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ChemEngineering
Volume 9
Issue 4
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ChemEngineering, Volume 9, Issue 4 (August 2025) – 28 articles

Cover Story (view full-size image): White-light-emitting diodes (wLEDs) typically rely on critical raw materials (CRMs), raising sustainability and supply concerns. In this study, we introduce a simple and low-cost method to produce photoluminescent nanostructures—oxidative debris (OD)—via alkaline treatment of graphene oxide (GO) with KOH solutions ranging from 0.04 to 1.78 M. The OD, recovered through acid precipitation, exhibits tunable photoluminescence from blue (~440 nm) to green (~500 nm) and yellow (~565 nm) under excitation between 300 and 390 nm. Structural and optical characterization (UV-Vis, AFM, FTIR, Raman) confirms the presence of oxidized aromatic domains. This approach offers a promising, sustainable route to develop CRM-free phosphors for use in next-generation wLEDs. View this paper  
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22 pages, 4532 KB  
Article
Research on Deep Separation Technology of Multi–Source By–Products in Coking Coal
by Andile Khumalo, Chuanzhen Wang, Tao Tan and Md. Shakhaoath Khan
ChemEngineering 2025, 9(4), 92; https://doi.org/10.3390/chemengineering9040092 - 18 Aug 2025
Viewed by 422
Abstract
This study proposes considering the effective re–benefication of coal middlings and other such considered waste materials as a way to ensure that clean coal in coal by–products can be extracted and effectively utilized, saving costs and reducing coal waste. To quantify the clean–coal [...] Read more.
This study proposes considering the effective re–benefication of coal middlings and other such considered waste materials as a way to ensure that clean coal in coal by–products can be extracted and effectively utilized, saving costs and reducing coal waste. To quantify the clean–coal yield and ash reduction that can be achieved by re–beneficiating four typical by–product streams from the Guobei Coal Preparation Plant (6 Mt a−1) were used for the study. Coking–coal middlings, flotation tailings, and pressure–filter cakes from preparation plants still contain 30–60% combustible matter. Re–beneficiation techniques have been considered to recover this often-wasted coal, reduce waste rock disposal, and cut greenhouse–gas emissions per ton of clean coal produced. Representative samples (n = 4) were collected, sample size–classified as (fine coal particles ≤0.5 mm and coarse particles ≥) and subjected to (i) magnetite removal, (ii) laboratory froth flotation (diesel 507 g t−1, sec–octanol 103 g t−1), and (iii) fine and large particle density separation at 1.3–1.8 g cm−3 ZnCO3 media. Clean–coal yield and ash were measured for each stream and the coal’s particle liberation was examined by SEM. Crushing, grinding and liberation equipment and techniques that aid in the treatment of coal and the re–beneficiation of coal middlings and tailings. The key findings recorded during the experiment are as follows: Flotation of <0.5 mm fractions delivered 46.9–58.3% clean–coal yield at 10.3–17.0% ash. Density separation of 0.5–1.0 mm middlings peaked at 1.4–1.5 g cm−3, yielding 34.2% clean coal at 15–18.4% ash. Scanning Electron Microscope analysis confirmed partial liberation as results from re–grinding + second flotation which increased yield by a further 8–12%. A calculated theoretical examination of the preliminary cost–benefit analysis indicates ≈36 CNY t−1≈9 million CNY a−1 in saved disposal costs alone. savings in disposal and 0.25 Mt a−1 additional clean coal for the Guobei plant. The research presented in this paper highlights the current work by Anhui University of Science and technology in collaboration with Guobei coal preparation plant and the results therein achieved. Full article
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21 pages, 2564 KB  
Article
Exploring the Physicochemical and Toxicological Study of G-Series and A-Series Agents Combining Molecular Dynamics and Quantitative Structure–Activity Relationship
by Michail Chalaris, Antonios Koufou, Sotiria Anastasiou, Pantelis-Alexandros Roupas and Georgios Nikolaou
ChemEngineering 2025, 9(4), 91; https://doi.org/10.3390/chemengineering9040091 - 18 Aug 2025
Viewed by 348
Abstract
This study explores the physicochemical and toxicological properties of six G-series and A-series chemical warfare agents (Sarin, Soman, Tabun, A230, A232, and A234) using an integrated computational approach combining molecular dynamics (MD) simulations and Quantitative Structure–Activity Relationship (QSAR) modeling. For the A-series nerve [...] Read more.
This study explores the physicochemical and toxicological properties of six G-series and A-series chemical warfare agents (Sarin, Soman, Tabun, A230, A232, and A234) using an integrated computational approach combining molecular dynamics (MD) simulations and Quantitative Structure–Activity Relationship (QSAR) modeling. For the A-series nerve agents, both Ellison–Hoenig and Mirzayanov structural proposals were examined. MD simulations (10 ns, NPT ensemble) provided key thermodynamic properties, including density, molar heat capacity, and diffusivity. Simulated densities for G-agents (e.g., Sarin: 1.09 g/cm3, Soman: 1.03 g/cm3) and A-agents (e.g., A230: 1.608 g/cm3, Ellison–Hoenig model) closely matched experimental data. Heat capacities ranged from 258 to 462 J/mol·K, and self-diffusion coefficients revealed lower mobility for A-agents, especially under the Ellison–Hoenig configurations. QSAR modeling focused on lipophilicity (LogP) and acute toxicity (LD50). Predicted LD50 values ranged from 0.012 to 0.017 mg/kg for G-agents and up to 1.23 mg/kg for A-agents. A-234 showed the highest lipophilicity (LogP = 2.97) and toxicity (LD50 = 0.51 mg/kg) within its group. Additional descriptors, such as molecular weight and polar surface area, supported toxicity predictions. Strong correlations emerged between MD-derived properties and QSAR outputs, validating the integrated approach. The combined use of MD and QSAR techniques provided a comprehensive view of the agents’ environmental behavior and toxicological impact, supporting safer assessment strategies and reinforcing the importance of multidisciplinary modeling for chemical threat mitigation. Full article
(This article belongs to the Topic Artificial Intelligence and Automation in Chemical Engineering)
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12 pages, 2161 KB  
Article
Bio-Based Nanocellulose Piezocatalysts: PH-Neutral Mechanochemical Degradation of Multipollutant Dyes via Ambient Vibration Energy Conversion
by Zhaoning Yang, Zihao Yang, Xiaoxin Shu, Wenshuai Chen, Jiaolong Liu, Keqing Chen and Yanmin Jia
ChemEngineering 2025, 9(4), 90; https://doi.org/10.3390/chemengineering9040090 - 15 Aug 2025
Viewed by 308
Abstract
Piezoelectric catalytic technology has attracted much attention in the field of dye wastewater treatment, in which inorganic piezoelectric materials have been widely studied. Its core mechanism involves utilizing the piezoelectric effect to generate positive and negative charges, which react with oxygen ions and [...] Read more.
