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.

Ensuring the consistency of electrode structure in proton-exchange-membrane fuel cells is highly desired yet challenging because of wide-existing and unguided cracks in the microporous layer (MPL). The first thing is to evaluate the homogeneity of MPL with cracks quantitatively. This paper proposes the homogeneity index of a full-scale MPL with an area of 50 cm², which is yet to be reported in the literature to our knowledge. Besides, the effects of the carbon material and surfactant on the ink and resulting MPL structure have been studied. The ink with a high network development degree produces an MPL with low crack density, but the ink with high PDI produces an MPL with low crack homogeneity. The polarity of the surfactant and the non-polarity of polytetrafluoroethylene (PTFE) are not mutually soluble, resulting in the heterogeneous PTFE distribution. The findings of this study provide guidelines for MPL fabrication.

Biochar is a reactive carrier as it may be partially gasified with steam in steam reforming, which could influence the formation of reaction intermediates and modify catalytic behaviors. Herein, the Ni/biochar as well as two comparative catalysts, Ni/Al₂O₃ and Ni/SiO₂, with low nickel loading (2% (mass)) was conducted to probe involvement of the varied carriers in the steam reforming. The results indicated that the Ni/biochar performed excellent catalytic activity than Ni/SiO₂ and Ni/Al₂O₃, as the biochar carrier facilitated quick conversion of the -OH from dissociation of steam to gasify the oxygen-rich carbonaceous intermediates like C=O and C-O-C, resulting in low coverage while high exposure of nickel species for maintaining the superior catalytic performance. In converse, strong adsorption of aliphatic intermediates over Ni/Al₂O₃ and Ni/SiO₂ induced serious coking with polymeric coke as the main type (21.5% and 32.1%, respectively), which was significantly higher than that over Ni/biochar (3.9%). The coke over Ni/biochar was mainly aromatic or catalytic type with nanotube morphology and high crystallinity. The high resistivity of Ni/biochar towards coking was due to the balance between formation of coke and gasification of coke and partially biochar with steam, which created developed mesopores in spent Ni/biochar while the coke blocked pores in Ni/Al₂O₃ and Ni/SiO₂ catalysts.

Sodium-contained compounds are promising sintering additives for the low-temperature preparation of reaction bonded SiC membranes. Although sodium-based sintering additives in various original states were attempted, their effects on microstructure and surface properties have rarely been studied. In this work, three types of sodium-based additives, including solid-state NaA zeolite residue (NaA) and liquid-state dodecylbenzene sulfonate (SDBS) and water glass (WG), were separately adopted to prepare SiC membranes, and the microstructure, surface characteristics and filtration performance of these SiC membranes were comparatively studied. Results showed that the SiC membranes prepared with liquid-state SDBS and WG (S-SDBS and S-WG) showed lower open porosity yet higher bending strength compared to those prepared with solid-state NaA (S-NaA). The observed differences in bending strength were further interpreted by analyzing the reaction process of each sintering additive and the composition of the bonding phase in the reaction bonded SiC membranes. Meanwhile, the microstructural differentiation was correlated to the original state of the additives. In addition, their surface characteristics and filtration performance for oil-in-water emulsion were examined and correlated to the membrane microstructure. The S-NaA samples showed higher hydrophilicity, lower surface roughness (1.80 μm) and higher rejection ratio (99.99%) in O/W emulsion separation than those of S-WG and S-SDBS. This can be attributed to the smaller mean pore size and higher open porosity, resulting from the originally solid-state NaA additives. Therefore, this work revealed the comprehensive effects of original state of sintering additives on the prepared SiC membranes, which could be helpful for the application-oriented fabrication by choosing additives in suitable state.

