Chinese Journal of Chemical Engineering最新文献

A synergistic solvent extraction system comprising trioctylamine (TOA) and ligands with hydroxyl and carboxyl groups can efficiently recover boric acid (H₃BO₃) and separate boron isotopes. However, the structure of ligands might impact H₃BO₃ extraction, boron isotope separation, and solvent loss, which has not been thoroughly investigated. This study initially evaluated the influence of ligand's type, pK_a, and substituents on H₃BO₃ extraction efficiency, as well as the impact of the B₍₄₎-O structure (boron is bound to four oxygen atoms) in the organic phase on isotope separation efficiency. Subsequently, by synthesizing the highly hydrophobic 2-hydroxydodecanoic acid (HYA), the extraction performance and mechanism of the TOA/HYA system were investigated. The findings highlight the superior extraction efficiency when employing di-phenolic hydroxyl, phenolic hydroxyl + carbinol hydroxyl, and alcoholic hydroxyl + carboxyl ligands compared to phenolic hydroxyl + carboxyl, phenolic hydroxyl + ethanol hydroxyl, diol hydroxyl, and dicarboxylic ligands. The organic phase anion complex, exclusively comprising the B₍₄₎-O structure, enhances isotope separation effectiveness. The TOA/HYA system achieves an 80% single-stage extraction efficiency for H₃BO₃. H₃BO₃ and HYA are extracted into the organic phase at a ratio of 1:2, with the anion complex solely containing the B₍₄₎-O structure. This study paves the way for the construction of novel boric acid extraction and boron isotope separation systems.

Graphene oxide (GO) filler containing diversified Nafion-based proton exchange membrane (PEM) is studied to know the unique physical and chemical properties and performances of PEM. Nafion-SPEEK 1%-GO 0.75% (NSG-0.75%) composite shows the highest proton conductivity of 0.327 S·cm⁻¹ at 90 °C and 100% RH (relative humidity) among all the PEM investigated. The descending order of significant proton conductivity is found as; Nafion-sPGO(1%) 0.306 S·cm⁻¹ > Nafion/ZIF-8@GO 0.280 S·cm⁻¹ > Nafion/PGO (2%) 0.277 S·cm⁻¹ > Nafion/GO-sulfur (3%) 0.232 S·cm⁻¹ > Nafion/GO-poly-SPM-co-PEGMEMA(1%) 0.229 S·cm⁻¹ > Nafion/Ce-sPGO(1%) 0.215 S·cm⁻¹. The proton conductivity, water uptake capacity and ion exchange capacity, hydration number, thermal and oxidative stability, mechanical integrity (tensile strength), maximum power, and current density are found to be increased while activation energy and fuel crossover show a decrement as GO or modified GO is incorporated in the Nafion matrix. Principal component analysis (PCA) predicted a significant correlation between the proton conductivity and the properties; the water uptake capacity, ion exchange capacity, hydration number, maximum power density, and maximum current density are 0.598%, 0.688%, 0.894%, 0.980%, and 0.852% accordingly. A multiple linear model equation of proton conductivity is defined with the parameters of water uptake capacity, ion exchange capacity, hydration number, maximum power density, and maximum current density whereas the regression coefficient is 0.9923.

Bimetallic CuCo catalysts with different Cu to Co ratios on N-doped porous carbon materials (N-C) were achieved using impregnation method and applied in the hydrogenation of furfural (FAL) to furfuryl alcohol (FOL). The high hydrogenation activity of FAL over Cu₁Co₁/N-C was originated from the synergistic interactions of Cu and Co species, where Co⁰ and Cu⁰ simultaneously adsorb and activate H₂, and Cu⁺ served as Lewis acid sites to activate CO. Meanwhile, electrons transfer from Cu to Co promoted the formation of Cu⁺. In situ Fourier transform infrared spectroscopy analysis indicated that Cu₁Co₁/N-C adsorbed FAL with a tilted η¹-(O) configuration. The superior Cu₁Co₁/N-C showed excellent adsorbed ability towards H₂ and FAL, but weak adsorption for FOL. Therefore, Cu₁Co₁/N-C possessed 93.1% FAL conversion and 99.0% FOL selectivity after 5 h reaction, which also exhibited satisfactory reusability in FAL hydrogenation for five cycles.

