Asia-Pacific Journal of Chemical Engineering最新文献

Modern chemical production processes are complex and diverse, and fault detection methods have always been an important part of complex chemical production process research. The variance and mean of the multibatch dynamic nonstationary process vary with time, which makes the dynamic canonical correlation analysis (DCCA) method deficient in calculating statistics and modeling the multibatch process. Therefore, the DCCA with multibatch benchmark distance (DCCA–MBD) for fault detection method is proposed in this paper. Based on the use of DCCA, the detection of multibatch dynamic nonstationary process is based on DCCA improved by the multibatch modeling scheme and statistic calculation method of the MBD method. Through numerical simulation and monitoring experiments of continuous stirred tank reactor production, it is verified that the method of this paper is more effective in dealing with multibatch dynamic nonstationary process compared with conventional methods.

As a functional artificial carbon material, mesophase coke has shown notable potential in various fields (particularly in energy storage and metal smelting) due to its outstanding properties. To achieve high-value utilization of mesophase coke in energy transition, 20 green cokes with distinct properties and structures were selected as raw materials and calcined to get mesophase coke. A series of properties were characterized and quantified. Meanwhile, the structure–activity relationship between optical microstructure and mesophase coke properties was established by linear fitting. In fact, mosaic and leaflet structures significantly influenced the disorder degree of mesophase coke, the former exhibiting a more pronounced effect than the latter. The total content of them showed strong correlations with micro-strength intensity and amorphous carbon content. In contrast, the fibrous structure contributed to structural regularity. The change of its content directly affected the true density and graphite microcrystal content. Moreover, fibrous and leaflet structures exhibited lower reactivity with oxygen. The combined content of them showed a negative correlation with the oxidation (combustion) reaction rate. Among these cokes, ZHC was most special. Its optical structure exhibited an extreme distribution, the mosaic structure content reached 97.1%, and OTI was only 128. It showed the highest disorder degree, which marked it as a potential hard carbon precursor. This work provides the theoretical and experimental foundations for the high-value utilization of mesophase coke.

The practical application of conventional Ti/SnO₂-Sb electrodes is hindered by their low oxygen evolution potential (OEP) and rapid deactivation. Rare earth doping has been proposed to enhance electrode stability and catalytic activity; however, the comparative effects of different rare earth elements (e.g., La vs. Eu) on both structural and electrochemical properties remain unclear. In this paper, the fabrication of lanthanum- and europium-doped Ti/SnO₂-Sb (TSS) electrodes and the electrochemical degradation of methylene blue (MB) were investigated. Although both lanthanum (La) and europium (Eu) are rare earth elements with many similarities, lanthanum (La)-modified electrode exhibits distinct performance characteristics. It is indicated that the Ti/SnO₂-Sb-La (TSSL) electrode has a comparatively better crystal phase, enhanced surface hydrophobicity, and better electrochemical performance. The TSSL electrode exhibits a higher OEP of 1.84 V than other electrodes, showing a 0.15 V increase when compared with the undoped electrode. The peak oxidation current reaches 0.82 mA/cm², which provides more active sites for the catalytic reaction. It is found that the La-doped electrode has better performance in wastewater treatment; the TSSL electrode shows a 45% increase in degradation efficiency when compared with the Ti/SnO₂-Sb-Eu (TSSE) electrode for treatment of 50 ppm MB in 25 min. Moreover, the effects of current density and the initial concentration of MB were also investigated. Considering the degradation rate and energy consumption, the optimum current density for wastewater treatment is 20 mA/cm². The outcome indicated that the degradation of MB was up to 98.5% in 25 min.

To address the technical bottleneck of low soft point pitches being difficult to fabricate high-performance hard carbon materials via conventional oxidative cross-linking methods, this study proposes a novel cross-linking strategy based on Friedel–Crafts alkylation. Medium–low temperature pitch as the precursor, a three-dimensional topological network interconnected by methylene-bridged, was successfully constructed by introducing p-xylene glycol as a cross-linker and boric acid catalytic system. The cross-linking conditions precisely control the molecular cross-linking degree of the pitch precursor, while the methylene-bridged topology substantially improves its thermal stability, resulting in a threefold increase in residual carbon yield relative to the untreated pitch. This distinctive architectural configuration critically inhibits the linear molecular alignment of pitch during carbonization, thereby facilitating the formation of an optically isotropic hard carbon material. This material exhibits a distinct structural organization featuring short-range order while maintaining long-range disorder, accompanied by significantly reduced stacking layers (R = 3.53) and notably expanded interlayer spacing (d₀₀₂ = 0.377 nm). The defect engineering arising from the self-doping effects of oxygen (originating from the pitch precursor) and boron (derived from the boric acid catalyst) during carbonization, synergistically coupled with the abundant closed-pore structures and pseudo-graphitic domains observed via HRTEM, is anticipated to collaboratively enhance the sodium-ion storage performance of the electrode material. This study provides a pioneering approach to the synthesis of optically isotropic hard carbons, and the resulting materials are expected to show significant potential for use in alkaline-ion battery anode materials.

Magnesium-based implants have garnered significant interest in orthopedic applications because of their favorable biodegradability, biocompatibility, and good mechanical strength. However, their rapid corrosion rate presents a considerable obstacle to widespread clinical adoption. This study investigates the application of a phosphate coating to pure magnesium substrates, exploring the impact of pH and hydrothermal temperature on phase composition to mitigate rapid degradation and preserve mechanical integrity. Although controlled temperature and pH in the precursor solution enabled the deposition of a uniform, dense, and defect-free magnesium phosphate coating via in situ conversion of pure magnesium, excellent corrosion resistance and minimized degradation led to vastly improved in vitro performance of these coatings on pure magnesium metal compared to the uncoated substrate.

