The crystallization has significant influence on fluidity of slag and slag discharge of entrained-flow-bed (EFB) gasifier. The crystallization characteristics and fluidity of five synthetic slags with different MgO/CaO ratios prepared on the basis of the range of oxide contents of Zhundong coal ash were investigated in this study. The results show that with the MgO/CaO ratio increase, the initial crystallization temperature increases, and the main temperature range of crystallization ratio growth moves to higher temperature range gradually which causes T_p25 (T_p25 is the temperature corresponding to the viscosity of 25 Pa·s) to increase. Mg-rich crystals are formed preferentially than Ca-rich crystals when adding the same amount of MgO and CaO during cooling. The effective slagging operating temperature range decrease from 217 ℃ for the slag with a 0:4 MgO/CaO ratio to 44 ℃ for the slag with a 4:0 MgO/CaO ratio with the MgO/CaO ratio increase. The slags with 2:2 and 1:3 MgO/CaO ratios show similar effective slagging operating temperature range, T_p25 and the temperature corresponding to the viscosity of 2 Pa·s. However, compared with the slag with a 1:3 MgO/CaO ratio, the crystallization ratio and rate of slag with a 2:2 MgO/CaO ratio are lower within lower temperature range (1300–1200 ℃), causing its lower critical viscosity temperature and wider actual operating temperature range. Of the five slags, the widest effective slagging operating temperature range and the lowest T_p25 of the slag with a 0:4 MgO/CaO ratio due to its low crystallization ratio, and wider actual operating temperature range of the slag with a 2:2 MgO/CaO ratio make the two slags suitable for slag discharge of EFB gasifier.

Adsorption dynamics of ethane in two granular fixed beds and structured fixed beds with microfibrous composites was studied. 5A zeolite membrane 5A/PSSF (paper-like sintered stainless steel fiber) and microfibrous entrapped activated carbon (MEAC) composites were prepared by wet layup papermaking/sintering technique and in-situ hydrothermal method. Microfibrous composites were characterized by X-ray diffraction, scanning electron microscopy and N₂ adsorption/desorption. Structured fixed beds were designed by filling granular adsorbents (5A zeolite or activated carbon) and microfibrous composites at the inlet and outlet of the beds, respectively. Effects of flow rate, bed height and structure on the breakthrough curves were investigated. The length of unused bed (LUB) was determined, and Yoon–Nelson model was used to fit the breakthrough curves. The experimental results showed ethane was effectively adsorbed on the granular adsorbents and microfibrous composites. Both composites could decrease the LUB values and enhance bed utilization. All breakthrough curves fitted well to Yoon–Nelson model, with correlation coefficient exceeding 0.89. The adsorption rate of ethane could be improved in the structured fixed beds, which showed an enhanced mass transfer efficiency for ethane adsorption. LUB values of structured fixed beds with 5A/PSSF composites were larger, the bed utilization values were lower, and the adsorption rate constants were higher than those with MEAC composites under the same conditions.

Soybean soapstock (SS) is one of the main solid wastes produced in the refinery of edible oil processing. In this study, the co-pyrolysis of SS with iron slag (IS) and aluminum scrap (AS) was carried out in a tubular furnace. The gas, liquid and solid products were characterized and the char yield decreased with increasing IS/AS ratio. IS and AS can improve the gas yield, and when the ratio of SS/IS was 1:0.25, the total pyrolysis gas and hydrogen contents were significantly increased. The content of oxygen compounds in pyrolysis oil decreased during co-pyrolysis, while AS promoted the content of polycyclic aromatic hydrocarbons in pyrolysis oil. The co-pyrolysis reaction can be divided into four stages, the mass loss rate reaches the maximum at the third stage (390–575 ℃). The molar ratio of H/C was lower for pyrolysis, indicating good stability of pyrolysis char owing to the high degree of carbonization and aromaticity. The possible co-pyrolysis reaction mechanism was explored.

The membrane fouling phenomenon, reflected with various fouling characterization in the membrane bioreactor (MBR) process, is so complicated to distinguish. This paper proposes a multivariable identification model (MIM) based on a compacted cascade neural network to identify membrane fouling accurately. Firstly, a multivariable model is proposed to calculate multiple indicators of membrane fouling using a cascade neural network, which could avoid the interference of the overlap inputs. Secondly, an unsupervised pretraining algorithm was developed with periodic information of membrane fouling to obtain the compact structure of MIM. Thirdly, a hierarchical learning algorithm was proposed to update the parameters of MIM for improving the identification accuracy online. Finally, the proposed model was tested in real plants to evaluate its efficiency and effectiveness. Experimental results have verified the benefits of the proposed method.

Diffusions of multiple components have numerous applications such as underground water flow, pollutant movement, stratospheric warming, and food processing. Particularly, liquid hydrogen is used in the cooling process of the aeroplane. Further, liquid nitrogen can find applications in cooling equipment or electronic devices, i.e., high temperature superconducting (HTS) cables. So, herein, we have analysed the entropy generation (EG), nonlinear thermal radiation and unsteady (time-dependent) nature of the flow on quadratic combined convective flow over a permeable slender cylinder with diffusions of liquid hydrogen and nitrogen. The governing equations for flow and heat transfer characteristics are expressed in terms of nonlinear coupled partial differential equations. The solutions of these equations are attempted numerically by employing the quasilinearization technique with the implicit finite difference approximation. It is found that EG is minimum for double diffusion (liquid hydrogen and heat diffusion) than triple diffusion (diffusion of liquid hydrogen, nitrogen and heat). The enhancing values of the radiation parameter R_d and temperature ratio θ_w augment the fluid temperature for steady and unsteady cases as well as the local Nusselt number. Because, the fluid absorbs the heat energy released due to radiation, and in turn releases the heat energy from the cylinder to the surrounding surface.

