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Abstract Highly permeable polyamide (PA) membrane capable of precise ionic sieving can be utilized for many energy-efficient chemical separations. To fulfill this target, it is crucial to innovate membrane-forming process to induce a narrow pore-size distribution. Herein, we report an anhydrous interfacial polymerization (AIP) at a solid-liquid interface where the amine layer sublimated is in direct contact with the alkane containing acyl chlorides. In such a heterophase interface, water-caused side reactions are eliminated, and the amines in compact arrangement enable an intensive and orderly IP reaction, leading to a unique PA layer with an ionic sieving accuracy of 0.5 Å. The AIP-PA membrane demonstrates excellent separation selectivities of monovalent and divalent cations such as Mg2+/Li+ (78.3) and anions such as Cl-/SO4 2- (29.2) together with a high water flux up to 13.6 L m−2 h−1 bar−1. Our AIP strategy may provide inspirations for engineering high-precision PA membranes available in various advanced separations.

To improve the mechanical properties of 2,4,6-trinitrobenzene-1,3,5-triamine (TATB)-based polymer bonded explosives (PBXs), four kinds of polythiourea binders, namely the polyetherthiourea (P1), aliphatic polythiourea (P2), aromatic polythiourea (P3) and silane polythiourea (P4), were prepared and used in the PBXs. These four polythioureas were synthesized via the copolymerization of carbon disulfide (CS2) and diamines with various structures under mild conditions. They were then characterized using nuclear magnetic resonance (NMR) and Fourier-transform infrared spectroscopy (FTIR). The interfacial binding energy between polythioureas and TATB was calculated via molecular dynamics simulations. The tensile and compression mechanical properties of various PBXs (PBX-Pn, n ​= ​1–4) were studied through Brazilian and compression tests and were then compared with those of the PBX with a conventional fluoro polymer binder (PBX-FP). The results show that the PBX-P1 possessed the strongest interfacial interaction energy and the best mechanical properties among all the prepared PBXs. Its Brazilian strength and strain was 11.0 ​MPa and 0.56%, which was 89% and 256% higher than those of the PBX-FP with the same binder proportion, respectively. Furthermore, PBX-P1 showed excellent compression mechanical properties, with a compression strength of 40.7 ​MPa and a compression strain of 3.53%. Moreover, its Brazilian and compression fracture energy was 600% and 101% higher than those of PBX-FP, respectively, which was beneficial for improving the PBX stability. The results of this study provide a new idea for designing TATB-based PBX with improved mechanical properties using polyetherthiourea binders.

Achieving a water–oil interface imbalance has been identified as a critical factor in the demulsification of water-in-oil emulsions. However, conventional demulsifying membranes generally break the interface balance by depending on a relatively high transmembrane pressure. Here, we present a “contact demulsification” concept to naturally and quickly achieve disruption of the water–oil interface balance. For this purpose, a novel demulsifying membrane with a high flux of the organic component has been developed via the simple vacuum assembly of zeolitic imidazolate framework-8 (ZIF-8)@reduced graphene oxide (rGO) microspheres (ZGS) on a polytetrafluoroethylene (PTFE) support, followed by immobilization processing in a polydimethylsiloxane (PDMS) crosslinking solution. Due to the micro-nano hierarchies of the ZGS, the prepared ZIF-8@rGO@PDMS/PTFE (ZGPP) membranes feature a unique superhydrophobic surface, which results in a water–oil interface imbalance when a surfactant-stabilized water-in-oil emulsion comes into contact with the membrane surface. Under a low transmembrane pressure of 0.15 bar (15 kPa), such membranes show an excellent separation efficiency (∼99.57%) and a high flux of 2254 L·m−2·h−1, even for surfactant-stabilized nanoscale water-in-toluene emulsions (with an average droplet size of 57 nm). This “contact demulsification” concept paves the way for developing next-generation demulsifying membranes for water-in-oil emulsion separation.

Membrane separation technology has been taken up for use in diverse applications such as water treatment, pharmaceutical, petroleum, and energy-related industries. Compared with the design of membrane materials, the innovation of membrane preparation technique is more urgent for the development of membrane separation technology, because it not only affects physicochemical properties and separation performance of the fabricated membranes, but also determines their potential in industrialized application. Among the various membrane preparation methods, spray technique has recently gained increasing attention because of its low cost, rapidity, scalability, minimum of environmental burden, and viability for nearly unlimited range of materials. In this Review article, we summarized and discussed the recent developments in separation membranes using the spray technique, including the fundamentals, important features and applications. The present challenges and future considerations have been touched to provide inspired insights for developing the sprayed separation membranes.

To meet the growing demand for integrated monitoring of complex power grid equipment, it is necessary to improve the situational awareness model of power transformers. The model is expected to assist monitoring personnel in timely identifying transformers with deteriorating trends among massive and discrete monitoring information, and to make responses in advance. However, the current transformer state awareness technology generally has the problem of single data source and poor timeliness, and still requires monitoring personnel to make artificial analysis and prediction in combination with telemetry information, which cannot fully meet the requirements of power grid equipment monitoring. This paper is based on multi-source data fusion technology, through associating and mining transformer alarm information, equipment maintenance records and power transmission and transformation online monitoring data, to extract the dimension features of transformer operation situation assessment. By constructing a multi-layer perceptron model, a transformer state transition model based on the principle of Markov chain is established, which can predict possible defects 2 h in advance and achieve good results, and determine the transformer state early warning index, providing sufficient time for monitoring personnel to deploy transformer operation and maintenance work in advance. Finally, the effectiveness of the method proposed in this paper is proved by the case of transformer crisis state in a city substation, and the method proposed in this paper has important significance for transformer state early warning. [ABSTRACT FROM AUTHOR]

In recent years, the research and application of distributed energy storage technology have received high attention from countries around the world and have achieved rapid development. Integrating distributed energy storage devices into the power grid is one of the effective ways to solve the problem of power quality in weak rural areas. Based on particle swarm optimization algorithm, this paper studies the regulation strategy of integrating distributed energy storage systems into weak rural areas to improve power quality. Based on the actual daily load curve of the distribution station area, optimization regulation strategies are obtained to generate success rate instructions to guide the actual grid connection operation process of the energy storage system.

