Industrial & Engineering Chemistry Research最新文献

Calgary Framework 20 (CALF-20) has emerged as a metal–organic framework (MOF) that is steam-stable and exhibits selective CO₂ physisorption over water vapor, which makes it a candidate for industrial-scale CO₂ capture from flue gases. In this work, multicomponent CO₂/H₂O adsorption data show that the α-to-β phase transformation has little impact on the multicomponent CO₂ adsorption capacity of CALF-20. Also, H₂O isotherms up to 175 °C reveal only limited changes in the water capacity as temperature increases above 45 °C. CO₂ and H₂O single-component diffusion rates were measured via concentration swing frequency response. The results show that the diffusion rate of water through CALF-20 is similar to that of water diffusion in the highly water-permeable MOF-333, as well as BPL-activated carbon. The data provides key insight into the fundamental thermodynamic and mass transfer parameters that govern the separation of CO₂ and H₂O using CALF-20 and provides quantified parameters that can be used to model adsorption systems based on CALF-20.

A very promising green chemistry concept that should gain more traction is the introduction of semiprepared azo dyes, which are made by modifying natural extracts with the azo group. This would reduce the dependency on toxic and nonbiodegradable synthetic dyes while also giving economic value to agricultural wastes. In the current study, an extract of peanut red skin was used as an agro-waste and a source of polyphenols to prepare azo dye by coupling it with a diazonium salt of ρ-nitroaniline. Then, the prepared dye was used to dye and improve the functional properties of natural cellulosic (cotton) and proteinic (wool) as well as synthetic (polyester) fabrics by using microwave irradiation, with a focus on the kinetic and isothermal adsorption aspects of dyeing processes. The effect of different parameters on fabric dyeability was studied using K/S and the CIE L* a* b*. The effect of dyeing on the multifunctional properties of dyed fabrics was investigated. The adsorption kinetics, isotherms, and mechanism studies of the dyeing process were investigated. The results show that after the fabrics were dyed with the prepared dye, a decorative color was obtained. The dyed fabrics showed very good fastness properties. The dyed fabrics showed excellent UV protection, excellent antimicrobial activity, and very good antioxidant properties. The adsorption kinetics was accurately represented by the pseudo-second-order kinetic model. The Temkin and Nernst models with the best correlation coefficients were discovered to be the most acceptable isotherm models.

Lightweight and high-performance complex-shaped polymeric foams are highly desirable for applications in aerospace, ships, wind power, transportation, etc. This work successfully synthesized the highly foamable P(MAA-co-MAN-co-tBMA) beads via aqueous suspension polymerization, which can be used as foamable precursors for the preparation of polymethacrylimide (PMI) foams by in-mold thermal foaming. For the synthesis of highly foamable P(MAA-co-MAN-co-tBMA) beads used as PMI precursor beads, the oil phase consists of methacrylic acid (MAA) and methacrylonitrile (MAN) as monomers with azodiisobutyronitrile (AIBN) as an initiator and tert-butyl methacrylate (tBMA) as a copolymerizable foaming agent, while the aqueous phase is composed of polyvinyl alcohol (PVA) as the dispersant, NaNO₂ as the aqueous phase inhibitor, and NaCl as a salting-out agent. The chemical structures, foaming behaviors, expansion ratio, and thermal properties of the foamable P(MAA-co-MAN-co-tBMA) beads were investigated in detail. The highly foamable P(MAA-co-MAN-co-tBMA) beads with an average bead diameter of 0.74 mm can be obtained, and their expansion ratio can reach as high as 50 upon free thermal foaming at 230 °C for 30 min. The lightweight and high-performance PMI foams with low mass densities of 60–120 kg/m³, an outstanding thermal stability of 400 °C, an excellent compression strength of 0.69–2.20 MPa, and low compression creep deformations of 1.14–3.39% at the high temperature of 140 °C for 24 h were prepared via in-mold thermal foaming. Moreover, the scalable preparation of complex-shaped PMI foam products is demonstrated based on the highly foamable P(MAA-co-MAN-co-tBMA) beads, which is promising for applications in aerospace, ships, wind power, transportation, etc.

