Separate Systems Research Articles

Contact-Electro-Catalysis-Assisted Separation via a Dancing PTFE Membrane for Fouling Control.

Advanced oxidization processes (AOPs) offer promising solutions for addressing the fouling issues in membrane separation systems. However, the high energy requirements for electrical or light power in the AOPs can be a drawback. In this study, we present a contact-electro-catalysis (CEC)-based approach for controlling membrane fouling, which is stimulated by mild ultrasonic irradiation. During this process, electrons are transferred between a dancing polytetrafluoroethylene membrane and water or oxygen molecules, resulting in the formation of free radicals •OH and •O2-. These free radicals are capable of degrading or inactivating foulants, eliminating the need for additional chemical cleaners, secondary waste disposal, or external stimuli. Furthermore, the time-dependent voltage spikes/oscillations (peak, +7.8/-8.2 V) generate a nonuniform electric field that drives dielectrophoresis, effectively keeping contaminants away from the membrane surface and further enhancing the antifouling performance of the dancing membrane. Therefore, the CEC-assisted membrane separation system offers a green and effective strategy for controlling membrane fouling through mild mechanical stimulation.

Social-economic assessment of integrated waste pickers in municipal solid waste management system: A case of Tianjin in China

Currently, China's municipal solid waste (MSW) management system has been changing from mixed collection and treatment system into separated collection and treatment system. Therefore, the source separated ability of MSW, the relevant policies of MSW classification and the MSW management system are still in the stage of exploration and improvement. This study chooses to integrate waste pickers (WPs) from the informal sector into the MSW management system, so that they can conduct secondary sorting of waste as a supplement to source separation. However, the existing research does not provide a method that allows the evaluation of integrated WPs from a dynamic and long-term perspective. In this paper, the system dynamics model of MSW management is improved to provide the ability to analyze the long-term evolution of social economic benefits of integrating WPs for secondary sorting. Taking Tianjin as an example, the scenario analysis is carried out. The results show that, on the basis of the existing mixed management mode, integrating WPs for secondary sorting (80% separated rate) can reduce the waste management cost per ton by 55 yuan in 2030. Under the current situation in Tianjin where the source separation rate of food waste is 20% and the source separation rate of recyclable waste is 60%, integrating WPs can reduce the social economic cost of Tianjin's urban MSW management system by 422.45 million yuan per year from 2022 to 2030. In addition, the results show that even if the source separated rate of food and recyclable waste increases, there is still room for 20%–80% increase in wages based on giving WPs a salary higher than the national per capita disposable income in 2022. This study provides a basis for integrating WPs into Tianjin MSW management system, as well as methods and quantitative tools to integrate WPs for cities in developing countries.

Development of web‐based hydrograph analysis tool considering seasonality and flow condition

AbstractBaseflow was proven to be the most unpredictable component of streamflow through various research. However, the recent method for estimating baseflow is due to the development of theoretical and computational techniques. This paper attempted to develop a fully automated baseflow separation system based on a recursive digital filter with an optimization algorithm for the single separation. Most of the previous baseflow separation methods use a single set of a parameter and BFImax (the maximum value of baseflow index), which can underestimate or overestimate the baseflow; however, the system developed in this study estimates multiple optimized a parameters using seasonality and flow conditions and uses them for BFImax calculation and baseflow separation. This system derived baseflow results in better understanding of watershed and streamflow tendency characteristics. This study developed a Web‐based Hydrograph Analysis Tool 2020 with a user‐friendly interface and new separation method regarding the seasonality and flow conditions with a fully automated python module to optimize a parameters and BFImax. The application to the two area show diverse parameter sets and different baseflow according to seasonality and flow conditions representing the flow characteristics. This study could be a fundamental tool for detailed watershed management decisions regarding water security in the dry season or environmental water for aquatic ecosystems.

Clean and efficient Zr/Hf(Ⅳ) separation system constructed by bisamide ionic liquid