With the increasing demand for high-purity products, the industrial application of melt crystallization technology has been highly concerned. In this study, the purification process of nitrochlorobenzene binary eutectic system (NBES) and naphthalene–benzothiophene solid solution system (NBSSS) in tower melting crystallizer is analyzed, and a mathematical model of crystallization process is established. The key parameters in terms of feed concentration, crystal bed height, reflux ratio and stirring speed efficiency on purification effects were discussed by the established model. The results show that the concentration of p-nitrochlorobenzene was purified from 90.85% to 99.99%, when the crystal bed height is 600 mm, the reflux ratio is 2.5, and the stirring speed is 12 r·min^-1. The naphthalene concentration is purified from 95.89% to 99.99%, when the crystal bed height is 400 mm, the reflux ratio is 1.43, and the stirring speed is 16 r·min^-1. The quality of the model is evaluated by the ARD (average relative deviation). The minimum ARD values of the NBES and NBSSS are 2.39% and 5.22%, respectively, indicating the model satisfactorily explains the purification process.

The Co₃O₄ nanoparticles, dominated by a catalytically active (110) lattice plane, were synthesized as a low-temperature NO_x adsorbent to control the cold start emissions from vehicles. These nanoparticles boast a substantial quantity of active chemisorbed oxygen and lattice oxygen, which exhibited a NO_x uptake capacity commensurate with Pd/SSZ-13 at 100°C. The primary NO_x release temperature falls within a temperature range of 200–350°C, making it perfectly suitable for diesel engines. The characterization results demonstrate that chemisorbed oxygen facilitate nitro/nitrites intermediates formation, contributing to the NO_x storage at 100°C, while the nitrites begin to decompose within the 150–200°C range. Fortunately, lattice oxygen likely becomes involved in the activation of nitrites into more stable nitrate within this particular temperature range. The concurrent processes of nitrites decomposition and its conversion to nitrates results in a minimal NO_x release between the temperatures of 150–200°C. The nitrate formed via lattice oxygen mainly induces the NO_x to be released as NO₂ within a temperature range of 200–350°C, which is advantageous in enhancing the NO_x activity of downstream NH₃-SCR catalysts, by boosting the fast SCR reaction pathway. Thanks to its low cost, considerable NO_x absorption capacity, and optimal release temperature, Co₃O₄ demonstrates potential as an effective material for passive NO_x adsorber applications.

CuCe/Ti-A and CuCe/Ti-R catalysts were prepared using anatase TiO₂ (TiO₂-A) and rutile TiO₂ (TiO₂-R) as supports using the incipient wetness impregnation method for the carbon monoxide (CO) oxidation reaction and were compared with a CuCe-C catalyst prepared using the co-precipitation method. The CuCe/Ti-A catalyst exhibited the highest activity, with complete CO conversion at 90 ℃, when the gas hourly space velocity was 24000 ml·g^-1·h^-1 and the CO concentration was approximately 1% (vol). A series of characterizations of the catalysts revealed that the CuCe/Ti-A catalyst has a larger specific surface area, more Cu⁺ species and oxygen vacancies, and the Cu species of CuCe/Ti-A catalyst is more readily reduced. In situ FT-IR results indicate that the bicarbonate species generated on the CuCe/Ti-A catalyst have lower thermal stability than the carbonate species on CuCe/Ti-R, and will decompose more readily to form CO₂. Therefore, CuCe/Ti-A has excellent catalytic activity for CO oxidation.

Presently, ammonia is an ideal candidate for future clean energy. The Haber-Bosch process has been an essential ammonia production process, and it is one of the most important technological advancements since its invention, sustaining the explosive growth of military munitions industry and fertilizers in the first half of the 20th century. However, the process is facing great challenges: the growing need for ammonia and the demands of environmental protection. High energy consumption and high CO₂ emissions greatly limit the application of the Haber-Bosch method, and increasing research efforts are devoted to “green” ammonia synthesis. Thermocatalytic, electrocatalytic, and photocatalytic ammonia production under mild conditions and the derived chemical looping and plasma ammonia production methods, have been widely developed. Electrocatalytic and photocatalytic methods, which use low fossil fuels, are naturally being considered as future directions for the development of ammonia production. Although their catalytic efficiency of ammonia generation is not yet sufficient to satisfy the actual demands, considerable progress has been made in terms of regulating structure and morphology of catalyst and improving preparation efficiency. The chemical looping approach of ammonia production differs from the thermocatalytic, electrocatalytic, and photocatalytic methods, and is the method of reusing raw materials. The plasma treatment approach alters the overall ammonia production approach and builds up a new avenue of development in combination with thermal, photocatalytic, and electrocatalytic methods as well. This review discusses several recent effective catalysts for different ammonia production methods and explores mechanisms as well as efficiency of these catalysts for catalytic N₂ fixation of ammonia.

