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In this study, Na2CO3 was used as an activator to roast and activate high aluminium fly ash (HAFA) via conventional heating. Microwave roasting technology was then used to strengthen the activation process and the reaction mechanism was discussed and compared with that of conventional heating. Microwave heating had an obvious effect on the HAFA activation process: with an aluminium leaching rate of approximately 93.00%, both the roasting time (30 min) and temperature (700 °C) were comparatively reduced, and the mass ratio of HAFA to Na2CO3 employed was 1:0.8. XRD analysis showed that the phase evolution of HAFA was not changed during microwave heating, but the Na2CO3-HAFA activation reaction was promoted. And SEM analysis showed that the micro-structure of roasted materials varied greatly with respect to the different heating methods. With microwave heating, overall breakage of mullite particles occurs and there is higher degree of breakage than conventional heating.

Magnesium–aluminium spinel powder was prepared by microwave hydrothermal synthesis method. The phase structure of the samples was analysed using X-ray diffractometer. The microscopic morphology of the samples was analysed by scanning electron microscope. The particle size of the powder was characterised. The effects of different microwave hydrothermal reaction temperatures on the phase structure, micromorphology and particle size distribution of the precursors were studied. Results show that when hydrothermal reaction temperature was controlled at 140 °C-180 °C, pure magnesium–aluminium composite hydroxyl-hydrate precursor can be obtained after 200 min. The median diameter of magnesium–aluminium spinel precursor powder under 150 °C was 5.958 μm, which is the minimum. After calcination, the morphology of the powder underwent a process from flaking and particle stacking to development of complete flake morphology as the microwave hydrothermal reaction temperature increased. The agglomeration phenomenon was very serious when the synthesis temperature was greater than 150 °C.

High-energy-density batteries are in demand to meet society's immense electricity consumption, especially for wearable and portable devices. Li–CO2 batteries have attracted increasing attention for their high theoretical capacity (1876 W h kg−1) and environmental benignity. Recent research efforts have been mainly focused on improving the performance of powder catalysts; however, the overall energy density is still limited due to the inevitable employment of extra gas diffusion layers (GDLs) in cathodes. Against this backdrop, we report a method of fabricating a freestanding cathode containing ultrafine MnO nanoparticles embedded in mesoporous carbon nanofibers (MnO@NMCNFs) using electrospun Mn metal–organic framework nanofibers as precursors. Benefiting from excellent mechanical strength of the nitrogen-doped carbon nanofiber matrix, abundant mesopores and fully exposed Mn(II) active sites, the obtained cathode guarantees high flexibility, high interface accessibility, high catalytic activity and high conductivity. Therefore, the corresponding Li–CO2 batteries achieved ultrahigh areal capacity (19.07 mA h cm−2), impressively low overpotential (0.73 V) and competitive cycling stability (>50 cycles under cut-off capacity of 1 mA h cm−2). A pouch-type flexible cell based on MnO@NMCNFs steadily lit up commercial LED devices at different bending angles. Our findings advance the application of high-energy Li–CO2 batteries in wearable energy storage systems.

Sr(Ti0.6Fe0.4)1-xO3-δ precursors were prepared through the sol–gel method. The samples sintered in air at 1350 °C for 300 min were characterized in terms of conductivity, bulk density, microstructure and phase analysis via AC impedance, scanning electron microscope (SEM), Archimedes’ method and X-ray diffraction (XRD). The total electrical conductivity of Sr(Ti0.6Fe0.4)1-xO3-δ samples can be remarkably improved by B-site-deficient level (x). When x = 0.07, the total electrical conductivity reaches a maximum of 0.3445 S/cm at 800 °C. The microstructure of the sample becomes more porous as the B-site-deficient level increases. The relative density of samples is becoming lower with B-site-deficient level increases. Diffraction peaks without impurities appear in the X-ray diffraction pattern, indicating the formation of a single perovskite structure. In addition, the Sr(Ti0.6Fe0.4)1-xO3-δ/YSZ samples show a great chemical stability and compatibility.

Eupatorium adenophorum, a kind of pernicious weed, is used to produce a photocatalyst-adsorbent composite, consisting of ZnO Fe3O4 particles on the surface of activated carbon, and bio-gas via catalytic pyrolysis. The photocatalyst-adsorbent composite was characterized by several characterization methods. The results show that the photocatalyst-adsorbent composite possesses adsorptive, photocatalytic degradative and magnetic properties. Methylene blue, a kind of dye, is used to evaluate the adsorption and photocatalytic degradation performance of photocatalyst-adsorbent composite. The maximum amount of methylene blue adsorption in photocatalyst-adsorbent composite was as high as 330.03 mg/g based on the adsorption experiment in dark conditions. The photocatalyst-adsorbent composite had good degradation performance with methylene blue, which was found to be 20.78% more efficient than the ZnO catalyst and 205% more efficient than the adsorption under ultra violet light irradiation. Photocatalyst-adsorbent composite could be conveniently separated from the aqueous solution by using an external magnetic field. The bio-gas was collected from the pyrolysis process, which mainly consisted of H2 and CO. The production cost of the photocatalyst-adsorbent composite is US$ 1,361/t based on the preliminary economic analysis.