Manganese-based materials are prime candidates for ozone (O₃) elimination, but powder materials are suffering from agglomeration and insights into the O₃ decomposition mechanism at the molecular level remain elusive. Herein, the PAN@NiMn-LDH membrane (PAN = polyacrylonitrile; LDH = layered double hydroxide) was synthesized by adopting an epitaxial growth strategy, resulting in the formation of a robust three-dimensional (3D) interwoven hierarchical structure. The resulting PAN@NiMn-LDH membrane presented a long-lasting 100% conversion efficiency of O₃ for over 75 h at 50 ppm at an ambient temperature. When a large-scale fabricated PAN@NiMn-LDH membrane (100 cm × 30 cm) was applied to a commercial air cleaner, an initial O₃ concentration of 10 ppm could be eliminated to 46 ppb within 6 min in a 36 m³ room, which was below the World Health Organization (WHO) guideline value (∼51 ppb). Compared with the previous studies, such superior activity can be ascribed to the following reasons: (1) the as-prepared PAN@NiMn-LDH membranes were beneficial for the capture of O₃ due to the 3D interwoven hierarchical structure with a high porosity of 63%. (2) The dual sites of Ni–OH/Mn–OH promoted the adsorption and activation of O₃, and thereby facilitated the formation of reactive oxygen species accompanied with the oxidation of Ni²⁺/Mn²⁺/Mn³⁺ to Ni³⁺/Mn⁴⁺.

High-temperature filtration is an energy-saving and efficient technology for treating high-temperature dusty exhaust, while most of the current studies focus on the design and preparation of high-temperature filtration materials and their application in room-temperature filtration. In this work, SiC ceramic membranes were prepared as typical high-temperature filtration materials to systematically investigate the high-temperature filtration process at 25–400 °C. The experimental results show that the filtration temperature has a significant effect on both initial filtration and cake filtration processes. The increase of temperature results in an increase of gas viscosity, which contributes to the increase of the initial filtration pressure drop (ΔP₀). Meanwhile, temperature can affect the forces on dust in the pore of the SiC membrane, and a higher temperature leads to the easy penetration of dust (especially for the ultrafine particles) through the membrane layer into the support body layer at the initial filtration process. Moreover, the higher temperature can reduce the porosity of the dust cake, leading to an increase in the cake pressure drop (ΔP_c). All above results were further proved during the experiments on studying the effect of the filtration velocity, dust concentration, and regeneration on the filtration performance of SiC membranes at 25 and 300 °C. Through this work, we expect to shed some light on the design and preparation of high-temperature filtration materials and on the understanding of the high-temperature filtration process.

N₂O/CO₂ separation in the tail gas of adipic acid presents a significant challenge due to the closely resembling physical characteristics exhibited by CO₂ and N₂O. Herein, adsorption and separation performances of CO₂ and N₂O on FAU-type zeolite Y with different cations (Na⁺ and Ag⁺) were studied comprehensively. After Ag⁺ exchange, zeolite Y changes from a CO₂-selective adsorbent to a N₂O-selective adsorbent. AgY shows high N₂O uptake (95.7 cm³/g) but relatively low adsorption heat (23.1 kJ/mol), making it suitable for N₂O/CO₂ separation. In situ Fourier transform infrared spectrometry indicates that N₂O is successfully adsorbed on AgY. The breakthrough experiment reveals that AgY exhibits superior performance in the separation of N₂O/CO₂ at a flow rate of 20 mL/min while also exhibiting a favorable retention time and ratio of retention time with CO₂ breakthrough time, which can reach up to 4.1 min and 0.24, respectively, which makes it an optimum N₂O/CO₂ separation material reported so far.

In terms of construction and maintenance costs, granular bed filters offer notable advantages over existing pollutant desorption technology methods. Achieving synergistic removal of PM_2.5 and CO₂ through a multideck granular bed is possible by incorporating an activated carbon deck between the granular bed decks. During the experimental process, the average PM_2.5 filtration efficiency exceeds 95%, while the average CO₂ adsorption efficiency surpasses 80%. Substituting activated carbon for one or more decks within the multideck bed during the synergistic removal process offers the dual benefit: (1) preventing PM_2.5 from interfering with CO₂ adsorption by the activated carbon; (2) the internal pore specific surface area advantage of the activated carbon bed can also provide an auxiliary adsorption effect when filtering PM_2.5. In addition, the granular bed showed a good synergistic regeneration performance. Consequently, this study introduces a new technological approach for the synergistic separation of PM_2.5 and CO₂, which informs the application of particulate bed filtration for the synergistic uptake of multiple pollutants.