Adenylate cyclase (AC) is the key enzyme that catalyzes the formation of cAMP from ATP. In this study, we discovered two novel class III ACs with a halophilic property from Thermobifida halotolerans DSM 44931 (ThAC) and Haloactinopolyspora alba DSM 45211 (HaAC), respectively. The recombinant ThAC and HaAC were expressed in Escherichia coli with molecular weights of 36.1 and 36.0 kDa respectively. The presence of 2500 and 2200 mmol·L^-1 NaCl significantly enhanced the enzyme activities of ThAC and HaAC, with 22-fold and 7.4-fold higher activities compared to those without NaCl, respectively. Several divalent metal ions were found to activate the recombinant ACs to different extents, and the optimal metal ion was Mg²⁺ for both ThAC and HaAC with concentrations of 80 mmol·L^-1 and 40 mmol·L^-1 respectively. Purified ThAC and HaAC had the optimal specific activities ((4.59 ±0.35)×10⁴ and (7.76 ±0.52)×10⁴ U·mg^-1) and catalytic efficiency (4.47 and 5.30 L·mmol^-1·s^-1) at 45 ℃ and 40 ℃ respectively, while the optimum pH of both two recombinant ACs was 10.0. This is the first report of the halophilic Class III ACs, which could make new contributions to explore and study ACs for further associated investigations.

The catalytic packing is the core component of the catalytic distillation, and how the catalyst exists in the packing has significant influence on the process. To investigate the effect of catalyst packings on the catalytic distillation process, the classical ethyl acetate reactive distillation system was utilized, and a supported catalytic packing (SCP) was prepared in comparison with the conventional tea-bag catalytic packing (TBP). Laboratory scale experiments showed that the ethyl acetate conversion of the SCP was superior to the TBP at a low catalyst loading. The effects of reaction kinetics, mass transfer performance and actual catalytic efficiency of the packings on this process were regarded as reasons and studied by combining the experiments and numerical simulation. Results suggested that the relatively immediate “in-situ separation” caused by the rapid reaction kinetics and better mass transfer performance of SCP may be a main reason for the difference of the conversion.

In this study, we proposed a self-healing conductive hydrogel based on polysaccharides and Li⁺ to serve as flexible sensors. At first, the oxidized sodium alginate (OSA) was obtained through the oxidation reaction of sodium alginate (SA). Then OSA, carboxymethyl chitosan (CMC), and agarose (AGO) were dissolved in LiCl solution, respectively. Finally, the hydrogel was obtained through heating, mixing, and cooling processes. Because of the Schiff base structure and hydrogen bonding, the hydrogel demonstrates good mechanical and self-healing properties. The presence of Li⁺ provides good conductivity for the hydrogel. In addition, we demonstrated the application of the hydrogel as the flexible sensors. It can perceive the process of pressing Morse code with the index finger as a pressure sensor and monitor sliding movement of the thumb as the strain sensor to browse the web with the mobile phone. Thus, the self-healing conductive hydrogel may have potential applications in flexible wearable sensors.

In this study, an optimization method is proposed to enhance the gas–liquid mass transfer in bubble column reactor based on the entropy generation extremum principle. The mass transfer–induced entropy generation can be maximized with the increase of mass transfer rate, based on which the velocity field can be optimized. The oxygen gas–liquid mass transfer is the major rate–limiting step of the toluene emissions biodegradation process in bubble column reactor, so the entropy generation due to oxygen mass transfer is used as the objective function, and the conservation equations of the gas–liquid flow and species concentration are taken as constraints. This optimization problem is solved by the calculus of variations, the optimal liquid flow pattern is obtained and the relationship of the maximum mass transfer enhancement on viscous dissipation is revealed, which can be used to improve the design of internal structure of the bubble column reactor.

A non-solvent induced phase separation (NIPS) process was used to fabricate a series of sulfonated polyethersulfone (SPES) membranes blending with different concentrations of SBA-15-g-PSPA with the applications in the ultrafiltration (UF) process. SBA-15 was modified with 3-methacrylate-propyltrimethoxysilane (MPS) to form SBA-15-g-MPS. It was further modified with the charge tailorable polymer chains by reacting with 3-sulfopropyl methacrylate potassium salt. The nanoparticles were uniformly dispersed and finger-like channels were developed within the membrane. The adding of surface modified SBA-15-g-PSPA nanoparticles has significantly improved membrane water permeability, hydrophilicity, and antifouling properties. The pure water fluxes of the composite SPES membranes were significantly higher than the pristine SPES membrane. For the membrane containing 5% (mass) of SBA-15-g-PSPA (MSSPA5), the pure water flux was increased dramatically to 402.15 L·m^-2·h^-1, which is ~1.5 times that of MSSPA0 (268.0 L·m^-2·h^-1). The high flux rate was achieved with 3% (mass) of SBA-15 nanoparticles with retained high rejection ratio 98% for natural organic matter. The results indicate that the fashioned composite membrane comprising SBA-15-g-PSPA nanoparticles have a promising future in ultrafiltration applications.

Oxygen reduction reaction over Pt-based catalyst is one of the most significant cathode reactions in fuel cells. However, low reserves and high price of Pt have motivated researchers worldwide seeking enhanced utilization efficiency and durability by doping non-noble metals to form Pt-based alloy catalysts. Alloying Pt with Co has been recognized as one of the most effective approaches to achieve this goal. PtCo bimetal combination is one of the most promising candidates to synthesize highly efficient catalysts for oxygen reduction reaction (ORR) applications, owing to its relatively more suitable oxygen binding energy for four-electron transfer reactions. Recently, impressive strategies have been developed to fabricate more active and stable PtCo-based multimetallic alloys with tailorable size and morphology. This paper aims to summarize the most recent highlights on the study of the relationship between preparation strategies, morphologies, electroactivities of the PtCo-based catalyst at atomic level and further the relevant reaction mechanism. The challenges and opportunities on the further development of electrocatalysts for fuel cells are included to provide reference for the practical application.