Piezoelectric catalytic technology has attracted much attention in the field of dye wastewater treatment, in which inorganic piezoelectric materials have been widely studied. Its core mechanism involves utilizing the piezoelectric effect to generate positive and negative charges, which react with oxygen ions and hydroxyl radicals, respectively, to generate reactive oxygen species to degrade organic pollutants. Currently, while organic piezoelectric catalysts theoretically offer significant advantages such as low cost and high processability, there has been a notable lack of research in this area, which presents an innovative opportunity for the exploration of new organic piezoelectric catalytic materials. In this study, new research using natural nanocellulose (FC) suspension as an efficient organic piezoelectric catalyst is reported for the first time. The experimental results showed that the catalyst exhibited excellent degradation performance for Rhodamine B (RhB), Acid Orange 7 (AO7), and Methyl Orange (MO) under ultrasonic vibration (40 kHz, 200 W): the degradation rates reached 95.4%, 72.4%, and 31.2%, respectively, for 150 min, and the corresponding first-order reaction kinetic constants were 0.0205, 0.00858, and 0.00249 min−1, respectively. It is noteworthy that the RhB solution can achieve the optimal degradation efficiency without adjustment under neutral initial pH conditions, which significantly enhances the practical application feasibility. The experimental results showed that the catalyst, with a measurable piezoelectric coefficient (d33 = 4.4 pm/V), exhibited excellent degradation performance for Rhodamine B (RhB), Acid Orange 7 (AO7), and Methyl Orange (MO) under ultrasonic vibration (40 kHz, 200 W). This organic piezoelectric catalyst, based on renewable biomass, innovatively converts mechanical vibration energy in the environment into the power to degrade pollutants. It not only expands the application boundaries of organic piezoelectric materials but also provides a new solution for sustainable water treatment technology, demonstrating extremely promising application prospects in the field of green and environmentally friendly water treatment. Full article
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36 pages, 5657 KB  
Article
Modeling of Temperature and Moisture Dynamics in Corn Storage Silos with and Without Aeration Periods in Three Dimensions
by F. I. Molina-Herrera, H. Jiménez-Islas, M. A. Sandoval-Hernández, N. E. Maldonado-Sierra, C. Domínguez Campos, L. Jarquín Enríquez, F. J. Mondragón Rojas and N. L. Flores-Martínez
ChemEngineering 2025, 9(4), 89; https://doi.org/10.3390/chemengineering9040089 - 15 Aug 2025
Viewed by 338
Abstract
This study analyzes the dynamics of temperature and moisture in a cylindrical silo with a conical roof and floor used for storing corn in the Bajío region of Mexico, considering conditions both with and without aeration. The model incorporates external temperature fluctuations, solar [...] Read more.
This study analyzes the dynamics of temperature and moisture in a cylindrical silo with a conical roof and floor used for storing corn in the Bajío region of Mexico, considering conditions both with and without aeration. The model incorporates external temperature fluctuations, solar radiation, grain moisture equilibrium with air humidity through the sorption isotherm (water activity), and grain respiration to simulate real storage conditions. The model is based on continuity, momentum, energy, and moisture conservation equations in porous media. This model was solved using the finite element method (FEM) to evaluate temperature and interstitial humidity variations during January and May, representing cold and warm environmental conditions, respectively. The simulations show that, without aeration, grain temperature progressively accumulates in the center and bottom region of the silo, reaching critical values for safe storage. In January, the low ambient temperature favors the natural dissipation of heat. In contrast, in May, the combination of high ambient temperatures and solar radiation intensifies thermal accumulation, increasing the risk of grain deterioration. However, implementing aeration periods allowed for a reduction in the silo’s internal temperature, achieving more homogeneous cooling and reducing the threats of mold and insect proliferation. For January, an airflow rate of 0.15 m3/(min·ton) was optimal for maintaining the temperature within the safe storage range (≤17 °C). In contrast, in May, neither this airflow rate nor the accumulation of 120 h of aeration was sufficient to achieve optimal storage temperatures. This indicates that, under warm conditions, the aeration strategy needs to be reconsidered, assessing whether a higher airflow rate, longer periods, or a combination of both could improve heat dissipation. The results also show that interstitial relative humidity remains stable with nocturnal aeration, minimizing moisture absorption in January and preventing excessive drying in May. However, it was identified that aeration period management must be adaptive, taking environmental conditions into account to avoid issues such as re-wetting or excessive grain drying. Full article
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15 pages, 2964 KB  
Article
Electrochemical Sensors Based on Track-Etched Membranes for Rare Earth Metal Ion Detection
by Nurdaulet Zhumanazar, Arman B. Yeszhanov, Galina B. Melnikova, Ainash T. Zhumazhanova, Sergei A. Chizhik and Ilya V. Korolkov
ChemEngineering 2025, 9(4), 88; https://doi.org/10.3390/chemengineering9040088 - 15 Aug 2025
Viewed by 286
Abstract
Electrochemical sensors have been developed based on polyethylene terephthalate track-etched membranes (PET TeMs) modified by photograft copolymerization of N-vinylformamide (N-VFA) and trimethylolpropane trimethacrylate (TMPTMA). The modification, structure and properties of the modified PET TeMs were thoroughly characterized using scanning electron microscopy (SEM) and [...] Read more.
Electrochemical sensors have been developed based on polyethylene terephthalate track-etched membranes (PET TeMs) modified by photograft copolymerization of N-vinylformamide (N-VFA) and trimethylolpropane trimethacrylate (TMPTMA). The modification, structure and properties of the modified PET TeMs were thoroughly characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM), thermogravimetric analysis (TGA), Fourier-transform infrared (FTIR) spectroscopy, gas permeability measurements and contact angle analysis. Optimal membrane modification was achieved using C = 10% (N-VFA), 60 min of UV irradiation and a UV lamp distance of 10 cm. Furthermore, the modified membranes were implemented in a two-electrode configuration for the determination of Eu3+, Gd3+, La3+ and Ce3+ ions via square-wave anodic stripping voltammetry (SW-ASV). The sensors exhibited a linear detection range from 10−7 M to 10−3 M, with limits of detection of 1.0 × 10−6 M (Eu3+), 6.0 × 10−6 M (Gd3+), 2.0 × 10−4 M (La3+) and 2.5 × 10−5 M (Ce3+). The results demonstrated a significant enhancement in electrochemical response due to the grafted PET TeMs-g-N-PVFA-TMPTMA structure, and the sensor showed practical applicability and consistent performance in detecting rare earth ions in tap water. Full article
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18 pages, 2396 KB  
Article
Robust Nonlinear Soft Sensor for Online Estimation of Product Compositions in Heat-Integrated Distillation Column
by Nura Musa Tahir, Jie Zhang and Matthew Armstrong
ChemEngineering 2025, 9(4), 87; https://doi.org/10.3390/chemengineering9040087 - 11 Aug 2025
Viewed by 310
Abstract
This paper proposes the development of a robust nonlinear soft sensor for online estimation of product compositions in a Heat-Integrated Distillation Column (HIDiC). Traditional composition analyzers, such as gas chromatographs, are costly and suffer from long measurement delays, making them inefficient for real-time [...] Read more.
