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Selective hydrodeoxygenation of guaiacol to cyclohexanol using activated hydrochar-supported Ru catalysts
Lignin, an abundant aromatic polymer in nature, has received significant attention for its potential in the production of bio-oils and chemicals owing to increased resource availability and environmental issues. The hydrodeoxygenation of guaiacol, a lignin-derived monomer, can produce cyclohexanol, a nylon precursor, in a carbon-negative and environmentally friendly manner. This study explored the porous properties and the effects of activation methods on the Ru-based catalyst supported by environmentally friendly and cost-effective hydrochar. Highly selective cleavage of C aryl–O bonds was achieved under mild conditions (160 °C, 0.2 MPa H 2, and 4 h), and alkali activation further improved the catalytic activity. Various characterization methods revealed that hydrothermal treatment and alkali activation relatively contributed to the excellent performance of the catalysts and influenced their porous structure and Ru dispersion. X-ray photoelectron spectroscopy results revealed an increased formation of metallic ruthenium, indicating the effective regulation of interaction between active sites and supports. This synergistic approach used in this study, involving the valorization of cellulose-derived hydrochar and the selective production of nylon precursors from lignin-derived guaiacol, indicated the comprehensive and sustainable utilization of biomass resources.
Journal Article
Alfred Nobel : the man behind the Peace Prize
Alfred Nobel was the man who founded the Nobel Prizes. Nobel also invented dynamite, becoming very wealthy from his invention. Saddened by its use for harmful destruction, Nobel left his fortune to create yearly prizes for those who have rendered the greatest services to mankind.
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A hybrid spatial-temporal deep learning prediction model of industrial methanol-to-olefins process
Methanol-to-olefins, as a promising non-oil pathway for the synthesis of light olefins, has been successfully industrialized. The accurate prediction of process variables can yield significant benefits for advanced process control and optimization. The challenge of this task is underscored by the failure of traditional methods in capturing the complex characteristics of industrial processes, such as high nonlinearities, dynamics, and data distribution shift caused by diverse operating conditions. In this paper, we propose a novel hybrid spatial-temporal deep learning prediction model to address these issues. Firstly, a unique data normalization technique called reversible instance normalization is employed to solve the problem of different data distributions. Subsequently, convolutional neural network integrated with the self-attention mechanism are utilized to extract the temporal patterns. Meanwhile, a multi-graph convolutional network is leveraged to model the spatial interactions. Afterward, the extracted temporal and spatial features are fused as input into a fully connected neural network to complete the prediction. Finally, the outputs are denormalized to obtain the ultimate results. The monitoring results of the dynamic trends of process variables in an actual industrial methanol-to-olefins process demonstrate that our model not only achieves superior prediction performance but also can reveal complex spatial-temporal relationships using the learned attention matrices and adjacency matrices, making the model more interpretable. Lastly, this model is deployed onto an end-to-end Industrial Internet Platform, which achieves effective practical results.
Journal Article
Synergistic effects and kinetics analysis for co-pyrolysis of vacuum residue and plastics
This study utilized a thermogravimetric analyzer to assess the thermal decomposition behaviors and kinetics properties of vacuum residue (VR) and low-density polyethylene (LDPE) polymers. The kinetic parameters were calculated using the Friedman technique. To demonstrate the interactive effects between LDPE and VR during the co-pyrolysis process, the disparity in mass loss and mass loss rate between the experimental and calculated values was computed. The co-pyrolysis curves obtained through estimation and experimentation exhibited significant deviations, which were influenced by temperature and mixing ratio. A negative synergistic interaction was observed between LDPE and VR, although this inhibitory effect could be mitigated or eliminated by reducing the LDPE ratio in the mixture and increasing the co-pyrolysis temperature. The co-pyrolysis process resulted in a reduction in carbon residue, which could be attributed to the interaction between LDPE and the heavy fractions, particularly resin and asphaltene, present in VR. These findings align with the pyrolysis behaviors exhibited by the four VR fractions. Furthermore, it was observed that the co-pyrolysis process exhibited lower activation energy as the VR ratio increased, indicating a continuous enhancement in the reactivity of the mixed samples during co-pyrolysis.
Journal Article
Rational design of practical layered transition metal oxide cathode materials for sodium-ion batteries
Sodium-ion batteries (SIBs), which serve as alternatives or supplements to lithium-ion batteries, have been developed rapidly in recent years. Designing advanced high-performance layered Na x TMO 2 cathode materials is beneficial for accelerating the commercialization of SIBs. Herein, the recent research progress on scalable synthesis methods, challenges on the path to commercialization and practical material design strategies for layered Na x TMO 2 cathode materials is summarized. Co-precipitation method and solid-phase method are commonly used to synthesize Na x TMO 2 on mass production and show their own advantages and disadvantages in terms of manufacturing cost, operative difficulty, sample quality and so on. To overcome drawbacks of layered Na x TMO 2 cathode materials and meet the requirements for practical application, a detailed and deep understanding of development trends of layered Na x TMO 2 cathode materials is also provided, including high specific energy materials, high-entropy oxides, single crystal materials, wide operation temperature materials and high air stability materials. This work can provide useful guidance in developing practical layered Na x TMO 2 cathode materials for commercial SIBs.