Graphene oxide (GO) channels exhibit unique mass transport behaviors due to their flexibility, controllable thinness and extraordinary physicochemical properties, enabling them to be widely used for adsorption and membrane separation. Nevertheless, the adsorption behavior of nanosized contaminants within the channels of GO membrane has not been fully discussed. In this study, we fabricated a GO membrane (PGn, where n represents the deposition cycles of GO) with multi channels via the cross-linking of GO and multibranched poly(ethyleneimine) (PEI). Phenol was used as molecularprobe to determine the correlations between dynamic adsorption behavior and structural parameters of the multilevel GO/PEI membrane. PG8 shows higher adsorption capacities and affinity, which is predominantly attributed to the multichannel structure providing a large specific surface for phenol adsorption, enhancing the accessibility of active sites for phenol molecules and the transport of phenol. Density functional theory calculations demonstrate that the adsorption mechanism of phenol within GO channel is energetically oriented by hydrogen bonds, which is dominated by oxygen-containing groups compared to amino groups. Particularly, the interfaces which facilitate strong π-π interaction and hydrogen bonds maybe the most active regions. Moreover, the as-prepared PG8 membrane showed outstanding performance for other contaminants such as methyl orange and Cr(VI). It is anticipated that this study will have implications for design of GO-related environmental materials with enhanced efficiency.

Chitin is a widely used important industrial polymer mainly from shrimp shells, but its commercial preparation is under the great challenge of serious pollution due to the requirement of HCl and NaOH. Herein, we demonstrated that high purity chitin can be obtained from waste shrimp shells (WSSs) by cascade separation with transition metal salt aqueous solution and ionic liquid (IL). Firstly, calcium carbonate of WSSs was effectively removed in the metal salt aqueous solution driven by the ion exchange interaction. Subsequently, 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) had bifunctional abilities to remove residual protein and introduced metal salts simultaneously by hydrogen bonding and coordination interactions. The key experimental factors affecting the separation process were systematically studied, including the type of metal salts, temperature, and [Bmim]Cl loading. After sequential treatment with a 20% (mass) NiSO₄ aqueous solution at 130 ℃ and [Bmim]Cl at 150 ℃, the purity of α-chitin can be up to 96.5% (mass) that meets commercial requirements. The use of metal salts with higher coordination ability makes the preparation of chitin no longer depend on the commonly acid-base reaction, which is conducive to the preservation of chitin structure.

Esterification is an important process in the food industry and can be carried out via homogeneous or heterogeneous catalysis. The homogeneous catalyst, despite providing high conversion, can cause corrosion in reactors, which is not observed with the use of heterogeneous catalysts. However, some of these catalysts require a high process temperature and may lose their catalytic activity with reuse. Thus, catalytic membranes have been proposed as a promising alternative. The combination of catalysis and separation in a single module provides greater conversion, reduction of excess reagents, compact industrial plant, making the process more efficient. Within this context, this work aims to present a literature review on the catalytic membrane for the synthesis of esters, improving the understanding of the production and development. This review examines the materials, catalysts used, and synthetic pathways. A comparison between the methods, as well as limitations and gaps in the literature, are highlighted.

The vapor–liquid equilibrium (VLE) data of α-pinene + camphene + [abietic acid + palustric acid + neoabietic acid] and α-pinene + longifolene + [abietic acid + palustric acid + neoabietic acid] systems at 313.15 K, 333.15 K and 358.15 K were measured by headspace gas chromatography (HSGC). These data was compared with the predictions value by conductor-like screening model for realistic solvation (COSMO-RS). Moreover, the calculated data of COSMO-RS and Non-Random Two-Liquids (NRTL) models showed good agreement with the experimental data. It was found that the three resin acids inhibited the volatility of α-pinene, camphene and longifolene and resulted in the decrease of total pressure. Moreover, H^E(HB) contributes the most to the excess enthalpy and the hydrogen bonding interaction is the dominant intermolecular force of α-pinene, camphene and longifolene with the three resin acids. In addition, the geometric structures optimization and binding energy were obtained by the DFT to further illustrate the hydrogen bonding interaction and the effects of the addition of the three resin acids on the isothermal VLE.

Membrane pollution caused by separating oily wastewater is a big challenge for membrane separation technology. Recently, plant-/mussel-inspired interface chemistry has received more and more attention. Herein, a high antifouling poly (vinylidene fluoride) (PVDF) membrane, coated with tea polyphenols (TP, extracted from green tea) and 3-amino-propyl-triethoxysilane (APTES), was developed to purify oil-in-water emulsions. ATR-FTIR, XPS and SEM were used to demonstrate the evolution of surface biomimetic hybrid coatings. The performances of the developed membranes were investigated by pure water permeability and oil rejection for various surfactant-stabilized oil-in-water emulsions. The experimental results revealed that the membrane deposited with a mass ratio of 0.1/0.2 exhibited ultrahigh pure water permeability (14570 L·m^-2·h^-1·bar^-1, 1 bar=0.1 MPa) and isooctane-in-water emulsion permeability (5391 L·m^-2·h^-1·bar^-1) with high separation efficiency (>98.9%). Even treated in harsh environment (acidic, alkaline and saline) for seven days, the membrane still maintained considerable underwater oleophobic property (148°–153°). The fabricated plant-inspired biomimetic hybrid membranes with excellent performances light a broad application prospect in the field of oily wastewater treatment.

