It is known that salt ions are abundant in the natural environment where natural gas hydrates are located; thus, it is essential to investigate the self-preservation effect of salt ions on methane hydrates. The dissociation behaviors of gas hydrates formed from various NaCl concentration solutions in a quartz sand system at 268.15 K were investigated to reveal the microscopic mechanism of the self-preservation effect under different salt concentrations. Results showed that as the salt concentration rises, the initial rate of hydrate decomposition quickens. Methane hydrate hardly shows self-preservation ability in the 3.35% (mass) NaCl and seawater systems at 268.15 K. Combined the morphology of hydrate observed by the confocal microscope with results obtained from in situ Raman spectroscopy, it was found that during the initial decomposition stage of gas hydrate below the ice point, gas hydrate firstly converts into liquid water and gas molecules, then turns from water to solid ice rather than directly transforming into solid ice and gas molecules. The presence of salt ions interferes with the ability of liquid water to condense into solid ice. The results of this study provide an important guide for the mechanism and application of the self-preservation effect on the storage and transport of gas and the exploitation of natural gas hydrates.

Water pollution regarding dyes and heavy metal ions is crucial facing the world. How to effectively separate these contaminants from water has been a key issue. Graphene oxide (GO) promises the green-water world as a long-lasting spotlight adsorbent material and therefore, harnessing GO has been the research hotspot for over a decade. The state of GO as well as its surface functional groups plays an important role in adsorption. And the way of preparation and structural modification matters to the performance of GO. In this review, the significance of the state of existence of stock GO and surface functional groups is explored in terms of preparation, structural modification, and adsorption. Besides, various adsorbates for GO adsorption are also involved, the discussion of which is rarely established elsewhere.

The kinetic behavior of esterification between methacrylic acid and methanol catalyzed by NKC-9 resin was studied in a fixed bed reactor. The reaction was conducted in the temperature range of 323.15 to 368.15 K with the molar ratio of reactants from 0.8 to 1.4 under certain pressure. The measurement data were regression with the pseudo-homogeneous (P-H), Eley-Rideal (E-R), and Langmuir-Hinshelwood (L-H) heterogeneous kinetic models. Independent adsorption experiments were implemented to gain the adsorption equilibrium constants of four components. Among the above three models, the L-H model exhibited the best fitting results. The stability of NKC-9 was evaluated by long-term running with the yield of methyl methacrylate no decrease during 3000 h operation. The structure and physicochemical properties of the new and used catalyst were performed by several characterizations including thermogravimetric analysis (TG), scanning electron microscope (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) and so on.

In this work, we utilize a cocrystallization technique to solve the problem of high hygroscopicity of the high-energy oxidant ammonium dinitramide (ADN). For this purpose, a non-hygroscopic oxidant, triaminoguanidine nitrate (TAGN), is selected as the cocrystallization ligand. The ADN/TAGN system is simulated by using Material Studio 5.5 software, and the DFT of ADN and TAGN molecules are calculated by Gaussian09 software. The most stable molar ratio of the ADN/TAGN cocrystallization is determined to be 1:1, and the hydrogen bonding between the H atom of ADN and the O atom in the TAGN is the driving force for the formation of cocrystals in this system. Moreover, the electrostatic potential interaction pairing energy difference (△E_pair) < 0 kJ·mol^-1 (-12.71 kJ·mol^-1) for n_ADN:n_TAGN = 1:1 again indicates cocrystallization at this molar ratio. The crystal structure and crystal morphology is predicted. And the hygroscopicity of ADN/TAGN cocrystal at 20 °C and 40% relative humidity is calculated to be only 0.45%. The mechanism of hygroscopicity is investigated by examining the roughness of each crystal surface. Overall, the more hygroscopic it is in terms of surface roughness, with the roughest crystal surface (0 1 $\overline{2}$) having a hygroscopicity of 1.78, which corresponds to a saturated hygroscopicity of 0.61%. The results show that the (0 0 1) crystal surface has the smallest band gap (1.06 eV) and the largest sensitivity. Finally, the oxygen equilibrium value for the ADN/TAGN system is calculated to be -8.2%.

