Frontiers of Chemical Science and Engineering最新文献

The persistent presence of levofloxacin (LEV) residues in aquatic environments considerably threatens ecological safety and human health, owing to the potential spread of microbial resistance genes, creating an urgent need for effective removal technologies. In this study, porous carbon materials with high specific surface areas were synthesized using a one-step KOH activation method, with medium-low-temperature coal tar pitch serving as a carbon precursor. In addition, the performance and mechanism of LEV degradation via peroxydisulfate (PDS) activation were systematically explored. Characterization techniques such as X-ray diffraction, Raman spectroscopy, N₂ adsorption-desorption analysis, and field-emission scanning electron microscopy revealed that K11 possessed abundant pores, a specific surface area of up to 1220 m²·g⁻¹, and numerous defects, which collectively provided a structural basis for its catalytic activity. Degradation experiments demonstrated that the LEV removal rate exceeded 91% under conditions of a 0.2 g·L⁻¹ PDS dosage, a 0.1 g·L⁻¹ K11 dosage, pH levels ranging from 3 to 9, and a temperature of 30 °C, with robust resistance to interference from co-existing ions and humic acid. Even in real water bodies, a removal rate of over 77.84% was maintained. Free-radical quenching experiments and electron spin resonance assays confirmed that the reaction proceeded predominantly via non-radical pathways, primarily involving the generation of singlet oxygen by PDS, along with a minor contribution from direct electron transfer pathways. High-performance liquid chromatography-mass spectrometry identified LEV degradation intermediates, suggesting that the degradation pathways include piperazine ring cleavage, defluorination, and oxidation of the quinolone backbone. This study offers theoretical insights and technical guidance for the resource utilization of coal tar pitch and the control of antibiotic pollution.

This study systematically studied the effects of Pr, Fe, and Na as representative rare earth, transition, and alkali metal dopants, respectively, on the photocatalytic activity of exfoliated graphitic carbon nitride (g-C₃N₄). The doped exfoliated g-C₃N₄ samples were prepared by integrating precursor ion intercalation into the pre-formed g-C₃N₄ with thermal treatment. The as-prepared catalysts were examined for crystal, textural, chemical, optical, and photoelectrochemical properties to explore the correlation between dopants and photocatalytic activity of the resulting composites. The detailed analyses revealed that the Pr-doped g-C₃N₄ exhibited superior photocatalytic activity in degrading methylene blue under visible light, achieving a ∼96% removal in 40 min. This was not only better than the activity of g-C₃N₄, but also much higher than that of Na-doped g-C₃N₄ or Fe-doped g-C₃N₄. The kinetic rate constant using Pr-doped g-C₃N₄ was 3.2, 5.1, and 2.0 times greater than that of the g-C₃N₄, Fe-doped g-C₃N₄, and Na-doped g-C₃N₄, respectively. The enhanced performance was attributed to its inherent characteristics after optimal tuning, including good surface area, improved porosity, enhanced visible light absorption, suitable electronic band structure, increased charge carrier density, promoted charge separation, and reduced charge transfer resistance. In addition, the optimized Pr(0.4)g-C₃N₄ was used to study the photocatalytic removal of methylene blue in detail under conditions with different initial methylene blue concentrations, types of dyes, catalyst dosages, initial solution pH, counter ions, and water matrices. Our results demonstrated the high photocatalytic activity of Pr(0.4)g-C₃N₄ under varying conditions, including in real wastewater media, which were collected from our local municipal wastewater treatment plant. The observed good reusability and stability after five cycles of photocatalytic degradation test further suggested a promising potential of Pr(0.4)g-C₃N₄ for practical application in wastewater treatment.

Microporous and mesoporous silicalite-1 (S-1) and titanium silicalite-1 (TS-1) zeolite supported molybdenum (Mo) catalysts were synthesized and applied in the transesterification of Jatropha seed oil (JO) to produce biodiesel. Various analytical results have revealed that the MoO₃ species are highly dispersed on their surface without destroying the zeolite framework and pore structure. Compared with the mesoporous 7Mo/mesoporous S-1 and 7Mo/mesoporous TS-1 catalysts, the microporous 7Mo/S-1 and 7Mo/TS-1 catalysts exhibit high Mo species contents and surface acidity, indicating that Mo species can enter the inner surface of mesoporous zeolites. However, the Mo species on the outer surface of catalysts are only activity centers owing to the accessibility between the Mo species and JO. Therefore, compared with the low activity of the S-1 and TS-1 catalysts, the 7Mo/S-1 catalyst exhibited the highest catalytic performance, with a JO conversion of 95.7% and a biodiesel selectivity of 99.9%. Finally, 7Mo/S-1 demonstrated good catalytic stability, regeneration performance and broad substrate versatility, and the fuel properties of the as-synthesized biodiesel conformed to the current international standard. The influence of the pore structure and Mo species on the catalytic activity has been clarified, providing a theoretical and practical foundation for developing efficient heterogeneous catalysts for biodiesel production.