This paper proposes the development of a robust nonlinear soft sensor for online estimation of product compositions in a Heat-Integrated Distillation Column (HIDiC). Traditional composition analyzers, such as gas chromatographs, are costly and suffer from long measurement delays, making them inefficient for real-time monitoring and control. To address this, data-driven soft sensors are developed using tray temperature data obtained from a high-fidelity dynamic HIDiC simulation. The study investigates both linear and nonlinear modeling strategies for composition estimation, including principal component regression (PCR), artificial neural networks (ANNs), and, for the first time in HIDiC modeling, a Bidirectional Long Short-Term Memory (BiLSTM) network. The objective is to evaluate the capability of each method for accurate estimation of product compositions in a HIDiC. The results demonstrate that the BiLSTM-based soft sensor significantly outperforms conventional methods and offers strong potential for enhancing real-time composition estimation and control in HIDiC systems. Full article
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21 pages, 4126 KB  
Article
A Glycerol Acetylation Study on a Tin Ferrite Nanocatalyst
by Rami Doukeh, Andreea-Cătălina Joe, Ion Onuțu, Iuliana Veronica Ghețiu, Marian Băjan, Gabriel Vasilievici, Dorin Bomboș, Abeer Baioun, Cașen Panaitescu, Ionuț Banu and Romuald Győrgy
ChemEngineering 2025, 9(4), 86; https://doi.org/10.3390/chemengineering9040086 - 8 Aug 2025
Viewed by 222
Abstract
In this study, a novel magnetic nanocatalyst based on tin ferrite (SnFe2O4) was synthesized via a chemical co-precipitation method and thoroughly characterized using XRD, SEM, TGA-DTG, BET, FTIR, and FTIR-pyridine techniques. The catalyst exhibited high crystallinity, a mesoporous structure [...] Read more.
In this study, a novel magnetic nanocatalyst based on tin ferrite (SnFe2O4) was synthesized via a chemical co-precipitation method and thoroughly characterized using XRD, SEM, TGA-DTG, BET, FTIR, and FTIR-pyridine techniques. The catalyst exhibited high crystallinity, a mesoporous structure with a specific surface area of 79.7 m2/g, and well-defined Lewis and Brønsted acid sites. Its catalytic performance was assessed in the esterification of glycerol with acetic acid to produce monoacetin (MAG), diacetin (DAG), and triacetin (TAG). A Box–Behnken experimental design was employed to evaluate the influence of temperature, catalyst loading, and the acetic-acid-to-glycerol molar ratio on product distribution and glycerol conversion. Statistical analysis and regression modeling revealed excellent predictive accuracy (R2 > 0.99), confirming the robustness of the model. Optimal reaction conditions (110 °C, 2 wt.% catalyst, and AA/GLY ratio of 3.6) yielded a maximum glycerol conversion of 93.2% and a combined DAG and TAG yield of ~59.1%. These results demonstrate the high efficiency and selectivity of the synthesized SnFe2O4 catalyst, making it a promising candidate for sustainable glycerol valorization. Full article
(This article belongs to the Special Issue Catalytic Reactions and Development of (Bio)Chemical Processes for Synthesizing Value Added Compounds)
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29 pages, 3173 KB  
Article
Graph Neural Networks for Sustainable Energy: Predicting Adsorption in Aromatic Molecules
by Hasan Imani Parashkooh and Cuiying Jian
ChemEngineering 2025, 9(4), 85; https://doi.org/10.3390/chemengineering9040085 - 6 Aug 2025
Viewed by 529
Abstract
The growing need for rapid screening of adsorption energies in organic materials has driven substantial progress in developing various architectures of equivariant graph neural networks (eGNNs). This advancement has largely been enabled by the availability of extensive Density Functional Theory (DFT)-generated datasets, sufficiently [...] Read more.
The growing need for rapid screening of adsorption energies in organic materials has driven substantial progress in developing various architectures of equivariant graph neural networks (eGNNs). This advancement has largely been enabled by the availability of extensive Density Functional Theory (DFT)-generated datasets, sufficiently large to train complex eGNN models effectively. However, certain material groups with significant industrial relevance, such as aromatic compounds, remain underrepresented in these large datasets. In this work, we aim to bridge the gap between limited, domain-specific DFT datasets and large-scale pretrained eGNNs. Our methodology involves creating a specialized dataset by segregating aromatic compounds after a targeted ensemble extraction process, then fine-tuning a pretrained model via approaches that include full retraining and systematically freezing specific network sections. We demonstrate that these approaches can yield accurate energy and force predictions with minimal domain-specific training data and computation. Additionally, we investigate the effects of augmenting training datasets with chemically related but out-of-domain groups. Our findings indicate that incorporating supplementary data that closely resembles the target domain, even if approximate, would enhance model performance on domain-specific tasks. Furthermore, we systematically freeze different sections of the pretrained models to elucidate the role each component plays during adaptation to new domains, revealing that relearning low-level representations is critical for effective domain transfer. Overall, this study contributes valuable insights and practical guidelines for efficiently adapting deep learning models for accurate adsorption energy predictions, significantly reducing reliance on extensive training datasets. Full article
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38 pages, 2180 KB  
Review
Ternary Choline Chloride-Based Deep Eutectic Solvents: A Review
by Abdulalim Ibrahim, Marc Mulamba Tshibangu, Christophe Coquelet and Fabienne Espitalier
ChemEngineering 2025, 9(4), 84; https://doi.org/10.3390/chemengineering9040084 - 6 Aug 2025
Viewed by 2500
Abstract
Ternary choline chloride-based deep eutectic solvents (TDESs) exhibit unique physicochemical properties, including lower viscosities, lower melting points, higher thermal stabilities, and enhanced solvations compared to binary deep eutectic solvents (BDESs). Although BDESs have been widely studied, the addition of a third component in [...] Read more.
Ternary choline chloride-based deep eutectic solvents (TDESs) exhibit unique physicochemical properties, including lower viscosities, lower melting points, higher thermal stabilities, and enhanced solvations compared to binary deep eutectic solvents (BDESs). Although BDESs have been widely studied, the addition of a third component in TDESs offers opportunities to further optimize their performance. This review aims to evaluate the physicochemical properties of TDESs and highlight their potential applications in sustainable industrial processes compared to BDESs. A comprehensive analysis of the existing literature was conducted, focusing on TDES properties, such as phase behavior, density, viscosity, pH, conductivity, and the effect of water, along with their applications in various fields. TDESs demonstrated superior physicochemical characteristics compared to BDESs, including improved solvation and thermal stability. Their applications in biomass conversion, CO2 capture, heavy oil upgrading, refrigeration gases, and as solvents/catalysts in organic reactions show significant promise for enhancing process efficiency and sustainability. Despite their advantages, TDESs face challenges including limited predictive models, potential instability under certain conditions, and scalability hurdles. Overall, TDESs offer significant potential for advancing sustainable and efficient chemical processes for industrial applications. Full article
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14 pages, 1483 KB  
Article
Molecular Dynamics Simulation of PFAS Adsorption on Graphene for Enhanced Water Purification
by Bashar Awawdeh, Matteo D’Alessio, Sasan Nouranian, Ahmed Al-Ostaz, Mine Ucak-Astarlioglu and Hunain Alkhateb
ChemEngineering 2025, 9(4), 83; https://doi.org/10.3390/chemengineering9040083 - 1 Aug 2025
Viewed by 417
Abstract
The contamination of drinking water by per- and polyfluoroalkyl substances (PFASs) presents a global concern due to their extreme persistence, driven by strong C–F bonds. This study investigated the potential of graphene as a filtration material for PFAS removal, focusing on six key [...] Read more.