The microwave-absorption capabilities of high-alumina fly ash (HAFA), Na2CO3 and HAFA–Na2CO2 mixtures were investigated by determining the dielectric properties [real part (e′), imaginary part (e″) and dielectric loss tangent (tan δ)] from 25°C to 800°C, using the microwave resonant cavity technique at a microwave frequency of 2450 MHz. The mass ratio of the HAFA–Na2CO3 mixtures used in all experiments was 1:1. The study found that the microwave absorption capabilities of HAFA alone do not change significantly within the range of temperatures examined. For both Na2CO3 and HAFA–Na2CO3 mixtures, however, a sharp increase in absorption capability was observed above 400°C. The microwave heating behavior of the HAFA–Na2CO3 mixtures can be divided into two stages: in the first stage (

Air filtration has become an essential need for passive pollution control. However, most of the commercial air purifiers rely on dense fibrous filters, which have good particulate matter (PM) removal capability but poor biocidal effect. Here we present the photocatalytic bactericidal properties of a series of metal-organic frameworks (MOFs) and their potentials in air pollution control and personal protection. Specifically, a zinc-imidazolate MOF (ZIF-8) exhibits almost complete inactivation of Escherichia coli (E. coli) (>99.9999% inactivation efficiency) in saline within 2 h of simulated solar irradiation. Mechanistic studies indicate that photoelectrons trapped at Zn+ centers within ZIF-8 via ligand to metal charge transfer (LMCT) are responsible for oxygen-reduction related reactive oxygen species (ROS) production, which is the dominant disinfection mechanism. Air filters fabricated from ZIF-8 show remarkable performance for integrated pollution control, with >99.99% photocatalytic killing efficiency against airborne bacteria in 30 min and 97% PM removal. This work may shed light on designing new porous solids with photocatalytic antibiotic capability for public health protection., Personal protective air filtration masks are becoming increasingly desirable, but most commercial air purifiers have poor biocidal capabilities. Here the authors fabricate metal–organic framework-based air filters with both high particulate matter removal efficiencies and photocatalytic bactericidal properties.

Nowadays, one of the most challenging sustainability issues faced by society is the safety of water resources. Water pollution caused by hazardous contaminants (e.g., heavy metal ions, emerging contaminants, organic dyes) is a serious issue because of acute toxicities and the carcinogenic nature of the pollutants. With the advent of materials engineering, unprecedented technical advances have been achieved through diverse technologies in recent decades, including photocatalytic oxidation, photo-Fenton, electron Fenton, adsorption, and separation. However, the applications of these technologies have suffered from several limitations, such as the uncompleted degradation efficiency, high energy consumption, narrow pH range for application etc. Metal–organic frameworks (MOFs) have aroused increasing studies in gas storage, separation, sensing, water/air purification, and catalysis. The effectiveness of the above applications has been extensively recognized. In recent years, these highly ordered and porous cry...

Li–CO2 batteries have been developed in recent years, aiming to utilize CO2, a major cause of the greenhouse effect, as an effective energy storage medium. However, current Li–CO2 batteries still suffer from low energy efficiency, poor rate capability and short cycle life, demanding the design of more efficient CO2 cathodes. Herein, we synthesized ultrafine MnO nanoparticles dispersed in a graphene-interconnected N-doped 3D carbon framework, MnO@NC-G, by pyrolyzing a composite of a GO-wrapped metal–organic framework (MOF) containing Mn(II) active sites as the cathode material for Li–CO2 batteries. This material can enable low voltage hysteresis (0.88 V at 50 mA g−1), high rate capability (up to 1 A g−1) and long cycle life (more than 200 cycles) in cells. By comparing MnO@NC-G with four other Mn(II)-based cathodes, MnO@NC, parent Mn-MOF, MnO@KB and bulk MnO, we propose three key aspects for designing CO2 cathodes: (1) dispersed catalytic species, (2) fast electron transport, and (3) a robust interconnected network. We also found that the performance of a cycled MnO@NC-G cathode can be replenished simply by replacing the anode, indicating that the cell cycle life can be further extended with effective anode protection. Our findings here provide useful guidelines for improving the performance of Li–CO2 batteries, thus shedding light on the development of practical Li battery systems based on gaseous cathodes.

Demand for germanium (Ge) is rapidly growing in recent years in various fields including semiconductors, aerospace, and solar cells. However, the Ge resources are very limited in the world. Hence, in this work, microwave-assisted leaching and conventional leaching methods are employed for the leaching of Ge from the Ge-rich lignite ash (GA). The effects of leaching temperature, leaching time, initial acid concentration, oxidizing agent amount, and stirring speed on leaching of Ge were investigated and microwave-assisted and conventional methods of leaching were compared. Here, HCl solution is used as a leaching agent, and MnO2 is used as an oxidizing agent. From the results, the leaching rate of Ge was found to be 89.49% in the microwave-assisted method, and 83.62% in the conventional leaching method. The optimal conditions for microwave-assisted method include a leaching temperature of 65°C, a leaching time of 90 min, an oxidizing agent amount of 10 g/l, an initial acid concentration of 10 mol/l, and a stirring speed of 250 rpm. The leaching rate of Ge significantly improved in the microwave-assisted method as compared to the conventional method. Therefore, the microwave-assisted method is a suitable method for the leaching of Ge from the GA and is a novel way for the efficient utilization of Ge concentrate.