The concentric internally heat-integrated distillation column (HIDiC) has advantages of low energy consumption and high thermodynamic efficiency. However, its drawbacks of limited heat transfer area, complex internal structure, and large number of control parameters hinder its widespread industrial applications. To solve these challenges, in this work a novel sleeve-like concentric heat-integrated separation column, namely temperature-controlled phase change column (TCPC), was developed to separate liquid mixtures in a more effective and energy-saving way with reflux section being moved and trays being replaced with spiral corrugation blades. The comprehensive performances of TCPC in ethanol–water system was firstly evaluated by experiments. The results showed that TCPC performs well in ethanol-water separation due to the internal spiral corrugation significantly reducing the vapor–liquid contact in separation section. Meanwhile, compared to the concentric HIDiC, TCPC has a higher total heat transfer coefficient due to the larger heat transfer area. Computational fluid dynamics simulation reveals the internal design of TCPC inducing secondary vortices of the vapor, enhancing condensation heat transfer and separation efficiency. Further, increasing the mass flow rate within a certain range would enhance the comprehensive performance factor and lead to more effective separation.

Fabric multifunctionality offers resource savings and enhanced human comfort. This study innovatively integrates cooling, heating, and antimicrobial properties within a Janus fabric, surpassing previous research focused solely on cooling or heating. Different effects are achieved by applying distinct coatings to each side of the fabric. One graphene oxide (GO) coating exhibits exceptional light-to-heat conversion, absorbing and transforming light energy into heat, thereby elevating fabric temperature by 15.4 °C, 22.7 °C, and 43.7 °C under 0.2, 0.5, and 1 sun irradiation, respectively. Conversely, a hydrogel coating on one side absorbs water, facilitating heat dissipation through evaporation upon light exposure, reducing fabric temperature by 5.9 °C, 8.4 °C, and 7.1 °C in 0.2, 0.5, and 1 sun irradiation, respectively. Moreover, both sides of Janus fabric exhibit potent antimicrobial properties, ensuring fabric hygiene. This work presents a feasible solution to address crucial challenges in fabric thermal regulation, providing a smart approach for intelligent adjustment of body comfort in both summer and winter. By integrating heating and cooling capabilities along with antimicrobial properties, this study promotes sustainable development in textile techniques.

In order to find the optimal combination method of secondary utilization of fly ash and graphite-phase carbon nitride (g-C₃N₄) modification, an efficient composite photocatalyst of γ-Al₂O₃/g-C₃N₄ was obtained by calcining the composite precursors of Al(OH)₃/ dicyandiamide (DCDA). The introduction of Al(OH)₃ prepared by combining fly ash into the precursors causes hydrogen-bonding interactions between Al(OH)₃ and DCDA, which facilitate the removal of N atoms from the edges of the CN framework of g-C₃N₄ during condensation, and the composites prepared possess more cyano defects. In addition, γ-Al₂O₃ and g-C₃N₄ form a chemical bond at the interface, and this chemical bonding causes the density of the electron cloud in the vicinity of the N atoms to increase. Among them, the strongest chemical bonding between Al₂O₃ and g-C₃N₄ was observed in ACN-1, whereas the most cyanine defects were formed in ACN-1, which made ACN-1 exhibit the best photocatalytic degradation of methylene blue, which is 2.48 times higher than that of the pristine g-C₃N₄.