In order to theoretically study the growth morphology of dihydroxylammonium 5,5'-bistetrazole-1,1'-diolate (TKX-50) crystal in different solvent systems, crystal–solvent models were established, and then molecular dynamics (MD) methods were adopted as a means to simulate particle motion. Modified attachment energy (MAE) model was employed to calculate the growth morphology of TKX-50. The simulation results demonstrate that COMPASS force field and RESP charge are suitable for molecular dynamics simulation of TKX-50. The morphologically dominant growth surfaces of TKX-50 in vacuum are (0 2 0), (0 1 1), (1 1 –1), (1 0 0) and (1 2 0), respectively. In water (H₂O) and N, N-dimethylformamide (DMF) solvents, the (1 1 –1) face is the largest in the habit face, the growth rate of (0 2 0) face becomes faster. With the increase of temperature, the aspect ratios of TKX-50 crystal in DMF solvent increase, and the areas of the (1 2 0) faces decrease. In ethylene glycol /H₂O mixed solvent system with volume ratio of 1/1, aspect ratio of TKX-50 is relatively small. In formic acid /H₂O mixed solvents with different volume ratios (1/4, 1/3, 1/2, 1/1 and 2/1), aspect ratio of TKX-50 is relatively small when volume ratio is 1/2.

The constant bubble size modeling approach (CBSM) and variable bubble size modeling approach (VBSM) are frequently employed in Eulerian–Eulerian simulation of bubble columns. However, the accuracy of CBSM is limited while the computational efficiency of VBSM needs to be improved. This work aims to develop method for bubble size modeling which has high computational efficiency and accuracy in the simulation of bubble columns. The distribution of bubble sizes is represented by a series of discrete points, and the percentage of bubbles with various sizes at gas inlet is determined by the results of computational fluid dynamics (CFD)–population balance model (PBM) simulations, whereas the influence of bubble coalescence and breakup is neglected. The simulated results of a 0.15 m diameter bubble column suggest that the developed method has high computational speed and can achieve similar accuracy as CFD–PBM modeling. Furthermore, the convergence issues caused by solving population balance equations are addressed.

High-quality data play a paramount role in monitoring, control, and prediction of wastewater treatment process (WWTP) and can effectively ensure the efficient and stable operation of system. Missing values seriously degrade the accuracy, reliability and completeness of the data quality due to network collapses, connection errors and data transformation failures. In these cases, it is infeasible to recover missing data depending on the correlation with other variables. To tackle this issue, a univariate imputation method (UIM) is proposed for WWTP integrating decomposition method and imputation algorithms. First, the seasonal-trend decomposition based on loess method is utilized to decompose the original time series into the seasonal, trend and remainder components to deal with the nonstationary characteristics of WWTP data. Second, the support vector regression is used to approximate the nonlinearity of the trend and remainder components respectively to provide estimates of its missing values. A self-similarity decomposition is conducted to fill the seasonal component based on its periodic pattern. Third, all the imputed results are merged to obtain the imputation result. Finally, six time series of WWTP are used to evaluate the imputation performance of the proposed UIM by comparing with existing seven methods based on two indicators. The experimental results illustrate that the proposed UIM is effective for WWTP time series under different missing ratios. Therefore, the proposed UIM is a promising method to impute WWTP time series.

Due to the special viscoelastic property, traditional rubber with high performance has been widely used in human life and production. However, it is challenging to improve the damping property without sacrificing the extensibility. In this work, a novel type of second-generation polyurethane dendrimer terminated with pyridine (G2-Py) was synthesized by using thiolactone chemistry and subsequently complexed with Zn ions. The structure and morphology of G2-Py were characterized. G2-Py-Zn²⁺ was then mixed with chlorinated butyl rubber (CIIR) by a two-roll mill. A series of CIIR/G2-Py-Zn²⁺ elastomers were obtained through vulcanization. CIIR/G2-Py-Zn²⁺ elastomers could achieve high stretchability (a strain of ~1035%), high mechanical strength (a tensile stress of 7.64 MPa). This was benefitted from the friction between G2-Py and CIIR as well as variety of non-covalent bonds provided by G2-Py-Zn²⁺, which can dissipate energy to further improve the strength and extensibility. The coordination of Zn²⁺-pyridine was confirmed by Fourier transform infrared spectroscopy, stress relaxation and cycle tensile test. To further investigate the morphology and damping properties of the elastomers, scanning electron microscopy and dynamic mechanical analysis were performed. CIIR-5 showed the best damping performance with higher tanδ_max and wider effective damping temperatures. Therefore, this dendrimer modification technology provides wider applications for CIIR elastomers in daily life.

Photocatalytic removal of tetracycline (TC) from the wastewater is of great value in the chemical and environmental engineering field. Here, we introduced a facile one-step method for the synthesis of BiOBr/Bi₂WO₆ heterojunctions by using cheap CTAB as the Br source. We showed the possibility of our method to fine-tune the content of BiOBr in the produced BiOBr/Bi₂WO₆ by simply changing the dosage of cetyltrimethylammonium bromide (CTAB), providing a platform for the delicate tuning of the visible-light absorbance ability of the composites. With a suitable heterojunction structure of BiOBr/Bi₂WO₆-0.2, it exhibited an ultrarapid photocatalytic activity towards TC (20 mg·L^-1), with a competitive removal efficiency of 88.1% within 60 min and an ultrahigh removal rate of 0.0349 min^-1. It could also be robustly recycled for at least 5 cycles with slight removal efficiency loss. We demonstrated that this exciting photocatalytic performance was due to the highly decreased recombination of photoinduced electrons and holes on our composites by constructing this heterojunction structure, and the resulting OH and contributed to the effective degradation of TC to CO₂.