Nuclear energy is an indispensable clean energy. We design a new type functional ILs [(RNCO)2Cn·H]2[MCl6] (M = Zr,Hf) by using the green solvent bisamide to separate the key metals Zr(IV) and Hf(IV) of nuclear energy field [(RNCO)2Cn·H2][Cl]2 was obtained by protonation reaction of bisamide (RNCO)2Cn, it can be used as an ionic liquid (ILs) to provide a cationic center [(RNCO)2CnH]+, but also has a dual function as a solvent. The ionic liquid (ILs) [(RNCO)2Cn·H]2[MCl6] can be rapidly formed by [(RNCO)2CnH]+ and transition metal anions ZrCl62−/HfCl62− in an acidic chloride system at a room temperature. From the perspective of material energy and frontier molecular orbital (FMO), it is confirmed that [(RNCO)2Cn·H]2[MCl6] is formed by an anion association mechanism [(RNCO)2Cn·H]2[MCl6] can be stable in organic solvents when contacting with a high concentration acidic chloride system. At the same time, the ILs have high thermal stability that decomposes temperature above 300 °C. It is surprising that separation and purification of Zr/Hf(Ⅳ) can be done efficiently via the different stability of anion centers formed by Zr/Hf(Ⅳ) in acidic chloride systems. When the concentration of (RNCO)2Cn is 25 %, the separation coefficient of Zr(IV) and Hf(IV) can reach 11.4. And this work proposes the concept of recycling of organic solvents and acidic solutions, which provides an effective research idea for the clean production of nuclear energy metals.

Quantitative Determination and Source Variation of Rutin in Fagopyrum Tataricum

Buckwheat (Fagopyrum sp.) is a traditional crop of Uttarakhand (India) known for its high Rutin content, a bioflavonoid with significant medicinal properties. This study explores the quantitative measurement of Rutin in various buckwheat varieties grown in different regions of Uttarakhand using Thin Layer Chromatography (TLC) and High-Performance Thin Layer Chromatography (HPTLC). Twelve seed sources of Fagopyrum tataricum from the Garhwal and Kumaon regions, along with Fagopyrum esculentum seeds for comparison, were collected. Preliminary phytochemical screening of the extracts revealed the presence of flavonoids, alkaloids, tannins, and carbohydrates, with methanolic extracts showing higher concentrations. TLC analysis was employed to determine the most effective solvent system for Rutin separation, leading to the identification of three samples with substantial Rutin content. HPTLC was then used for quantitative Rutin assessment, with a calibration curve established using standard Rutin solutions. The three selected samples, along with the standard, were applied to HPTLC plates, and the Rutin content was measured based on peak areas and peak heights. The sample collected from Joshimath, Uttarakhand, known as "JOG," exhibited the highest Rutin content. This study provides valuable insights into the phytochemical composition of buckwheat varieties in Uttarakhand, which can inform the development of high-quality functional foods. Rutin, a potent antioxidant with various health benefits, underscores the significance of buckwheat as a naturally occurring functional food source. The results contribute to understanding the Rutin-rich potential of buckwheat grown in Uttarakhand and its applications in functional foods and nutraceuticals. Further research in this field can promote the cultivation and utilization of buckwheat as a source of this valuable bioactive compound with numerous health benefits.

Cyclic testing of two-level control system using friction-yielding top plates in beam-to-column rigid connections

The use of two-level control systems in structures is one of those having attracted the attention of researchers in the last decade. The design idea of the mentioned systems is to combine two separate control systems with different stiffness and strength in series, which creates dual seismic behaviors due to appropriate energy dissipation at different levels of earthquakes. In this study, at the first stage a two-level passive control system using friction-yielding top plate in beam-to-column rigid connections is presented and its cyclic behavior is evaluated with nonlinear static and dynamic analyses using finite element method by ABAQUS software. In the next stage, the hysteresis curves are investigated, which indicates a very ductile behavior for the proposed damping system in the rigid connection. In addition, the obtained hysteresis curves show that the system can reliably dissipate energy at different earthquake levels, as expected, satisfying the seismic criteria for the special moment resisting frames. In this system, maximum base shear decreased by 20% compared to traditional rigid connections in a single-story moment frame under dynamic time-history analysis.

Experimental Study of a Pump-Driven Microchannel-Separated Heat Pipe System

The current situation of high energy consumption in data centers places high demands on the energy consumption and heat-dissipation efficiency of cooling technology. This article studies the steady-state flow and heat-transfer characteristics of a pump-driven separated heat pipe system from an experimental perspective. After designing and selecting the pump-driven microchannel-separated heat pipe system, an experimental platform is built to test the pump-driven microchannel-separated heat pipe system under variable operating conditions. It is found that the optimal filling rate range of the system is 75% to 95%, and the optimal condensing air volume is 4250 m3/h. The relationship between the circulating mass flow rate and the heat-transfer capacity of the heat pipe system is comprehensively influenced by the resistance of each section and the heat-transfer coefficient at the heat exchanger. When the indoor and outdoor temperature difference increases from 10 °C to 30 °C, the heat transfer increases by 261.5%, and the working medium of R410a has a better heat-transfer performance than R134A at outdoor temperatures ranging from 0 to 15 °C. The results contribute to the application of pump-assisted microchannel heat pipe systems in data center machines, which provide guidance for the application of cabinet-level thermal management.

