Chinese Journal of Chemical Engineering最新文献

5-Hydroxymethylfurfural (5-HMF) is one of the important bio-based platform compounds, and the catalytic conversion of glucose to 5-HMF is a highly desirable approach that is receiving increasing attention. Herein, we reported the synthesis of lignin-derived carbon supported tin oxides (SnO_x/LC) catalyst via a two-step hydrothermal-pyrolytic method using wheat straw alkali lignin as a cost-effective carbon source with high carbon content. The key preparation conditions of the catalyst and its catalytic conditions for the conversion of glucose to 5-HMF were investigated, respectively. Results show that under the preparation conditions of tin tetrachloride dosage of 3.0 mmol and pyrolysis temperature of 500 °C, the optimized catalyst (3.0-SnO_x/LC-500) with a high yield of 63.4% exhibits good catalytic performance of 5-HMF yield of 50.1% and reaction selectivity of 86.0% under the optimum conditions of reaction temperature and time of 190 °C and 3 h, initial glucose concentration of 10 %(mass), 3.0-SnO_x/LC-500 dosage of 100 mg in a biphasic solvent system of volume ratio of water to tetrahydrofuran of 1:4. In addition, 3.0-SnO_x/LC-500 exerts an excellent reusability in a five-cycle experiment. Furthermore, SnO_x/LC was characterized in detail using X-ray diffraction patterns (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), ammonia temperature-programmed-desorption (NH₃-TPD), pyridine adsorption infrared spectroscopy (Py-FTIR), scanning electron microscope (SEM) and thermal gravimetric analysis (TGA). Results indicate that Brønsted acid sites and Lewis acid sites coexist on 3.0-SnO_x/LC-500, and more Sn⁴⁺, as well as a proper ratio of weak acidity to medium acidity, are conductive to its catalytic performance in glucose-to-5-HMF reaction.

A series of BiOBr@biomass carbon derived from locust leaves materials (BiOBr@BC) were fabricated and the photocatalytic property was investigated for photocatalytic degradation of rhodamine B (RhB) under visible light. The morphology, structure and photoelectrochemical properties of the photocatalysts were characterized by means of SEM, TEM, XRD, XPS, FT-IR, BET, PL, UV–vis/DRS, and EIS techniques. The results showed that the introduction of BC significantly enhanced the photocatalytic activity. When the content of biomass carbon (BC) in a composite is 3% (based on the mass of BiOBr), the obtained BiOBr@BC-3 exhibits excellent photocatalytic activity, degrading 99% of RhB within 20 min. The excellent degradation efficiency after the introduction of BC can be attributed to the enhanced visible light absorption, narrower band gap, and fast electron-hole pair separation rate. The photocatalytic mechanism on the degradation of RhB was illustrated based on the radicals' trapping experiments and semiconductor energy band position. The proposed material is expected to be of significant application value in the field of wastewater treatment.

The characterization of a particle ensemble (rather than a single particle) is of paramount significance to various particle technologies and has long been a fundamental subject in the fluidization realm. However, many of such bulk characterizations as loosely-packed density (ρ_bl), minimum fluidization velocity (U_mf), sphericity (φ), discharge rate through orifice (q), angle of repose (β), and segregation index (S), were found to be poorly reproducible, making the reported results seldom comparable. Since these bulk characterizations started from the packed state of particles, such poor reproducibility was ascribed to the polymorphism of packed particles in this work. We observed that in the fluidized bed, the settled/packed state of particles varied monotonously with the settling rate (α) from complete fluidization to zero. This phenomenon confirmed the polymorphic characteristic of packed particles and further enabled us to systematically disclose/clarify its influences on the aforementioned bulk characterizations. Such influences could be comprehensively and intuitively reflected by the impacts induced by α. With the decrease of α, ρ_bl, φ and q first increased, then decreased, and finally leveled off while U_mf and β showed an opposite trend. On the other hand, S first increased and then remained invariant. As per these findings and definitions of these bulk characterizations, benchmarks were indicated to unify the selection of settled state among future scholars and further make their outcomes become fairly comparable. Additionally, most packed states of the particle ensemble were proved to be metastable with their formation and behavior being identical to those of the amorphous state.

The highly selective hydrogenation of 5-hydroxymethylfurfural to 2,5-dihydroxymethylfuran is an important reaction in the field of biomass hydrogenation, because it is a bridge between biomass resources and chemical industry. Here, we precisely constructed carbon nitride supported Pd-based catalysts by a simple impregnation-reduction method. By changing the reduction temperature, catalysts with different oxidation state could be precisely constructed. Moreover, the important correlation between the ratio of Pd⁰/Pd²⁺ and catalytic activity is revealed during the selective hydrogenation of HMF. The Pd/g–C₃N₄–300 catalyst with a Pd⁰/Pd²⁺ ratio of 3/2 showed the highest catalytic activity, which could get 96.9% 5-hydroxymethylfurfural conversion and 90.3% 2,5-dihydroxymethylfuran selectivity. Further density functional theory calculation revealed that the synergistic effect between Pd⁰ and Pd²⁺ in Pd/g–C₃N₄–300 system could boost the adsorption of the substrate and the dissociation of hydrogen. In this work, we highlight the important correlation between metal oxidation state and catalytic activity, which provides valuable insights for the rational design of precious metal catalysts for hydrogenation reactions.

