selectivity index compared to conventional magnetic separators. These studies have shown that the developed magnetic separator has a potential to improve the efficiency of existing magnetic separation process as well as its application can be explored for other multi-magnetic mineral materials such as electronic waste, ilmenite, chromite, etc.

Switchable Separation Strategy via Host–Guest Locks

Universal separation strategies are the ultimate goal in separation science. However, there is always a tradeoff between universality and selectivity due to the negative influence among different recognition domains. With the goal of universal separation in mind, an unprecedented, switchable, and versatile separation strategy using reversible supramolecular host-guest interactions has been developed. These adjustable separation mediums were prepared using surface-grafted cationic cyclodextrin to firmly bind negatively charged adamantane derivatives. By changing guest structures, the surface functionality of the separation medium can be precisely regulated to be selective for a variety of substrates including chiral or achiral molecules, thus producing satisfactory single-column universality. This method offers a new approach to move beyond conventional separation methodologies and should stimulate the design of switchable functional materials.

Preparation of OH/TiO2/PES composite membrane by a novel gas-phase hydrolysis method in gas-liquid membrane contactor to improve the separation efficiency of CO2 and CH4

Conventional gas separation methods are very limited for CO2 separation in terms of separation efficiency and cost. In this study, We obtained fluorinated TiO2/polyethersulfone (PES) composite membranes by gas-phase hydrolysis and compared the characterization results with the composite membranes prepared by the graft coating method. In the mixed gas separation experiment, we used diethanolamine (DEA) as the absorbent to test the separation performance of CO2/CH4 using the composite membranes prepared by gas phase hydrolysis in a gas-liquid membrane contactor (GLMC) system. DEA flow rate and concentration and feed gas flow were found to have a significant effect on separation performance. When the feed gas flow rate was kept constant at 30 ml/min and the DEA flow rate and concentration were 16 L/h and 1 mol/L, respectively, the collected CH4 concentration was 99.4 %. Meanwhile, the CO2 flux was 10.096 × 10−3 mol m−2 s−1, and the separation factor reached 110.444. Collectively, the application of TiO2/PES composite membranes in GLMC is an efficient method for CO2 capture and mixed gas separation.

Disentangling kinetics from thermodynamics in heterogeneous colloidal systems

In Nucleation and Growth, the process by which most heterogeneous systems form, thermodynamics sets the asymptotic boundaries toward which the system must evolve, while kinetics tries to cope with it by imposing the transport rates. In all heterogeneous colloidal systems observed in nature, composition, shape, structure and physical properties result from the trade-off between thermodynamics and kinetics. Here we show, by carefully selecting colloidal systems and controlling phase separation in microfluidic devices, that it becomes possible to disentangle kinetics effects from thermodynamics. Using amyloids and nanocellulose filamentous colloids, we demonstrate that decoupling kinetics from thermodynamics in the phase separation process unveils new physical phenomena, such as orders of magnitude shorter timescales, a wider phase diagram, and structures that are not observable via conventional liquid-liquid phase separation. Our approach enables on-demand fabrication of multicomponent heterogeneous liquid crystals, enhancing their potential, and introducing original fundamental and technological directions in multicomponent structured fluids.

Bi-Morphological Form of SiO2 on a Separator for Modulating Li-Ion Solvation and Self-Scavenging of Li Dendrites in Li Metal Batteries.

The lithium (Li) metal anode is highly desirable for high-energy density batteries. During prolonged Li plating-stripping, however, dendritic Li formation and growth are probabilistically high, allowing physical contact between the two electrodes, which results in a cell short-circuit. Engineering the separator is a promising and facile way to suppress dendritic growth. When a conventional coating approach is applied, it usually sacrifices the bare separator structure and severely increases the thickness, ultimately decreasing the volumetric density. Herein, we introduce dielectric silicon oxide with the feature of bi-morphological form, i.e., backbone-covered and backbone-anchored, onto the conventional polyethylene separator without any volumetric change. These functionally vary the Li+ transference number and the ionic conductivity so as to modulate Li-ion solvation and self-scavenging of Li dendrites. The proposed separator paves the way to maximizing the full cell performance of Li/NCM622 toward practical application.