Copper-based metal-organic frameworks (Cu-MOFs) are a promising multiphase catalyst for catalyzing C-S coupling reactions by virtue of their diverse structures and functions. However, the unpleasant odor and instability of the organosulfur, as well as the mass-transfer resistance that exists in multiphase catalysis, have often limited the catalytic application of Cu-MOFs in C-S coupling reactions. In this paper, a Cu-MOFs catalyst modified by cetyltrimethylammonium bromide (CTAB) was designed to enhance mass transfer by increasing the adsorption of organic substrates using the long alkanes of CTAB. Concurrently, elemental sulfur was used to replace organosulfur to achieve a highly efficient and atom-economical multicomponent C-S coupling reaction.

In order to comprehend the applicability of microwave irradiation for recovering coalbed methane, it is necessary to evaluate the microwave irradiation-induced alterations in coals with varying levels of metamorphism. In this work, the carbon molecular sieve combined with KMnO₄ oxidation was selected to fabricate carbon molecular sieve with diverse oxidation degrees, which can serve as model substances toward coals. Afterwards, the microwave irradiation dependences of pores, functional groups, and high-pressure methane adsorption characteristics of model substances were studied. The results indicated that microwave irradiation causes rearrangement of oxygen-containing functional groups, which could block the micropores with a size of 0.40-0.60 nm in carbon molecular sieve; meanwhile, naphthalene and phenanthrene generated by macro-molecular structure pyrolysis due to microwave irradiation could block the micropores with a size of 0.70-0.90 nm. These alterations in micropore structure weaken the saturated methane adsorption capacity of oxidized carbon molecular sieve by 2.91%-23.28%, suggesting that microwave irradiation could promote methane desorption. Moreover, the increased mesopores found for oxidized carbon molecular sieve after microwave irradiation could benefit CH₄ diffusion. In summary, the oxidized carbon molecular sieve can act as model substances toward coals with different ranks. Additionally, microwave irradiation is a promising technology to enhance coalbed methane recovery.

Silicone rubber (SR) is widely used in the field of electronic packaging because of its low dielectric properties. In this work, the porosity of the SR was improved, and the dielectric constant of the SR foam was reduced by adding expanded microspheres (EM). Then, the thermal conductivity of the system was improved by combining the modified boron nitride (f-BN). The results showed that after the f-BN was added, the dielectric constant and dielectric loss were much lower than those of pure SR. Micron-sized modified boron nitride (f-mBN) improved the dielectric and thermal conductivity of the SR foam better than that of nano-sized modified boron nitride (f-nBN), but f-nBN improved the volume resistivity, tensile strength, and thermal stability of the SR better than f-mBN. When the mass ratio of f-mBN and f-nBN is 2:1, the thermal conductivity of the SR foam reaches the maximum value of 0.808 W·m^-1·K^-1, which is 6.5 times that before the addition. The heat release rate and fire growth index are the lowest, and the improvement in flame retardancy is mainly attributed to the high thermal stability and physical barrier of f-BN.

The higher capacity of CO₂ adsorption on the surface of magnesium oxide (MgO) with low-coordination O^2- sites would effectively enhance the catalytic reduction of CO₂. Herein, a series of copper oxide (CuO) and MgO composites with different mass ratios have been prepared by hydrothermal method and used for photothermal synergistic catalytic reduction of CO₂ to ethanol. The catalyst with CuO mass ratio of 1.6% shows the best yield (15.17 μmol·g^-1·h^-1) under 3 h Xenon lamp illumination. The improved performance is attributable to the loose nano-sheet structure, uniform dispersion of active sites, the increased specific surface area, medium-strengthbasicity, the high separation efficiency of electrons and holes, and the formation of Mg-O-Cu species. The synthesized CuO and MgO composites with loose nano-sheet structure facilitate the diffusion of reactants CO₂, so an excellent CO₂ adsorption performance can be obtained. Meanwhile, the introduction of CuO in the form of bivalence provides higher specific surface area and porosity, thus obtaining more active sites. Moreimportantly, the Mg-O-Cu species make the donation of electrons from MgO to CO₂ easier, resulting in the breaking of the old Mg-O bond and the formation of C—O bond, thus promoting the adsorption and conversion of CO₂ to ethanol.

