Processes

19 pages, 2292 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Analysis and Prediction of Concentration Polarization in a Pilot Reverse Osmosis Plant with Seawater at Different Concentrations Using Python Software

by Jesús Álvarez-Sánchez, Germán Eduardo Dévora-Isiordia, Yedidia Villegas-Peralta, Luis Enrique Chaparro-Valdez, Sebastian Alonso Meza-Tarin, Claudia Rosario Muro-Urista, Reyna Guadalupe Sánchez-Duarte, Sergio Pérez-Sicairos, Emilio Medina-Bojorquez and Salvador Rascon-Leon

Processes 2025, 13(10), 3139; https://doi.org/10.3390/pr13103139 - 30 Sep 2025

Viewed by 744

Abstract

Reverse osmosis (RO) is the most widely used technology in seawater desalination, accounting for around 70% of installations worldwide due to its efficiency and lower energy consumption compared to conventional thermal processes. However, a major challenge for RO is concentration polarization (CP), a [...] Read more.

Reverse osmosis (RO) is the most widely used technology in seawater desalination, accounting for around 70% of installations worldwide due to its efficiency and lower energy consumption compared to conventional thermal processes. However, a major challenge for RO is concentration polarization (CP), a phenomenon that reduces permeate flow, increases osmotic pressure, and compromises salt rejection, affecting the useful life of the membranes. In this work, an RO pilot plant was operated with synthetic solutions ranging from 4830 to 39,850 mg L⁻¹ at pressures between 0.69 and 5.79 MPa, to analyze and predict CP behavior. The results obtained showed salt rejection percentages ranging from 98.80% to 99.63%. The adjusted polynomial models presented correlation coefficients close to unity, which supports their high predictive capacity and statistical robustness for estimating the behavior of CP as a function of pressure. These models were implemented in Python software, allowing for the simulation of non-experimental scenarios and the anticipation of critical conditions that could compromise the RO process. Therefore, this work provides a robust predictive simulation tool to optimize RO processes and ensure the sustainable supply of drinking water in regions with water availability problems. Full article

(This article belongs to the Special Issue Control and Supervision Strategies on Desalination Processes: Focused on Key Process Variables)

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20 pages, 1964 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Hydrocracking of Algae Oil and Model Alkane into Jet Fuel Using a Catalyst Containing Pt and Solid Acid

by Yanyong Liu

Processes 2025, 13(10), 3129; https://doi.org/10.3390/pr13103129 - 29 Sep 2025

Viewed by 726

Abstract

Aluminum polyoxocations were introduced into a lamellar zirconium phosphate (α-ZrP) via ion exchange. The Al polyoxocation pillars transformed into Al₂O₃ particles within the interlayer zone after calcination at 673 K. The resulting Al₂O₃-α-ZrP exhibited a large [...] Read more.

Aluminum polyoxocations were introduced into a lamellar zirconium phosphate (α-ZrP) via ion exchange. The Al polyoxocation pillars transformed into Al₂O₃ particles within the interlayer zone after calcination at 673 K. The resulting Al₂O₃-α-ZrP exhibited a large BET surface area and medium-strength acidity. Pt-supported Al₂O₃-α-ZrP was used as a catalyst for hydrocracking squalene and Botryococcus braunii oil in an autoclave batch system. In a one-step squalene hydrocracking process, the yield of jet-fuel-range hydrocarbons was 52.8% on 1 wt.% Pt/Al₂O₃-α-ZrP under 2 MPa H₂ at 623 K for 3 h. A two-step process was designed with the first step at 523 K for 1 h and the second at 623 K for 3 h. During the first step, the squalene was hydrogenated to squalane without cracking, and in the second step, the squalane was hydrocracked. This two-step catalytic process increased the yield of jet-fuel-range hydrocarbons to 65% in squalene hydrocracking. For algae oil hydrocracking, the jet-fuel-range hydrocarbons occupied 66% of the total products in the two-step reaction. Impurities in algae oil, mainly fatty acids, did not affect the yield of jet-fuel-range hydrocarbons because they were deoxygenated into hydrocarbons during the reaction. The activity of Pt/Al₂O₃-α-ZrP remained unchanged after four reuses through simple filtration. Full article

(This article belongs to the Special Issue Biomass to Renewable Energy Processes, 2nd Edition)

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28 pages, 2202 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Dynamic Modeling, Control, and Upscaling of Solar-Hybridized Biomass Gasification for Continuous and Stabilized Syngas Fuel Production

by Axel Curcio, Sylvain Rodat, Valéry Vuillerme and Stéphane Abanades

Processes 2025, 13(10), 3109; https://doi.org/10.3390/pr13103109 - 28 Sep 2025

Viewed by 668

Abstract

Solar biomass gasification results in reducing CO₂ emissions while saving biomass resources and producing higher-quality syngas when compared with conventional autothermal processes that require partial feedstock combustion for supplying the process heat. However, the solar process suffers from inherent barriers related to [...] Read more.