Lignin–Chitosan Gel Polymer Electrolytes for Stable Zn Electrodeposition

Electrochemical energy storage technologies offer means to transition toward a decarbonized society and carbon neutrality by 2050. Compared to conventional lithium-ion batteries, aqueous zinc-ion chemistries do not require scarce materials or toxic and flammable organic-based electrolytes to function, making them favorable contenders in the scenario of intensifying climate change and supply chain crisis. However, environmentally benign and bio-based materials are needed to substitute fossil-based battery materials. Accordingly, this work taps into the possibilities of lignin together with chitosan to form gel polymer electrolytes (GPEs) for zinc-ion chemistries. A simple fabrication process enabling free-standing sodium lignosulfonate–chitosan and micellar lignosulfonate–kraft lignin–chitosan GPEs with diameters exceeding 80 mm is developed. The GPEs combine tensile strength with ductility, reaching Young’s moduli of 55 ± 4 to 940 ± 63 MPa and elongations at break of 14.1 ± 0.2 to 43.9 ± 21.1%. Competitive ionic conductivities ranging from 3.8 to 18.6 mS cm–1 and electrochemical stability windows of up to +2.2 V vs Zn2+/Zn were observed. Given the improved interfacial adhesion of the GPEs with metallic Zn promoted by the anionic groups of the lignosulfonate, a stable cycling of the Zn anode is obtained. As a result, GPEs can operate at 5000 μA cm–2 with no short-circuit and Coulombic efficiencies above 99.7%, outperforming conventional separator–liquid electrolyte configurations such as the glass microfiber separator soaked into 2 M ZnSO4 aqueous electrolyte, which short-circuits after 100 μA cm–2. This work demonstrates the potential of underutilized biorefinery side-streams and marine waste as electrolytes in the battery field, opening new alternatives in the sustainable energy storage landscape beyond LIBs.

Segmented two-dimensional liquid chromatography. Proof of concept study

The separation in liquid chromatography is defined either by the space domain where it proceeds until the least retained analyte reaches the outlet of the column or by the time when individual analytes elute out of the column. These two approaches lead to the four possible combinations of two-dimensional liquid chromatography with online space x time coupling being the least experimentally feasible. Here, we show the development of a novel two-dimensional liquid chromatography method combining separation defined by space and the conventional elution-based separation. First-dimension column consisted of four capillary segments coupled serially via two-position six-port valves allowing an online and comprehensive transfer of analytes from the first to the second dimension. After initial experiments using homemade monolithic capillary columns, we tested commercially available columns in both dimensions. We ended with the combination of packed capillary columns in the first dimension and monolithic capillary column in the second dimension. We used a reversed-phase retention mechanism in the first spatial dimension, while HILIC was in the second, time-based dimension. We also developed a theoretical model to describe the proposed two-dimensional separation that was further confirmed by utilizing both an isocratic and gradient elution in the second dimension. Finally, we applied our experimental setup to separate neurotransmitters contained in human urine.

Mixed matrix membranes comprising 6FDA-based polyimide blends and UiO-66 with co-continuous structures for gas separations