Large language model-based agent systems are emerging as transformative technologies in chemical process simulation, enhancing efficiency, accuracy, and decision-making. By automating data analysis across structured and unstructured sources—including process parameters, experimental results, simulation data, and textual specifications—these systems address longstanding challenges such as manual parameter tuning, subjective expert reliance, and the gap between theoretical models and industrial application. This paper reviews the key barriers to broader adoption of large language model-based agent systems, including unstable software interfaces, limited dynamic modeling accuracy, and difficulties in multimodal data integration, which hinder scalable deployment. We then survey recent progress in domain-specific foundation models, model interpretability techniques, and industrial-grade validation platforms. Building on these insights, we propose a technical framework centered on three pillars: multimodal task perception, autonomous planning, and knowledge-driven iterative optimization. This framework supports adaptive reasoning and robust execution in complex simulation environments. Finally, we outline a next-generation intelligent paradigm where natural language-driven agent workflows unify high-level strategic intent with automated task execution. The paper concludes by identifying future research directions to enhance robustness, adaptability, and safety, paving the way for practical integration of large language model based agent systems into industrial-scale chemical process simulation.

To obtain high-performance flame-retardant epoxy resin (EP), diglycidyl ether of (2,5-dihydroxyphenyl) diphenyl phosphine oxide (DPO-HQ-EP) was synthesized. EP/DPO-HQ-EP samples with varying phosphorus contents were prepared by curing a mixture of DPO-HQ-EP and diglycidyl ether of bisphenol A. The incorporation of DPO-HQ-EP significantly enhanced the flame retardancy of EP without compromising its glass transition temperature. The EP/DPO-HQ-EP/0.6 exhibited a limited oxygen index of 31.7% and achieved a V-0 rating in the vertical burning test. In the cone calorimeter test, due to the incorporation of DPO-HQ-EP, the peak of heat release rate and total heat release of EP/DPO-HQ-EP/0.6 decreased by 39.4% and 15.9% compared with the values for pure EP. A detailed investigation of the flame-retardant mechanism revealed that the improved flame retardancy of EP/DPO-HQ-EP samples was attributed to the release of phosphorus-containing free radicals and non-flammable gases in the gas phase, as well as the formation of a continuous and dense char layer in the condensed phase. Moreover, the dielectric constant and dielectric loss factor of EP/DPO-HQ-EP samples were lower than those of EP/0. The water absorptivity and transparency of EP were effectively preserved with the incorporation of DPO-HQ-EP. These findings highlighted the potential of EP/DPO-HQ-EP for industrial applications in an electrical field.

The rapid accumulation of plastic waste poses severe environmental challenges. Cold plasma-driven degradation offers a promising route to convert plastic waste into high-value chemicals. In this study, a single-stage plasma reactor coupling cold plasma (dielectric barrier discharge) with Hβ zeolites was developed for polyethylene degradation under relatively mild conditions, without external thermal input or participation of noble metals. The effects of zeolite pore structure and acidity toward product distribution were investigated, revealing that Hβ-25 exhibited the highest C₁–C₆ yield (76 wt %) and a space-time yield of 103.8 mmol·g_cat⁻¹·h⁻¹ compared to other zeolite catalysts during the plasma-catalytic process. Meanwhile, it was revealed that efficient pre-cracking initiated by plasma activation and the optimal structural compatibility between Hβ-zeolite pore channels and primary cracking products were the key factors enabling the selective conversion of polyethylene into C₁–C₆ hydrocarbons. Additionally, metal incorporation significantly enhanced C–H bond cleavage compared to Hβ-25 support. Especially, 10Ni/Hβ-25 exhibited the highest hydrogen yield (7.87 mmol·g_plastic⁻¹) under plasma-assisted mode, markedly surpassing its yield under thermal-cracking conditions, demonstrating the significant potential of plasma-catalytic degradation for hydrogen production from polyethylene.