The contamination of drinking water by per- and polyfluoroalkyl substances (PFASs) presents a global concern due to their extreme persistence, driven by strong C–F bonds. This study investigated the potential of graphene as a filtration material for PFAS removal, focusing on six key compounds regulated by the U.S. EPA: PFOA, PFNA, GenX, PFBS, PFOS, and PFHxS. Using molecular simulations, adsorption energy, diffusion coefficients, and PFAS-to-graphene distances were analyzed. The results showed that adsorption strength increased with molecular weight; PFOS (500 g/mol) exhibited the strongest adsorption (−171 kcal/mol). Compounds with sulfonic acid head groups (e.g., PFOS) had stronger interactions than those with carboxylate groups (e.g., PFNA), highlighting the importance of head group chemistry. Shorter graphene-to-PFAS distances also aligned with higher adsorption energies. PFOS, for example, had the shortest distance at 8.23 Å (head) and 6.15 Å (tail) from graphene. Diffusion coefficients decreased with increasing molecular weight and carbon chain length, with lower molecules like PFBS (four carbon atoms) diffusing more rapidly than heavier ones like PFOS and PFNA. Interestingly, graphene enhanced PFAS mobility in water, likely by disrupting the water structure and lowering intermolecular resistance. These results highlight graphene’s promise as a high-performance material for PFAS removal and future water purification technologies. Full article
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21 pages, 12700 KB  
Article
Optimization of Developed TiO2 NWs-Fe2O3 Modified PES Membranes for Efficient NBB Dye Removal
by Mouna Mansor Hussein, Qusay F. Alsalhy, Mohamed Gar Alalm and M. M. El-Halwany
ChemEngineering 2025, 9(4), 82; https://doi.org/10.3390/chemengineering9040082 - 1 Aug 2025
Viewed by 376
Abstract
Current work investigates the fabrication and performance of nanocomposite membranes, modified with varying concentrations of hybrid nanostructures comprising titanium nanowires coated with iron nanoparticles (TiO2 NWs-Fe2O3), for the removal of Naphthol Blue Black (NBB) dye from industrial wastewater. [...] Read more.
Current work investigates the fabrication and performance of nanocomposite membranes, modified with varying concentrations of hybrid nanostructures comprising titanium nanowires coated with iron nanoparticles (TiO2 NWs-Fe2O3), for the removal of Naphthol Blue Black (NBB) dye from industrial wastewater. A series of analytical tools were employed to confirm the successful modification including scanning electron microscopy and EDX analysis, porosity and hydrophilicity measurements, Fourier-transform infrared spectroscopy, and X-Ray Diffraction. The incorporation of TiO2 NWs-Fe2O3 has enhanced membrane performance significantly by increasing the PWF and improving dye retention rates of nanocomposite membranes. At 0.7 g of nanostructure content, the modified membrane (M8) achieved a PWF of 93 L/m2·h and NBB dye rejection of over 98%. The flux recovery ratio (FRR) analysis disclosed improved antifouling properties, with the M8 membrane demonstrating a 73.4% FRR. This study confirms the potential of TiO2 NWs-Fe2O3-modified membranes in enhancing water treatment processes, offering a promising solution for industrial wastewater treatment. These outstanding results highlight the potential of the novel PES-TiO2 NWs-Fe2O3 membranes for dye removal and present adequate guidance for the modification of membrane physical properties in the field of wastewater treatment. Full article
(This article belongs to the Special Issue New Advances in Chemical Engineering)
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16 pages, 4017 KB  
Article
Recyclable Platinum Nanocatalyst for Nitroarene Hydrogenation: Gum Acacia Polymer-Stabilized Pt Nanoparticles with TiO2 Support
by Supriya Prakash, Selvakumar Ponnusamy, Jagadeeswari Rangaraman, Kundana Nakkala and Putrakumar Balla
ChemEngineering 2025, 9(4), 81; https://doi.org/10.3390/chemengineering9040081 - 30 Jul 2025
Viewed by 340
Abstract
Platinum has emerged as an optimal catalyst for the selective hydrogenation of nitroarenes owing to its high hydrogenation activity, selectivity, and stability. In this study, we report the fabrication of platinum nanoparticles stabilized on a composite support consisting of gum acacia polymer (GAP) [...] Read more.
Platinum has emerged as an optimal catalyst for the selective hydrogenation of nitroarenes owing to its high hydrogenation activity, selectivity, and stability. In this study, we report the fabrication of platinum nanoparticles stabilized on a composite support consisting of gum acacia polymer (GAP) and TiO2. It was engineered for the targeted reduction of nitroarenes to arylamines via selective hydrogenation in methanol at ambient temperature. The non-toxic and biocompatible properties of GAP enable it to act as a reducing and stabilizing agent during synthesis. The synthesized nanocatalyst was characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Morphological and structural analyses revealed that the fabricated catalyst consisted of minuscule Pt nanoparticles integrated within the GAP framework, accompanied by the corresponding TiO2 nanoparticles. Inductively coupled plasma optical emission spectrometry (ICP-OES) was employed to ascertain the Pt content. The mild reaction conditions, decent yields, trouble-free workup, and facile separation of the catalyst make this method a clean and practical alternative to nitroreduction. Selective hydrogenation yielded an average arylamine production of 97.6% over five consecutive cycles, demonstrating the stability of the nanocatalyst without detectable leaching. Full article
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33 pages, 4670 KB  
Article
Universal Prediction of CO2 Adsorption on Zeolites Using Machine Learning: A Comparative Analysis with Langmuir Isotherm Models
by Emrah Kirtil
ChemEngineering 2025, 9(4), 80; https://doi.org/10.3390/chemengineering9040080 - 28 Jul 2025
Viewed by 624
Abstract
The global atmospheric concentration of carbon dioxide (CO2) has exceeded 420 ppm. Adsorption-based carbon capture technologies, offer energy-efficient, sustainable solutions. Relying on classical adsorption models like Langmuir to predict CO2 uptake presents limitations due to the need for case-specific parameter [...] Read more.
The global atmospheric concentration of carbon dioxide (CO2) has exceeded 420 ppm. Adsorption-based carbon capture technologies, offer energy-efficient, sustainable solutions. Relying on classical adsorption models like Langmuir to predict CO2 uptake presents limitations due to the need for case-specific parameter fitting. To address this, the present study introduces a universal machine learning (ML) framework using multiple algorithms—Generalized Linear Model (GLM), Feed-forward Multilayer Perceptron (DL), Decision Tree (DT), Random Forest (RF), Support Vector Machine (SVM), and Gradient Boosted Trees (GBT)—to reliably predict CO2 adsorption capacities across diverse zeolite structures and conditions. By compiling over 5700 experimentally measured adsorption data points from 71 independent studies, this approach systematically incorporates critical factors including pore size, Si/Al ratio, cation type, temperature, and pressure. Rigorous Cross-Validation confirmed superior performance of the GBT model (R2 = 0.936, RMSE = 0.806 mmol/g), outperforming other ML models and providing comparable performance with classical Langmuir model predictions without separate parameter calibration. Feature importance analysis identified pressure, Si/Al ratio, and cation type as dominant influences on adsorption performance. Overall, this ML-driven methodology demonstrates substantial promise for accelerating material discovery, optimization, and practical deployment of zeolite-based CO2 capture technologies. Full article
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27 pages, 2690 KB  
Article
Adsorption of Methylene Blue on Metakaolin-Based Geopolymers: A Kinetic and Thermodynamic Investigation
by Maryam Hmoudah, Rosanna Paparo, Michela De Luca, Michele Emanuele Fortunato, Olimpia Tammaro, Serena Esposito, Riccardo Tesser, Martino Di Serio, Claudio Ferone, Giuseppina Roviello, Oreste Tarallo and Vincenzo Russo
ChemEngineering 2025, 9(4), 79; https://doi.org/10.3390/chemengineering9040079 - 25 Jul 2025
Viewed by 404
Abstract
Metakaolin-based geopolymers with different molar ratios of Si/Al were synthesized and utilized as an efficient adsorbent for the removal of methylene blue (MB) as a model cationic dye from aqueous solution. Various analytical techniques were employed to characterize the synthesized geopolymers. The influence [...] Read more.