This work provides an overview of distillation processes, including process design for different distillation processes, selection of entrainers for special distillation processes, system integration and intensification of distillation processes, optimization of process parameters for distillation processes and recent research progress in dynamic control strategies. Firstly, the feasibility of using thermodynamic topological theories such as residual curve, phase equilibrium line and distillation boundary line to analyze different separation regions is discussed, and the rationality of distillation process design is discussed by using its feasibility. Secondly, the application of molecular simulation methods such as molecular dynamics simulation and quantum chemical calculation in the screening of entrainer is discussed for the extractive distillation process. The thermal coupling mechanism of different distillation processes is used to explore the process of different process intensifications. Next, a mixed integer nonlinear optimization strategy for the distillation process based on different algorithms is introduced. Finally, the improvement of dynamic control strategies for different distillation processes in recent years is summarized. This work focuses on the application of process intensification and system optimization in the design of distillation process, and analyzes the challenges, prospects, and development trends of distillation technology in the separation of multicomponent azeotropes.

Acetic acid and furfural are known as prevalent inhibitors deriving from pretreatment during lignocellulosic ethanol production. They negatively impact cell growth, glucose uptake and ethanol biosynthesis of Saccharomyces cerevisiae strains. Development of industrial S. cerevisiae strains with high tolerance towards these inhibitors is thus critical for efficient lignocellulosic ethanol production. In this study, the acetic acid or furfural tolerance of different S. cerevisiae strains could be significantly enhanced after adaptive evolution via serial cultivation for 40 generations under stress conditions. The acetic acid-based adaptive strain SPSC01-TA9 produced 30.5 g·L^-1 ethanol with a yield of 0.46 g·g^-1 in the presence of 9 g·L^-1 acetic acid, while the acetic acid/furfural-based adaptive strain SPSC01-TAF94 produced more ethanol of 36.2 g·L^-1 with increased yield up to 0.49 g·g^-1 in the presence of both 9 g·L^-1 acetic acid and 4 g·L^-1 furfural. Significant improvements were also observed during non-detoxified corn stover hydrolysate culture by SPSC01-TAF94, which achieved ethanol production and yield of 29.1 g·L^-1 and 0.49 g·g^-1, respectively, the growth and fermentation efficiency of acetic acid/furfural-based adaptive strain in hydrolysate was 95% higher than those of wildtype strains, indicating the acetic acid- and furfural-based adaptive evolution strategy could be an effective approach for improving lignocellulosic ethanol production. The adapted strains developed in this study with enhanced tolerance against acetic acid and furfural could be potentially contribute to economically feasible and sustainable lignocellulosic biorefinery.

Biofouling, which comprises the absorption of proteins and the adhesion of bacteria to the surface of living entities, is a severe concern for the maritime sector since it ultimately leads to hydrodynamic drag, resulting in a higher increase in fuel consumption. As a result, polymer resins are crucial in the marine sector for anti-biofouling coatings. In this work, the poly(caprolactone-ethylene glycol-caprolactone)-polyurethane (PECL-PU) are prepared through ε-caprolactone (CL), poly(ethylene glycol) (PEG), 4,4'-methylene bis(cyclohexyl isocyanate) and 1,4 butanediol. Our study demonstrate that the PECL-PU copolymer degraded in artificial seawater (5.21%), enzymatic solution (12.63%), and seawater (13.75%) due to the presence of PEG segments in the laboratory-based test under static condition. Because the addition of PEG segments are increased the polymer's amorphous area and decreased the crystallization of the polycaprolactone (PCL) in the copolymer, as demonstrated by differential scanning calorimetry, X-ray diffraction, and water contact angle studies. Therefore, the hydrolysis rates of PECL-PU were higher than the caprolactone-co-polyurethane (CL-PU). The antifouling test showed that PECL-PU3 copolymer had about 90.29% protein resistance, 85.2% Escherichia coli (E. coli) reduction and 94.61% marine diatom Navicula incerta reduction comparison to the control. We have developed an eco-friendly and inexpensive promising degradable polyurethane for reduction of bacterial biofilm, which can preserve the formation of biofouling on marine coating under practical sea conditions.