Membrane gas separation is considered a highly promising alternative to conventional gas separation. Recently, mixed matrix membranes containing UiO-66 metal–organic frameworks (MOFs) have been demonstrated to achieve high gas separation performance, especially in CO2-related separation. To date, few studies have used morphological control strategies to enhance the gas transport properties of mixed matrix membranes. In this study, we fabricated mixed matrix membranes comprising porous UiO-66 nanoparticles and immiscible 6FDA-based polyimide blends with co-continuous structures. The selective location of UiO-66 nanoparticles within one polymer phase of the co-continuous polymer blend was observed. However, this co-continuous structure cannot be referred to as a double-percolative morphology since the percolative UiO-66 networks did not successfully form. The gas permeability and gas sorption properties of pure gases (H2, CO2, N2, O2, and CH4) in the dense membranes and mixed matrix membranes were measured using the constant-volume variable-pressure method and the dual-volume pressure decay method, respectively. On the basis of the solution–diffusion mechanism, the contributions of gas sorption and gas transport to the overall gas permeation properties were determined and examined. When the UiO-66 content reached 35 wt%, the CO2 permeability of the mixed matrix membranes was significantly increased from 16.5 Barrer to 104.7 Barrer (by 635 %) without scarifying the permeability selectivities of CO2/N2 (16.5 ± 1.5) and CO2/CH4 (31.7 ± 5.8). The results suggest that both the addition of porous UiO-66 nanoparticles and the co-continuous structures contributed to the strongly enhanced gas separation performance of the mixed matrix membranes.

Latest advances and perspectives of liquid biopsy for cancer diagnostics driven by microfluidic on-chip assays.

Microfluidic-based lab-on-a-chip technology is a multidisciplinary approach, which has evolved rapidly in the past decade and remains a hot research topic as a promising microanalysis platform for a plethora of biomedical applications. Microfluidic chips have been successfully applied in cancer diagnosis and monitoring, given that they can lead to the effective separation and analysis of cancer-derived substances such as extracellular vesicles (EVs), circulating tumour cells (CTCs) and circulating DNA (ctDNA), proteins and other metabolites. In particular, EVs and CTCs are two outstanding objects for cancer liquid biopsy, which share similar membrane structures but possess different sizes. Through molecular typing and concentration detection of EVs, CTCs and ctDNA, disease-related information can be well-learned, including the development stage and prognosis of cancer. However, the conventional separation and detection methods are often time-consuming with limited efficiency. In comparison, the use of microfluidic platforms can effectively simplify the separation and enrichment process and improve the detection efficiency significantly. Although review papers have been published on the application of microfluidic chips for the analysis of objects of liquid biopsy, generally they focused on a specific detection target, lacking a descriptive extraction of the commonality of LOC devices used in liquid biopsy. Thus, few of them present a comprehensive overview and outlook on the design and application of microfluidic chips for liquid biopsy. This motivated us to prepare this review paper, which is divided into 4 parts. The first part aims to elucidate the material selection and fabrication approaches of microfluidic chips. In the second part, the important separation strategies, including physical methods and biological methods, are discussed. The third part highlights the advanced on-chip technologies for the detection of EVs, CTCs and ctDNA by providing practical examples. In the fourth part, novel on-chip applications of single cells/exosomes are introduced. Finally, the prospective outlook and challenges for the long-term development of on-chip assays are envisioned and discussed.

Particle Removal and Antibacterial of Nanofiber Doped with Metal and Ions Prepared by Electrospinning

Due to the increase in human activities and the application of nanotechnology, people's exposure to nano and submicron particles is increasing. Conventional particle separation technologies, such as electrostatic precipitators, cyclone, wet washing, and filtration method, cannot work well. In addition, the fiber diameter and pore size of the traditional fiber filter material is too large, and the bulk density is difficult to control. Nanofiber membranes have a large surface area, small pore size and high porosity. The nanofiber membranes prepared by electrospinning technology are easy to intercept submicron and nanoparticles. Furthermore, the electrospinning technology is simple to operate, makes fibers of various materials easy, and is convenient for assembly and replacement. The most common bacteria are Escherichia coli, which harms the ecological environment and human health. Therefore, this study used bacteria and particles as the target pollutants and controlled by prepared nanostructured materials doped with metals and ions. In order to improve the treatment efficiency of particles and bacteria, this study added various metals and ions to nylon 6 nanofibers and explored the antibacterial and filterability of artificial fibrils. Different operation parameters, such as types of metal, types of ion, metal and concentration, and surface velocity, were also investigated to prepare various fibers to make the best performance fiber. In addition, the best-operating conditions could be obtained through a filtration test. Different salts, metals and metal ions with different concentrations, three metal oxides (TiO2, CeO2 and ZnO) and three ions (Ag+, K+ and Na+) were used to test the filtration performance of various particle sizes for the best metal ion concentration, best filtration and bacterial removal performance. The experimental results show that the filtration efficiency of the composite fiber can reach 99%, and the composite fiber sprayed with a self-made antibacterial liquid has the best antibacterial ability.