Metakaolin-based geopolymers with different molar ratios of Si/Al were synthesized and utilized as an efficient adsorbent for the removal of methylene blue (MB) as a model cationic dye from aqueous solution. Various analytical techniques were employed to characterize the synthesized geopolymers. The influence of the main operation conditions on the adsorption kinetics of MB onto the geopolymer was examined under various operating conditions. Results showed a significant maximum MB adsorption capacity at the temperature of 30 °C for all four types of geopolymers studied (designated as A, B, C, and D) up to 35.3, 23.6, 25.5, and 19.0 mg g−1, respectively. The corresponding order of Si/Al ratio was A < C < B < D. Adsorption kinetics was so fast and reached equilibrium in 10 min, and the experimental results were described using the adsorption dynamic intraparticle model (ADIM). The equilibrium data for MB removal was in agreement with the Langmuir isotherm. Full article
(This article belongs to the Special Issue New Advances in Chemical Engineering)
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10 pages, 460 KB  
Article
Industry 5.0 and Digital Twins in the Chemical Industry: An Approach to the Golden Batch Concept
by Andrés Redchuk and Federico Walas Mateo
ChemEngineering 2025, 9(4), 78; https://doi.org/10.3390/chemengineering9040078 - 25 Jul 2025
Viewed by 800
Abstract
In the context of industrial digitalization, the Industry 5.0 paradigm introduces digital twins as a cutting-edge solution. This study explores the concept of digital twins and their integration with the Industrial Internet of Things (IIoT), offering insights into how these technologies bring intelligence [...] Read more.
In the context of industrial digitalization, the Industry 5.0 paradigm introduces digital twins as a cutting-edge solution. This study explores the concept of digital twins and their integration with the Industrial Internet of Things (IIoT), offering insights into how these technologies bring intelligence to industrial settings to drive both process optimization and sustainability. Industrial digitalization connects products and processes, boosting the productivity and efficiency of people, facilities, and equipment. These advancements are expected to yield broad economic and environmental benefits. As connected systems continuously generate data, this information becomes a vital asset, but also introduces new challenges for industrial operations. The work presented in this article aims to demonstrate the possibility of generating advanced tools for process optimization. This, which ultimately impacts the environment and empowers people in the processes, is achieved through data integration and the development of a digital twin using open tools such as NodeRed v4.0.9 and Python 3.13.5 frameworks, among others. The article begins with a conceptual analysis of IIoT and digital twin integration and then presents a case study to demonstrate how these technologies support the principles of the Industry 5.0 framework. Specifically, it examines the requirements for applying the golden batch concept within a biological production environment. The goal is to illustrate how digital twins can facilitate the achievement of quality standards while fostering a more sustainable production process. The results from the case study show that biomaterial concentration was optimized by approximately 10%, reducing excess in an initially overdesigned process. In doing so, this paper highlights the potential of digital twins as key enablers of Industry 5.0—enhancing sustainability, empowering operators, and building resilience throughout the value chain. Full article
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19 pages, 10374 KB  
Article
Nanoscale Nickel Oxide: Synthesis, Characterization, and Impact on Antibacterial Activity Against Representative Microorganisms
by Daniela Istrate, Mihai Oproescu, Ecaterina Magdalena Modan, Sorin Georgian Moga, Denis Aurelian Negrea and Adriana-Gabriela Schiopu
ChemEngineering 2025, 9(4), 77; https://doi.org/10.3390/chemengineering9040077 - 25 Jul 2025
Cited by 1 | Viewed by 496
Abstract
Among the various available synthesis approaches, hydrolytic precipitation offers a simple, cost-effective, and scalable route for producing phase-pure NiO with a controlled morphology and crystallite size. However, the influence of calcination temperature on its crystalline phase, particle size, and antimicrobial activity remains an [...] Read more.
Among the various available synthesis approaches, hydrolytic precipitation offers a simple, cost-effective, and scalable route for producing phase-pure NiO with a controlled morphology and crystallite size. However, the influence of calcination temperature on its crystalline phase, particle size, and antimicrobial activity remains an active field of research. This study aims to investigate the structural, morphological, and antibacterial properties of NiO nanoparticles synthesized via hydrolytic methods and thermally treated at different temperatures. XRD data indicate the presence of the hexagonal crystallographic phase of NiO (space group 166: R-3m), a structural variant less commonly reported in the literature, stabilized under mild hydrolytic synthesis conditions. The average crystallite size increases significantly from 4.97 nm at 300 °C to values of ~17.8 nm at 500–700 °C, confirming the development of the crystal lattice. The ATR-FTIR analysis confirms the presence of the characteristic Ni–O band for all samples, positioned between 367 and 383 cm−1, with a reference value of 355 cm−1 for commercial NiO. The displacements and variations in intensity reflect a thermal evolution of the crystalline structure, but also an important influence of the size of the crystallites and the agglomeration state. The results reveal a systematic evolution in particle morphology from porous, flake-like nanostructures at 300 °C to dense, well-faceted polyhedral crystals at 900 °C. With an increasing temperature, particle size increases. EDS spectra confirm the high purity of the NiO phase across all samples. Additionally, the NiO nanoparticles exhibit calcination-temperature-dependent antibacterial activity, with the complete inhibition of Escherichia coli and Enterococcus faecalis observed after 24 h for the sample calcined at 300 °C and over 90% CFU reduction within 4 h. A significant reduction in E. faecalis viability across all samples indicates time- and strain-specific bactericidal effects. Due to its remarkable multifunctionality, NiO has emerged as a strategic nanomaterial in fields ranging from energy storage and catalysis to antimicrobial technologies, where precise control over its structural phase and particle size is essential for optimizing performance. Full article
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13 pages, 3937 KB  
Article
Vanillin Quantum–Classical Photodynamics and Photostatic Optical Spectra
by Vladimir Pomogaev and Olga Tchaikovskaya
ChemEngineering 2025, 9(4), 76; https://doi.org/10.3390/chemengineering9040076 - 23 Jul 2025
Viewed by 337
Abstract
Vanillin photoinduced deprotonation was evaluated and analyzed. Vibronic states and transitions were computationally investigated. Optimizations and vertical electron transitions in the gas phase and with the continuum solvation model were computed using the time-dependent density functional theory. Static absorption and emission (photostatic optical) [...] Read more.
