Journal Description
ChemEngineering
ChemEngineering
is an international, peer-reviewed, open access journal on the science and technology of chemical engineering, published bimonthly online by MDPI.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, ESCI (Web of Science), Inspec, CAPlus / SciFinder, and other databases.
- Journal Rank: JCR - Q2 (Engineering, Chemical) / CiteScore - Q2 (General Engineering )
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 32.8 days after submission; acceptance to publication is undertaken in 6.1 days (median values for papers published in this journal in the second half of 2024).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
Impact Factor:
2.8 (2023);
5-Year Impact Factor:
2.6 (2023)
Latest Articles
The Re-Modeling of a Polymeric Drug Delivery System Using Smart Response Surface Designs: A Sustainable Approach for the Consumption of Fewer Resources
ChemEngineering 2025, 9(3), 60; https://doi.org/10.3390/chemengineering9030060 (registering DOI) - 1 Jun 2025
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Introduction: The use of response surface designs for drug formulation is highly warranted nowadays. Such smart designs reduce the number of required experiments compared to full-factorial designs, while providing highly accurate and reliable results. Aim: This study compares the effectiveness of
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Introduction: The use of response surface designs for drug formulation is highly warranted nowadays. Such smart designs reduce the number of required experiments compared to full-factorial designs, while providing highly accurate and reliable results. Aim: This study compares the effectiveness of two of the most commonly used response surface designs—Central Composite Design (CCD) and D-optimal Design (DOD)—in modeling a polymer-based drug delivery system. The performance of the two designs was further evaluated under a challenging scenario where a central point was deliberately converted into an outlier. Methods: Both methods were assessed using ANOVA, R-squared values, and adequate precision, and were assessed through an experimental validation point. Results: Both models demonstrated statistical significance (p-value < 0.05), confirming their ability to describe the relationships between formulation variables and critical quality attributes (CQAs). CCD achieved higher R-squared and predicted R-squared values compared to DOD (0.9977 and 0.9846 vs. 0.8792 and 0.7858, respectively), rendering it as the superior approach in terms of modeling complex variables’ interactions. However, DOD proved to be more predictive as it scored a lower percentage relative error. Conclusion: The demonstrated resilience of both models, despite the introduction of an outlier, further validates their utility in real-world applications, instead of the exhaustive full-factorial design.
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Open AccessArticle
Solving a Challenge in the Tequila Industry: A New Continuous Rectification Process for Reducing Higher Alcohols and Obtaining Products Within the Official Tequila Standard
by
Héctor Flores Martínez, Isaac Guadalupe Tejeda Arandas, Mirna Estarrón Espinosa and José Daniel Padilla de la Rosa
ChemEngineering 2025, 9(3), 59; https://doi.org/10.3390/chemengineering9030059 (registering DOI) - 1 Jun 2025
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This work is the first to study the effect of residence time on the volatile composition of distilled fractions of ordinario using a horizontal continuous distiller of our own manufacture. The ordinario used in this research had a high amount of higher alcohol,
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This work is the first to study the effect of residence time on the volatile composition of distilled fractions of ordinario using a horizontal continuous distiller of our own manufacture. The ordinario used in this research had a high amount of higher alcohol, so its adequate distillation is complicated. The fractions rectified by continuous distillation were compared with those obtained by batch distillation. Five distilled fractions were collected, and their combined volume was subjected to gas chromatography (GC) analysis to determine the principal volatile compounds (furfural, aldehyde, higher alcohol, methanol, and ester contents). A variance analysis of each group of volatile compounds was conducted to evaluate the effect of residence time (2 and 4 h) in continuous distillation compared to batch distillation (4 h). Continuous rectification allowed for obtaining a distillate within the permissible limits specified by the Official Mexican Standard (NOM-006-SCFI-2012). For the continuous 2 h, continuous 4 h, and batch 4 h processes, the higher alcohols, esters, and aldehydes showed a decreasing pattern, while methanol and furfural showed an increasing pattern in relation to the fraction number. An analysis of variance showed no statistically significant differences in terms of the regulated volatile composition (higher alcohols, esters, methanol, and furfural) according to process type (continuous 2 h, continuous 4 h, and batch 4 h), except for aldehydes, which presented differences. This new continuous rectification process increases productivity while reducing the processing time by 50%, keeping the composition and volume of the heart fraction.
