Asia-Pacific Journal of Chemical Engineering最新文献

This study proposes a hybrid cooling system design that constructs a phase change material (PCM) filled layer between a liquid cooling jacket and cylindrical battery cells, combining the advantages of efficient liquid cooling and passive temperature control from PCM. The system performance was optimized through numerical simulation. First, cooling effects and pressure drop characteristics of different channel shapes were compared. Subsequently, single-factor analysis was used to investigate the effects of PCM thickness, contact angle/height, Reynolds number (Re), and coolant initial temperature on system performance. Multi-objective optimization was conducted using orthogonal experimental design. Results show that increasing Re has limited improvement in the cooling performance. The optimal parameter combination is a PCM thickness of 4 mm, contact angle of 180°, contact height of 14 mm, and coolant initial temperature of 15°C. Compared with the initial structure, the optimized system reduces the maximum temperature by 6.44%, the maximum temperature difference by 7.34%, and the PCM liquid-phase fraction by 63%. Optimizing the coolant flow direction further controls the maximum temperature of the battery pack below 34.88°C and reduces the maximum temperature difference to 3.69°C, a 4.69°C decrease compared with the pure liquid cooling system. The liquid fraction of PCM in the optimized hybrid cooling model is as low as 23.37%, which greatly reduces the risk of leakage and can promote the development of sustainable energy storage technologies.

Coal is a natural macromolecular substance composed of complex organic molecules and a small amount of minerals. Its chemical composition and microstructure are highly complex and variable, and no unified definition exists. This inherent structural complexity underscores the theoretical significance of constructing accurate macromolecular models to elucidate the multiphase reaction mechanisms involved in gasification, pyrolysis, and combustion processes. This paper provides a systematic review of the structural features and development trends of molecular models for representative coal ranks, including lignite, bituminous coal, and sub-bituminous coal. Advanced multi-scale structural features were characterized through a combination of techniques, such as solid-state ¹³C nuclear magnetic resonance (¹³C-NMR), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) spectroscopy; this study conducts a comprehensive analysis of key structural parameters in coal, such as the aromatic condensation degree, functional group distribution, and heteroatom occurrence. Based on simulation methods, the microscopic structure, physicochemical properties, and reaction mechanisms of coal can be systematically investigated. The rationality of coal molecular modeling can be further verified by vibrational spectroscopy simulation and covalent bond concentration correction. This paper provides theoretical support for scholars in the field to understand coal properties under different conditions and to carry out model construction and validation.

The suboptimal efficiency of current biomass conversion processes necessitates the optimization of biochar production methodologies to enhance desired biochar characteristics. In this study, an investigation was conducted to determine the optimal air inlet configuration within a top-lit updraft gasifier system for enhancing biochar properties from African mesquite biomass. The conversion process, lasting 130 min, utilized three distinct carbonization chambers, each engineered with varying air inlet orifice diameters of 1 mm (PA 1), 1.5 mm (PA 1.5) and 2 mm (PA 2), to evaluate the influence of air inlet geometry on biochar production. The key findings revealed that biochar yields were 53.2% (PA 1), 49.4% (PA 1.5) and 48.1% (PA 2), demonstrating an inverse relationship between yield and orifice diameter, while Fourier-transform infrared spectroscopy (FTIR) analysis indicated that increasing the gasifier air inlet size modified the relative abundance and distribution of specific functional groups within the biochar. Additionally, enlarging the air inlet diameter led to greater surface area and pore volume in the produced biochars, and facilitated the development of a more porous and heterogeneous surface morphology. Thermal stability of biochars also improved with increasing diameter, with higher diameter-sized gasifiers generally showing optimal qualities for improving biochar properties.