Vanillin photoinduced deprotonation was evaluated and analyzed. Vibronic states and transitions were computationally investigated. Optimizations and vertical electron transitions in the gas phase and with the continuum solvation model were computed using the time-dependent density functional theory. Static absorption and emission (photostatic optical) spectra were statistically averaged over the excited instantaneous molecular conformers fluctuating on quantum–classical molecular dynamic trajectories. Photostatic optical spectra were generated using the hybrid quantum–classical molecular dynamics for explicit solvent models. Conical intersection searching and nonadiabatic molecular dynamics simulations defined potential energy surface propagations, intersections, dissipations, and dissociations. The procedure included mixed-reference spin–flip excitations for both procedures and trajectory surface hopping for photodynamics. Insignificant structural deformations vs. hydroxyl bond cleavage followed by deprotonation were demonstrated starting from different initial structural conditions, which included optimized, transition state, and several other important fluctuating configurations in various environments. Vanillin electronic structure changes were illustrated and analyzed at the key points on conical intersection and nonadiabatic molecular dynamics trajectories by investigating molecular orbital symmetry and electron density difference. The hydroxyl group decomposed on transition to a σ-molecular orbital localized on the elongated O–H bond. Full article
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20 pages, 1857 KB  
Article
Application of Risk Management in Applied Engineering Projects in a Petrochemical Plant Producing Polyvinyl Chloride in Cartagena, Colombia
by Juan Pablo Bustamante Visbal, Rodrigo Ortega-Toro and Joaquín Alejandro Hernández Fernández
ChemEngineering 2025, 9(4), 75; https://doi.org/10.3390/chemengineering9040075 - 21 Jul 2025
Viewed by 656
Abstract
Risk management is crucial in engineering projects, especially in highly complex environments like petrochemical plants producing polyvinyl chloride (PVC). This study proposes a tailored risk management model, using analytic hierarchy process (AHP) and linear regression analysis, alongside MS Excel and IBM SPSS® [...] Read more.
Risk management is crucial in engineering projects, especially in highly complex environments like petrochemical plants producing polyvinyl chloride (PVC). This study proposes a tailored risk management model, using analytic hierarchy process (AHP) and linear regression analysis, alongside MS Excel and IBM SPSS® version 23, to identify, assess, and prioritize key risks. Surveys and interviews revealed seven management factors (budget, schedule, safety, productivity, contracting, quality, and environment) and 18 critical risks, including design errors and procurement delays. The model quantifies risk impacts, provides a regression equation for risk classification, and supports effective mitigation strategies. Based on this model, decision-making can be facilitated for the implementation of effective mitigation strategies. It also promotes continuous improvement, optimizing economic resources and minimizing environmental impacts, addressing a research gap in Colombia’s petrochemical sector and paving the way for broader industrial applications. Full article
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29 pages, 3084 KB  
Article
The Cascade Transformation of Furfural to Cyclopentanone: A Critical Evaluation Concerning Feasible Process Development
by Christian A. M. R. van Slagmaat
ChemEngineering 2025, 9(4), 74; https://doi.org/10.3390/chemengineering9040074 - 19 Jul 2025
Viewed by 605
Abstract
Furfural is a fascinating bio-based platform molecule that can be converted into useful cyclic compounds, among others. In this work, the hydrogenative rearrangement-dehydration of furfural towards cyclopentanone using a commercially available Pt/C catalyst was investigated in terms of its reaction performance to assess [...] Read more.
Furfural is a fascinating bio-based platform molecule that can be converted into useful cyclic compounds, among others. In this work, the hydrogenative rearrangement-dehydration of furfural towards cyclopentanone using a commercially available Pt/C catalyst was investigated in terms of its reaction performance to assess its feasibility as an industrial process. However, acquiring an acceptable cyclopentanone yield proved very difficult, and the reaction was constrained by unforeseen parameters, such as the relative liquid volume in the reactor and the substrate concentration. Most strikingly, the sacrificial formation of furanoic oligomers that precipitated onto the catalyst’s surface was a troublesome key factor that mediated the product’s selectivity versus the carbon mass balance. By applying a biphasic water–toluene solvent system, the yield of cyclopentanone was somewhat improved to a middling 59%, while tentatively positive distributions of reaction components over these solvent phases were observed, which could be advantageous for anticipated down-stream processing. Overall, the sheer difficulty of controlling this one-pot cascade transformation towards a satisfactory product output under rather unfavorable reaction parameters renders it unsuitable for industrial process development, and a multi-step procedure for this chemical transformation might be considered instead. Full article
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18 pages, 5293 KB  
Article
Fluorescent Moieties Through Alkaline Treatment of Graphene Oxide: A Potential Substitute to Replace CRM in wLEDS
by Maria Lucia Protopapa, Emiliano Burresi, Martino Palmisano and Emanuela Pesce
ChemEngineering 2025, 9(4), 73; https://doi.org/10.3390/chemengineering9040073 - 18 Jul 2025
Viewed by 334
Abstract
White-light-emitting diodes (wLEDs) are central to next-generation lighting technologies, yet their reliance on critical raw materials (CRMs), such as rare-earth elements, raises concerns regarding sustainability and supply security. In this work, we present a simple, low-cost method to produce photoluminescent carbon-based nanostructures—known as [...] Read more.
White-light-emitting diodes (wLEDs) are central to next-generation lighting technologies, yet their reliance on critical raw materials (CRMs), such as rare-earth elements, raises concerns regarding sustainability and supply security. In this work, we present a simple, low-cost method to produce photoluminescent carbon-based nanostructures—known as oxidative debris (OD)—via alkaline treatment of graphene oxide (GO) using KOH solutions ranging from 0.04 M to 1.78 M. The resulting OD, isolated from the supernatant after acid precipitation, exhibits strong and tunable photoluminescence (PL) across the visible spectrum. Emission peaks shift from blue (~440 nm) to green (~500 nm) and yellow (~565 nm) as a function of treatment conditions, with excitation wavelengths between 300 and 390 nm. Optical, morphological. and compositional analyses were performed using UV-Vis, AFM, FTIR, and Raman spectroscopy, confirming the presence of highly oxidized aromatic domains. The blue-emitting (S2) and green/yellow-emitting (R2) fractions were successfully separated and characterized, demonstrating potential color tuning by adjusting KOH concentration and treatment time. This study highlights the feasibility of reusing GO-derived byproducts as sustainable phosphor alternatives in wLEDs, reducing reliance on CRMs and aligning with green chemistry principles. Full article
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12 pages, 1130 KB  
Article
Production of 2,2,3,3,4,4,4-Heptafluorobutyl Acetate from Acetic Acid and 2,2,3,3,4,4,4-Heptafluorobutan-1-ol by Batch Reactive Distillation
by Andrei V. Polkovnichenko, Egor V. Lupachev, Evgenia I. Kovaleva, Sergey Ya. Kvashnin, Tatiana V. Chelyuskina and Andrey A. Voshkin
ChemEngineering 2025, 9(4), 72; https://doi.org/10.3390/chemengineering9040072 - 11 Jul 2025
Viewed by 406
Abstract
In the present study, a process for the production of 2,2,3,3,4,4,4-heptafluorobutyl acetate (HFBAc) is proposed for the first time. The production process of HFBAc from acetic acid (AAc) and 2,2,3,3,4,4,4-heptafluorobutan-1-ol (HFBol) was carried out at laboratory scale using batch reactive distillation (BRD). The [...] Read more.