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Open AccessSystematic Review
Valorization of Lignocellulosic Biomass to Biofuel: A Systematic Review
by
Mbuyu Germain Ntunka, Siphesihle Mangena Khumalo, Thobeka Pearl Makhathini, Sphesihle Mtsweni, Marc Mulamba Tshibangu and Joseph Kapuku Bwapwa
ChemEngineering 2025, 9(3), 58; https://doi.org/10.3390/chemengineering9030058 - 29 May 2025
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Lignocellulosic biomass, derived from plant materials, represents a renewable alternative to fossil fuels and plays a crucial role in advancing environmental sustainability. This systematic review investigates recent developments in the conversion of lignocellulosic biomass into biofuels, with a focus on pre-treatment technologies that
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Lignocellulosic biomass, derived from plant materials, represents a renewable alternative to fossil fuels and plays a crucial role in advancing environmental sustainability. This systematic review investigates recent developments in the conversion of lignocellulosic biomass into biofuels, with a focus on pre-treatment technologies that enhance enzymatic hydrolysis, a critical step in efficient biofuel production. This review addresses two primary questions: (1) What are the most effective pre-treatment methods for enhancing enzymatic hydrolysis in lignocellulosic biomass conversion? (2) How do these pre-treatment methods compare in terms of efficiency, environmental impact, and economic feasibility? Consequently, studies were selected based on inclusion criteria that focus on research investigating these pre-treatment methods and their comparative performance. A structured search of original studies was applied across databases such as Crossref, Google Scholar, Scopus, PubMed, and Semantic Scholar, resulting in the inclusion of 17 peer-reviewed articles published between 2019 and 2024. The findings highlight effective pre-treatment methods that significantly improve enzymatic accessibility and bioethanol yields. However, ongoing challenges such as feedstock variability, process efficiency, and cost-effectiveness remain. These results highlight the need for further research and development to optimize conversion technologies and identify new areas for exploration.
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Open AccessArticle
Effect of Rotation Speed and Powder Bed Volume on Powder Flowability Measured by a Powder Rheometer: Evaluation of the Humidity Effect on Lactose Powder Flowability
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Takamasa Mori, Kanaho Sakurada and Kenta Kitamura
ChemEngineering 2025, 9(3), 57; https://doi.org/10.3390/chemengineering9030057 - 29 May 2025
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Relative humidity during storage is known to affect powder flowability, although its effect on powder flowability remains unclear. Various techniques have been used to evaluate powder flowability, including measurement of the rotational torque of the powder bed, which is a novel method. However,
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Relative humidity during storage is known to affect powder flowability, although its effect on powder flowability remains unclear. Various techniques have been used to evaluate powder flowability, including measurement of the rotational torque of the powder bed, which is a novel method. However, studies investigating the effect of relative humidity on powder flowability using rotational torque measurements are limited. Therefore, this study aimed to examine the influence of relative humidity during storage on the flowability of lactose powder through rotational torque measurement of the powder bed using an Anton Paar powder rheometer. Rotation speed had a minimal effect, except when the powder was stored at a high relative humidity of 99%. The effect of relative humidity was more pronounced at a smaller powder volume (30 mL) than that at the other volumes tested. Of the techniques employed, including the angle of repose and bulk density measurements, the rotational torque measurement of the powder rheometer exhibited the highest sensitivity to variations in relative humidity. It was also found that the measured rotation torque hardly changed when the rotation speed was below a critical value, indicating that the optimal rotation speed exists to measure the representative rotation torque of each powder.
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Open AccessReview
Liposome-Based Drug Delivery Systems: From Laboratory Research to Industrial Production—Instruments and Challenges
by
Suman Basak and Tushar Kanti Das
ChemEngineering 2025, 9(3), 56; https://doi.org/10.3390/chemengineering9030056 - 27 May 2025
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Liposome-based drug delivery systems have revolutionized modern pharmaceutics, offering unparalleled versatility and precision in therapeutic delivery. These lipid vesicles, capable of encapsulating hydrophilic, hydrophobic, and amphiphilic drugs, have demonstrated significant potential in addressing pharmacokinetic challenges such as poor solubility, systemic toxicity, and rapid
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Liposome-based drug delivery systems have revolutionized modern pharmaceutics, offering unparalleled versatility and precision in therapeutic delivery. These lipid vesicles, capable of encapsulating hydrophilic, hydrophobic, and amphiphilic drugs, have demonstrated significant potential in addressing pharmacokinetic challenges such as poor solubility, systemic toxicity, and rapid clearance. This review provides a comprehensive exploration of the evolution of liposomes from laboratory models to clinically approved therapeutics, highlighting their structural adaptability, functional tunability, and transformative impact on modern medicine. We discuss pivotal laboratory-scale preparation techniques, including thin-film hydration, ethanol injection, and reverse-phase evaporation, along with their inherent advantages and limitations. The challenges of transitioning to industrial-scale production are examined, with emphasis on achieving batch-to-batch consistency, scalability, regulatory compliance, and cost-effectiveness. Innovative strategies, such as the incorporation of microfluidic systems and advanced process optimization, are explored to address these hurdles. The clinical success of Food and Drug Administration (FDA)-approved liposomal formulations such as Doxil® and AmBisome® underscores their efficacy in treating conditions ranging from cancer to fungal infections. Furthermore, this review delves into emerging trends, including stimuli-responsive and hybrid liposomes, as well as their integration with nanotechnology for enhanced therapeutic precision. As liposomes continue to expand their role in gene therapy, theranostics, and personalized medicine, this review highlights their potential to redefine pharmaceutical applications. Despite existing challenges, ongoing advancements in formulation techniques and scalability underscore the bright future of liposome-based therapeutics in addressing unmet medical needs.