In the industrial treatment of waste volatile organic compound (VOC) streams by membrane technology, a third impurity, generally, water vapor, coexists in the mixture of VOC and nitrogen or air, and can affect membrane performance and the design of the industrial process. This study focused on the investigation of the effect of water vapor on the separation performance of the separation of VOC/water/nitrogen mixtures by a polydimethylsiloxane (PDMS) membrane. Three types of VOCs: water-miscible ethanol, water-semi-miscible butanol, and water-immiscible cyclohexane, were selected for the study. Different operating parameters including, concentration of the feed VOC, feed temperature, and concentration of the feed water were compared for the separation of binary and ternary VOC/nitrogen mixtures. The interaction between the VOC and water was analyzed to explain the transportation mechanism after analyzing the difference in the membrane performance for the separation of binary and ternary mixtures. The results indicated that the interaction between the VOC (or nitrogen) and water is the key factor affecting membrane performance. Water can promote the permeation of hydrophilic VOC but prevent hydrophobic VOC through the membrane for the separation of ternary VOC/water/nitrogen mixtures. These results will provide fundamental insights for the design of the recovery application process for industrial membrane-based VOCs, and also guidance for the investigation of the separation mechanism in vapor permeation.

The separation of aromatic/aliphatic hydrocarbon mixtures is crucial in the petrochemical industry. Pervaporation is regarded as a promising approach for the separation of aromatic compounds from alkanes. Developing membrane materials with efficient separation performance is still the main task since the membrane should provide chemical stability, high permeation flux, and selectivity. In this study, the hyperbranched polymer (HBP) was deposited on the outer surface of a polyvinylidene fluoride (PVDF) hollow-fiber ultrafiltration membrane by a facile dip-coating method. The dip-coating rate, HBP concentration, and thermal cross-linking temperature were regulated to optimize the membrane structure. The obtained HBP/PVDF hollow-fiber-composite membrane had a good separation performance for aromatic/aliphatic hydrocarbon mixtures. For the 50%/50% (mass) toluene/n-heptane mixture, the permeation flux of optimized composite membranes could reach 1766 g·m^-2·h^-1, with a separation factor of 4.1 at 60 ℃. Therefore, the HBP/PVDF hollow-fiber-composite membrane has great application prospects in the pervaporation separation of aromatic/aliphatic hydrocarbon mixtures.

The technological revolution has spawned a new generation of industrial systems, but it has also put forward higher requirements for safety management accuracy, timeliness, and systematicness. Risk assessment needs to evolve to address the existing and future challenges by considering the new demands and advancements in safety management. The study aims to propose a systematic and comprehensive risk assessment method to meet the needs of process system safety management. The methodology first incorporates possibility, severity, and dynamicity (PSD) to structure the “51X” evaluation indicator system, including the inherent, management, and disturbance risk factors. Subsequently, the four-tier (risk point-unit-enterprise-region) risk assessment (RA) mathematical model has been established to consider supervision needs. And in conclusion, the application of the PSD-RA method in ammonia refrigeration workshop cases and safety risk monitoring systems is presented to illustrate the feasibility and effectiveness of the proposed PSD-RA method in safety management. The findings show that the PSD-RA method can be well integrated with the needs of safety work informatization, which is also helpful for implementing the enterprise's safety work responsibility and the government's safety supervision responsibility.