A Comparative Study of Chamomile Essential Oils and Lipophilic Extracts Obtained by Conventional and Greener Extraction Techniques: Chemometric Approach to Chemical Composition and Biological Activity

Bearing in mind the centuries-old traditional use of chamomile, but also the increasing demand for its products in modern industry, oriented toward sustainable development, there are increasing efforts for the efficient extraction of high-value compounds of this plant, as well as obtaining its products with added value. With that goal, conventional and contemporary separation techniques were applied in this work. Both hydrodistillation processes (HD), conducted in a traditional manner and coupled with microwave irradiation (MWHD), were used for essential oil isolation. In parallel with those procedures, chamomile lipophilic extracts were obtained by Soxhlet extraction applying organic solvents and using supercritical fluid extraction as a greener approach. The obtained extracts and essential oils were characterized in terms of chemical composition (GC analysis, contents of total phenolics and flavonoids) and biological potential. GC analysis revealed that oxygenated sesquiterpenes and non-terpene compounds were the dominant compounds. α-Bisabolol oxide A (29.71–34.41%) and α-bisabolol oxide B (21.06–25.83%) were the most abundant individual components in samples obtained by distillation while in supercritical and Soxhlet extracts, major compounds were α-bisabolol oxide A and pentacosane. The biological potential of essential oils and extracts was tested by applying a set of analyzes to estimate the inhibition of biologically important enzymes (amylase, glucosidase, acetylcholinesterase, butyrylcholinesterase, tyrosinase) and antioxidant capacity (DPPH, ABTS, CUPRAC, FRAP, chelating and total antioxidant capacity). The results suggested essential oils as better antioxidants, while the extracts were proven to be better inhibitors of the tested enzymes. Principal Component Analysis was conducted using the experimental results of the composition of extracts and EOs of chamomile obtained by different separation techniques, showing clear discrimination between methods applied in correlation with the chemical profile. Molecular docking was applied for the identification of the main active principles present in the essential oil, among which α-bisabolol-oxide B (cp3) showed a higher affinity for tyrosinase.

Insights into the synergistic adsorption mechanism of mixed SDS/DDA collectors on biotite using quartz crystal microbalance with dissipation

Biotite is critical in numerous fields. The conventional magnetic separation method has many disadvantages. Herein, the flotation behaviors and mechanisms of sodium dodecylsulfonate (SDS)/dodecylamine (DDA) collectors on the biotite surface were investigated systematically by various characterizations, including surface tension measurement, fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) analyses, and quartz crystal microbalance with dissipation (QCM-D). Micro-flotation experiments showed that the recovery of biotite increased to above 90 % upon adding mixed SDS/DDA collectors under the concentration of 5 × 10−4 mol/L with a molar ratio of 5:1 at alkaline pH (10–11), while that of quartz was below 10 %. The surface tension tests showed that the mixed collectors were easier to absorb on interface due to a strong synergistic effect. The FTIR and XPS measurements indicated that DDA was absorbed on biotite through electrostatic attraction and hydrogen bonds, and SDS could be co-adsorbed by the interaction with DDA and the electrostatic attraction with metal ions of the biotite. The QCM-D data revealed that a rigid and thin adsorption film formed when DDA reacted with the biotite surface. After continuing to inject SDS, a rigid and compact multilayer was generated.