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(This article belongs to the Special Issue New Trends in (Bio)chemical Engineering: Biobased Pharmaceutical Processes)
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Open AccessArticle
Electrification of Compressor in Steam Cracker Plant: A Path to Reduced Emissions and Optimized Energy Integration
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Joana Cordeiro Torcato, Rodrigo Silva and Mário Eusébio
ChemEngineering 2025, 9(3), 55; https://doi.org/10.3390/chemengineering9030055 - 27 May 2025
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Electrification is a highly effective decarbonization and environmental incentive strategy for the chemical industry. Nevertheless, it may lead to downstream challenges in the process. This study analyzes the consequences of electrifying compressors within the steam cracker (SC) condensate system, focusing on the reduction
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Electrification is a highly effective decarbonization and environmental incentive strategy for the chemical industry. Nevertheless, it may lead to downstream challenges in the process. This study analyzes the consequences of electrifying compressors within the steam cracker (SC) condensate system, focusing on the reduction in greenhouse gas (GHG) emissions and energy consumption without compromising the process’s energy efficiency. The aim is to study the impact that the reduction in steam expanded by turbines has on boiler feedwater (BFW) temperature and, subsequently, the behavior it triggers in fuel gas (FG) consumption and carbon dioxide (CO2) emissions in furnaces. It was concluded that condensate imports from the Energies and Utilities Plant (E&U) would increase by a factor of four, with approximately 60% of the imported condensate being cold condensate. The study revealed a mitigation of CO2 emissions, resulting in a 1.3% reduction and a reduction in FG consumption of 1.8% preventing an increase in site energy consumption by 795.4 kW in furnaces. Condenser optimization reduces CO2 emissions by 60%. Energy integration with quench water resulted in heat saving of 1824 kW in hot utility consumption and generating annual savings of EUR 2.3 M. The global carbon dioxide balance can achieve up to a 25% reduction.
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Open AccessArticle
From Conjugation to Detection: Development of Lateral Flow Assay for Zearalenone
by
Vinayak Sharma, Bilal Javed, Hugh J. Byrne and Furong Tian
ChemEngineering 2025, 9(3), 54; https://doi.org/10.3390/chemengineering9030054 - 26 May 2025
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The development of rapid, sensitive and cost-effective lateral flow assays is crucial for the detection of mycotoxins, ideally at the point-of-care level. This study presents the design and optimization of a competitive lateral flow assay based on gold nanoparticles (AuNPs) for the detection
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The development of rapid, sensitive and cost-effective lateral flow assays is crucial for the detection of mycotoxins, ideally at the point-of-care level. This study presents the design and optimization of a competitive lateral flow assay based on gold nanoparticles (AuNPs) for the detection of zearalenone in food samples. Beginning with the synthesis and functionalization of gold nanoparticles, it proceeds to compare the immobilization of antibodies using chemical conjugation and physical adsorption binding strategies, upon optimizing parameters including the pH, antibody concentration and blocking conditions to enhance the stability of the prepared bioconjugates. The bioconjugates are characterized using UV–visible absorption spectroscopy and dynamic light scattering to monitor changes in the spectra and hydrodynamic size of AuNPs upon the addition of antibodies. The assessment of these bioconjugates is based on their ability to bind and manifest a color, developed due to nanoparticle binding with the test zone on the strip with the toxin–protein conjugate. The lateral flow immunochromatographic assay (LFIA) strips are then prepared by dispensing a control line (IgG) and test line (toxin–protein conjugate) on a nitrocellulose membrane using a lateral flow strip dispenser. The sensitivity of the LFIA strips is evaluated after standardizing the conditions by varying the concentration of zearalenone in the spiked samples and optimizing the running buffer solution. The limit of detection and limit of quantification under optimized conditions are determined to be 0.7 ng/mL and 2.37 ng for zearalenone-spiked samples. Furthermore, the mean pixel intensity and RGB values are plotted against the concentration of zearalenone, which can be used in a colorimetric smartphone-based application for the quantification of the amount of mycotoxin in the sample.