Using N-methyl-D-glucosamine (NMDG) as the functional monomer, glycidyl methacrylate (GMA) as the connecting monomer, functionalized Fe₃O₄ nano-particles (NPs) as the support, three adsorbents were prepared including direct polymer GMA-NMDG, magnetic GMA-NMDG polymer (MGN), and boron magnetic ion-imprinted polymer (BMIIP). Based upon the optimization of synthesis conditions, the prepared adsorbents and intermediate products were characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscope, energy dispersive spectroscopy, X-ray diffraction, vibrating sample magnetometer, and Brunauer-Emmett-Teller to investigate the synthesis process, the morphological structure and the functional properties of the materials. The optimum performances of GMA-NMDG, MGN and BMIIP were obtained in the initial neutral solution (pH of 6.5). Moreover, GMA-NMDG and MGN reached the maximum adsorption capacity at 120 min, whereas BMIIP reached adsorption saturation at 60 min. The pseudo-second-order kinetic model was more suitable for the adsorption of boron using the adsorbents. The maximum adsorption capacity of GMA-NMDG was found to be 43.4 mg·g^-1, while those of MGN and BMIIP were 32.5 and 28.3 mg·g^-1, respectively. The Langmuir isotherm model was more appropriate to describe the adsorption process. The adsorbents maintained satisfactory adsorption performance within a certain temperature range. Competing ions had little effect on the adsorption of boron, and would be adsorbed simultaneously, due to which, the effect of co-adsorption can be considered. The adsorption capacity of GMA-NMDG was high, while the adsorption selectivity of BMIIP was much better. Furthermore, BMIIP showed good adsorption after five cycles of adsorption and desorption. The comparison of adsorbents showed that GMA-NMDG had the highest adsorption capacity and was suitable for co-adsorption. MGN had a high adsorption capacity, good comprehensive performance and magnetic properties. BMIIP had better adsorption rate, adsorption selectivity and recyclability. Through the optimization of synthesis conditions, the adsorption capacity of the traditional monomer NMDG polymer was increased, and the magnetism was given to facilitate rapid recovery. Combined with the ion imprinting technology, it showed higher boron adsorption selectivity in the presence of competitive ions.

Deuterium (D₂) is one of the important fuel sources that power nuclear fusion reactors. The existing D₂/H₂ separation technologies that obtain high-purity D₂ are cost-intensive. Recent research has shown that metal–organic frameworks (MOFs) are of good potential for D₂/H₂ separation application. In this work, a high-throughput computational screening of 12020 computation-ready experimental MOFs is carried out to determine the best MOFs for hydrogen isotope separation application. Meanwhile, the detailed structure-performance correlation is systematically investigated with the aid of machine learning. The results indicate that the ideal D₂/H₂ adsorption selectivity calculated based on Henry coefficient is strongly correlated with the 1/ΔAD feature descriptor; that is, inverse of the adsorbility difference of the two adsorbates. Meanwhile, the machine learning (ML) results show that the prediction accuracy of all the four ML methods is significantly improved after the addition of this feature descriptor. In addition, the ML results based on extreme gradient boosting model also revealed that the 1/ΔAD descriptor has the highest relative importance compared to other commonly-used descriptors. To further explore the effect of hydrogen isotope separation in binary mixture, 1548 MOFs with ideal adsorption selectivity greater than 1.5 are simulated at equimolar conditions. The structure-performance relationship shows that high adsorption selectivity MOFs generally have smaller pore size (0.3–0.5 nm) and lower surface area. Among the top 200 performers, the materials mainly have the sql, pcu, cds, hxl, and ins topologies. Finally, three MOFs with high D₂/H₂ selectivity and good D₂ uptake are identified as the best candidates, of all which had one-dimensional channel pore. The findings obtained in this work may be helpful for the identification of potentially promising candidates for hydrogen isotope separation.