Effect of acid surface pretreatment on the floatability difference between ilmenite and titanaugite pre-absorbed by flotation reagents

Minerals in the unqualified ilmenite concentrate collected by flotation reagents appeared the similar surface hydrophobicity and floatability. In this work, acid surface pretreatment was applied to improve the difference in surface properties of ilmenite and gangue minerals pre-absorbed by reagents. Microflotation experiments showed that after ilmenite and titanaugite were treated with high concentrations of NaOL followed by acid surface pretreatment, their recovery differences increased from around 45% to stable 80% regardless of the collector dosage later. AFM and XPS analyses revealed that acid surface pretreatment strengthened the distribution densities of original Fe and new Ti sites and the strengths chemisorbed NaOL onto ilmenite surfaces, while it dissolved intrinsic Ca and Mg sites on titanaugite surfaces. These changes increased the differences in surface hydrophobicity and NaOL adsorption on ilmenite and titanaugite surfaces, which was certified by contact angle and zeta potential. Compared to conventional separation methods, the best result was obtained after rougher flotation concentrate was treated with acid surface pretreatment and three cleaning flotation stages, producing a concentrate with a TiO2 grade of 47.68% and a TiO2 recovery of 26.66%. Taken together, acid surface pretreatment is a potential and novel method to reinforce the separation of ilmenite flotation.

Developing High-Performance In-Plane Flexible Aqueous Zinc-Ion Batteries with Laser-Scribed Carbon-Supported All Electrodeposited Electrodes.

Developing high-performance, safer, and affordable flexible batteries is of urgent need to power the fast-growing flexible electronics market. In this respect, zinc-ion chemistry employing aqueous-based electrolytes represents a promising combination considering the safety, cost efficiency, and both high energy and high-power output. Herein, we represent a high-performance flexible in-plane aqueous zinc-ion miniaturized battery constructed with all electrodeposited electrodes, i.e., MnO2 cathode and zinc anode with polyimide-derived interdigital patterned laser-scribed carbon (LSC) as the current collector as well as the template for electrodeposition. The LSC possesses a cross-linked network of graphitic carbon sheet, which offers large surface area over low footprint and ensures active materials loading with a robust conductive network. The LSC with high zincophilic characteristic also offers dendrite-free zinc deposition with very low Zn2+ plating stripping overpotential. Benefitting from the Zn//MnO2-rich redox chemistry, the ability of the 3D LSC network to uniformly distribute reaction sites, and the architectural merits of in-plane interdigitated electrode configuration, we report very high capacity values of ∼549 mAh/g (or ∼523 μAh/cm2) and 148 mAh/g (or 140 μAh/cm2) at 0.1 A/g (0.095 mA/cm2) and 2 A/g (1.9 mA/cm2) currents, respectively. The device was also able to maintain a high capacity of 196 mAh/g (areal capacity of 76.19 μAh/cm2) at 1 A/g (0.95 mA/cm2) current after 1350 cycles. The flexibility of the device was demonstrated in polyacryl amide (PAM) gel polymer soaked with a 2 M ZnSO4 and 0.2 M MnSO4 electrolyte, which exhibited a comparable specific capacity of ∼102-110 mAh/g in flat condition and different bending (100° or 160° bending) conditions. The device does not use any conventional current collector, separator, and conductive or polymer additives. The overall process is highly scalable and can be completed in less than a couple of hours.

Enhanced iron recovery from magnetic separation of ultrafine specularite through polymer-bridging flocculation: A study of flocculation performance and mechanism