In this work, a new ZnO/CoNiO₂/CoO/C metal oxides composite is prepared by cost-effective hydrothermal method coupled with annealing process under N₂ atmosphere. Notably, the oxidation-defect annealing environment is conducive to both morphology and component of the composite, which flower-like ZnO/CoNiO₂/CoO/C is obtained. Benefited from good chemical stability of ZnO, high energy capacity of CoNiO₂ and CoO and good conductivity of C, the as-prepared sample shows promising electrochemical behavior, including the specific capacity of 1435 C·g^-1 at 1 A·g^-1, capacity retention of 87.3% at 20 A·g^-1, and cycling stability of 90.5% for 3000 cycles at 5 A·g^-1, respectively. Furthermore, the prepared ZnO/CoNiO₂/CoO/C/NF//AC aqueous hybrid supercapacitors device delivers the best specific energy of 55.9 W·h·kg^-1 at 850 W·kg^-1. The results reflect that the as-prepared ZnO/CoNiO₂/CoO/C microflowers are considered as high performance electrode materials for supercapacitor, and the strategy mentioned in this paper is benefit to prepare mixed metal oxides composite for energy conversion and storage.

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 co-pyrolysis of natural gas and coal is a promising way for the production of acetylene due to its high efficiency for energy and hydrogen utilization. This work investigated the thermodynamics for the co-pyrolysis reaction of natural gas and coal using density functional theory. The favorable reaction conditions are presented in the form of phase diagrams. The calculation results show that the extra amount of methane may benefit the production of acetylene in the co-pyrolysis reaction, and the C/H ratio of 1:1, temperature around 3000 K and pressure at 0.1 MPa are most favorable. The results would provide basic data for related industrial process for the production of acetylene.

The objective in this study is to investigate the adsorption-degradation of the methylene blue (MB) dye using a fabricated heterojunction Ag@TiO₂ nanocomposite. The batch factors used in photo catalytic reactions were pH, UV-irradiation time, temperature, catalytic dosage, and concentration of MB. The results showed that 0.2×10³ g·ml^-1) of the catalytic dose caused the Ag@TiO₂ adsorption to degrade by 96.67% with darks and UV exposure. Using the Langmuir-Hinshelwood model to determine the kinetic, the Ag@TiO₂ displays a greater kinetic rate than TiO₂ and silver nanoparticle (AgNPs). The photocatalytic degradation of MB, which is an endothermic reaction involving all catalysts, is shown by the thermodynamic parameter to have the positive value of enthalpy (ΔH°). The enthalpies observed were Ag@TiO₂ (126.80 kJ·mol^-1) < AgNPs (354.47 kJ·mol^-1) < TiO₂ (430.04 kJ·mol^-1). Ascorbic acid (^·OH scavenger), 2-propanol (^·O₂ scavenger), and ammonium oxalate (AO) (hole h⁺ scavenger) were employed to conduct the scavenger effects. The Ag@TiO₂ demonstrated a reduction in MB degradation when combined with 2-propanol, and this clearly demonstrated that, in contrast to hydroxyl radicals (^·OH) and hole (h⁺) scavengers, superoxide radical anion (^·O₂ scavenger) plays a significant role in MB degradation. Utilizing density functional theory (DFT) to elucidate the mechanism and B3LYP/6-311+G(d,p) level optimization, the degradation-adsorption process was explained. When the N-N, C-N or C-C bonds were severed, the Fukui faction was demonstrated for nucleophilic, electrophilic, and radical attack.

Indeed, polymeric materials have thrived in worldwide sectors over the last five decades due to their versatility and durability, to the point that we can no longer envisage a product that does not contain them. However, many synthetic polymers that have been produced are mostly sourced from petroleum and coal as raw materials, making them environmentally incompatible because they cannot be integrated with what is a natural recycling system. One of the most important aspects of the transition to a circular bioeconomy (CBE) is the provision of more sustainable strategies for resource and waste management. Considering the environmental consequences associated with petroleum-based polymers (PBPs), natural biopolymers, originating from biomass, can be conceived as a promising solution to gradually replace the PBPs, and address, and resolve the potential challenges and prevailing research gaps in the PBPs. The biopolymers have significant advantages over PBPs in terms of low-cost/zero-cost precursors, environmental friendliness, and user-friendliness. The present review dissects the sources, synthesis pathways, structures, characterization, and employment of biopolymers and their composites in water and wastewater treatment applications via different scenarios. Furthermore, the CBE model framework proposes potential approaches to applying CBE principles in the wastewater management sector, with a heavy emphasis on not only technology but also organizational and societal reforms. To sum up, the reliance on biopolymers can be considered a crucial tool for assessing the global progress toward CBE, as well as future environmental management and planning.