Electrode materials with high desalination capacity and long-term cyclic stability are the focus of capacitive deionization (CDI) community. Understanding the causes of performance decay in traditional carbons is crucial to design a high-performance material. Based on this, here, nitrogen-doped activated carbon (NAC) was prepared by pyrolyzing the blend of activated carbon powder (ACP) and melamine for the positive electrode of asymmetric CDI. By comparing the indicators changes such as conductivity, salt adsorption capacity, pH, and charge efficiency of the symmetrical ACP-ACP device to the asymmetric ACP-NAC device under different CDI cycles, as well as the changes of the electrochemical properties of anode and cathode materials after long-term operation, the reasons for the decline of the stability of the CDI performance were revealed. It was found that the carboxyl functional groups generated by the electro-oxidation of anode carbon materials make the anode zero-charge potential (E_pzc) shift positively, which results in the uneven distribution of potential windows of CDI units and affects the adsorption capacity. Furthermore, by understanding the electron density on C atoms surrounding the N atoms, we attribute the increased cyclic stability to the enhanced negativity of the charge of carbon atoms adjacent to quaternary-N and pyridinic-oxide-N.

Glycerol monolaurate (GML) is a widely used industrial chemical with excellent emulsification and antibacterial effect. The direct esterification of glycerol with lauric acid is the main method to synthesize GML. In this work, the kinetic process of direct esterification was systematically studied using p-toluenesulfonic acid as catalyst. A complete kinetic model of consecutive esterification reaction has been established, and the kinetic equation of acid catalysis was deduced. The isomerization reactions of GML and glycerol dilaurate were investigated. It was found that the reaction was an equilibrium reaction and the reaction rate was faster than the esterification reaction. The kinetic equations of the consecutive esterification reaction were obtained by experiments as k₁ = (276+92261X_cat)exp(-37720/RT) and k₂ = (80 +4413X_cat)exp(-32240/RT). The kinetic results are beneficial to the optimization of operating conditions and reactor design in GML production process.

To solve the environmental pollution and low yield during the sythesis of zeolitic imidazolate frameworks (ZIFs) and their derived materials, a KOH-assisted aqueous strategy is proposed to synthesize cobalt zeolitic imidazolate framework (ZIF-67) polyhedrons, which are used as precursors to prepare cobalt selenide/carbon composites with different crystal phases (Co_0.85Se, CoSe₂). When evaluated as anode material for lithium ion batteries, Co_0.85Se/C composites deliver a reversible capacity of 758.7 mA·h·g^-1 with a capacity retention rate of 90.5% at 1.0 A·g^-1 after 500 cycles, and the superior rate capability is 620 mA·h·g^-1 at 2.0 A·g^-1. The addition of KOH accelerates the production of ZIF-67 crystals by boosting deprotonation of dimethylimidazole, resulting in rapid growth and structures transition from two-dimensional to three-dimensional of ZIF-67 in aqueous solution, which greatly promotes the application of MOFs in the field of energy storage and conversion.