A clean process for the recovery of rare earth and transition metals from NiMH battery based on primary amine and lauric acid

A novel rare earth separation system composed of lauric acid (LA) and primary ammonium (RNH2) was studied. Compared with individual LA and RNH2, the mixed extraction system can significantly improve the extraction and separation ability of rare earth (RE). When LA and RNH2 are mixed in an equal molar ratio, the synergistic coefficient for extracting Nd(III) in the system reaches 136.85. Effective separation of Nd from Co and Ni can be achieved, with the separation coefficients of 1503 and 2762 for Nd/Co and Nd/Ni, respectively. The ion association mechanism of developed extraction system can avoid the generation of saponification wastewater. Thus, the negative impact of saponification wastewater on the economy and environment can be reduced. The extraction system is simple to be prepared and easy to be stripped, which helps to reduce acid and alkali consumption. Application of this extraction system can effectively realize the separation of RE elements La, Ce, Pr, Nd and transition metals Co, Ni, Mn in nickel-metal hydride (NiMH) battery. This paper provides a new strategy for the development of ionic liquid saponification technology without saponified wastewater.

Spatiotemporal expression patterns of anxiety disorder-associated genes

Anxiety disorders (ADs) are the most common form of mental disorder that affects millions of individuals worldwide. Although physiological studies have revealed the neural circuits related to AD symptoms, how AD-associated genes are spatiotemporally expressed in the human brain still remains unclear. In this study, we integrated genome-wide association studies of four human AD subtypes—generalized anxiety disorder, social anxiety disorder, panic disorder, and obsessive-compulsive disorder—with spatial gene expression patterns. Our investigation uncovered a novel division among AD-associated genes, marked by significant and distinct expression enrichments in the cerebral nuclei, limbic, and midbrain regions. Each gene cluster was associated with specific anxiety-related behaviors, signaling pathways, region-specific gene networks, and cell types. Notably, we observed a significant negative correlation in the temporal expression patterns of these gene clusters during various developmental stages. Moreover, the specific brain regions enriched in each gene group aligned with neural circuits previously associated with negative decision-making and anxious temperament. These results suggest that the two distinct gene clusters may underlie separate neural systems involved in anxiety. As a result, our findings bridge the gap between genes and neural circuitry, shedding light on the mechanisms underlying AD-associated behaviors.

An Assessment of Examination Procedures Administered by Punjab Examination Commission in Primary and Elementary Schools of District Faisalabad

Education is important in society's political, social, and economic development. Education is a basic ingredient of human development. Education is an individual's fundamental right, and it plays a key role in personality improvement. Early years are very important in human life. Keeping this in mind, the educationists have developed a separate curriculum and examination system for early childhood education. Punjab Examination Commission (PEC) is an independent body created by the Punjab Government in 2005 to examine 5th and 8th standard students. The objectives of this study were to examine the PEC's functionality, the respondents' awareness level about the PEC, the advantages and disadvantages of the PEC system, and the effects of PEC examinations. The population for the study was 249 teachers randomly selected from 20 schools in the district of Faisalabad. A random sampling technique was used to select a sample from the population. The population for this study was all elementary and primary schools in the Faisalabad district, and data were collected from primary and elementary school teachers. A well-structured questionnaire was used as a research tool. The sample size of 151 had been determined with a 95% confidence level and 5% confidence interval. Respondents were given a questionnaire according to objectives, and SPSS software was utilized to examine the questions. The findings revealed that the majority of the respondents “awareness level for exams for Primary and Elementary classes” (3.51±1.53) and “conducting examinations by Punjab examination commission is trying to improve literacy rate in Punjab” (3.92±1.65). Furthermore, “result system of PEC can be utilized further” (4.72±1.54) is considered as an advantage of PEC, while “fair educational policy is required” (4.97±1.28) is considered as a disadvantage of PEC. It is suggested that it “encourages more learning and written practices” (4.95±1.34) as the usefulness of PEC.