In this article, the adsorption process of transition metal Fe-doped ZIF-67 material on characteristic gases in oil was investigated based on the first principles. The geometry optimisation model, adsorption parameters, energy band structure, TDOS and PDOS of each adsorption system were analysed and compared. The results showed that Fe-ZIF-67 chemically adsorbed all four characteristic gases in oil. And after doping, the adsorption energy of ZIF-67 material to CO gas can be greatly improved, but the adsorption energy to C2H2 gas is reduced. The adsorption performance ranking is CO > C2H2 > C2H4 > C2H6. This result shows that the addition of Fe enhances the selective absorption of characteristic gases in oil by ZIF-67 materials. The addition of Fe enhances the selective absorption of characteristic gases in oil by the ZIF-67 material. This article offers part of the theoretical evidence for the selective detectability and gas adsorption of characteristic gases in oil by ZIF-67 material. [ABSTRACT FROM AUTHOR]

At high temperatures, the rapid and effective detection of SF6 decomposition gas is a major challenge. Therefore, online detection of SF6 decomposition gas at high temperatures for Gas Insulated Switchgear fault diagnosis is necessary. In this work, first-principles calculations are used to examine the adsorption and sensing properties of pristine WS2 and transition metal Co, Rh, and Ir-modified WS2 toward H2S, SO2, SOF2, and SO2F2. Our study delved into the adsorption energy and mechanisms of each system, exploring various aspects including adsorption energy, band gap, electron density, frontier orbital theory, conductivity, and recovery time. The findings indicate that the transition metal Co, Rh, and Ir-modified WS2 surface exhibits excellent adsorption capabilities for the decomposed gases. Co-WS2 has good sensing performance for H2S, SO2, and SOF2 and can achieve faster desorption for these three decomposed gases at high temperatures (598 K). SO2F2 can be desorbed rapidly (0.65 s) from the surface of Rh-WS2 at room temperature, and Rh-WS2 has good selectivity for SO2F2. Interestingly, Ir-WS2 remains difficult to desorb even at high temperatures for H2S (−2.642 eV), SO2 (−2.260 eV), SOF2 (−1.945 eV), and SO2F2 (−2.841 eV) and can be used as a scavenger for these four gases. Therefore, the simulation experiments in this study aim to investigate the advantages of transition metal Co, Rh, and Ir-modified WS2 for detecting SF6 decomposition gases. [ABSTRACT FROM AUTHOR]

Oil-immersed power transformers generate characteristic gases after failure,Therefore, it is necessary to analyse and monitor the soluble gases in transformer oil samples. In this study, the DFT calculation method was used to study the adsorption properties of H2, CO, C2H2, and C2H4 gases in oil on both intrinsic MoTe2 and Rh-doped MoTe2 films. In order to analyse the adsorption characteristics, this paper first obtains the most stable Rh-doped MoTe2 monolayer model through the modelling and computational analysis of different doping sites, then, the adsorption of these gases on the material surface is studied by analysing adsorption energy, charge transfer, total state density, parting density, energy band structure, differential charge density map, molecular front orbital and desorption time, and finally concludes that Rh-MoTe2 monolayer film is the ideal material for hydrogen sensing elements, due to the extremely long desorption time of CO gas, indicating that CO gas is hard to desorption on the surface of adsorbent,which shows that this process has played a certain role in promoting CO removal. Highlights Study focused on gas adsorption using DFT: Rh-MoTe2 ideal for hydrogen sensing and effective for CO removal, intrinsic MoTe2 ineffective and required metal doping. Rh doping enhanced conductivity and gas adsorption capacity in MoTe2. Rh-MoTe2 was suitable for detecting H2, C2H2, and C2H4 gases. Desorption times vary with temperature, with CO removal particularly effective at higher temperatures. Findings suggest potential applications for Rh-MoTe2 in gas sensing and removal. [ABSTRACT FROM AUTHOR]

Covalent Organic Frameworks (COFs) have attracted significant interest as promising separation membrane materials for their well-organized porous system and highly ordered crystalline structure. However, compared with the molecular and ionic separation in liquid phase, the advance of the COF membrane in gas separation has been relatively slow. To achieve desirable gas separation performance, the pore size of the COF membrane is expected to be regulated into the gas molecule-selective region, and also the tuning of pore enviroment is of importance. This review focuses on the key progress of the pore regulation strategies for the COF membrane towards gas separation. We highlight the different design concepts for selective gas transport channels, and introduce the specific applications to elucidate the structure-performance relationship of the COF membrane. We discuss the critical challenges and opportunities faced by the COF membranes in the field of gas separation, aiming at guiding the direction of the future efforts and promoting their development.