As promising catalysts for the degradation of organic pollutants, metal–organic frameworks (MOFs) often face limitations due to the particle agglomeration and challenging recovery in liquid-catalysis application, stemming from their powdery nature. Engineering macroscopic structures from pulverous MOF is thus of great importance for broadening their practical applications. In this study, three-dimensional porous MOF aerogel catalysts were successfully fabricated for degrading organic dyes by activating peroxymonosulfate (PMS). MOF/gelatin aerogel (MOF/GA) catalysts were prepared by directly integrating bimetallic FeCo-BDC with gelatin solutions, followed by freeze-drying and low-temperature calcination. The FeCo-BDC-0.15/GA/PMS system exhibited remarkable performance in degrading various organic dyes, eliminating 99.2% of rhodamine B within a mere 5 min. Compared to the GA/PMS system, there was over a 300-fold increase in the reaction rate constant. Remarkably, high removal efficiency was maintained across varying conditions, including different solution pH, co-existing inorganic anions, and natural water matrices. Radical trapping experiments and electron paramagnetic resonance analysis revealed that the degradation involved radical (SO₄^-·) and non-radical routes (¹O₂), of which ¹O₂ was dominant. Furthermore, even after a continuous 400-min reaction in a fixed-bed reactor at a liquid hourly space velocity of 27 h^-1, the FeCo-BDC/GA composite sustained a degradation efficiency exceeding 98.7%. This work presents highly active MOF-gelatin aerogels for dye degradation and expands the potential for their large-scale, continuous treatment application in organic dye wastewater management.

Catalytic pyrolysis of digestate to produce aromatic hydrocarbons can be combined with anaerobic fermentation to effectively transform and utilize all biomass components, which can achieve the meaningful purpose of transforming waste into high-value products. This study explored whether catalytic pyrolysis of digestate is feasible to prepare aromatic hydrocarbons by analyzing the thermogravimetric characteristics, pyrolysis characteristics, and catalytic pyrolysis characteristics of digestate. For digestate pyrolysis, an increase in temperature was found to elevate the CO, CH₄, and monocyclic aromatic hydrocarbon (benzene, toluene, and xylene; BTX) content, whereas it decreased the contents of phenols, acids, aldehydes, and other oxygenates. Furthermore, the catalytic pyrolysis process effectively inhibited the acids, phenols, and furans in the liquid, whereas the yield of BTX increased from 25.45% to 45.99%, and the selectivity of xylene was also increased from 10.32% to 28.72% after adding ZSM-5. ZSM-5 also inhibited the production of nitrogenous compounds.

The catalytic hydrogenation of 2-nitro-4-acetylamino anisole (NMA) is a less-polluting and efficient method to produce 2-amino-4-acetamino anisole (AMA). However, the kinetics of catalytic hydrogenation of NMA to AMA remains obscure. In this work, the kinetic models including power-law model and Langmuir-Hinshelwood-Hougen-Watson (LHHW) model of NMA hydrogenation to AMA catalyzed by Raney nickel catalyst were investigated. All experiments were carried out under the elimination of mass transfer resistance within the temperature range of 70–100 ℃ and the hydrogen pressure of 0.8–1.5 MPa. The reaction was found to follow 0.52-order kinetics with respect to the NMA concentration and 1.10-order kinetics in terms of hydrogen pressure. Based on the LHHW model, the dual-site dissociation adsorption of hydrogen was analyzed to be the rate determining step. The research of intrinsic kinetics of NMA to AMA provides the guidance for the reactor design and inspires the catalyst modification.

The in-situ growing approach was utilized in this article to construct the magnesium-aluminum layered double hydroxide (MgAl-LDH) film on the surface of a 1060 aluminum anodized film. To improve the corrosion resistance and friction qualities of aluminum alloy, the MgAl-LDH coating was treated using stearic acid (SA) and thiourea (TU). The aluminum substrate and anodized aluminum film layer corroded to varying degrees after 24 h of immersion in 3.5% (mass) NaCl solution, while the modified hydrotalcite film layer continued to exhibit the same microscopic morphology even after being immersed for 7 d. The results show that the synergistic action of thiourea and stearic acid can effectively improve the corrosion resistance of the MgAl-LDH substrate. The tribological testing reveals that the hydrotalcite film layer and the modified film layer lowered the friction coefficient of the anodized aluminum surface substantially. The results of the simulations and experiments demonstrate that SA forms the dense LDH-TU interlayer film layer by exchanging NO₃^- ions between TU layers on the one hand and the LDH-SA film layer by adsorption on the surface of LDH on the other. Together, these two processes create LDH-TU-SA, which can significantly increase the substrate's corrosion resistance. This synergistically modified superhydrophobic and retardant hydrotalcite film layer offers a novel approach to the investigation of wear reduction and corrosion protection on the surface of aluminum and its alloys.