Implementation of an automated process for Limnospira indica harvesting and culture medium recycling for space applications

Future long-term space exploration missions require the implementation of circular life support systems for the supply of water, oxygen and food from mission wastes. Therefore, separation systems dealing with multi-phasic streams need to be addressed. The BioHarvest (BHV) study focused on solid/liquid separation in space with the aim to demonstrate the continuous separation and harvesting of the cyanobacterium Limnospira indica from its culture broth under axenic conditions. The cyanobacterium biomass is intended to be used for further food processing while the broth free of organic matter and resupplied with nutrients should be directly recycled into the photobioreactor (PBR). In this study, an automated breadboard model based on a two-step process was built. First, a Biomass Harvesting Unit (BHU) separates the biomass produced in the PBR from the culture medium with dead-end filtration. Second, the Medium Filtration Unit (MFU) further treats the culture medium to retain the dissolved organic compounds using crossflow filtration. The performances of BHU and MHU met the requirements in batch mode and in short continuous mode: the BHU was able to retain all the biomass and the MFU could retain more than 90% of organic matter while being permeable to nutrients. The productivity of the MFU was also very good, with a high permeation flux allowing treating the targeted 80 L of culture per day. However, continuous operation of the BHV technology could not be achieved in the long term due to biomass accumulation as a sticky cake with a high specific resistance on the BHU filter, despite backwashing cycles and intense vibrations. Future work shall therefore focus on this critical step, to improve process performance by preventing fouling of the filter sheets.

Conveniently synthesis of porous crown-based resin with efficient 90Sr capture from highly acidic wastewater

Effective removal of radioactive 90Sr is crucial for both management of spent nuclear fuel and recovery of radioactive strontium resources, while it’s still a great challenge due to the presence of high acid levels and intense radiation. Herein, a novel porous resin (DtBuCH18C6@CG-71) were synthesized by introducing 4′,4″(5″)-di-tert-butyldicyclohexano-18-crown-6 onto CG-71 resin using vacuum impregnation. The DtBuCH18C6@CG-71 resin maintains superior adsorption abilities in extreme conditions, including high acid resistance (3–12 mol/L HNO3), substantial γ-irradiation (200 kGy 60Co), and elevated temperatures (50–100 ℃). Impressively, even when exposed to a high concentration of matrix ions (59 elemental ions), the Sr(II) adsorption ratio onto DtBuCH18C6@CG-71 resin remains near 100 % even in highly acidic condition, which performance outpaces most of commercial resins. Dynamic column tests using an automated separation system further confirmed the superior ability of DtBuCH18C6@CG-71 in term of extracting Sr(II) from wastewater. Given its impressive features, cost-effectiveness, and scalability, DtBuCH18C6@CG-71 resin holds promising potential for 90Sr disposal in nuclear wastewater.

Electromagnetic Detection System with Magnetic Dipole Source for Near-Surface Detection.

This paper proposes a nondestructive, separate transmitter-receiver (TX-RX) electromagnetic measurement system for near-surface detection. Different from the traditional dual-coil integrated design, the proposed transient electromagnetic (TEM) system performs shallow subsurface detection using independent TX coil and movable RX coils. This configuration requires a large primary field so that the far-away secondary field is able to generate reliably induced voltages. To achieve this goal, a bipolar current-pulsed power supply (BCPPS) with a late resonant charging strategy is designed to produce a sufficiently large magnetic moment for the exciting coil with low source interference. The magnetic dipole source (MDS) with a large proportion of weight is separated from the field observation device and does not need to be dragged or transported during the detection process. This setup lowers the weight of the scanning device to 3 kg and greatly improves the measurement efficiency. The results of the laboratory test verify the effectiveness of the separate MDS and RX module system. Field experimental detection further demonstrates that the proposed system can realize highly efficient and shallow surface detection within a 200 m range of the MDS device.

CRISPR screening in human trophoblast stem cells reveals both shared and distinct aspects of human and mouse placental development.

The placenta serves as the interface between the mother and fetus, facilitating the exchange of gases and nutrients between their separate blood circulation systems. Trophoblasts in the placenta play a central role in this process. Our current understanding of mammalian trophoblast development relies largely on mouse models. However, given the diversification of mammalian placentas, findings from the mouse placenta cannot be readily extrapolated to other mammalian species, including humans. To fill this knowledge gap, we performed CRISPR knockout screening in human trophoblast stem cells (hTSCs). We targeted genes essential for mouse placental development and identified more than 100 genes as critical regulators in both human hTSCs and mouse placentas. Among them, we further characterized in detail two transcription factors, DLX3 and GCM1, and revealed their essential roles in hTSC differentiation. Moreover, a gene function-based comparison between human and mouse trophoblast subtypes suggests that their relationship may differ significantly from previous assumptions based on tissue localization or cellular function. Notably, our data reveal that hTSCs may not be analogous to mouse TSCs or the extraembryonic ectoderm (ExE) in which in vivo TSCs reside. Instead, hTSCs may be analogous to progenitor cells in the mouse ectoplacental cone and chorion. This finding is consistent with the absence of ExE-like structures during human placental development. Our data not only deepen our understanding of human trophoblast development but also facilitate cross-species comparison of mammalian placentas.