Covalent organic framework (COF) films combine the processability of polymers with the porosity and atomic precision of crystalline porous materials, properties that are long-sought-after in electronics yet hard to realize. Herein, we prepared four flexible COF films with different alkoxy side chains via interfacial polymerization. The COF films exhibit an ultralow dielectric constant (κ=1.19±0.04 at 105 Hz), small dielectric loss ( 63 kV cm-1 ) and low leakage current (10-10 A cm-2 at 1 kV cm-1 ). They have considerable mechanical strength, and ability to withstand high humidity (RH 70 % for 10 days) and repeated bending (1000 times) without losing their dielectric properties. Extension of the alkoxy chains reduces the film's κ and enhances its moisture resistance, while incorporation of guest molecules further increase the κ value up to 43 times.

Herein, we report a large-scale production protocol of MOF-derived (MOF: metal–organic framework) coatings for functional interlayers by retrofitting the industrialized battery manufacturing process. An electrode caster and a modified hot-rolling compressor were assembled to continuously spread the precursors and generate nanocrystals of MOF, respectively. Co nanoparticles wrapped within N-doped porous carbon (Co@NPC) are formed after calcination and serve as powerful “anchors” to greatly enhance the charge transfer kinetics and completeness of Li2Sx → Li2S conversion, largely improving the utilization of S. With unmodified S electrodes, the functionalized interlayer achieves a near theoretical capacity of 1618 mA h g–1 in the first cycle at 1 C, which retains 1064 mA h g–1 after 200 cycles; under increased S loading levels of 5.8 and 13.4 mg cm–2, it exhibits 1010 and 710 mA h g–1 at 0.1 C, 113% and 295% those obtained by the bare counterpart. The scalable protocol of MOF and MOF-derived functionalizatio...

The use of vacuum distillation for commercial biodiesel production has become a reliable post-treatment method for removing multiple impurity types, consistently producing high-grade biodiesel. Dur...

The kinetic studies performed on the forward extract of cerium(III) from chloride solution with the complex agents, citric acid (H3Cit) and lactic acid (HLac) in the presence of di-(2-ethylhexyl)phosphoric acid (D2EHPA, H2A2) have been investigated using a constant interfacial area cell with laminar flow. The effects of stirring speed, temperature, and specific interfacial area on the extraction rate are discussed separately, and the results show that the extraction process is a diffusion-controlled kinetics process with an interfacial reaction. Studies on the effect of pH value and H2A2 concentration on the extraction rate are used to obtain the rate equation. The rate-controlling step is also suggested by the predictions derived from the interfacial reaction models, and the rate equation obtained by the kinetic model is consistent with that obtained by the experimental results. The information on the extraction kinetics in this extraction system will provide some knowledge of its application.

The production of hydrogen through electrolysis is considered as a feasible strategy to quench the world’s clean-energy thirst. Compared with water electrolysis, urea electrolysis presents a more promising prospect in the way that it could carry out sewage treatment as well as energy-efficient hydrogen production at the same time. Herein, highly porous pomegranate-like Ni/C was synthesized from multivariate metal–organic frameworks and exhibits excellent hydrogen evolution activity with an unprecedented low overpotential of 40 mV at the current density of 10 mA cm–2 in 1 M KOH, ranking among the best earth-abundant electrocatalysts deposited on glassy carbon electrodes reported to date. In addition, it also displays superb anodic urea oxidation activity with an onset potential of 1.33 V vs RHE. Furthermore, a two-electrode urea electrolyzer with Ni/C as both the cathode and anode electrocatalyst was fabricated and generates 52 times more hydrogen than the water electrolyzer under the same conditions.

Transition-metal oxides are one of the most promising anode materials for energy storage in lithium- and sodium-ion batteries (LIBs and NIBs, respectively). To improve the electrochemical performance of metal oxides (e.g., Co3 O4 ), such as capacity and cyclability, a convenient strategy (with a metal-organic framework as a template) is introduced to generate Zn- or Ni-doped Co3 O4 . The obtained hollow core-shell nanosized Co3 O4 (denoted as Zn/Ni-Co-Oxide) derived from pyrolyzing zinc or nickel co-doped ZIF-67 (Co(mIm)2 ; mIm=methylimidazole) shows a drastically enhanced capacity of 1300 mAh g-1 at a high current density of 5000 mA g-1 , compared with that of pristine cobalt oxide (800 mAh g-1 ) in LIBs. A zinc-doped Zn-Co-Oxide demonstrates a stable capacity of 1600 mAh g-1 at 1000 mA g-1 for 700 cycles and an excellent performance in full coin cells (cycled with LiNi0.5 Co0.3 Mn0.2 O2 ). Moreover, NIB tests show a stable capacity of 300 mAh g-1 for more than 250 cycles.

Connection is an important part of the bamboo and timber structure, and it directly influences the overall structural performance and safety. Based on a comprehensive analysis of the mechanical performance of several wood connections, a new connector for the bamboo (timber) frame joint was proposed in this paper. Three full-scale T-type joint specimens were designed to study the mechanical performance under cyclic loading. The thickness of the hollow steel column was different among three specimens. The specimens were loaded under displacement control with a rate of 10 mm per minute until the specimens reach failure. It was observed that the failures of three specimens were caused by the buckling of flanges in the compression and that the steel of connections does not yield. The load-displacement hysteretic curve for three specimens is relatively plump, and the stiffness of connection degenerates with the increasing of cyclic load. The maximum rotation is 0.049 rad, and the energy dissipation coefficient is 1.77. The thickness of the hollow steel column of the connector has significant impact on the energy dissipation capacity and the strength of the connection. A simplified moment-rotation hysteresis model for the joint was proposed.