Levulinic acid (LA) is one of the top-12 most promising biomass-based platform chemicals, which has a wide range of applications in a variety of fields. However, separation and purification of LA from aqueous solution or actual hydrolysate continues to be a challenge. Among various downstream separation technologies, liquid–liquid extraction is a low-cost, effective, and simple process to separate LA. The key breakthrough lies in the development of extractants with high extraction efficiency, good hydrophobicity, and low cost. In this work, three hydrophobic deep eutectic solvents (DESs) based on tri-n-octylamine (TOA) as hydrogen bond acceptor (HBA) and alcohols (butanol, 2-octanol, and menthol) as hydrogen bond donors (HBDs) were developed to extract LA from aqueous solution. The molar ratios of HBD and HBA, extraction temperature, contact time, solution pH, and initial LA concentration, DES/water volume ratios were systematically investigated. Compared with 2-octanol–TOA and menthol–TOA DES, the butanol–TOA DES exhibited the superior extraction performance for LA, with a maximum extraction efficiency of 95.79 ±1.4%. Moreover, the solution pH had a great impact on the LA extraction efficiency of butanol–TOA (molar ratio = 3:1). It is worth noting that the extraction equilibrium time was less than 0.5 h. More importantly, the butanol–TOA (3:1) DES possesses good extraction abilities for low, medium, and high concentrations of LA.

One-step separation of high-purity ethylene (C₂H₄) from C₂ hydrocarbon mixture is critical but challenging because of the very similar molecular sizes and physical properties of C₂H₄, ethane (C₂H₆), and acetylene (C₂H₂). Herein, we report a robust zirconium metal-organic framework (MOF) Zr-TCA (H₃TCA = 4,4',4″-tricarboxytriphenylamine) with suitable pore size (0.6 nm×0.7 nm) and pore environment for direct C₂H₄ purification from C₂H₄/C₂H₂/C₂H₆ gas-mixture. Computational studies indicate that the abundant oxygen atoms and non-polar phenyl rings created favorable pore environments for the preferential binding of C₂H₂ and C₂H₆ over C₂H₄. As a result, Zr-TCA exhibits not only high C₂H₆ (2.28 mmol·g^-1) and C₂H₂ (2.78 mmol·g^-1) adsorption capacity but also excellent C₂H₆/C₂H₄ (2.72) and C₂H₂/C₂H₄ (5.64) selectivity, surpassing most of one-step C₂H₄ purification MOF materials. Dynamic breakthrough experiments confirm that Zr-TCA can produce high-purity C₂H₄ (>99.9%) from a ternary gas mixture (1/9/90 C₂H₂/C₂H₆/C₂H₄) in a single step with a high C₂H₄ productivity of 5.61 L·kg^-1.

A correct and timely fault diagnosis is important for improving the safety and reliability of chemical processes. With the advancement of big data technology, data-driven fault diagnosis methods are being extensively used and still have considerable potential. In recent years, methods based on deep neural networks have made significant breakthroughs, and fault diagnosis methods for industrial processes based on deep learning have attracted considerable research attention. Therefore, we propose a fusion deep-learning algorithm based on a fully convolutional neural network (FCN) to extract features and build models to correctly diagnose all types of faults. We use long short-term memory (LSTM) units to expand our proposed FCN so that our proposed deep learning model can better extract the time-domain features of chemical process data. We also introduce the attention mechanism into the model, aimed at highlighting the importance of features, which is significant for the fault diagnosis of chemical processes with many features. When applied to the benchmark Tennessee Eastman process, our proposed model exhibits impressive performance, demonstrating the effectiveness of the attention-based LSTM FCN in chemical process fault diagnosis.