Ultrasound-enhanced separation characteristics of gas-solid fluidized bed for fine-grained fluorite ore

Due to the increasing mechanization of mining, there is an urgent need to develop dry separation technology for effective pre-enrichment of fine-grained fluorite ore and promote the efficient use of fluorite in arid or water-scarce areas. Therefore, we tried to enhance the separation performance of fine-grained fluorite ore by introducing ultrasound into the gas–solid separation fluidized bed. Fluidization test and high-speed dynamic image analysis were used to reveal the mechanism of density separation of two-component materials enhanced by ultrasound. The effects of gas velocity, static bed height, separation time and amplitude transformer diameter on density segregation of two-component materials were further studied. In addition, a gas–solid fluidized bed separation system under the action of ultrasound was established for the pre-enrichment of fluorite ore with different particle sizes. The study showed that the stability of the bed is improved by the introduction of ultrasound. And the separation efficiency was increased by 15.46% compared with ordinary fluidized bed. The possible deviation (E) values of 1–0.5 mm and 0.5–0.25 mm fluorite ore were 0.22 g/cm3 and 0.175 g/cm3 respectively. This study provides new insights into the separation of fine-grained fluorite ore by gas–solid fluidized bed under the action of ultrasound.

Цифровые технологии пропуска по перегонам и станциям — основа организации движения на Московских центральных диаметрах

train separation, automatic block system, ABTC-MSh system, moving block, interlocking, automatic cab signalling, train control system The article discusses the development of automatic block systems, which form the basis of separation systems. It also highlights the key factors limiting the capacity on open lines, and ways to solve them. A brief overview of the foreign experience of the organization of train separation using automatic block system based on track circuits is given. The article shows the capabilities and role of the computerbased automatic block signalling system with a centralized placement of equipment, audio frequency track circuits and duplicating information transmission channels as an important element of the train traffic management at the sections of Moscow Central Diameters. The significance of the implemented non-stop passage of trains along the main station tracks providing substantial section capacity increase is demonstrated. The necessity of building a digital system for train spacing is shown, which makes it possible to implement the moving block technology with-in the station ensuring the movement of trains on open lines and at stations with the same headway. The advantages of a new type of the computer-based automatic block signalling system as a basic element of a promising Russian train traffic control system and the positive effects of its implementation on the Russian railway network are indicated. The direction of development of train separation systems is outlined within the framework of further digitalization.

A pH-Mediated Highly Selective System Enabling Simultaneous Analysis of Circulating RNAs Carried by Extracellular Vesicles and Lipoproteins.

Extracellular vesicles (EVs) and lipoproteins (LPPs) serve as important carriers of circulating miRNAs in peripheral blood, offering immense potential for disease diagnosis and therapeutic interventions. Due to their shared physicochemical attributes, EVs and LPPs are frequently coisolated, potentially leading to misunderstandings regarding their distinct functional roles in physiological and pathological processes. Here, we report a highly selective magnetic system based on the pH-mediated affinity displayed by cibacron blue (CB) toward EVs and LPPs, enabling successful separation and collection of these two nanoparticles without cross-contamination for subsequent circulating RNA analysis. First, we found that CB-modified magnetic beads (CBMBs) exhibit a strong affinity toward LPP particles while displaying little interaction with EVs in standard samples under physiological pH conditions. We further demonstrate that the affinity between CB molecules and bionanoparticles in plasma samples is highly pH-dependent. Specifically, CBMBs show affinities for both LPP and EV particles under neutral and acidic conditions. However, at basic pH levels, CB molecules selectively bind only to LPP particles. Consequently, the remaining EV particles present in plasma are subsequently isolated by using titanium dioxide-modified beads (TiMBs) through phospholipid affinity. The simultaneous analysis of the transcriptomic contents of EV and LPP reveals clear differences in their small RNA profiles, with the differentially expressed RNAs reflecting distinct biological processes. Significantly, in a proof-of-concept study, we successfully demonstrated a strong correlation between miRNAs carried by both EV and LPP particles with the occurrence of ocular neovascularization during the progression of diabetic retinopathy. The involved miRNAs may serve as potential biomarkers for DR diagnostics and severity classification. To sum up, this pH-mediated separation system is not only user-friendly but also highly compatible, rendering it a potent tool for probing the molecular compositions, biomarkers, and underlying biological mechanisms of EVs and LPPs.