The actual working environment temperature of the horizontal well tractor is too high, which leads to position sensor of general brushless DC motor (BLDCM) cannot work normally. Therefore, the position sensorless drive system is designed to overcome the problems caused by the position sensor in the actual working conditions. The principle of sensorless BLDCM work is introduced in detail, And drive system of Sensorless BLDCM was established by using simulation software. The use of three stage start make motor smoothly start, the motor speed detection based on model reference adaptive control (MRAC), ensures accurate commutation. Finally, the hardware and software design of the BLDCM system based on digital signal controller (DSC) is introduced and tested. The experimental results show that the drive system can start the BLDCM smoothly in the high temperature environment, and can quickly track the given speed, which meet the actual work demand of the horizontal well tractor.

Parallel strand bamboo (PSB) is a latest construction material; to know more about mechanical properties of PSB, 5 groups of specimens with difference only in bolt diameter were designed to study the impact of the fastener diameter on embedding strength perpendicular to grain of PSB. Based on the tested result, the feasibility for PSB of the theoretical equation in the American code and European code on embedding strength predication was assessed. A controlled displacement was used to load till specimen failure, the stress-displacement curve of all specimens was obtained in terms of the tested results, and the yielding tested strength based on 5% bolt diameter offset proposed by the American code was found. The tested results showed that the yielding strength perpendicular to grain of PSB was stable, the variable coefficient was between 5.88% and 13.34%, and the average yielding strength values were 80.84 MPa, 77.40 MPa, 76.52 MPa, 74.20 MPa, and 67.01 MPa, respectively, which decreased with the increase of bolt diameter, and the average yielding strength values are larger than the calculated results using theoretical formula. Therefore, the theoretical equation on embedding yielding strength of wood in the American code and European code applies to PSB.

Improving the reversibility and energy efficiency of Li–CO2 electrochemistry would help in developing practical Li–air batteries capable of providing stable power supply in the presence of CO2. However, it is hard for most existing electrodes to convert CO2 effectively (high discharge capacity) and efficiently (low charge potential). Herein, we have, for the first time, identified the potential of metal–organic frameworks (MOFs) as porous catalysts in CO2 electrodes, taking advantage of their high capability for CO2 capture and monodispersed active metal sites for Li2CO3 decomposition. In particular, eight porous MOFs (Mn2(dobdc), Co2(dobdc), Ni2(dobdc), Mn(bdc), Fe(bdc), Cu(bdc), Mn(C2H2N3)2, and Mn(HCOO)2) and two nonporous materials (MnCO3 and MnO) were investigated. Among them, Mn2(dobdc) achieves a remarkable discharge capacity of 18 022 mA h g−1 at 50 mA g−1, while Mn(HCOO)2 retains a low charge potential of ∼4.0 V even at 200 mA g−1 for over 50 cycles. The Li–CO2 electrochemistry on MOF electrodes was investigated with an arsenal of characterization techniques, including X-ray diffraction, scanning electron microscopy, electrochemical impedance spectroscopy, Raman spectroscopy and in situ differential electrochemical mass spectrometry. The findings provide useful design principles for improving the reversibility and energy efficiency of Li–CO2 electrochemistry and will herald the advent of practical technologies that enable energy-efficient utilization of CO2 for electrochemical energy storage and supply.

Extractive and separation of Pr/Ce using a Y-junction serpentine microreactor, with 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester (EHEHPA, P507), has been investigated. The results clearly indicate separation factor of Pr/Ce (> 3) is to be higher in the microfluidic extraction as compared to separation factor of around 2 to 3 for batch systems. The optimized residence time of 12 s in micro-flow is much less than that in batch system (≅ 300 s). The extraction rates for Pr and Ce are found to match first order kinetics with the rate constants being 0.2649 s− 1 and 0.2279 s− 1, respectively, which are > 20 times higher than those for batch extraction. The volumetric mass transfer coefficients (KLa) for various operating conditions vary between 0.007 and 0.57 s− 1, which decrease with increase in channel size (channel width and length). The experimentally mass transfer coefficients are compared with those with conventional extractors such as mixer settler and centrifugal extractors.

The removal of $$\hbox {H}_{2}\hbox {S}$$ from copper smelting contaminated acid using sodium hydroxide (NaOH) as absorbent was investigated in a RPB reactor. The influences of operating parameters were assessed on the removal efficiency of $$\hbox {H}_{2}\hbox {S}$$ (E) and overall volumetric gas side mass transfer coefficient ( $$K_{\mathrm{G}}a$$ ). The results illustrate that E and $$K_{\mathrm{G}}a$$ increased with increase in high gravity factor, flow rate and concentration of sodium hydroxide while decreased with increase in mass concentration of $$\hbox {H}_{2}\hbox {S}$$ in feed gas. With increase in $$\hbox {H}_{2}\hbox {S}$$ gas flow rate, E was found to decrease while $$K_{\mathrm{G}}a$$ was found to increase. The increase in the temperature of absorption did not show any significant effect on E and $$K_{\mathrm{G}}a$$ . The $$K_{\mathrm{G}}a$$ of the rotating packed bed reactor was about 30 times higher than the conventional packed bed at similar gas liquid throughputs. The superior performance of RBP certainly demands further investigation, process development, scale-up for economical commercial adoption.