This review explores recent advancements in using environmentally benign monometallic nanoparticles (MMNPs) and bimetallic nanoparticles (BMNPs) for photocatalytic water purification, addressing the urgent need for sustainable solutions to global water scarcity. This study systematically analyzes how key photocatalysis variables, including nanocatalyst concentration, dye selection, and pollutant concentration, influence dye degradation outcomes. Standardized experimental conditions utilizing UV irradiation, 10 ppm, methylene blue (MB), and green synthesis routes were employed for comparative assessment. Results indicate that BMNPs, particularly Ag-Cu BMNPs composites, consistently outperform their MMNPs, achieving degradation rates between 90% and 99%, compared to 70%–85% for MMNPs. This superior performance is attributed to synergistic effects between the constituent metals. The review further highlights the advantages of plant-based synthesis methods, which offer a safer, more economical, and stable alternative to conventional chemical methods. By critically evaluating the potential of these NPs under controlled scenarios, this work underscores the transformative potential of engineering BMNPs in advancing next-generation water treatment technologies.

Electrodialysis plays an important role in lithium extraction from brine. A two-dimensional mathematical model for steady electrolyte transport during electrodialysis desalination is constructed in this study to uncover the mechanism of lithium-ion transfer and forecast the behavior of electrodialysis. The effects of ionic charge number, ion diffusion coefficient, applied voltage, and channel flow rate on mass transfer are examined by analyzing the distributions of the lithium-ion concentration, electric potential, and flux in an electrodialysis device. Results demonstrate that an increase in the ionic charge number resulted in an increase in both the electromigration flux and the total flux. Ionic charge is the primary factor influencing ion flux. The larger the diffusion coefficient, the greater the total transfer flux and electromigration flux of Li⁺. High applied voltages and channel flow rates are beneficial for increasing the overall Li⁺ transfer flux. Furthermore, model validity is confirmed by comparing simulation results with experimental electrodialysis data. This study aims to develop a complete model for lithium recovery through electrodialysis by rationalizing and integrating previously neglected assumptions. It elucidates the sensitivity of the electrodialysis process to various parameters and provides guidelines for optimizing design, material selection, and operating conditions. Furthermore, the model can be employed to narrow the parameter range for experimental investigations of selectivity, thereby offering theoretical guidance and data references to facilitate the process optimization of electrodialysis-based lithium-ion recovery.

Large quantities of rice hulls are common at milling sites in Nigeria. They are a by-product of rice processing and can contribute to environmental degradation if not properly managed. In this study, rice hulls were pretreated by ensiling at ambient temperature and then used as substrate for medium-chain carboxylates (MCCs) production employing batch and semicontinuous approaches. Ensiling was carried out with (TRT) and without (CTR) the addition of molasses to improve the water-soluble carbohydrate content of the waste biomass. After 240 days, the study showed that ensiling significantly reduced the structural carbohydrate content of rice hulls. Batch fermentation results showed a total MCC yield of 54.69 g kg⁻¹ VS from CTR, while TRT yielded 97.79 g kg⁻¹ VS total MCCs. A kinetic evaluation showed that the modified Gompertz model predicted the production of MCCs better than the first-order model. During the semicontinuous fermentation, which lasted for 100 days, an increase in HRT from 2 to 3 days significantly improved the yield of MCCs, with the production of 93, 49.5, and 69 g kg⁻¹ VS of caproate, enanthate, and caprylate, respectively.

A novel, efficient, and eco-friendly sustainable process has been developed for the extraction of cellulose nanofibers (CNF) from durian rinds. The method utilizes low-molecular-weight 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) as an oxidation agent, in conjunction with sonication treatment, resulting in a significant reduction of processing time and energy consumption compared to conventional techniques. Various delignification methods and sonication times were investigated. For delignification, a sodium hydroxide solution (10%, w/v) at a biomass-to-solvent ratio of 1:30 resulted in the highest cellulose content of 82.07% in cellulose durian rind powder. In addition, the yield of durian rind-based CNF from sonication treatment was found to be as high as 96.26%. The CNF exhibited exceptional characteristics, including a diameter ranging from 8 to 50 nm and a length of several micrometers. This sustainable and environmentally friendly approach demonstrates significant potential for the valorization of agricultural waste into high-performance nanocellulose materials, contributing to the advancement of sustainable materials and applications.