Alumina (Al₂O₃) is widely used in the chemical industry as the catalyst and support due to its high specific surface area, abundant pore size distribution and chemical stability. However, the occurrence of hydration in water environment, result in outstanding decrease in specific surface area and collapse of pore structure. In this work, dodecyl phosphoric acid (PA) is used to modify the surface of Al₂O₃ to obtain a series of hydrophobic material (Al₂O₃-PA). Based on XPS and NMR analysis, PA is chemically bonded on Al₂O₃ to form P-O-Al bond. Furthermore, BET and WCA results display that Al₂O₃-1PA exhibits excellent the hydrophobicity and hydrothermal stability while maintains the pore structure. Take it as the substrate to support the Pd nanoparticles, the as-prepared Pd/Al₂O₃-PA shows the superior catalytic performance in the hydrogenation of phenol and anthraquinone relative to Pd/Al₂O₃, indicating the accessibility of Pd sites after PA modification. Especially, the significantly enhanced stability is also obtained in four cycles for aqueous phenol hydrogenation. This can be ascribed that the PA modification inhibits the aggregation of Pd nanoparticles and the products adhesion in the reaction process. The extension of PA coatings to monolithic catalysts could expand their current capabilities in industrial applications and warrants ongoing investigation.

High-purity ethylene carbonate (EC) is widely used as battery electrolyte, polycarbonate monomer, organic intermediate, and so on. An economical and sustainable route to synthesize high-purity ethylene carbonate (EC) via the transesterification of dimethyl carbonate (DMC) with ethylene glycol (EG) is provided in this work. However, this reaction is so fast that the reaction kinetics, which is essential for the industrial design, is hard to get by the traditional measuring method. In this work, an easy-to-assemble microreactor was used to precisely determine the reaction kinetics for the fast transesterification of DMC with EG using sodium methoxide as catalyst. The effects of flow rate, microreactor diameter, catalyst concentration, reaction temperature, and reactant molar ratio were investigated. An activity-based pseudo-homogeneous kinetic model, which considered the non-ideal properties of reaction system, was established to describe the transesterification of DMC with EG. Detailed kinetics data were collected in the first 5 min. Using these data, the parameters of the kinetic model were correlated with the maximum average error of 11.19%. Using this kinetic model, the kinetic data at different catalyst concentrations and reactant molar ratios were predicted with the maximum average error of 13.68%, suggesting its satisfactory prediction performance.

Encapsulation of Fe nanoparticles in zeolite is a promising way to significantly improve the catalytic activity and stability of Fe-based catalysts during the degradation process of organic pollutants. Herein, Fe nanocatalysts were encapsulated into silicalite-1 (S-1) zeolite by using a ligand-protected method (with dicyandiamide (DCD) as a organic ligand) under direct hydrothermal synthesis condition. High-resolution transmission electron microscopy (HRTEM) results confirmed the high dispersion of Fe nanocatalysts which were successfully encapsulated within the voids among the primary particles of the S-1 zeolite. The developed S-1 zeolite encapsulated Fe nanocatalyst (Fe@S-1) exhibited significantly improved catalytic activity and reusability in the catalytic degradation process of methylene blue (MB). Specifically, the developed Fe_0.021@S-1 catalyst showed high catalytic degradation activity, giving a high MB degradation efficiency of 100% in 30 min, outperformed the conventional impregnated catalyst (Fe/S-1). Moreover, the Fe@S-1 catalyst afforded an outstanding stability, showing only ca. 7.9% activity loss after five cycling tests, while the Fe/S-1 catalyst presented a significantly activity loss of 50.9% after only three cycles. Notably, the encapsulation strategy enabled a relatively lower Fe loading in the Fe@S-1 catalyst in comparison with that of the Fe/S-1 catalyst, i.e., 0.35% vs. 0.81% (mass). Radical scavenging experiments along with electron spin resonance (ESR) measurements confirmed that the major role of OH in the MB degradation process. Specifically, Fe@S-1 catalyst with high molar ratio of [Fe(DCD)]Cl₃ is beneficial to form Fe complexes/nanoclusters in the voids (which has large pore size of 1–2 nm) among the primary particles of the zeolite, and thus improving the diffusion and accessibility of reactants to Fe active sites, and thus exhibiting a relatively higher degradation efficiency. This work demonstrates that zeolite-encapsulated Fe nanocatalysts present potential applications in the advanced oxidation of wastewater treatment.

In this study, the solid structure, dissolution behavior, thermodynamic properties and nucleation kinetics of malonamide were explored. Firstly, the Hirshfeld surface analysis and molecular electrostatic potential surface were plotted to reveal the percentage contribution of various intermolecular contacts and location of the strongest hydrogen bond. Next, the solubility of malonamide in 12 solvents was determined by dynamic method at temperatures from 278.15 K to 318.15 K. Four thermodynamic models were applied to analyze solubility results. In addition, the thermodynamic properties were calculated to further analyze and discuss the dissolution behavior of malonamide. Moreover, the physicochemical properties of solvents were explored to express the solvent effects. The results illustrate “like dissolves like”, “mass transfer” and “solvent–solute interaction” rules play the synergistic effects on the dissolution process. The molecular dynamic simulation, including radial distribution function analysis and solvent free energy, was used to further explain the dissolution behavior. At last, the nucleation rate and effective interfacial energy in methanol solvent was measured and calculated to reveal the nucleation behaviour.