Three-dimensional covalent organic frameworks (3D COFs) are promising crystalline materials with well-defined structures, high porosity, and low density; however, the limited choice of building blocks and synthetic difficulties have hampered their development. Herein, we used a flexible and aliphatic macrocycle, namely γ-cyclodextrin (γ-CD), as the soft struts for the construction of a polymeric and periodic 3D extended network, with the units joined via tetrakis(spiroborate) tetrahedra with various counterions. The inclusion of pliable moieties in the robust open framework endows these CD-COFs with dynamic features, leading to a prominent Li ion conductivity of up to 2.7 mS cm−1 at 30 °C and excellent long-term Li ion stripping/plating stability. Exchanging the counterions within the pores can effectively modulate the interactions between the CD-COF and CO2 molecules.

Parameters of technique to prepare of V2O5 by microwave intensification from ammonium metavanadate were optimized using central composite design of response surface methodology. A quadratic equation model for decomposition rate was built and effects of main factors and their corresponding relationships were obtained. The microwave heating behavior indicated that ammonium metavanadate had weak capability to absorb microwave radiation, while V2O5 had good capability to absorb microwave radiation. The results of the statistical analysis showed that the decomposition rate of ammonium metavanadate was significantly affected by calcination temperature and calcination time in the range studied. The optimized conditions were as follows: calcination temperature 645.35 K, calcination time 9.66 min and 4.3 g, respectively. The decomposition rates of ammonium metavanadate were 99.13%, which coincided well with experiments values 99.33% under these conditions. These suggest that regressive equation fits the decomposition rates perfectly. XRD reveals that it is feasible to prepare the V2O5 by microwave intensification from ammonium metavanadate, which mixed with small amounts of V2O5.

The advantages in high theoretical capacity and low electrochemical potential have made Li metal one of the most promising anode materials satisfying the surging requirement of high energy density for the next-generation batteries. However, safety issues caused by the Li dendrite growth during cycling have greatly thwarted its application. Herein, a hybrid artificial protective layer, constructed by the one-step method through chemical reactions between Li metal and 1H,1H,1H,2H-perfluorodecyltrimethoxysilane, is demonstrated to guide Li deposition and protect lithium batteries from the destruction of Li dendrites. A synergistic effect of the inorganic and organic components in the protective layer significantly enhances the electrochemical performance of symmetric Li|Li and Li|LiFePO4 cells. This work provides a facile, simple, and scalable method to design a hybrid artificial protective layer for long-lifespan Li metal batteries.

Indium and iron were co-doped at the Ti site of strontium titanate (SrTiO3) as dopant to improve the electrical properties of the anode material for solid oxide fuel cells. The effect of B-site deficiency on the weight loss, phase, lattice parameter, density, microstructure and electrical properties of Sr(Ti0.8In0.1Fe0.1)1−xO3−δ (x = 0, 0.02, 0.06) samples was investigated. A compound solid solution was formed at 977 °C. Sr(Ti0.8In0.1Fe0.1)1−xO3−δ powders sintered at 1435 °C for 5 h in air exhibited a single-phas cubic perovskite structure. With increasing B-site deficiency level, the relative density and sinterability of (In, Fe) co-doped SrTiO3 decrease, whereas its lattice parameter, porosity and total conductivity increase.

Metal-organic frameworks (MOFs) and covalent-organic frameworks (COFs) are two emerging and explosively growing families of crystalline porous materials (CPMs). These robust frameworks are characterized by their extraordinary porosity, tremendous structural diversity, and versatile functional tunability with precision at the molecular level. In this review, we present recent milestones of MOFs and COFs in the fields of batteries and supercapacitors, two important technologies in electrochemical energy storage (EES), and highlight the functions that a CPM can offer in EES devices, including the storage of electrochemical energy, stabilization of electrode materials, pathways for charge transport, manipulation on mass transport, and promotion of electrochemical reactions. Key requirements for each function are discussed, with future directions provided for further development.

Nowadays, horizontal well technology is being applied to the development of oilfield production capacity more and more. The horizontal well tractor can effectively solve the problem that the instrument can not get to the target layer by gravity. However, in actual conditions, Brushless DC motor (BLDCM) there is a large torque ripple problem, resulting in motor running is not smooth, vibration and noise is too large, can not meet the demand. Therefore, propose horizontal well tractor PMSM sine wave drive technology. The paper discusses the mathematical model of permanent magnet synchronous motor, analyzes the working principle of space vector pulse width modulation (SVPWM) technology, and establishes a speed and current double closed-loop space vector control system of the permanent magnet synchronous motor by using PSIM simulation software. Simulation results verify the robustness of the control system, and the torque ripple of the motor is small, in line with the working conditions of horizontal well tractor.

Multivariate metal-organic frameworks with active Fe/Ni building blocks that are spatially arranged in an open structure are synthesized and explored for oxygen evolution reaction. The heterogeneity and porosity of this system prove to show synergy effect and give low onset overpotential at 170 mV. These MOFs are further fabricated into thin films over nickel foam by controlled electrochemical deposition to improve the surface conductivity and the overall stability. The Fe/Ni metal-organic framework film exhibits outstanding electrocatalytic activity with low overpotential of 270 mV at 10 mA cm(-2), small Tafel slope, high Faradaic efficiency, high turnover frequency, and great stability.