Alkaline metal salt-promoted MgO sorbents are effective for CO₂ capture, but they face challenges with decreased CO₂ capture performance and powder elutriation in practical applications, arising due to the loss of pore structures and poor mechanical strength of alkaline metal salt-promoted MgO sorbent powder. Herein, granulation technology was employed to resolve the above problem. The optimized alkaline metal salt-promoted MgO sorbent pellets exhibited a CO₂ capture capacity of 11.46 mmol·g⁻¹ and a mechanical strength of 11.14 MPa. This mechanical strength was nearly three times greater than that of alkaline metal salt-promoted MgO sorbent pellets without granulation promoters. After 20 cycles, CO₂ capture capacity stabilized at 8.71 mmol·g⁻¹, while mechanical strength was maintained at 8.92 MPa. Through characterization, it was revealed that the pore structure generated by the pyrolysis of the granulation promoters notably increased the specific surface area, leading to high CO₂ capture capacity. Meanwhile, the strengthened mechanical strength of the alkaline metal salt-promoted MgO sorbent pellets was primarily due to the in situ formation of a γ-AlOOH sol-gel cluster skeleton. Thus, this study provides an effective technological pathway to enhance the performance of the alkaline metal salt-promoted MgO sorbent pellets for industrial applications.

5-Hydroxymethylfurfural (5-HMF) is a versatile platform chemical that can be derived from renewable biomass using homogeneous or heterogeneous acid catalysts. However, efficiently separating and purifying 5-HMF from reaction mixtures remains a critical challenge for its high-value conversion from renewable biomass. To address this challenge, various separation methods have been developed, including distillation, adsorption, liquid-liquid extraction, supercritical carbon dioxide extraction, and integrated separation processes. This review summarizes and discusses recent advancements in the separation and purification of 5-HMF from reaction solutions. It evaluates key parameters such as adsorption capacity, separation selectivity, recovery efficiency, and their influencing factors. The liquid-liquid extraction using biphasic solvents has proven to be a simple, cost-effective, and efficient approach. The ionic liquid extraction, deep eutectic solvent extraction, supercritical carbon dioxide extraction, and integrated separation technologies (e.g., liquid-liquid extraction combined with vacuum distillation, distillation integrated with adsorption) are discussed. This review also provides insight into the mechanisms of different separation methods, which may contribute to the development of new processes for the purification of 5-HMF. This review aims to provide a theoretical basis for the future large-scale, efficient, and economic production of high-purity 5-HMF.

The selective oxidation of ethylene glycol to glycolic acid on the Pt₄, Pt₁₃, Pt₃₈, and Pt₅₅ clusters was investigated by using density-functional theory calculations. The calculated results imply that glycolic acid is preferentially generated through the dehydrogenation of ethylene glycol by OH to form HOCH₂CH₂O on the Pt₄, Pt₁₃, and Pt₃₈ surfaces, but that this process occurs directly without OH participation on the Pt₅₅ surface. The observed effect likely arises from the addition of OH, which modulates the electron density in the O atom of ethylene glycol, thereby affecting the cleavage of the O–H bond. Furthermore, the glycolic acid formation on the Pt_n clusters is limited by the β–H elimination of HOCH₂CH₂O to HOCH₂CHO, which exhibits the lowest energy barrier on the Pt₁₃ surface. It is because the d-band center of the Pt₁₃ cluster is closer to the Fermi energy than that of other clusters, which then enhances the electronic density of Pt. This facilitates the adsorption of HOCH₂CH₂O at the Pt sites and the activation of the C–H bond in HOCH₂CH₂O and therefore results in superior catalytic performance. This paper offers theoretical insights into the influence of Pt size on the selective oxidation of ethylene glycol to glycolic acid.

Graphdiyne represents an emerging nanofiller of mixed matrix membranes for high-performance alcohol recovery by pervaporation due to its unique alkyne-rich and porous framework and hydrophobicity. However, such membranes often encounter a persistent challenge of nanofiller agglomeration within the polymer matrix, which diminishes the efficacy of graphdiyne during alcohol recovery. This study proposes a multilevel dispersion strategy that synergistically combines in situ confined growth, ultrasonication, atomization, and rotational shearing throughout membrane preparation to mitigate particle aggregation. The particle agglomeration scale in the polydimethylsiloxane matrix can be effectively reduced from 660 nm of triphenylamine-based graphdiyne to about 291 nm compared to the general stirring-casting method. The mixed matrix membrane loaded with 2.5 wt % triphenylamine-based graphdiyne demonstrated a permeate flux of 2.35 kg·m⁻²·h⁻¹ alongside a separation factor of 11.31 for a 5 wt % ethanol/water solution. Compared to the stirring-casting method, these performances represent enhancements of 41% in permeate flux and 80% in separation factor. Furthermore, a 96 h-continuous pervaporation test indicated the robust stability of the membrane, underscoring the potential for industrial alcohol recovery.