The refractory low-grade iron ores are generally ground to fine particles in beneficiation, and the conventional magnetic separation process has difficulties in sufficiently recovering ultrafine Fe-bearing minerals, resulting in the loss of Fe to the tailings. In this study, the polymer-bridging flocculation performance of cross-linked starch (CLS), carboxymethyl starch (CMS), and sodium alginate (SA) on ultrafine specularite were explored by flocculation-magnetic separation and flocculation-sedimentation tests. The characteristics of specularite flocs and flocculation mechanism of three polymeric agents on specularite were researched with microscopic observation, laser particle measurement, zeta potential test, and FTIR analysis. The results showed that the flocculation of ultrafine specularite with CLS, CMS and SA increased the iron concentrate yield by 12.50%, 6.40% and 18.74% under optimal conditions. The CLS and CMS performed excellent selectivity for specularite, while SA exhibited poor selectivity due to its flocculation behavior on quartz. After the addition of CLS, CMS and SA, the ultrafine specularite was flocculated significantly, with the content of particles smaller than 20 μm reduced from 82.68% to 67.72%, 68.92% and 45.23%, correspondingly. The flocculation mechanism confirmed that the interactions of three flocculants with specularite included hydrogen bonding, chemisorption of carboxyl and hydroxyl groups, while neither CLS nor CMS interacted with quartz except for the hydrogen bonding adsorption of SA on the quartz surface.

Emerging technologies for selenium separation and recovery from aqueous systems: A review for sustainable management strategy

AbstractSelenium (Se) is known both as an essential micronutrient for human health as well as a toxic element when consumed in excess. This work endeavours to critically review the existing selenium literature over the period 1980–2021, following a systematic sub‐classification into the domains of occurrence, speciation, and existing conventional and advanced technologies, while directing further research towards emerging integrated sustainable recovery strategies. The review reveals that the majority of the conventional and advanced separation techniques eventually lead to secondary pollution rather than offering a complete solution, whereas resource recovery studies from water are very scant. Some of the techniques, being miserably slow, cannot be applied in the situations of the occurrence of excess selenium in drinking water, posing a serious threat to human health. Research efforts have so far been directed mainly at the removal of selenium rather than recovery through processes that have the potential of turning selenium abatement technology into a sustainable one with value addition. Emerging integrated technologies involving resource recovery from waste streams or generated sludge such as physicochemical technologies, biochemical reduction, electro‐biological reduction, and membrane‐based hybrid technologies are presently at a very early development stage. Moreover, the application of studies where Se nanoparticles (SeNPs) ormetal selenides are obtained is very limited, which may be attributed to the particle size, purity, morphology, and challenges involved in their separation. This review evaluates the challenges in separation and resource recovery from contaminated streams and points future research in a new direction.

Organic solvent-free polyelectrolyte complex membrane preparation: Effect of monomer mixing ratio and casting solution temperature

The organic solvent-free aqueous phase separation (APS) process is a new and sustainable alternative to the conventional nonsolvent-induced phase separation (NIPS) process. However, low water permeability is a primary concern of such APS membranes. Herein, we introduced casting solution temperature and mixing ratio as two key parameters to improve the performance of poly (sodium 4-styrene sulfonate) (PSS) and branched Polyethylenimine (PEI) complex membrane prepared by pH shift-induced APS process. It was found that PSS-PEI monomer mixing ratios of 1:1.65 and 1:1.70 resulted in nanofiltration membranes with pure water permeability (PWP) of ∼4.5 and ∼8 LMHbar−1. The salt retention tests of these membranes showed higher divalent salt retention than monovalent salt following the order of MgCl2 > MgSO4 > Na2SO4 >NaCl. In comparison, PSS-PEI monomer mixing ratios of 1:1.75 and 1:1.80 led to the formation of ultrafiltration membranes with BSA retention of ∼98% and ∼36%, and PWP of ∼40 and ∼199 LMHbar−1, respectively. The variation of casting solution temperature also showed a significant influence on membrane morphology and performance. The increase in temperature from 25 to 60 °C resulted in ultrafiltration membranes with high BSA retention (>90%) and PWP in the range of ∼53–140 LMHbar−1. This sharp increase in PWP was attributed to the combined effect of the thinner skin layer and larger pore size of the membranes. Overall, this work demonstrated that casting solution temperature and monomer mixing ratio could be used as new tuning parameters for high-performance PSS-PEI membrane fabrication with excellent control over membrane structure and performance.