The parameters to prepare of Co3O4 by microwave calcination from basic cobalt carbonate were optimized based on the thermal gravity analysis–differential thermal gravity (TG–DTG) using with...

Water pollution relating to human beings' health is a universal problem across community society. Highly efficient, economically feasible and easily achievable approaches are long-sought-after for water purification. Adsorption processes with porous materials (e.g. zeolites, activated carbon, silica gel, metal-organic frameworks (MOFs)) have drawn much attention in this field during past decades. In it, MOFs with numerous active sites, uniform porosity and tailorable structure diversity are arising to be one of the most promising adsorbents for water purification. During the adsorption processes, influence factors that determine or affect the usability and performances of MOFs are mainly focused on the stability of MOFs, their affinity for contaminants and the conducting conditions (pH, initial concentration of the contaminants). In this review, we will systematically present the performances of MOFs (mainly focused on MOF crystals, MOF nanomaterial or MOF composites will be beyond the scope of this review) for contaminants purification (inorganic and organic contaminants) in water and give a detailed discussion about the connection among their performances, conducting condition factors and potential interaction mechanisms (e.g. electrostatic interactions, coordination or p-p interaction). We hope this review will be beneficial to the design, regeneration and reuse of MOF adsorbents and promote the development of MOFs for water purification.

Porous carbon materials derived from metal-organic frameworks (MOFs) have been brought into stage due to the intrinsic advantages of MOFs such as high porosity and tailorable structure diversity, which might provide infinite possibility in producing porous carbons with diverse structures and various decorations. Inherited from MOFs, the porosity in carbon materials is an important factor to evaluate the performances of porous carbons (e.g. gas sorption properties, electrochemical and catalytic behaviors). Factors that affect the porosity of porous carbon materials are mainly focused on the porosity of pristine MOFs, additives and conducting conditions. However, during past decades there were still no systematical reports on the influence factors of porosity in MOFs derived porous carbon materials and corresponding gas sorption properties. In this review, we will summarize the performances of MOF-derived carbon materials (i.e. non-doped porous carbons, heteroatoms doped porous carbons, metal/metal oxide decorated porous carbons) and give a detailed discussion about the connections between the properties and four major effects (calcination temperature, loading of additional precursor, post-synthetic treatment as well as intrinsic properties of MOFs).

In the process of steel manufacture, up to tens of millions of tons of sintering dusts are produced annually in China, which contain noble metals such as Ag. Therefore, the recovery of Ag from sintering dust could be a potential economic and environmental activity. The present work attempts to use ultrasound for leaching silver from the water-leaching residue of sintering dust (WLR-SD) by acidic thiourea at atmospheric pressure. The effects of particle size, leaching temperature, and thiourea concentration were assessed on the leaching efficiency. Mineralogical changes of the WLR-SD were estimated using X-ray fluorescence, X-ray diffraction, and scanning electron microscope. The results have shown that under the conditions used, up to 94% silver could be leached. The leaching kinetics was estimated to follow the first-order kinetic model, and the activation energy was estimated to be 20.7 kJ/mol, confirming an internal diffusion-controlled leaching process. The order of the reaction with respect to the thiourea concentration was estimated to be 0.68.

Herein, we report an effective surface modification for a high energy cathode material, LiNi0.6Co0.2Mn0.2O2 (NCM-622), using an Al-based MOF (NH2-MIL-53), as a precursor to produce MOF-derived alumina (MDA) coatings. The MDA-coating (2.5 wt%) is well-dispersed on the surface of NCM-622 with an amorphous structure. By virtue of the MDA-coating, NCM-622 shows greatly enhanced electrochemical performance: 214.6 mA h g−1 and 196.5 mA h g−1 (3.0–4.5 V vs. Li+/Li) at 0.2C and 1C, respectively, with a capacity retention of 92.7% after 100 cycles at 1C; even at high rates of 5C and 10C, the discharge capacity still approaches 168.5 mA h g−1 and 150.0 mA h g−1, respectively. We found that these enhancements can be ascribed to the improved structural stability and electrochemical kinetics of NCM-622 by the MDA-coating.

Metal–organic frameworks (MOFs) are a class of porous materials that have attracted enormous attention during the past two decades due to their high surface areas, controllable structures and tunable pore sizes. Besides the applications in gas storage and separation, catalysis, sensor, and drug delivery, MOFs are receiving increasing research interest in the field of electrochemical energy storage. By focusing on recent advances, this review provides a broad overview of MOF-based or MOF-derived rechargeable lithium ion batteries and supercapacitors.

Membrane technology has attracted tremendous attention in the field of gas separation due to its low cost and energy consumption. Polymer membranes are used in some industrial-scale gas separation processes, however, they often suffer a trade-off between permeability and selectivity. To overcome this limitation, porous materials with molecular sieve properties have been combined with polymers to give membranes with enhanced gas separation performance. Metal–organic frameworks (MOFs) are nanoporous materials possessing ultrahigh porosity, large surface area, structural diversity and rich functionalities, which make them promising candidates for gas separation. This review primarily focuses on the fabrication methods of MOF–polymer composite membranes including MOF-based mixed-matrix membranes (MMMs) and polymer supported MOF membranes. Recent progress in MOF membrane fabrication, incorporating the challenges and difficulties faced, are presented. Furthermore, corresponding solutions and strategies are given in detail to offer instructions to fabricate membranes with ideal morphology and performance.