Taylor dispersion in arbitrarily shaped axisymmetric channels

Advective dispersion of solutes in long thin axisymmetric channels is important to the analysis and design of a wide range of devices, including chemical separation systems and microfluidic chips. Despite extensive analysis of Taylor dispersion in various scenarios, most studies focus on long-term dispersion behaviour and cannot capture the transient evolution of the solute zone across the spatial variations in the channel. In the current study, we analyse the Taylor–Aris dispersion for arbitrarily shaped axisymmetric channels. We derive an expression for solute dynamics in terms of two coupled ordinary differential equations, which allow prediction of the time evolution of the mean location and axial (standard deviation) width of the solute zone as a function of the channel geometry. We compare and benchmark our predictions with Brownian dynamics simulations for a variety of cases, including linearly expanding/converging channels and periodic channels. We also present an analytical description of the physical regimes of transient positive versus negative axial growth of solute width. Finally, to further demonstrate the utility of the analysis, we demonstrate a method to engineer channel geometries to achieve desired solute width distributions over space and time. We apply the latter analysis to generate a geometry that results in a constant axial width and a second geometry that results in a sinusoidal axial variance in space.

Inter-event and intra-event dynamics of microplastic emissions in an urban river during rainfall episodes

Urban rivers represent the major conduits for land-sourced microplastics in the global oceans, yet the real-time dynamics of their emissions in rivers during rainfall (and runoff) events are poorly understood. Herein, we report the results of high-frequency sampling of microplastic particles (MPs) and fibers (MPFs) in the surface water of an urban river in Japan over the course of three rainfall events (i.e., light, moderate, and heavy rainfalls). The event mean concentrations (EMCs) of MPs amounted to 35,000 items/m3, 929,000 items/m3, and 331,000 items/m3; and the corresponding total loads were 0.5 kg, 19.8 kg, and 35.0 kg for light, moderate and heavy rainfalls, respectively. The inter-event total loads of MPs correlate well with the total rainfall, while the concentrations were linked with the number of antecedent dry days. The dynamic trends show that <2000 μm MPs displayed first flush effects during light to moderate rainfall events (>50% mass discharged with the initial 20–40% of flow). Small-sized MPs (10–40 μm) mobilized rapidly at lower rainfall intensities, whereas MPs over 2000 μm discharged immediately after the peak rainfall intensity. Moreover, <70 μm MPs depicted a surge following heavy rainfall events due to turbulent flow conditions reverting the deposited MPs into suspension. Overall, the three events increased the loads by 4–110 folds, and EMCs by 10–350 folds compared to the concentrations during dry weather while portraying a significant impact on 300–1000 μm MPs. The dynamics of MPs were correlated with those of suspended solids in river water, and the characteristics were comparable to the same of road dust sampled in Japan. Although the dynamic trends between MPs and MPFs in river water were comparable, MPFs were relatively less impacted by rain, likely due to the intervention of separate sewer systems in the study area.

Advancements in Gas Separation for Energy Applications: Exploring the Potential of Polymer Membranes with Intrinsic Microporosity (PIM).

Membrane-based Polymers of Intrinsic Microporosity (PIMs) are promising candidates for energy-efficient industrial gas separations, especially for the separation of carbon dioxide over methane (CO2/CH4) and carbon dioxide over nitrogen (CO2/N2) for natural gas/biogas upgrading and carbon capture from flue gases, respectively. Compared to other separation techniques, membrane separations offer potential energy and cost savings. Ultra-permeable PIM-based polymers are currently leading the trade-off between permeability and selectivity for gas separations, particularly in CO2/CH4 and CO2/N2. These membranes show a significant improvement in performance and fall within a linear correlation on benchmark Robeson plots, which are parallel to, but significantly above, the CO2/CH4 and CO2/N2 Robeson upper bounds. This improvement is expected to enhance the credibility of polymer membranes for CO2 separations and stimulate further research in polymer science and applied engineering to develop membrane systems for these CO2 separations, which are critical to energy and environmental sustainability. This review aims to highlight the state-of-the-art strategies employed to enhance gas separation performances in PIM-based membranes while also mitigating aging effects. These strategies include chemical post-modification, crosslinking, UV and thermal treatment of PIM, as well as the incorporation of nanofillers in the polymeric matrix.