Improving energy efficiency in plasma NO removal is a critical issue. When the surface dielectric barrier discharge (SDBD) device is considered as a combination of multiple plasma actuators, the induced plasma aerodynamic effect cannot be ignored, which can affect the mass transfer, then affect the chemical reactions. Five SDBD devices with different electrode arrangements are studied for NO conversion. They correspond to different flow patterns. We find that the energy efficiency in an SDBD device with a common structure (Type 1) is 28% lower than that in SDBD devices with a special arrangement (Types 2–5). Two reasons may explain the results. First, fewer active species are produced in Type 1 because the development of discharge is hindered by the mutually exclusive electric field forces caused by the symmetrically distributed charged particles. Second, the plasma wind induced by the plasma actuator can enhance the mass and heat transfer. The mixing of reactants and products is better in Types 2–5 than Type 1 due to higher turbulence kinetic energy.

Synthesis of new carbon nanostructures with tunable properties is vital for precisely regulating electrochemical performance in the wide applications. Herein, we report a novel approach for the oxidative polymerization of N- and P-bearing copolymers from the self-assembly of three different monomers (aniline, pyrrole, and phytic acid), and further prepare the respective carbon nanostructures with relatively consistent N dopant (6.2%–8.0%, atom) and varying P concentrations (0.4%–2.8%, atom) via controllable pyrolysis. The impacts of phytic acid addition on the compositional, structural, and morphological evolution of the copolymers and the resulting nanocarbons are well studied through a spectrum of characterizations including N₂ sorption, Fourier transform infrared spectroscopy, gel permeation chromatograph, scanning/transmission electron microscopy, and X-ray photoelectron spectroscopy. Gradual fragmentation of the nanosphere structures is evidenced with increasing addition of phytic acid, leading to different nanostructures from hollow nanospheres to 3D aggregates. Nanocarbons decorated with N and P dopants from pyrolysis are further utilized as anode materials in lithium-ion batteries, demonstrating enhanced electrochemical performance, i.e., a reversible capacity of 380 mA·h·g^-1 at 2 A·g^-1 for NPC-0.5 during 200 cycles. The superior performance originates from the balanced porosity, and appropriate concentrations of P and pyrrolic N, thus pointing the direction for designing high-performance anode materials.

A high performance preoxidized poly(acrylonitrile) (O-PAN) nanofiber membrane with excellent solvent resistance, thermal stability and flexibility was fabricated by the preoxidation of electrospun PAN nanofiber membrane. The performance of resultant O-PAN nanofiber membrane was optimized by altering the PAN concentration and preoxidation temperature. The results showed that the O-PAN nanofiber membrane which made from PAN concentration of 14% (mass) and preoxidation temperature of 250.0 ℃ have a more optimal comprehensive performance. In the long-term separation test of SiO₂ particle (1 μm) in DMAc suspension, the permeate flux of O-PAN nanofiber membrane stabilized at 227.91 L·m^-2·h^-1 (25 ℃, 0.05 MPa) while the SiO₂ rejection above 99.6%, which showed excellent solvent resistance and separation performance. In order to further explore the application of the O-PAN nanofiber membrane, the O-PAN nanofiber membrane was treated with fluoride and used in oil/water separation process. The O-PAN nanofiber membrane after hydrophobic treatment showed excellent hydrophobicity and good oil/water separation performance with the permeate flux about 969.59 L·m^-2·h^-1 while the separation efficiency above 96.1%. The O-PAN nanofiber membrane exhibited a potential application prospect in harsh environment separation.

As one of the few renewable aromatic resources, the research of depolymerization of lignin into high-value chemicals has attracted extensive attention in recent years. Catalytic wet aerobic oxidation (CWAO) is an effective technology to convert lignin like sodium lignosulfonate (SL), a lignin derivative, into aromatic aldehydes such as vanillin and syringaldehyde. However, how to improve the yield of aromatic aldehyde and conversion efficiency is still a challenge, and many operating conditions that significantly affect the yield of these aromatic compounds have rarely been investigated systematically. In this work, we adopted the stirred tank reactor (STR) for the CWAO process with nano-CuO as catalyst to achieve the conversion of SL into vanillin and syringaldehyde. The effect of operating conditions including reaction time, oxygen partial pressure, reaction temperature, SL concentration, rotational speed, catalyst amount, and NaOH concentration on the yield of single phenolic compound was systematically investigated. The results revealed that all these operating conditions exhibit a significant effect on the aromatic aldehyde yield. Therefore, they should be regulated in an optimal value to obtain high yield of these aldehydes. More importantly, the reaction kinetics of the lignin oxidation was explored. This work could provide basic data for the optimization and design of industrial operation of lignin oxidation.

2,5-Dicyanofuran (DCF) is an important biomass-derived platform compound primarily used to prepare bio-based adiponitrile, which is the key precursor for the synthesis of nylon 66 and 1,6-hexanediisocyanate (HDI). In this study, one-pot, green and safe synthesis of DCF from 2,5-diformylfuran (DFF) and hydroxylamine ionic liquid salts was proposed. Eco-friendly hydroxylamine ionic liquid salts were used as the nitrogen source. Ionic liquid exhibited three-fold function of cosolvent, catalysis and phase separation. The conversion of DFF and yield of DCF reached 100% under the following optimum reaction conditions: temperature of 120 ℃ for 70 min, volume ratio of paraxylene: [HSO₃-b-Py]·HSO₄ of 2:1, and molar ratio of DFF:(NH₂OH)₂·[HSO₃-b-Py]·HSO₄ of 1:1.5. The reaction mechanism for the synthesis of DCF was proposed, and the kinetic model was established. The reaction order with respect to DFF and intermediate product 2,5-diformylfuran dioxime (DFFD) was 1.06 and 0.16, and the reaction activation energy was 64.07 kJ·mol^-1 and 59.37 kJ·mol^-1 respectively. After the reaction, the ionic liquid was easy to separate, recover and recycle.