A copper(II)-based MOF film (MOF-199/Ni) prepared by electrodeposition shows exceptionally high photocatalytic hydrogen production rates of 8000 μmol h−1 g−1 (based on the mass of MOF-199) and 24 400 μmol h−1 g−1 with Pt as the co-catalyst and eosin Y as the photosensitizer. The activity is one of the highest among all the reported MOF-based hydrogen production systems. With nickel foam as a substrate, the deactivation of MOF-199 is largely alleviated, and the MOF-199/Ni film can be easily recycled and reused after photocatalytic hydrogen production.

Lithium ion batteries (LIBs) have achieved great success in powering portable electronic devices in our modern society, and are to find use in the electrification of transportation and the storage of wind or solar energy in smart grids in the near future. However, there is increasing concern on the safety issues of current LIBs based on organic liquid electrolytes, which are volatile and flammable. This leads to the exploration and development of solid electrolytes to improve the safety of next-generation high-energy LIBs. In this review, we describe two inorganic–organic hybrid solid electrolyte systems for LIBs. Firstly, we present polymer electrolytes with different types of inorganic fillers, discussing how the fillers affect the electrochemical and physical properties of the electrolyte. Secondly, we introduce recent progress in MOF-based solid electrolytes and show how MOFs can contribute to such an inorganic–organic hybrid system. Finally, outlook and future directions for safe and high performance inorganic–organic hybrid solid electrolytes are proposed.

A continuous fast microwave-assisted pyrolysis system was designed, fabricated, and tested with sewage sludge. The system is equipped with continuous biomass feeding, mixing of biomass and microwave absorbent, and separated catalyst upgrading. The effect of the sludge pyrolysis temperature (450, 500, 550, and 600 °C) on the products yield, distribution and potentially energy recovery were investigated. The physical, chemical, and energetic properties of the raw sewage sludge and bio-oil, char and gas products obtained were analyzed using elemental analyzer, GC–MS, Micro-GC, SEM and ICP-OES. While the maximum bio-oil yield of 41.39 wt% was obtained at pyrolysis temperature of 550 °C, the optimal pyrolysis temperature for maximum overall energy recovery was 500 °C. The absence of carrier gas in the process may be responsible for the high HHV of gas products. This work could provide technical support for microwave-assisted system scale-up and sewage sludge utilization.

Covalent organic frameworks (COFs) have attracted growing interest by virtue of their structural diversity and tunability. Herein, we present a novel approach for the development of organic rechargeable battery cathodes in which three distinct redox-active COFs were successfully prepared and delaminated into 2D few-layer nanosheets. Compared with the pristine COFs, the exfoliated COFs with shorter Li+ diffusion pathways allow a significant higher utilization efficiency of redox sites and faster kinetics for lithium storage. Unlike diffusion-controlled manners in the bulk COFs, the redox reactions in ECOFs are mainly dominated by charge transfer process. The capacity and potential are further engineered by reticular design of COFs without altering the underlying topology. Specifically, DAAQ-ECOF exhibits excellent rechargeability (98% capacity retention after 1800 cycles) and fast charge–discharge ability (74% retention at 500 mA g–1 as compared to at 20 mA g–1). DABQ-ECOF shows a specific capacity of 210 ...

Caltrans is currently implementing a California version of the superior performing asphalt pavements (Superpave) mix design procedure for hot-mix asphalt (HMA) to replace the long been used Hveem mix design process, and is interested in including performance-related tests for mix design and quality assurance. The objective of this study was to compare the repeated load triaxial (RLT) rutting test using the asphalt mixture performance tester (AMPT) and the repeated shear test at constant height (RSCH) using repeated simple shear tester (RSST) for characterization for Caltrans mechanistic-empirical (ME) pavement design in terms of usefulness of the results, difficulty, and time required to obtain results. The results indicated that there is potential to use the unconfined RLT test as a substitute for the RSCH test for mix design and quality assurance, and to use the confined or unconfined RLT for ME characterization. However, the preliminary results regarding shift factors to convert results from RL...

A powerful roll-to-roll hot-pressing strategy for mass production of metal-organic framework (MOF)-based filters (MOFilters) using various MOF systems with ranges of substrates is presented. Thus-obtained MOFilters show superior particulate matter removal efficiency under desired working temperatures. Such versatile MOFilters can be scaled up and purposely designed, which endows MOFilters with great potentials in both residential and industrial pollution control.

The applications of metal-organic frameworks (MOFs) toward industrial separation, catalysis, sensing, and some sophisticated devices are drastically affected by their intrinsic fragility and poor processability. Unlike organic polymers, MOF crystals are insoluble in any solvents and are usually not thermoplastic, which means traditional solvent- or melting-based processing techniques are not applicable for MOFs. Herein, a continuous phase transformation processing strategy is proposed for fabricating and shaping MOFs into processable fluids, shaped bodies, and even MOF foams that are capable of reversible transformation among these states. Based on this strategy, a cup-shaped Cu-MOF composite and hierarchically porous MOF foam were developed for highly efficient catalytic C-H oxidation (conv. 76% and sele. 93% for cup-shaped Cu-MOF composite and conv. 92% and sele. 97% for porous foam) with ease of recycling and dramatically improved kinetics. Furthermore, various MOF-based foams with low densities (0.1 g cm(-3)) and high MOF loadings (up to 80 wt %) were obtained via this protocol. Imparted with hierarchically porous structures and fully accessible MOFs uniformly distributed, these foams presented low energy penalty (pressure drop20 Pa, at 500 mL min(-1)) and showed potential applications as efficient membrane reactors.