Small-molecule drugs are essential for maintaining human health. The objective of this study is to identify a molecule that can inhibit the Factor Xa protein and be easily procured. An optimization-based de novo drug design framework, DrugCAMD, that integrates a deep learning model with a mixed-integer nonlinear programming model is used for designing drug candidates. Within this framework, a virtual chemical library is specifically tailored to inhibit Factor Xa. To further filter and narrow down the lead compounds from the designed compounds, comprehensive approaches involving molecular docking, binding pose metadynamics (BPMD), binding free energy calculations, and enzyme activity inhibition analysis are utilized. To maximize efficiency in terms of time and resources, molecules for in vitro activity testing are initially selected from commercially available portions of customized virtual chemical libraries. In vitro studies assessing inhibitor activities have confirmed that the compound EN300-331859 shows potential Factor Xa inhibition, with an IC₅₀ value of 34.57 μmol·L⁻¹. Through in silico molecular docking and BPMD, the most plausible binding pose for the EN300-331859-Factor Xa complex are identified. The estimated binding free energy values correlate well with the results obtained from biological assays. Consequently, EN300-331859 is identified as a novel and effective sub-micromolar inhibitor of Factor Xa.

An anion exchange membrane (AEM) is generally expected to possess high ion exchange capacity (IEC), low water uptake (WU), and high mechanical strength when applied to electrodialysis desalination. Among different types of AEMs, semi-interpenetrating polymer networks (SIPNs) have been suggested for their structural superiorities, i.e., the tunable local density of ion exchange groups for IEC and the restrained leaching of hygroscopic groups by insolubility for WU. Unfortunately, the conventional SIPN AEMs still struggle to balances IEC, WU, and mechanical strength simultaneously, due to the lack of the compact crosslinking region. In this work, we proposed a novel SIPN structure of polyvinylidene difluoride/polyvinylimidazole/1,6-dibromohexane (PVDF/PVIm/DBH). On the one hand, DBH with two cationic groups of imidazole groups are introduced to enhance the ion conductivity, which is different from the conventional monofunctional modifier with only one cationic group. On the other hand, DBH has the ability to bridge with PVIm, where the mechanical strength of the resulting AEM is increased by the increase of crosslinking degree. Results show that a low WU of 38.1% to 62.6%, high IEC of 2.12–2.22 mmol·g⁻¹, and excellent tensile strength of 3.54–12.35 MPa for PVDF/PVIm/DBH membrane are achieved. This work opens a new avenue for achieving the high-quality AEMs.

Supporting sustainable green energy systems, there is a big demand gap for grid energy storage. Sodium-ion storage, especially sodium-ion batteries (SIBs), have advanced significantly and are now emerging as a feasible alternative to the lithium-ion batteries equivalent in large-scale energy storage due to their natural abundance and prospective inexpensive cost. Among various anode materials of SIBs, beneficial properties, such as outstanding stability, great abundance, and environmental friendliness, make sodium titanates (NTOs), one of the most promising anode materials for the rechargeable SIBs. Nevertheless, there are still enormous challenges in application of NTO, owing to its low intrinsic electronic conductivity and collapse of structure. The research on NTOs is still in its infancy; there are few conclusive reviews about the specific function of various modification methods. Herein, we summarize the typical strategies of optimization and analysis the fine structures and fabrication methods of NTO anodes combined with the application of in situ characterization techniques. Our work provides effective guidance for promoting the continuous development, equipping NTOs in safety-critical systems, and lays a foundation for the development of NTO-anode materials in SIBs.

The development of environmentally friendly catalysts has become a top priority for acetylene hydrochlorination. However, difficulties remain in systematic studies on the applicability of kinetic models for the industrialization of Cu-based catalysts. Therefore, a strategy involving reactor modeling, parameter estimation, and model testing is developed to evaluate the predictive ability of kinetic models. In order to search for reliable and widely applicable reaction kinetic models for Cu-based catalysts, a case study is conducted. Multiple possible kinetic models derived from the power law, adsorption mechanism, and reaction path are sifted through collecting and testing activity data from tens of Cu-based catalysts. Different optimum applicable ranges of these kinetic models are presented. According to the comparative analysis on their applications in various industrial scenarios, this research suggests that kinetic models derived from reaction path exhibits the best extrapolation ability and has the greatest potential for application in the scale-up design of reactors.