This study delves into the intricate deposition dynamics of submicron particles within electric-flow coupled fields, underscoring the unique challenges posed by their minuscule size, aggregation tendencies, and biological reactivity. Employing an operando investigation system that synergizes microfluidic technology with advanced micro-visualization techniques within a lab-on-a-chip framework enables a meticulous examination of the dynamic deposition phenomena. The incorporation of object detection and deep learning methodologies in image processing streamlines the automatic identification and swift extraction of crucial data, effectively tackling the complexities associated with capturing and mitigating these hazardous particles. Combined with the analysis of the growth behavior of particle chain under different applied voltages, it established that a linear relationship exists between the applied voltage and θ. And there is a negative correlation between the average particle chain length and electric field strength at the collection electrode surface (4.2×10⁵ to 1.6×10⁶ V·m^–1). The morphology of the deposited particle agglomerate at different electric field strengths is proposed: dendritic agglomerate, long chain agglomerate, and short chain agglomerate.

The rising motion of single bubble in still liquid is a natural phenomenon, which has high theoretical research significance and engineering application prospect. Experimental observations and numerical simulations for prediction of the rising trajectory of a single bubble in still liquid are being carried out, while the concise but accurate theoretical or mechanism model is still not well developed. In this article, a theoretical model of a single bubble based on experimental observation of flow around bluff body is proposed to predict the rising trajectory of zigzagging bubbles in still water. The prediction correlation of bubble lateral movement frequency and bubble steer angle are established based on three degrees of freedom frame. The model has achieved good trajectory prediction effect in the bubble rising experiment. The average simulation time per unit moving time of bubble is 2.5 s.

The isobaric energy recovery device can significantly reduce the energy consumption of the seawater reverse osmosis system by recycling the residual pressure energy of high-pressure concentrated brine. Three-cylinder valve-controlled energy recovery device (TC-ERD) solves the fluid pulsation of traditional two-cylinder devices, but the use of a “liquid piston” exacerbates the mixing between brine and seawater. Herein, the evolutionary law of “liquid piston” and the relationship between volumetric mixing degree and operating conditions are explored. The results show that the “liquid piston” first axially expands and then gradually stabilizes, isolating the brine and seawater. Additionally, as long as the volume utilization ratio (U_R) of the pressure exchange cylinder remains constant, there will not be much difference in the volumetric mixing degree after stabilization of the “liquid piston” (V_m-max) regardless of changes in the processing capacity (Q) and cycle time (T₀). Therefore, the equation for V_m-max with respect to the operating parameters (Q, T₀) is derived, which can not only predict the V_m-max of the TC-ERD, but also provide an empirical reference for the design of other valve-controlled devices with “liquid piston”. When the V_m-max is 6%, the efficiency of the TC-ERD at design conditions (30 m³·h⁻¹, 5.0 MPa) is 97.53%.

Dye pollution is a common pollutant in wastewater that poses a serious threat to human health. Layered double hydroxide (LDH) is a commonly used adsorbent for dye removal. However, its adsorption efficiency is significantly limited by the limited adsorption active sites of the adsorbent. In this paper, a defects-rich MgFe LDH adsorbent for anionic dye wastewater was synthesized by a simple hydrothermal method and alkaline etching. Different analytical techniques, such as XRD, FT-IR, SEM, TEM, XPS, and N₂ adsorption–desorption isotherm, were used to verify the chemical composition and surface characteristics of the materials, and the effects of pH, temperature, and contact time on the adsorption effect of methyl orange and the adsorption mechanism were analyzed. Alkaline etching of Al and Zn in the laminate generated defects that expose unsaturated coordination centers and create abundant adsorption sites, which can electrostatically attract and coordinate with dye ions. At 25 °C, the adsorption capacity of MgFe LDH with Al etched and MgFe LDH with Zn etched for methyl orange dye reached 1722 mg·g^–1 and 1685 mg·g^–1, respectively, much higher than that of MgFe LDH (544 mg·g^–1). This work provides a promising method for the removal of dye wastewater by adsorption and a new idea for the design and development of high-performance dye wastewater adsorbents.