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Open AccessArticle
An Upgraded FOS/TAC Titration Model Integrating Phosphate Effects for Accurate Assessments of Volatile Fatty Acids and Alkalinity in Anaerobic Media
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Xiaojun Liu, André Pauss, Laura André and Thierry Ribeiro
ChemEngineering 2025, 9(3), 53; https://doi.org/10.3390/chemengineering9030053 - 22 May 2025
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The accurate determination of volatile fatty acids (VFAs) and total alkalinity (TAC, mostly carried by bicarbonate ions) is critical for operating anaerobic digesters. The FOS/TAC titration method developed by Nordmann is widely used due to its simplicity and affordability. This method has known
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The accurate determination of volatile fatty acids (VFAs) and total alkalinity (TAC, mostly carried by bicarbonate ions) is critical for operating anaerobic digesters. The FOS/TAC titration method developed by Nordmann is widely used due to its simplicity and affordability. This method has known limitations in dosing VFAs and TAC, since the presence of one interferes with the determination of the other, especially at higher VFA or bicarbonate concentrations. This study builds upon our prior research in 2021 by integrating the influence of phosphate (H2PO4−/HPO42−) into numerical models correcting FOS/TAC titration results. A Scilab-based program was used to assess the impact of phosphate on titration results, revealing significant biases at lower concentrations. A revised multivariate regression formula was developed, incorporating phosphate effects, and demonstrating superior accuracy. The mean absolute percentage errors (MAPE) for TAC and VFA estimation were reduced to less than 0.3%. The model maintains compatibility with standard Nordmann’s titration protocols and equipment while significantly improving reliability. These findings highlight the necessity of considering phosphate interference in FOS/TAC titration, particularly in AD systems with variable buffering conditions. The proposed correction model enhances process monitoring and control, providing a more robust tool for both research and industrial practice in anaerobic digestion.
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Open AccessArticle
Robust Enhanced Auto-Tuning of PID Controllers for Optimal Quality Control of Cement Raw Mix via Neural Networks
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Dimitris Tsamatsoulis
ChemEngineering 2025, 9(3), 52; https://doi.org/10.3390/chemengineering9030052 - 20 May 2025
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Ensuring efficient long-term quality control of the raw mix remains a priority for the cement industry, supporting initiatives to lower the CO2 footprint by incorporating significant amounts of alternative fuels and raw materials in clinker production. This study presents an effective method
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Ensuring efficient long-term quality control of the raw mix remains a priority for the cement industry, supporting initiatives to lower the CO2 footprint by incorporating significant amounts of alternative fuels and raw materials in clinker production. This study presents an effective method for creating a robust auto-tuner for proportional–integral–differential (PID) controller control of the lime saturation factor (LSF) of the raw mix using artificial neural networks (ANNs). This auto-tuner, combined with a previously studied robust PID controller, forms an integrated system that adapts to process changes and maintains low long-term variance in LSF. The ANN links each of the three PID gains to the process dynamic parameters, with the three ANNs also interconnected. We employed the Levenberg–Marquardt method to optimize the ANNs’ synaptic weights and applied the weight decay method to prevent overfitting. The industrial implementation of our control system, using the auto-tuner for 16,800 h of raw mill operation, shows an average LSF standard deviation of 2.5, with fewer than 10% of the datasets exceeding a standard deviation of 3.5. Considering that the measurement reproducibility is 1.44 and assuming a low mixing ratio of the raw meal in the silo equal to 2, the LSF standard deviation in the kiln feed approaches the analysis reproducibility, indicating that disturbances in the raw meal largely diminish in the kiln feed. In conclusion, integrating traditional, well-established tools like PID controllers with newer advanced techniques, such as ANNs, can yield innovative solutions.
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Open AccessArticle
Waste-to-Energy Potential of Petroleum Refinery Sludge, Statistical Optimization, Machine Learning, and Life Cycle Costs Models
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Seyyed Roohollah Masoomi, Mohammad Gheibi, Reza Moezzi, Kourosh Behzadian, Atiyeh Ardakanian, Farzad Piadeh and Andres Annuk
ChemEngineering 2025, 9(3), 51; https://doi.org/10.3390/chemengineering9030051 - 16 May 2025
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Sludge management in petroleum refineries is a costly and complex challenge, posing environmental risks and health hazards for humans. This study explores sludge incineration as a viable energy recovery method, using a case study from an Iranian refinery. Analysis of 15 sludge samples
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Sludge management in petroleum refineries is a costly and complex challenge, posing environmental risks and health hazards for humans. This study explores sludge incineration as a viable energy recovery method, using a case study from an Iranian refinery. Analysis of 15 sludge samples via bomb calorimetry revealed an average heat value of 3100 kcal/kg, which declines with increased moisture content, while higher chemical oxygen demand (COD) enhances energy yield. Over five years, 4000 tonnes of accumulated sludge presented an energy potential of 12,400 Gcal. Statistical modeling, including polynomial regression and response surface methodology (RSM), mapped sludge storage profiles and predicted calorific values based on COD and moisture variations. The results indicate anaerobic digestion at greater depths reduces organic matter, lowering energy potential. Differential scanning calorimetry (DSC) analysis confirmed key thermal transitions, supporting sludge incineration as an effective waste-to-energy strategy. Implementing this approach within a circular economy framework can optimize refinery waste management while reducing pollution, though proper combustion byproduct control is essential for sustainability and regulatory compliance.