Journal Article
Segregation of binary particles in gas-solid fluidized bed
Particle segregation and mixing behavior play a crucial role in industrial processes. This study investigates the saturated jetsam fraction, which indicates the maximum capacity of flotsam to entrain jetsam, in an initially separated binary fluidized bed with particle size differences. According to the value of saturated jetsam fraction, three distinct regimes—segregation, mixing, and an intermediate regime—are identified. Moreover, intriguing relationships between the saturated jetsam fraction and superficial gas velocity are observed, exhibiting monotonic trends in both the segregation and mixing regimes, while a unique volcano-shaped curve in the intermediate regime. Additionally, a comprehensive entrainment model based on two-fluid model elucidates the observed phenomena, emphasizing the significance of mixing behavior in fluidized layer on the saturated jetsam fraction. This work offers potential insights for evaluating segregation in industrial applications.
Journal Article
Advancing oxygen separation: insights from experimental and computational analysis of La0.7Ca0.3Co0.3Fe0.6M0.1O3−δ (M = Cu, Zn) oxygen transport membranes
In this study, perovskite-type La
0.7
Ca
0.3
Co
0.3
Fe
0.6
M
0.1
O
3−
δ
(M = Cu, Zn) powders were synthesized using a scalable reverse co-precipitation method, presenting them as novel materials for oxygen transport membranes. The comprehensive study covered various aspects including oxygen permeability, crystal structure, conductivity, morphology, CO
2
tolerance, and long-term regenerative durability with a focus on phase structure and composition. The membrane La
0.7
Ca
0.3
Co
0.3
Fe
0.6
Zn
0.1
O
3
−
δ
exhibited high oxygen permeation fluxes, reaching up to 0.88 and 0.64 mL·min
−1
cm
−2
under air/He and air/CO
2
gradients at 1173 K, respectively. After 1600 h of CO
2
exposure, the perovskite structure remained intact, showcasing superior CO
2
resistance. A combination of first principles simulations and experimental measurements was employed to deepen the understanding of Cu/Zn substitution effects on the structure, oxygen vacancy formation, and transport behavior of the membranes. These findings underscore the potential of this highly CO
2
-tolerant membrane for applications in high-temperature oxygen separation. The enhanced insights into the oxygen transport mechanism contribute to the advancement of next-generation membrane materials.
Journal Article
Enhanced C3H6/C3H8 separation performance in polysulfone membrane blended with rigid ZIF-8 crystals
Metal-organic frameworks have a wide range of applications in the field of membrane separation, but the inherent flexible structure and the difficulty for scale-up hinder their further applications. Herein, the relatively rigid zeolitic imidazolate framework-8 particles prepared under an electric field (E-ZIF-8) were used as the fillers in polysulfone (PSF) to form series of mixed matrix membranes. It was found that the introduction of E-ZIF-8 improves both the C
3
H
6
permeability and C
3
H
6
/C
3
H
8
selectivity of the membranes. Compared with the bare PSF membrane, the C
3
H
6
/C
3
H
8
selectivity of the 30 wt % E-ZIF-8@PSF membrane increased by ∼230%, while the C
3
H
6
permeability was enhanced by ∼830%. In addition, time and pressure dependence analysis demonstrated that such E-ZIF-8@PSF membranes also exhibited good long-term stability and pressure resistance, offering significant industrialization advantages.
Journal Article
Surface engineering with ionic polymers on membranes for boron removal
Removal of boric acid from seawater and wastewater using reverse osmosis membrane technologies is imperative and yet remains inadequately addressed by current commercial membranes. Existing research efforts performed post-modification of reverse osmosis membranes to enhance boron rejection, which is usually accompanied by substantial sacrifice in water permeability. This study delves into the surface engineering of low-pressure reverse osmosis membranes, aiming to elevate boron removal efficiency while maintaining optimal salt rejection and water permeability. Membranes were modified by the self-polymerization and co-deposition of dopamine and polystyrene sulfonate at varying ratios and concentrations. The surfaces became smoother and more hydrophilic after modification. The optimum membrane exhibited a water permeability of 9.2 ± 0.1 L·m −2·h −1·bar −1, NaCl rejection of 95.8% ± 0.3%, and boron rejection of 49.7% ± 0.1% and 99.6% ± 0.3% at neutral and alkaline pH, respectively. The water permeability is reduced by less than 15%, while the boron rejection is 3.7 times higher compared to the blank membrane. This research provides a promising avenue for enhancing boron removal in reverse osmosis membranes and addressing water quality concerns in the desalination process.
Journal Article