In this study, high-gravity intensified heterogeneous catalytic ozonation is utilized for treatment of phenol-containing wastewater, and the kinetics of the direct reaction between ozone and phenol in the presence of excess tertiary butanol (TBA) is investigated. It is revealed that the direct reaction between ozone and phenol in the rotating packed bed (RPB) follows the pseudo-first-order kinetics with a reaction rate constant higher than that in the conventional bubbling reactor (BR). Under different conditions of temperature, initial pH, high-gravity factor, and gaseous ozone concentration, the apparent reaction rate constant varies in the range of 0.0160–0.115 min^-1. An empirical power-exponential model is established to characterize the effects of these parameters on the direct reaction between ozone and phenol by high-gravity intensified heterogeneous catalytic ozonation.

Palmitoleic acid (POA) can be naturally found only in few oil seeds and has significant applications in pharmaceutical industry. Recently, the isolated oleaginous yeast Scheffersomyces segobiensis DSM 27193 was identified with high content of POA in its intracellular lipid (13.80%). In this study, process optimization focused on dissolved oxygen regulation to improve POA production was conducted. Dynamic agitation was found to do significant enhancement on POA-rich lipid production than aeration regulation. Under the best condition of 1000 r·min^-1 of agitation and 1 vvm (airvolume/culture volume/min) of aeration, no ethanol was detected during the whole fermentation process, while a dry biomass concentration of 44.80 g·L^-1 with 13.43 g·L^-1 of lipid and 2.93 g·L^-1 of POA was achieved. Transcription analysis revealed that the ethanol synthetic pathway was downregulated under the condition of high agitation, while the expression of the key enzymes responsible for lipid and POA accumulation were enhanced.

The concept of “carbon neutrality” poses a huge challenge for chemical engineering and brings great opportunities for boosting the development of novel technologies to realize carbon offsetting and reduce carbon emissions. Developing high-efficient, low-cost, energy-efficient and eco-friendly microfluidic-based microchemical engineering is of great significance. Such kind of “green microfluidics” can reduce carbon emissions from the source of raw materials and facilitate controllable and intensified microchemical engineering processes, which represents the new power for the transformation and upgrading of chemical engineering industry. Here, a brief review of green microfluidics for achieving carbon neutral microchemical engineering is presented, with specific discussions about the characteristics and feasibility of applying green microfluidics in realizing carbon neutrality. Development of green microfluidic systems are categorized and reviewed, including the construction of microfluidic devices by bio-based substrate materials and by low carbon fabrication methods, and the use of more biocompatible and non-destructive fluidic systems such as aqueous two-phase systems (ATPSs). Moreover, low carbon applications benefit from green microfluidics are summarized, ranging from separation and purification of biomolecules, high-throughput screening of chemicals and drugs, rapid and cost-effective detections, to synthesis of fine chemicals and novel materials. Finally, challenges and perspectives for further advancing green microfluidics in microchemical engineering for carbon neutrality are proposed and discussed.

In order to better guide the design of industrial process for purification and recovery of VOCs, temperature swing adsorption (TSA) and temperature vacuum swing adsorption (TVSA) process for VOCs purification and recovery were studied systematically with activated carbon adsorbent. The adsorption and desorption behaviors of benzene on activated carbon in above two processes were investigated systematically. Effects of operating parameters on process performances were further analyzed, including as regeneration temperature, purging feed ratio and hot–cold purging ratio. The results showed that the increase of hot–cold purging ratio (HP/CP) could obtain the same regeneration effect as the increase of desorption temperature. Increasing the feed purge ratio without increasing the hot–cold purging ratio is not conducive to bed regeneration, because a large number of cold purge gases cannot utilize the residual heat of temperature wave, thus reducing the desorption effect of the cooling step on the bed. In addition, the vacuum step can enhance the regeneration ability of hot nitrogen to the bed at the same regeneration temperature, making the bed regeneration of TVSA process more thorough. Temperature in the middle and lower part of the bed in TVSA process was higher and the regeneration was more thorough. In conclusion, TVSA has more obvious advantages than TSA in terms of energy consumption, hot or cold purge volume and bed regeneration.

In this work, the computational fluid dynamics method is used to study the liquid hydrodynamics behavior in the microchannel without central insert (MC1) and the central insert microchannel (MC2), respectively. The maximum deviation between simulation and experiment is 24%. The formations of flow patterns are explained based on contours and force analysis where the flow pattern maps are established by two-phase flow rate. The effects of aqueous phase viscosity and two-phase flow rate on the characteristic sizes of each flow pattern are also explored. Specifically, four unconventional flow patterns are found in MC2, namely the unique droplet flow, the unique slug flow, the unique coarse annular flow and the unique film annular flow. Though the insert occupies part of the channel, the pressure difference in the channel is significantly reduced compared with MC1. Moreover, the insert significantly changes the formation velocity range of each flow pattern, greatly broadens the formation range of annular flow and also has an important influence on the characteristic size of the flow pattern. The organic-phase dimensionless axial size (L_o/W) and the dimensionless radial size (D_o/W) of the droplet (slug) are negatively related to the aqueous-phase viscosity (μ_a) and flow rate (u_a). The D_o/W of the annular is negatively correlated with μ_a and positively correlated with organic-phase flow rate (u_o). This study provides direct numerical evidence that the insert is key to the formation of bicontinuous phase flow pattern, as well as further strengthens our understanding of the flow characteristics and optimization design of insert microchannels.