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(This article belongs to the Special Issue Innovative Approaches for the Environmental Chemical Engineering)
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Open AccessArticle
Decoloration of Waste Cooking Oil by Maghnia Algerian Clays via Ion Exchange and Surface Adsorption
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Abdelhak Serouri, Zoubida Taleb, Alberto Mannu, Chahineze Nawel Kedir, Cherifa Hakima Memou, Sebastiano Garroni, Andrea Mele, Oussama Zinai and Safia Taleb
ChemEngineering 2025, 9(3), 50; https://doi.org/10.3390/chemengineering9030050 - 16 May 2025
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The purification of waste cooking oils (WCOs) through clay-based adsorption is an established recycling method, yet the relationship between clay composition and adsorption efficiency remains an area of active research. The aim of the present research work was to assess the performance of
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The purification of waste cooking oils (WCOs) through clay-based adsorption is an established recycling method, yet the relationship between clay composition and adsorption efficiency remains an area of active research. The aim of the present research work was to assess the performance of Maghnia bentonite in WCO decoloration and to gain information about the specific refining process. Thus, natural bentonite from the Maghnia region (Algeria) was investigated as an adsorbent for WCO refining for biolubricant production. The adsorption efficiency was evaluated under different conditions, achieving up to 70% decolorization at 10 wt% clay after 4 h of treatment. Structural characterization of the bentonite before and after adsorption was conducted using FT-IR spectroscopy, powder X-ray diffraction (XRD), and X-ray fluorescence (XRF) to assess compositional and morphological changes. FT-IR analysis confirmed the adsorption of organic compounds, XRD indicated minor alterations in interlayer spacing, and XRF revealed ion exchange mechanisms, including a reduction in sodium and magnesium and an increase in calcium and potassium. Adsorption kinetics followed a pseudo-second-order model, with desorption effects observed at prolonged contact times. The pHPZC of 8.3 suggested that bentonite adsorption efficiency is enhanced under acidic conditions. The high decoloration capacity of Maghnia bentonite, combined with the availability and the low cost of the material, suggests a possible industrial application of this material for WCO refinement, especially in lubricant production.
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Open AccessArticle
CFD Simulation and Design of Non-Newtonian Fluid Polymer Grinding Pump Under Turbulent Flow
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Hong Du, Chenxi Wang, Jian Zhang, Xianjie Li, Xiujun Wang, Xuecheng Zheng and Xin He
ChemEngineering 2025, 9(3), 49; https://doi.org/10.3390/chemengineering9030049 - 8 May 2025
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The performance of the grinding pump, a device for crushing and stretching conventional polymers, is mainly affected by its stage number, diameter, and tooth count. In this paper, Fluent software was utilized, employing the Eulerian model in conjunction with non-Newtonian fluid models (such
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The performance of the grinding pump, a device for crushing and stretching conventional polymers, is mainly affected by its stage number, diameter, and tooth count. In this paper, Fluent software was utilized, employing the Eulerian model in conjunction with non-Newtonian fluid models (such as the power-law model and Bingham plastic model) and turbulence models (like the k-ε model) to establish a model for CFD (Computational Fluid Dynamics) simulations. These simulations analyzed the turbulence characteristics of non-Newtonian fluids in grinding mixing pumps, as well as the basic performance of the pumps, including pressure, velocity, viscosity, and volume fraction distributions. The effects of different structural parameters (stage number, pump diameter, and tooth count) on the instant dissolving effect of polymers were compared, and the optimal structure was determined. Based on pressure profile, velocity profile analysis, and polymer distribution simulation results, the optimal grinding mixing pump was found to have three stages, with a diameter of d = 140 mm and 60 teeth yielding the best grinding effect. Increasing the stage number and pump diameter can improve the grinding and mixing effect, but an excessively large pump diameter can reduce it. Changes in tooth count have a minor impact on viscosity but affect distribution uniformity.