Poly(ether imide) Porous Membrane Developed by a Scalable Method for High-Performance Lithium-Sulfur Batteries: Combined Theoretical and Experimental Study.

Lithium-sulfur (Li-S) batteries are one of the emerging candidates for energy storage systems due to their high theoretical energy density and the abundance/nontoxicity/low cost of sulfur. Compared with conventional lithium-ion batteries, multiple new challenges have been brought into this advanced battery system, such as polysulfide shuttling in conventional polyolefin separators and undesired lithium dendrite formation of the Li metal anode. These issues severely affect the cell performance and impede their practical applications. Herein, we develop a poly(ether imide) (PEI)-based membrane with a sponge-like pore morphology as the separator for the Li-S battery by a simplified phase inversion method. This new separator can not only alleviate the new challenges in Li-S batteries but also exhibit excellent ion conductivity, better thermal stability, and higher mechanical strength compared to those of the conventional polypropylene (PP) separator. A combined experimental and theoretical study indicates that the sponge-like morphology of the PEI membrane and its good wettability toward the electrolyte can facilitate uniform ion transportation and suppress dendrite growth. Meanwhile, the PEI molecules exhibit a strong interaction with polysulfides and avoid their shuttling effectively. As a result, the PEI-based Li-S battery shows a much better performance from various aspects (capacity, rate capability, and cycling stability) than that of the PP-based Li-S battery, especially at high charge/discharge current densities and high sulfur loadings. Since the developed PEI membrane can be easily scaled up, this work may accelerate the practical applications of Li-S batteries from the point of separators.

Circular Bowing, Cyclical Work

Circular Bowing, Cyclical Work explores the collaboration between composer Henrik Strindberg and myself, violinist Karin Hellqvist, from my viewpoint as performer and co-creator. On my initiative, as part of my PhD in artistic research at the Norwegian Academy of Music in Oslo, a cyclical collaborative practice is being developed. Our process differs from the conventional separation of roles that I have so far experienced as a performer of contemporary Western classical music. The exposition highlights how my understanding of the emerging concept of 'the artistic palette' develops through the shared work and dialogue around Cirkulära Stråk for violin and electronics, when expanding my practice and establishing a new work mode. Through examples from the artistic process, the exposition aims at further unfolding how we as collaborators develop ways of challenging each other. A keyword for my defiance of the traditional and formal task division, is the search for connection – connection to my collaborator, the work, and the embodied knowledge of my artistic palette. The exposition comprises written reflections, transcribed dialogue and sketches as well as video and audio documentation. Documentary video conversations are held in Swedish with English subtitles.

Architecting dual coordination interactions in polyimide for constructing structurally controllable high-performance nanofiltration membranes

Polyimide-based nanofiltration membranes (NF) featuring customizable chemical structure and outstanding comprehensive performance have garnered tremendous interest for potential applications in ions rejection. Coordinated interactions can build supramolecular networks in polyimide that reshuffle phase separation behavior during membrane formation, thus conferring microstructural flexibility to nanofiltration membranes. In this paper, novel nanofiltration membranes were prepared by constructing dual coordination interactionsin polyimide, and the structures were confirmed by NMR, FTIR, EDX, and XPS analyses. As expected, the skin and supporting layers of the PI-based NF membranes can be controlled by designing coordination conditions during membrane formation. A promising result is that the resulted NF membranes occur higher reject of metal ions than the pristine membranes prepared by conventional non-solvent induced phase separation methods. The optimized performance showed significantly higher permeability for removing Mg2+ions, giving water permeance of 477.7 L m−2 h−1·bar−1and a rejection of over 80%. Moreover, the resulted PI-based NF membranes occur better solvent resistance than the pristine NF membranes due to the enhanced coordination structures. As a preliminary study, this work gives a new strategy to regulate the microstructure of nanofiltration membranes, promising further potential for applications in ion removal.