This study investigates the development, characterisation and hydrolytic degradation of cellulose acetate and polyurethane-based bioactive food packaging wraps incorporated with spring onion leaf extract. Various ratios of wraps were formulated, and their physicochemical, mechanical, thermal and functional properties were evaluated. The incorporation of polyurethane improved the mechanical strength of the cellulose acetate matrix. At the same time, the addition of SO extracts further enhanced antioxidant and antibacterial properties because of the presence of phenolic compounds. Thermal analysis showed improved stability in composite wraps, and FTIR confirmed intermolecular bonding among components. SEM images revealed morphological compatibility, and water contact angle measurements reflected tunable surface wettability. The optimised wrap demonstrated significant free radical scavenging, high antibacterial efficacy and superior preservation performance when used for grape storage over 14 days, and it was aqueously degraded within 10 weeks. These results confirm the potential of composite wraps as sustainable, multifunctional food packaging materials that extend shelf life and enhance food safety.

The oscillation behavior of bubble plume in power-law fluids is investigated by using experimental and theoretical methods. The effects of gas phase conditions and liquid phase rheological properties on the oscillation characteristics and diffusion characteristics of bubble plume are analyzed. The results show that the amplitudes and core widths of the plume in tap water and sodium carboxymethyl cellulose (CMC) aqueous solutions both increase with the increase of the superficial gas velocity (u_g = 4.18 × 10⁻³ m·s⁻¹ ~ 1.67 × 10⁻² m·s⁻¹), and the diffusivity of tap water gradually increases from 0.011 to 0.013. The bubble clusters represent spiral oscillating upward movement in tap water and CMC aqueous solution. The oscillation period of the CMC aqueous solution is 0.9–1.39 times that of the tap water. The significant difference in liquid phase rheological properties between tap water and CMC aqueous solution significantly affects the oscillation mechanism of bubble plume. For the rheological properties, the oscillation period of plume is prolonged and the amplitude decreases; the oscillation period of plume in CMC aqueous solution is higher than that in tap water. Based on experimental characteristic parameters of the bubble plume, a mathematical model of plume oscillation period was established to predict the plume oscillation period.

Understanding the effect of inorganic cations on coal slurry conditioning is the premise of optimizing coal flotation. We studied the interaction between coal and dodecane via Materials Studio (MS) software. The difference in electrostatic potential energy was the essential factor of the different adsorption behavior of water and dodecane molecules at the coal surface. The interaction force, detachment force, and wettability of different coal types were measured using the interaction force test system. As the Ca²⁺ concentration increased, the interaction force between coal and the solution decreased while the wettability increased. The adsorption rate and contact angle of dodecane on the coal surface were measured via ultraviolet spectrophotometer. Both the adsorption rate and contact angle between coal and dodecane generally decreased as the Ca²⁺ concentration increased independently of coal type. Our results can provide valuable insight into the development of technology for coal slurry conditioning and flotation.

The present study unveils a novel approach in the facile fabrication of carbon soot-based electrodes for supercapacitor application. We utilize castor oil as a precursor material, a unique choice that has not been explored in this context. The soot derived from castor oil, with a major carbon composition of 95.5%, has a specific surface area of 114.99 m² g⁻¹. This work delves into the structural characteristics and electrochemical performance of the castor oil-derived soot-based electrodes for supercapacitors. The carbon soot electrode-based symmetric electric double-layer capacitor exhibits a specific capacitance of 50 F g⁻¹ at 0.5 A g⁻¹, with a remarkable capacitance retention of 95% and a columbic efficiency of 97% over 2000 cycles with excellent cyclic stability. It also has a high energy density of 4.44 W h kg⁻¹ at a power density of 400 W kg⁻¹. This study not only sheds light on the viability of castor oil-derived soot as a cost-efficient and sustainable material for supercapacitor technology but also introduces a new perspective by examining the effect of soot on the device's capacitance, charge–discharge properties, and overall efficiency.

Process intensification is essential for developing sustainable, efficient, and cost-effective processes in chemical and biological industries. Ultrasound, with its energy-saving, environmentally friendly, and safe characteristics, offers great promise in this regard. Ultrasound induces acoustic cavitation, leading to effects such as acoustic streaming and enhanced mixing, which can improve yields in various bioprocesses. The present study focuses on intensifying the fermentative production of erythromycin (EMC) using low-frequency ultrasound. Saccharopolyspora erythreae, the only known EMC-producing microorganism, offers limited nutrient flow due to its clumsy morphology, restricting EMC production. Controlled ultrasound treatment was applied during fermentation to improve the microorganism's morphological traits and enhance EMC yield. Optimized ultrasound (US) parameters were established using the one-factor-at-a-time (OFAT) methodology as 100 W power, 44 kHz frequency, 20% duty cycle, and 15 min treatment period. Under these conditions, EMC production increased significantly, achieving a 73.47% improvement over non-sonicated fermentation, with EMC yield rising from 0.49 to 0.85 g/L. The work clearly elucidated the process intensification benefits obtained by using ultrasound and also the need for detailed optimization of the operating conditions.