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Open AccessArticle
Influence of Substrate Concentrations on the Performance of Fed-Batch and Perfusion Bioreactors: Insights from Mathematical Modelling
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John J. Fitzpatrick, Fionn O'Leary, Ali Hill, James Daly, Fergal Lalor and Edmond P. Byrne
ChemEngineering 2025, 9(3), 48; https://doi.org/10.3390/chemengineering9030048 - 6 May 2025
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Fed-batch and perfusion bioreactors are commonly used in biopharmaceutical production. This study applies mathematical models to investigate the influence of substrate concentration in the media added ( ), operating substrate concentration in the bioreactor ( ), and bioreaction time on
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Fed-batch and perfusion bioreactors are commonly used in biopharmaceutical production. This study applies mathematical models to investigate the influence of substrate concentration in the media added ( ), operating substrate concentration in the bioreactor ( ), and bioreaction time on the performance of both bioreactors. The performance parameters are titer, productivity, product yield, wasted substrate, and mean product residence time. The difference between the substrate concentration in the media and the operating substrate concentration has a major impact on performance parameters. For a fixed , operating at higher values of is more beneficial to both fed-batch and perfusion performance. Higher productivities are obtained in perfusion, and mean product residence times are shorter. Furthermore, perfusion can obtain titers comparable to fed-batch when operated at similar substrate concentrations. All this suggests that perfusion is more advantageous. It is advantageous to operate the bioreactors over a longer bioreaction time. However, for fed-batch bioreactors, there exists an optimal time after which there is a major progressive reduction in productivity.
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Open AccessArticle
Steady-State Simulation of a Fixed-Bed Reactor for the Total Oxidation of Volatile Organic Components: Application of the Barkelew Criterion
by
Philippe M. Heynderickx and Joris W. Thybaut
ChemEngineering 2025, 9(3), 46; https://doi.org/10.3390/chemengineering9030046 - 30 Apr 2025
Abstract
A steady-state tubular reactor for total oxidation reaction under typical industrial conditions in the removal of volatile organic components (VOC) is described using a one-dimensional heterogeneous reactor model with intraparticle diffusion, using a fully developed Langmuir–Hinshelwood reaction rate expression. The effectiveness factor, accounting
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A steady-state tubular reactor for total oxidation reaction under typical industrial conditions in the removal of volatile organic components (VOC) is described using a one-dimensional heterogeneous reactor model with intraparticle diffusion, using a fully developed Langmuir–Hinshelwood reaction rate expression. The effectiveness factor, accounting for these intraparticle diffusion limitations, is calculated with a generalized Thiele modulus. The actual inclusion of this factor shows that higher operational reactor temperatures can be possible, since this diffusion limitation restricts the heat production inside the catalyst particle. Special attention is given to the outlet concentration of propane, taken as the model VOC, and runaway criteria, reported in the literature, are evaluated. Furthermore, the well-known Barkelew criterion (to evaluate runaway for exothermic reactions) is implemented for practical and safe reactor design. This work identifies that the critical couples populating the Barkelew diagram are positioned lower (up to a 50% difference, compared to Barkelew’s original report), so that operation of the reactor under higher hydrocarbon molar inlet fractions is possible while maintaining safe performance.
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(This article belongs to the Special Issue Advances in Catalytic Kinetics)
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Open AccessArticle
Microwave-Mediated Extraction of Critical Metals from LED E-Waste
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Athanasios B. Bourlinos, Christina Papachristodoulou, Anastasios Markou, Nikolaos Chalmpes, Emmanuel P. Giannelis, Dimitrios P. Gournis, Constantinos E. Salmas and Michael A. Karakassides
ChemEngineering 2025, 9(3), 47; https://doi.org/10.3390/chemengineering9030047 - 29 Apr 2025
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This study introduces a microwave-assisted technique for extracting critical minerals from LED electronic waste. The process begins with microwave irradiation, which thermally decomposes the LED’s plastic lens into a brittle, charred residue. During this stage, the LED chip undergoes deflagration—being rapidly ejected from
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This study introduces a microwave-assisted technique for extracting critical minerals from LED electronic waste. The process begins with microwave irradiation, which thermally decomposes the LED’s plastic lens into a brittle, charred residue. During this stage, the LED chip undergoes deflagration—being rapidly ejected from the reflective cavity and becoming embedded within the decomposed lens material. Consequently, the chip is encapsulated in the resulting charred residue. This composite, consisting of the charred lens and the LED chip, can be easily separated from the metallic pins (Fe, Ni, Ag), which remain almost undamaged. Subsequent calcination of the charred material in air exposes the materials making up the LED chip, which contain critical metals (e.g., Ga, As, In, Y, Au). These metals are then extracted through a two-step acid leaching process involving aqua regia followed by hot concentrated hydrochloric acid, yielding them in potentially recoverable forms. The synergistic effect of microwave irradiation and acid treatment achieves an average extraction efficiency of 96% for critical metals. Notably, this approach enables complete and loss-free recovery of the LED chip, offering a practical and efficient solution for LED e-waste recycling.