In this study, new nano spherical graphene modified with LDH (Layered Double Hydroxide) was prepared and used to remove As(III) ion from aqueous solutions. At first, graphene oxide was synthesized from graphite using a well-known Hammer method. The obtained graphene oxide solution was sprayed in octanol solution under different temperatures and sprayed speed as influenced variables. The structure and physical characterization of synthesized spherical graphene oxide were determined by various techniques, including FT-IR, N₂ adsorption–desorption, SEM, TEM, and EDX. In the next step, the hydrothermal method was applied to deposition LDH on the spherical graphene oxide. The synthesized spherical graphene modified by LDH was used to remove As(III) as a toxic heavy metal ion. The effect of influenced variables including pH, contact time, amount of sorbent, and type eluent studied and the optimum values were as 8, 30, 50, and HCl (0.5 mol·L^-1), respectively. After optimization, the studied sorbent was shown a high adsorption capacity (149.3 mg·g^-1). The adsorption mechanism and kinetic models exhibited good agreement with the Langmuir isotherm and pseudo-second-order trends, respectively. Besides, the synthesized product was tested for seven times without significant loss in its sorption efficiency.

With increasing strict regulation on single-use plastics, lactic acid (LA) and alkyl lactates, as essential monomers for bio-degradable polylactic acid (PLA) plastic products, have gained worldwide attention in both academia and industry. While LA is still dominantly produced through fermentation processes from start, chemical synthesis from cellulosic biomass remains a grand challenge, owing to poor selectivity in activating C-H and C-C bonds in sugar molecules. To our best knowledge, recent publications have been focused on hydrothermal conversion of glucose to LA, while this review summarizes the highlights on direct thermal conversion of fructose as starting material to LA and derivatives. In particular, the synergies of metal/metal cations and acid/base catalysts will be critically revised on retro-aldol and dehydration reactions. This work will provide insights into rational design of active and selective catalysts for the production of carboxylic acids from biomass feedstocks.

Methacrylic acid, an important organic chemical, is commercially manufactured starting from fossil feedstock. The decarboxylation of itaconic acid derived for biomass is a green route to the synthesis of methacrylic acid. In view of the problems existing in the researches on this route such as use of noble metal catalyst, harsh reaction conditions and low desired-product yield, we prepared a series of hydroxyapatite catalysts with different Ca/P molar ratios and evaluated their catalytic performance. The results showed that the hydroxyapatite catalyst with a Ca/P molar ratio of 1.58 had the best catalytic activity. The highest yield of MAA up to 61.2% was achieved with basically complete conversion of itaconic acid under the suitable reaction conditions of 1 equivalent of NaOH, 2 MPa of N₂, 250 ℃, and 2 h. On this basis, a reaction network for the decarboxylation of itaconic acid to methacrylic acid catalyzed by hydroxyapatite was established. With the aid of catalyst characterization using X-ray powder diffraction, NH₃/CO₂ temperature-programmed desorption, N₂ physisorption, inductively coupled plasma optical emission spectrometry, and scanning electron microscopy, we found that the distribution of surface acid sites and basic sites, crystal growth orientation, texture properties and morphology of hydroxyapatite varied with the Ca/P molar ratio. Furthermore, the change of the crystal growth orientation and its influence on the surface acidity and alkalinity were clarified.

The oxygen distribution and evolution within the oxygen carrier exert significant influence on chemical looping processes. This paper describes the influence of oxygen bulk diffusion within FeVO₄ oxygen carrier pellets on the chemical looping oxidative propane dehydrogenation (CL-ODH). During CL-ODH, the oxygen concentration at the pellet surface initially decreased and then maintained stable before the final decrease. At the stage with the stable surface oxygen concentration, the reaction showed a stable C₃H₆ formation rate and high C₃H₆ selectivity. Therefore, based on Fick’s second law, the oxygen distribution and evolution in the oxygen carrier at this stage were further analyzed. It was found that main reactions of selective oxidation and over-oxidation were controlled by the oxygen bulk diffusion. C₃H₈ conversion rate kept decreasing during this stage due to the decrease of the oxygen flux caused by the decline of oxygen gradient within the oxygen carrier, while C₃H₆ selectivity increased due to the decrease of over-oxidation. In addition, reaction rates could increase with the propane partial pressure due to the increase of the oxygen gradient within the oxygen carrier until the bulk transfer reached its limit at higher propane partial pressure. This study provides fundamental insights for the diffusion-controlled chemical looping reactions.

Functional multiblock poly(ether-b-amide) (PEBA) copolymers, comprised of PA1212 (polyamide 1212) as hard segments and Jeffamine ED-2003 as soft segments, were successfully prepared via two-step melt polycondensation without any amidation catalyst. Here, using diamino-terminated poly(propylene oxide)-poly(ethylene oxide)-poly(propylene oxide) (PPO-PEO-PPO), Jeffamine ED-2003, enhances the compatibility between polyamide oligomer and polyether, which is better than the traditional route using hydroxyl-terminated polyether. The chemical structure of multiblock PEBAs, as well as the microphase separated structure with crystalline phase of polyamide and polyether, were confirmed by heteronuclear multiple-bond correlation spectrum, heteronuclear multiple quantum correlation spectrum, Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry and dynamic mechanical analysis. The hydrophilic PEBA copolymers showed water adsorption ranging from 87.3% to 17.1% depending on the polyether content, and specially showed moisture responsive behavior within seconds when exposed to moisture. The corresponding mechanism was studied using time-resolved attenuated total reflectance FT-IR spectroscopy in the molecular level and the water diffusion coefficient was estimated to be 1.07×10^–8 cm²·s^-1. Two-dimensional correlation FT-IR spectra analysis was performed to confirm that the interaction between water and polyether phase was in preference to that between water and polyamide matrix, and water molecule only forms hydrogen bond with the polyether segment. Due to the incorporation of PEO segments, the PEBAs have the surface resistivity varying from 5.6×10⁹ to 6.5×10¹⁰ Ω, which makes PEBA potential candidate as permanent antistatic agent.