Metal-organic frameworks (MOFs), by virtue of their remarkable uptake capability, selectivity, and ease of regeneration, hold great promise for carbon capture from fossil fuel combustion. However, their stability toward moisture together with the competitive adsorption of water against CO2 drastically dampens their capacity and selectivity under real humid flue gas conditions. In this work, an effective strategy was developed to tackle the above obstacles by partitioning the channels of MOFs into confined, hydrophobic compartments by in situ polymerization of aromatic acetylenes. Specifically, polynaphthylene was formed via a radical reaction inside the channels of MOF-5 and served as partitions without altering the underlying structure of the framework. Compared with pristine MOF-5, the resultant material (PN@MOF-5) exhibits a doubled CO2 capacity (78 vs 38 cm(3)/g at 273 K and 1 bar), 23 times higher CO2/N2 selectivity (212 vs 9), and significantly improved moisture stability. The dynamic CO2 adsorption capacity can be largely maintained (90%) under humid conditions during cycles. This strategy can be applied to other MOF materials and may shed light on the design of new MOF-polymer materials with tunable pore sizes and environments to promote their practical applications.

Environmental challenges especially air pollution (particulate matter (PM) and toxic gases) pose serious threats to public health globally. Metal-organic frameworks (MOFs) are crystalline materials with high porosity, tunable pore size, and rich functionalities, holding the promise for poisonous pollutants capture. Here, nanocrystals of four unique MOF structures are processed into nanofibrous filters (noted as MOFilter) with high MOF loadings (up to 60 wt %). The MOFilters show high PM removal efficiencies up to 88.33 ± 1.52% and 89.67 ± 1.33% for PM2.5 and PM10, respectively, in the hazy environment, and the performance remains largely unchanged over 48 h of continuous filtration. For the first time, the interactions between such porous crystalline material and particulate pollutants were explored. These thin MOFilters can further selectively capture and retain SO2 when exposed to a stream of SO2/N2 mixture, and their hierarchical nanostructures can easily permeate fresh air at high gas flow rate with the pressure drop20 Pa.

Microwave absorption capabilities of siderite, Fe3O4 and Fe2O3 were investigated by measuring the dielectric characterization (dielectric constant, loss factor and loss tangent) from room temperature to 900 °C using the microwave cylindrical resonant cavity technique at 2450 MHz. There was little change in the microwave absorption capabilities of siderite before 600 °C. As the temperature increasing, the microwave absorption capabilities of siderite increased sharply due to the generation of Fe3O4. However, the microwave absorption capabilities of siderite decreased when temperature higher than 900 °C, which was attributed to the formation of Fe2O3 by the oxidation of Fe3O4. The microwave heating behavior of siderite was studied and the result showed that the heating rate of siderite became slower when temperature higher than 550 °C, this was because amount of decomposition reaction of siderite occurred in this stage which consuming large amounts of heat.

In the process of steel manufacture, up to ten millions of tons of sintering dust (SD) are produced annually in China, which contain noble metals such as Ag. Therefore, recovery of silver (Ag) from SD could be a potential economic and environmental activity. The purpose of this article is to generate information about reaction kinetics of silver leaching with thiourea from SD, comparing the conventional and ultrasonic-augment leaching. The effects of various control parameters such as the ultrasound power, particle size, leaching temperature and thiourea concentration on leaching rate of silver were studied. The results showed 89% silver recovery for conventional process against 95% for ultrasound assisted leaching. The ultrasonic wave increased the leaching rate and shorten the reaction time. The rate controlling step was analyzed using shrinking core model and the rate controlling step is identified to be the diffusion through the product layer in both conventional and ultrasonic-augment leaching processes. The activation energies were estimated to be 28.01 kJ/mol and 18.19 kJ/mol, and the reaction order were 0.89 and 0.71, respectively.

Metal-organic frameworks (MOFs), with their well-defined pores and rich structural diversity and functionality, have drawn a great deal of attention from across the scientific community. However, industrial applications are hampered by their intrinsic fragility and poor processability. Stable and resilient MOF devices with tunable flexibility are highly desirable. Herein, we present a solvent- and binder-free approach for producing stable MOF coatings by a unique hot-pressing (HoP) method, in which temperature and pressure are applied simultaneously to facilitate the rapid growth of MOF nanocrystals onto desired substrates. This strategy was proven to be applicable to carboxylate-based, imidazolate-based, and mixed-metal MOFs. We further successfully obtained superhydrophobic and "Janus" MOF films through layer-by-layer pressing. This HoP method can be scaled up in the form of roll-to-roll production and may push MOFs into unexplored industrial applications.

Shipping heavy-duty goods or equipment is being a new sector recently, and the pallet is rather important. In this article, a comparison of various materials revealed that laminated veneer lumber was ideal for heavy-duty packaging industry. For various pallets with random parameters, a hybrid reliability optimization design method was proposed, which aimed to provide an effective computational tool for reliability design of pallet system. With first-order second-moment method, the separation and combination of component and system failure probabilities were obtained. Several case studies were included to illustrate the computational procedures, as well as to discuss the effects of dimension and quantity of members. Using design of experiment method, the sensitivities of each parameter were significant, and the optimization of whole system was realized. To reduce the cost, recycling and standardization were worth considering in the future.