The pore structure of mesoporous silica is crucial to its application as a substrate for CO₂ capture sorbents. In this work, the synthesis of resin-templated silica, a new class of hierarchically meso-/macroporous silica for fabrication of CO₂ capture sorbents, was reported. Unlike the conventional acid-catalyzed synthesis of mesoporous silica using self-assembled surfactant or block copolymer templates, the resin-templated silica is derived from porous ion-exchange resin templates using a catalyst-free method that involves three simple steps of silane soaking, moisture exposure, and air calcination. The resin-templated silica reproduced the spherical shape of the porous ion-exchange resin template. It was also found that pores in resin templates were crucial to creating mesoporosity in resin-templated silica. The resin-templated silica has simultaneous attractive surface area and pore volume, which were both substantially higher than those of the ion-exchange resin template. Impregnation of the mesopores and macropores by polymeric amine provided novel amine-oxide sorbents for CO₂ capture, that is, resin-templated sorbents. The resin-templated sorbents impregnated using a 15 wt % polyethylenimine (PEI)/methanol solution showed competitive direct air capture (at 400 ppm) performance with a CO₂ sorption capacity of 2.1 mmol of CO₂/g of SiO₂ and amine efficiency of 0.11 mol of CO₂/mol of N at an amine loading of 0.83 g of PEI/g of SiO₂.

The impact of direct H₂O₂ injection on the selective CH₄ coupling reaction at high temperatures was investigated both experimentally and by kinetic modeling to provide insight into the reaction mechanism of the catalytic oxidative coupling of methane (OCM). H₂O₂ injection transforms CH₄ into C₂H₆ and C₂H₄ at high selectivity, confirming the effectiveness of the involvement of H₂O₂ by generating OH radicals in OCM. For carbon oxides, there was only CO formation without CO₂ at CH₄ conversions at or below 10%, as expected from the pure contribution of the gas phase. These results were consistent with simulation results using kinetic modeling of gas-phase elementary reactions. Rate of production (ROP) analysis suggests that OH radicals formed from H₂O₂ decomposition were responsible for the high selectivity toward C₂ products. The major loss of C₂ selectivity and CH₄ conversion is due to HO₂ radicals, a secondary product in H₂O₂ decomposition. The HO₂ radicals were found to both oxidize CH₃ radicals and neutralize OH radicals. The kinetic model consistently overpredicted the CH₄ conversion and C₂ selectivity over the experimental results, which can be attributed to the radical quenching and overoxidation reaction on the surface of the quartz tube reactor. The findings in this work help create a better understanding of the requirements of selective C₂ formation under OCM conditions.

Aceclofenac (ACF) is a kind of antipyretic, analgesic, and antiarthritic drug, which is clinically suitable for the treatment of rheumatoid arthritis. However, the morphology of ACF produced in the crystallization process is easily regulated by different solvents, which has a significant effect on the powder properties of the ACF crystals. Therefore, the study of crystal habits is needed for producing ACF with a better performance. In this study, the effects of different solvents on the growth of the ACF crystal were studied by analyzing the morphology of ACF in various solvents and comprehensive simulation calculations. It was found that the ACF crystals in ethanol (EAL) and acetonitrile (ACE) were quadrangular in shape. In methyl acetate (MA), acetone (ACT), and n-propanol (NPL), the lateral aspect of the (101̅) facet is clearly prominent. More interestingly, pentagonal crystals are found only in methanol (MEL), and the (002) facet eventually disappears as they grow. Through molecular dynamics simulations, we have found that the attachment energy E_att of crystal facets, the Connolly surface coefficient R, and solvent effects E_s are the main factors influencing the growth of ACF crystals. The competitive adsorption of ACF and solvent molecules onto crystal facets accounts for morphology change during the growth process. By establishing a strong link between experimental observations and simulation results, this study favors the morphology control of the ACF crystal.