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Open AccessArticle
Quality Management in Chemical Processes Through Fuzzy Analysis: A Fuzzy C-Means and Predictive Models Approach
by
Gabriel Marín Díaz
ChemEngineering 2025, 9(3), 45; https://doi.org/10.3390/chemengineering9030045 - 28 Apr 2025
Abstract
Ensuring high levels of quality and efficiency is essential for compliance with ISO standards in chemical manufacturing. Traditional methods, such as Statistical Process Control (SPC) and Six Sigma, often lack adaptability and fail to offer interpretable insights. This study proposes a hybrid quality
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Ensuring high levels of quality and efficiency is essential for compliance with ISO standards in chemical manufacturing. Traditional methods, such as Statistical Process Control (SPC) and Six Sigma, often lack adaptability and fail to offer interpretable insights. This study proposes a hybrid quality control model based on Explainable Artificial Intelligence (XAI), integrating fuzzy C-means clustering (FCM), machine learning (ML), and Fuzzy Inference Systems (FISs) to enhance defect prediction and interpretability in industrial environments. The approach uses fuzzy clusters to segment production batches, improving the understanding of process variability. A supervised ML model (XGBoost) is trained on historical data to predict defect probabilities, while an explainable FIS refines the final assessment using expert-defined rules. XAI techniques (SHAP and LIME) offer transparency and insight into the decision-making process. Experimental validation using a real-world white wine dataset, evaluated in terms of accuracy and interpretability, shows that the proposed model outperforms traditional approaches in both predictive performance and transparency. The results demonstrate the effectiveness of combining unsupervised clustering, predictive analytics, and fuzzy reasoning in an Industry 4.0 framework. This study provides a scalable and adaptable solution for real-time quality control in chemical manufacturing, improving decision support systems and enabling automated and explainable quality assessments.
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(This article belongs to the Special Issue New Advances in Chemical Engineering)
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Open AccessArticle
Lagrangian for Real Systems Instead of Entropy for Ideal Isolated Systems
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Nikolai M. Kocherginsky
ChemEngineering 2025, 9(3), 44; https://doi.org/10.3390/chemengineering9030044 - 24 Apr 2025
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The Second Law of Thermodynamics states that entropy S increases in a spontaneous process in an ideal isothermal and isolated system. Real systems are influenced by external forces and fields, including the temperature field. In this case, only entropy is not enough, and
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The Second Law of Thermodynamics states that entropy S increases in a spontaneous process in an ideal isothermal and isolated system. Real systems are influenced by external forces and fields, including the temperature field. In this case, only entropy is not enough, and we suggest using a new function, , which is analogous to the Lagrangian in classical mechanics. It includes total potential energy but instead of mechanical kinetic energy, includes the product ST, and the system always evolves towards increasing this modified Lagrangian. It reaches an equilibrium when total potential force is balanced by both entropic and thermal forces. All forces have the same units, Newton/mol, and may be added or subtracted. For condensed systems with friction forces, it is a molecular transport velocity, and not acceleration, which is proportional to the acting force. Our approach has several advantages compared to Onsager’s non-equilibrium thermodynamics with its thermodynamic forces, which may have different units, including 1/T for energy transport. For isolated systems, the description is reduced to Second Law and Clausius inequality. It easily explains diffusion, Dufour effect, and Soret thermodiffusion. The combination of electric, thermal, and entropic forces explains thermoelectric phenomena, including Peltier–Seebeck and Thomson (Lord Kelvin) effects. Gravitational and entropic forces together inside a black hole may lead to a steady state or the black hole evaporation. They are also involved in and influenced by solar atmospheric processes.