In this work, we report the synthesis of a novel Ag-decorated V₂O₅ nanozyme with intrinsic oxidase-like activity for the colorimetric detection of Hg²⁺ ions. The Ag/V₂O₅ hollow microspheres were synthesized via a simple hydrothermal method followed by Ag nanoparticle decoration and thoroughly characterized by XRD, XPS, SEM, TEM, HRTEM, and EDX. The resulting nanozyme exhibited excellent oxidase-like catalytic activity, which was further enhanced upon interaction with Hg²⁺, enabling the oxidation of TMB (3,3′,5,5′-tetramethylbenzidine) without the need for H₂O₂. Under optimized conditions, the proposed sensor showed a linear response to Hg²⁺ concentrations in the range of 1.25–8.0 μM with a low detection limit of 0.39 μM. Mechanistic studies revealed that reactive oxygen species (superoxide radicals and singlet oxygen) played a dominant role in the oxidation process. The sensor exhibited remarkable selectivity toward Hg²⁺ over other common metal ions, along with outstanding stability. These results suggest that Ag/V₂O₅ nanozymes offer a robust nanozyme platform for the development of simple, sensitive, and stable colorimetric biosensors for the detection of toxic heavy metals in environmental and biological samples.

The aim of the current study is to investigate the CO₂ adsorption on the mesoporous silica. The adsorbent was characterized by XRD, TEM, SEM, and N2 adsorption desorption. The adsorption isotherms of carbon dioxide (CO₂) on the silica were investigated using a static volumetric method at various temperatures. The response surface methodology (RSM) was applied to the influence of different variables and their interaction on the response (CO₂ adsorption capacity) in order to obtain the optimal conditions. According to the analysis of variance, the pressure and the temperature parameters are the variables that influence the CO₂ adsorption capacity. Freundlich, Langmuir, and Langmuir–Freundlich (L-F) models were used to depict the isothermal data, and the L-F model exhibited the best correlation with the experimental isotherm. In addition, the temperature-dependent L-F model was applied to adjust the CO₂ adsorption data on the adsorbent, and the isosteric heat of CO₂ was calculated. Additionally, compared with other samples, the mesoporous silica demonstrated superior regenerability and thermal stability.

With the increasing global energy demand and the growing prominence of environmental issues, biodiesel has garnered significant attention as a renewable, low-emission green energy source. Conventional hydrotalcite-based catalysts often suffer from insufficient basicity and limited accessibility of active sites, leading to relatively long reaction times and limited efficiency. This study synthesizes Mg-Al hydrotalcites composed of various metal salts via the co-precipitation method and employs them as supports for K₂CO₃ to efficiently produce biodiesel. The transesterification performance of different Mg-Al hydrotalcite catalysts was evaluated using a three-component reaction (rapeseed oil, methanol, and methyl acetate) under conditions of an oil-ester-alcohol ratio of 1:1:10, a catalyst loading of 10 wt%, and a reaction temperature of 60°C. Results indicated that Mg-Al hydrotalcite derived from acetate metal salts using K₂CO₃ as the precipitant achieved a high biodiesel yield of 98.79% within 15 min, which is substantially faster than most reported hydrotalcite-based reactions that typically require 30–120 min under comparable conditions. TG-DTA analysis revealed that the formation of potassium aluminum oxide after high-temperature calcination, which provides more alkaline sites as suggested by CO₂-TPD profiles, is a key reason for the high catalytic activity. BET and SEM analyses showed that the catalysts possess a large specific surface area and rich pore structure, significantly enhancing the dispersion of alkaline sites. These synergistic features enable ultrafast biodiesel synthesis and provide a promising strategy for designing efficient and sustainable solid base catalysts for large-scale biofuel production.