In the present study, a process for the production of 2,2,3,3,4,4,4-heptafluorobutyl acetate (HFBAc) is proposed for the first time. The production process of HFBAc from acetic acid (AAc) and 2,2,3,3,4,4,4-heptafluorobutan-1-ol (HFBol) was carried out at laboratory scale using batch reactive distillation (BRD). The process was conducted at atmospheric pressure in the presence of an acid catalyst, with an excess of AAc relative to HFBol (initial molar ratio of reagents HFBol/AAc is 45/55). During the BRD, the aqueous phase of the distillate was withdrawn from the system, while the organic phase of the distillate was returned as reflux. Since part of AAc is lost along with the aqueous phase of the distillate, a minor excess of AAc is reasonable for maximizing the conversion of the most expensive reagent—HFBol. The losses of AAc and HFBol with the aqueous phase of the distillate were less than 2 mole % and less than 0.5 mole % of the feed, respectively. The purity of HFBAc after BRD was 97.9 wt. %, and the conversion of HFBol exceeded 99 mole % of the feed. The purity of certain product fractions of HFBAc was greater than 99.6 wt. %. The obtained data can be used for industrial technology development to obtain HFBAc. Full article
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15 pages, 3671 KB  
Article
Improving the Water–Gas Shift Performance of a Co/CeO2 Catalyst for Hydrogen Production
by Nipatta Chumanee and Pannipa Nachai
ChemEngineering 2025, 9(4), 71; https://doi.org/10.3390/chemengineering9040071 - 10 Jul 2025
Viewed by 483
Abstract
The aim of this study was to improve the water–gas shift efficiency of Co/CeO2 catalyst by incorporating praseodymium and rhenium. The catalysts were synthesized via combustion method and characterized using X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) surface area analysis, Scanning Electron Microscope (SEM), [...] Read more.
The aim of this study was to improve the water–gas shift efficiency of Co/CeO2 catalyst by incorporating praseodymium and rhenium. The catalysts were synthesized via combustion method and characterized using X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) surface area analysis, Scanning Electron Microscope (SEM), H2-temperature programmed reduction (H2-TPR), NH3-temperature programmed desorption (NH3-TPD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). These characterization techniques evaluate the increase of the surface acidity and oxygen vacancies in Co-based catalysts, which leads to an increase in water–gas shift performance because CO molecules prefer to react with surface oxygen, then followed by the production of CO2 and oxygen vacancies which act as active sites for H2O dissociation. The 1%Re4%Co/Ce-5%Pr-O catalyst exhibited a maximum CO conversion of 86% at 450 °C, substantially outperforming the 5%Co/Ce-5%Pr-O catalyst, which showed only 62% CO conversion at 600 °C. In addition, 1%Re4%Co/Ce-5%Pr-O catalyst is more resistant towards deactivation than 5%Co/Ce-5%Pr-O. The result presented that the catalytic activity of 1%Re4%Co/Ce-5%Pr-O catalyst was kept constant for the whole period of 50 h, while a 6% decrease in water–gas shift activity was found for the 5%Co/Ce-5%Pr-O catalyst. Moreover, the addition of rhenium into the Co/Ce-Pr-O catalyst reveals that the enhancement of oxygen vacancy concentration, oxygen mobility, and surface acidity, thereby enhances CO conversion efficiency. Full article
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19 pages, 1240 KB  
Article
Extending the Recovery Ratio of Brackish Water Desalination to Zero Liquid Discharge (>95%) Through Combination of Nanofiltration, 2-Stage Reverse-Osmosis, Silica Precipitation, and Mechanical Vapor Recompression
by Paz Nativ, Raz Ben-Asher, Yaron Aviezer and Ori Lahav
ChemEngineering 2025, 9(4), 70; https://doi.org/10.3390/chemengineering9040070 - 3 Jul 2025
Viewed by 657
Abstract
Extending the recovery ratio (RR) of brackish water reverse osmosis (RO) plants to zero liquid discharge (ZLD, i.e., ≥95%) is vital, particularly inland, where the cost of safe retentate disposal is substantial. Various suggestions appear in the literature; however, many of these are [...] Read more.
Extending the recovery ratio (RR) of brackish water reverse osmosis (RO) plants to zero liquid discharge (ZLD, i.e., ≥95%) is vital, particularly inland, where the cost of safe retentate disposal is substantial. Various suggestions appear in the literature; however, many of these are impractical in the real world. Often, the limiting parameter that determines the maximal recovery is the SiO2 concentration that develops in the RO retentate and the need to further desalinate the high osmotic pressure retentates produced in the process. This work combines well-proven treatment schemes to attain RR ≥ 95% at a realistic cost. The raw brackish water undergoes first a 94% recovery nanofiltration (NF) step, whose permeate undergoes a further 88-RR RO step. To increase the overall RR, the retentate of the 1st RO step undergoes SiO2 removal performed via iron electro-dissolution and then a 2nd, 43% recovery, RO pass. The retentate of this step is combined with the NF retentate, and the mix is treated with mechanical vapor recompression (MVR) (RR = 62.7%). The results show that >95% recovery can be attained by the suggested process at an overall cost of ~USD 0.70/m3. This is ~60% higher than the USD 0.44/m3 calculated for the baseline operation (RR = 82.7%), making the concept feasible when either the increase in the plant’s capacity is regulatorily requested, or when the available retentate discharge method is very costly. The cost assessment accuracy was approximated at >80%. Full article
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12 pages, 3309 KB  
Article
A Study on the Effects of Solvent and Temperature on 2-Amino-7-Nitro-Fluorene (ANF) Using Synchronous Fluorescence
by Suresh Sunuwar, Miguel Rodriguez-Escalante, Priscila Blanco-Cortés and Carlos E. Manzanares
ChemEngineering 2025, 9(4), 69; https://doi.org/10.3390/chemengineering9040069 - 27 Jun 2025
Viewed by 420
Abstract
Synchronous fluorescence spectra are presented to investigate solute–solvent interactions in liquids. To this end, the spectra of 2-amino-7-nitro-fluorene (ANF) in six different solvents—acetic anhydride, acetone, acetonitrile, benzene, chlorobenzene, and ethyl acetate—are presented. The study also examines ANF’s synchronous fluorescence signals at five temperatures [...] Read more.
Synchronous fluorescence spectra are presented to investigate solute–solvent interactions in liquids. To this end, the spectra of 2-amino-7-nitro-fluorene (ANF) in six different solvents—acetic anhydride, acetone, acetonitrile, benzene, chlorobenzene, and ethyl acetate—are presented. The study also examines ANF’s synchronous fluorescence signals at five temperatures from 25 °C to 5 °C, providing a comprehensive analysis of its fluorescence characteristics in different environments and temperatures. An ANF sample dissolved in benzene at 5 °C produced a synchronous band with the largest intensity and smallest frequency shift. The results show that higher-intensity peaks are obtained at lower temperatures with solvents with a small dipole moment and dielectric constant. This suggest that the best conditions to detect ANF and similar molecules at very low concentrations are with non-polar solvents at low temperatures. Full article
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17 pages, 3372 KB  
Article
Combustion Air Humidifier for a Biomass Boiler with Flue Gas Condensation
by Jan Havlík and Tomáš Dlouhý
ChemEngineering 2025, 9(4), 68; https://doi.org/10.3390/chemengineering9040068 - 25 Jun 2025
Viewed by 368
Abstract
This paper deals with combustion air humidification for application with a biomass boiler and a spray flue gas condenser. The use of a combustion air humidifier increases the dew point temperature of the flue gas, thereby increasing the potential for heat recovery in [...] Read more.