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Open AccessArticle
CrS2 Supported Transition Metal Single Atoms as Efficient Bifunctional Electrocatalysts: A Density Functional Theory Study
by
Ying Wang
ChemEngineering 2025, 9(3), 43; https://doi.org/10.3390/chemengineering9030043 - 23 Apr 2025
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Transition metal dichalcogenides (TMDs) are recognized for their exceptional energy storage capabilities and electrochemical potential, stemming from their unique electronic structures and physicochemical properties. In this study, we focus on chromium disulfide (CrS2) as the primary research subject and employ a
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Transition metal dichalcogenides (TMDs) are recognized for their exceptional energy storage capabilities and electrochemical potential, stemming from their unique electronic structures and physicochemical properties. In this study, we focus on chromium disulfide (CrS2) as the primary research subject and employ a combination of density functional theory (DFT) and first-principle calculations to investigate the effects of incorporating transition metal elements onto the surface of CrS2. This approach aims to develop a class of bifunctional single-atom catalysts with high efficiency and to analyze their catalytic performance in detail. Theoretical calculations reveal that the Au@CrS2 single-atom catalyst demonstrates outstanding catalytic activity, with a low overpotential of 0.34 V for the oxygen evolution reaction (OER) and 0.37 V for the oxygen reduction reaction (ORR). These results establish Au@CrS2 as a highly effective bifunctional catalyst. Moreover, the catalytic performance of Au@CrS2 surpasses that of traditional commercial catalysts, such as Pt (0.45 V) and IrO2 (0.56 V), suggesting its potential to replace these materials in fuel cells and other energy applications. This study provides a novel approach to the design and development of advanced transition metal-based catalytic materials.
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Open AccessArticle
Silver-Based Catalysts on Metal Oxides for Diesel Particulate Matter Oxidation: Insights from In Situ DRIFTS
by
Punya Promhuad, Boonlue Sawatmongkhon, Thawatchai Wongchang, Ekarong Sukjit, Nathinee Theinnoi and Kampanart Theinnoi
ChemEngineering 2025, 9(3), 42; https://doi.org/10.3390/chemengineering9030042 - 22 Apr 2025
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Diesel particulate matter (DPM) represents a deleterious environmental contaminant that necessitates the development of effective catalytic oxidation methodologies. This research delineates a comparative analysis of silver-supported metal oxide catalysts (Ag/Al2O3, Ag/TiO2, Ag/ZnO, and Ag/CeO2), with
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Diesel particulate matter (DPM) represents a deleterious environmental contaminant that necessitates the development of effective catalytic oxidation methodologies. This research delineates a comparative analysis of silver-supported metal oxide catalysts (Ag/Al2O3, Ag/TiO2, Ag/ZnO, and Ag/CeO2), with an emphasis on the effects of silver distribution and the metal-support interaction on the oxidation of DPM. An array of characterization techniques including XRD, HRTEM, XPS, H2-TPR, TEM, GC-MS, TGA, and in situ DRIFTS was employed. The novelty of this study resides in elucidating the oxidation mechanism through a tripartite pathway and recognizing Ag0 as the predominant active species involved in soot oxidation. The Ag/Al2O3 catalyst demonstrated superior catalytic performance, achieving a reduction in the ignition temperature by more than 50 °C, attributable to the optimal dispersion of Ag nanoparticles and a balanced metal-support interaction. Conversely, an excessive interaction observed in Ag/ZnO resulted in diminished catalytic activity. The oxidation of DPM transpires through the volatilization of VOCs (<300 °C), the oxidation by reactive oxygen species, and the combustion of soot (>300 °C). This investigation offers significant contributions to the formulation of highly efficient silver-based catalysts for emissions control, with a particular focus on optimizing Ag dispersion and support interactions to enhance catalytic efficacy.
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Environmental Dispersion of Toxic Effluents from Waste Polyethylene Fires: Simulations with ALOFT
by
Giulia De Cet and Chiara Vianello
ChemEngineering 2025, 9(2), 41; https://doi.org/10.3390/chemengineering9020041 - 17 Apr 2025
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In recent years, the Italian peninsula has frequently been affected by fires in waste storage facilities, both accidental and malicious. Waste storage activities must comply with a series of regulations that require the employer to carefully assess the risks associated with the operation
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In recent years, the Italian peninsula has frequently been affected by fires in waste storage facilities, both accidental and malicious. Waste storage activities must comply with a series of regulations that require the employer to carefully assess the risks associated with the operation of the plant. All prevention and protection measures must be taken to reduce the risk of fires in order to safeguard both people and the environment. In addition, with new regulations coming into force in November 2022, efforts are being made to regulate waste treatment and storage facilities in terms of fire safety. This work presents simulations of the dispersion into the environment of toxic effluents produced during a polyethylene fire at a storage site, with the aid of dedicated software. Simulations were carried out using ALOFT, varying the parameters of the simulations (e.g., the burnt area, environmental characteristics, and toxic effluent investigated). In total, 24 simulations were carried out to investigate the emissions of particulate matter and volatile organic compounds in the case of polyethylene fires. The simulations showed that atmospheric stability class and wind speed had a significant impact on the dispersion. The proposed methodology can be applied both in the risk assessment and emergency phases and, eventually, as a valuable tool in post-accident analysis.
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