This paper deals with combustion air humidification for application with a biomass boiler and a spray flue gas condenser. The use of a combustion air humidifier increases the dew point temperature of the flue gas, thereby increasing the potential for heat recovery in the flue gas condenser and increasing the amount of heat supplied to the thermal system. The air humidification process in a counter current spray humidifier was experimentally analysed under conditions corresponding to the use before a biomass boiler with a flue gas condenser. For air heating and humidification, temperature factor values of up to 0.90 can be obtained; this value is mainly influenced by the ratio of the spray water and humidified air flow rates. The volumetric heat transfer coefficient is significantly affected by the humidified air velocity, although this velocity is negligible compared to the counter current spray water velocity. The volumetric heat transfer coefficient reaches higher values at higher spray water temperatures and therefore higher air heating. The whole process is also affected by the saturation of the incoming air, where the dew point temperature of the air drawn in from the surroundings is lower than its temperature. These results can be used as basic information for the design of combustion air humidifiers, for the selection of their operating parameters, and for a basic balancing of the energy contribution of the combustion air humidifier before a more detailed design of the whole system. Full article
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11 pages, 1639 KB  
Article
New Approach to the Combined Removal of NOx and SO2 for Circulating Fluidized Beds
by Chao Wang and Qinggang Lyu
ChemEngineering 2025, 9(4), 67; https://doi.org/10.3390/chemengineering9040067 - 25 Jun 2025
Viewed by 374
Abstract
Post-combustion technology is a new kind of low-nitrogen combustion technology. To achieve the combined removal of nitrogen oxides (NOx) and sulfur dioxide (SO2) emissions, the post-combustion technology combined with the sorbent injection in the furnace and post-combustion chamber is [...] Read more.
Post-combustion technology is a new kind of low-nitrogen combustion technology. To achieve the combined removal of nitrogen oxides (NOx) and sulfur dioxide (SO2) emissions, the post-combustion technology combined with the sorbent injection in the furnace and post-combustion chamber is proposed. Experiments investigating the effects of the sorbent addition in a post-combustion chamber and post-combustion air arrangement on NOx and SO2 emissions were conducted in a 0.1 MWth circulating fluidized bed test platform. In addition, a comparative analysis of the NOx and SO2 emissions under both combined removal methods was also performed. The results indicated that adding sorbent to the post-combustion chamber can reduce SO2 emissions, but further increasing the amount of sorbent will not significantly improve the desulfurization effect. The injection position of the post-combustion air will affect the emissions of NOx and SO2 in the flue gas. When the three-stage distribution of post-combustion air is adopted, the further back the third nozzle is distributed, the lower the temperature in the post-combustion chamber, which is beneficial to the control of NOx and SO2 emissions. Compared with the conventional combined removal method, the NOx emissions were significantly reduced under the new combined removal method. Through secondary desulfurization in the furnace and post-combustion chamber, oxygen-deficient combustion in the furnace can achieve the combined removal of NOx and SO2. Full article
(This article belongs to the Special Issue Fuel Engineering and Technologies)
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17 pages, 5119 KB  
Article
Anode-Supported SOFCs with a Bi2O3-Doped NiO–ScSZ Anode and ScSZ Electrolyte: Low-Temperature Co-Sintering and High Performance
by Shang Peng, Zhao Liu, Pairuzha Xiaokaiti, Tiancheng Fang, Jiwei Wang, Guoqing Guan and Abuliti Abudula
ChemEngineering 2025, 9(4), 66; https://doi.org/10.3390/chemengineering9040066 - 24 Jun 2025
Viewed by 489
Abstract
In this study, a novel anode-supported solid oxide fuel cell (SOFC) comprising a Bi2O3-doped NiO-ScSZ anode and an ScSZ electrolyte was successfully fabricated via a low-temperature co-sintering process at 1300 °C. The incorporation of 3 wt% Bi2O [...] Read more.
In this study, a novel anode-supported solid oxide fuel cell (SOFC) comprising a Bi2O3-doped NiO-ScSZ anode and an ScSZ electrolyte was successfully fabricated via a low-temperature co-sintering process at 1300 °C. The incorporation of 3 wt% Bi2O3 effectively promoted the sintering of both the anode support and electrolyte layer, resulting in a dense, gas-tight electrolyte and a mechanically robust porous anode support. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses confirmed the formation of phase-pure, highly crystalline ScSZ with an optimized microstructure. Electrochemical performance measurements demonstrated that the fabricated cells achieved excellent power density, reaching a peak value of 0.861 W cm−2 at 800 °C under humidified hydrogen fuel conditions. The cells maintained stable performance under dry methane operation, with a maximum power density of 0.624 W cm−2 at 800 °C, indicating resistance to carbon deposition. Gas chromatographic analyses further revealed that the Bi2O3-doped NiO-ScSZ anode facilitated earlier and more stable electrochemical oxidation of methane-derived species compared with the conventional NiO-YSZ system, even under conditions of an elevated methane partial pressure. These findings demonstrate that Bi2O3 co-doping, combined with low-temperature co-sintering, provides an effective approach for fabricating high-performance intermediate-temperature SOFCs with enhanced structural integrity and electrochemical stability. The developed methodology presents a promising pathway toward achieving cost-effective and durable SOFC technologies. Full article
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18 pages, 6497 KB  
Article
Characterization of HFE 7500 Refrigerant Suspensions Containing Oxide and Nitride Nanoparticles: Thermal, Rheological, and Electrokinetic Insights
by Serdar Ozturk and Keagan Schmidt
ChemEngineering 2025, 9(4), 65; https://doi.org/10.3390/chemengineering9040065 - 24 Jun 2025
Viewed by 484
Abstract
Nanofluids—engineered suspensions of nanometer-sized particles—have attracted significant attention due to their reportedly enhanced thermal properties, making them promising candidates for advanced heat transfer applications. However, despite extensive studies, uncertainties remain regarding the magnitude and origin of these effects, limiting their practical implementation. To [...] Read more.
Nanofluids—engineered suspensions of nanometer-sized particles—have attracted significant attention due to their reportedly enhanced thermal properties, making them promising candidates for advanced heat transfer applications. However, despite extensive studies, uncertainties remain regarding the magnitude and origin of these effects, limiting their practical implementation. To address this, we present a comprehensive study on nanofluid formulations based on the commercial refrigerant HFE-7500, incorporating surfactant-stabilized dispersions of several metal oxide and nitride nanoparticles. We measured key physicochemical properties, including zeta potential, particle size, viscosity, and thermal conductivity. Our results show that while the nanofluids exhibited high stability, their particle sizes in suspension were significantly larger than the primary nanoparticle sizes measured by TEM. Notably, alumina-based suspensions demonstrated the greatest enhancement, exhibiting approximately 10–15% increases in thermal conductivity as a function of volume percentage. These surpassed the 5–10% improvements observed with other metal oxides, an effect that may be linked to their comparatively larger particle sizes. However, the observed enhancements were lower than some previously reported values that claimed anomalously high thermal conductivity increases. Furthermore, steady shear viscosity increased with particle concentration, showing enhancements of 10–20%, which suggests a potential trade-off for practical implementation. Our findings refine the understanding of nanofluid behavior in refrigerants and establish a foundation for optimizing their performance in thermal management applications. However, viscosity increases must be carefully considered when designing next-generation nanofluids for real-world use. Full article
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