Solar biomass gasification results in reducing CO₂ emissions while saving biomass resources and producing higher-quality syngas when compared with conventional autothermal processes that require partial feedstock combustion for supplying the process heat. However, the solar process suffers from inherent barriers related to the variability of solar energy caused by cloud passages and shutdowns at night. The concept of hybrid solar gasification thus appears attractive for continuous and stabilized operation under intermittent or variable solar irradiation. This study addresses the dynamic simulation and control of hybrid solar–autothermal biomass gasification for continuous and stabilized syngas fuel production. A hybridization path with a constant H₂ + CO production was retained, and this control strategy was implemented in a second-by-second dynamic optimization problem using a model predictive control (MPC) algorithm. Its feasibility was demonstrated both at the small scale and industrial scale, and daily to yearly performance results were provided. For a 10 MW hybrid gasifier, the yearly solar heat share was 22% for a controlled 1000 NL/s production rate of H₂ + CO (corresponding to the complete allothermal gasification of ~2 t/h of wood at 1200 K), and this decreased with increasing H₂ + CO production objectives (17.4% at 1300 NL/s). A total of 24,200 t of wood feedstock and 8290 t of O₂ were required annually to generate 1410 t of H₂ and 19,200 t of CO, with a 1.03 average H₂:CO molar ratio. In addition, solar-only gasification and hybridization with external heating were also assessed. External auxiliary heating might be as efficient as in situ oxy-combustion and would not affect syngas composition by contamination from combustion products throughout hybridization. However, similar to external heat storage, the related thermal efficiency and heat losses must be considered. Full article

(This article belongs to the Special Issue Biomass to Renewable Energy Processes, 2nd Edition)

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18 pages, 1428 KB

Open AccessFeature PaperEditor’s ChoiceReview

Waste to Value: L-Asparaginase Production from Agro-Industrial Residues

by Enzo Corvello, Bruno C. Gambarato, Nathalia V. P. Veríssimo, Thiago Q. J. Rodrigues, Alice D. R. Pesconi, Ana K. F. Carvalho and Heitor B. S. Bento

Processes 2025, 13(10), 3088; https://doi.org/10.3390/pr13103088 - 26 Sep 2025

Viewed by 732

Abstract

The agro-industrial sector is a key pillar of the global economy, playing a central role in the supply of food, energy, and industrial inputs. However, its production chain generates significant amounts of residues and by-products, which, if not properly managed, may cause considerable [...] Read more.

The agro-industrial sector is a key pillar of the global economy, playing a central role in the supply of food, energy, and industrial inputs. However, its production chain generates significant amounts of residues and by-products, which, if not properly managed, may cause considerable environmental impacts. In this context, the search for alternatives to reuse these materials is essential, particularly when they can be converted into high-value products. One promising application is their use as a nutrient source for microorganisms in high-value biotechnological processes, such as the production of L-Asparaginase, an important enzyme used both in mitigating acrylamide formation in foods and as a biopharmaceutical in Acute Lymphoblastic Leukemia therapy. This approach offers a sustainable and competitive pathway, combining robust, scalable, and economical enzyme production with waste valorization and circular economy benefits. Although interest in developing more sustainable processes is growing, supported by international agreements and strategies for the valorization of agricultural residues, important challenges remain. The variability and impurity of residues pose significant challenges for producing biological products for the pharmaceutical and food industries. In addition, meeting regulatory requirements is essential to ensure product safety and traceability, while achieving high yields is crucial to maintain production viability compared to conventional media. Overcoming these barriers is critical to enable industrial-scale application of this approach. This review provides a residue-centered revision of the most relevant agro-industrial by-products used as substrates for L-asparaginase production, systematically comparing their compositional characteristics, fermentation strategies, and reported yields. Additionally, we present a novel SWOT (Strengths, Weaknesses, Opportunities, Threats) analysis that critically examines the technical, regulatory, and economic challenges of implementing residue-based processes on an industrial scale. Full article

(This article belongs to the Section Biological Processes and Systems)

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18 pages, 2855 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Disruption of Early Streptococcus mutans Biofilm Development on Orthodontic Aligner Materials

by Matea Badnjević, Mirna Petković Didović, Ivana Jelovica Badovinac, Sanja Lučić Blagojević, Marko Perčić, Stjepan Špalj and Ivana Gobin

Processes 2025, 13(10), 3069; https://doi.org/10.3390/pr13103069 - 25 Sep 2025

Viewed by 652

Abstract

(1) Background: This study aimed to determine the optimum parameters for the treatment of Streptococcus mutans biofilm on clear dental aligners. (2) Methods: A 24-h-old S. mutans biofilm was grown on polyurethane (PU) and poly(ethylene terephthalate glycol) (PETG) aligners. These samples were treated [...] Read more.

(1) Background: This study aimed to determine the optimum parameters for the treatment of Streptococcus mutans biofilm on clear dental aligners. (2) Methods: A 24-h-old S. mutans biofilm was grown on polyurethane (PU) and poly(ethylene terephthalate glycol) (PETG) aligners. These samples were treated with three chlorhexidine digluconate (CHX)-based antiseptic solutions, manual brushing, and a combination of both, with varying exposure times. The number of adhered bacteria was determined in both untreated and treated samples after sonication. Materials were analyzed with atomic force and scanning electron microscopy, and surface free energy (SFE) values were determined using three different models. (3) Results: Our findings indicated that control strategies do not depend on the type of material. PU and PETG surfaces exhibited similar SFE values (41–45 mJ/m²). Differences in surface roughness were insufficient to cause significant changes in S. mutans behavior. The highest efficacy of all three tested antiseptics was established for the exposure time of 1 min, with efficacy deteriorating just after 3 min. (4) Conclusions: The efficacy of CHX against S. mutans early biofilm is material-independent and time-dependent. The optimal exposure time of 1 min should be combined with brushing, with a general recommendation of the antiseptic-first approach. Full article

(This article belongs to the Special Issue Microbial Biofilms: Latest Advances and Prospects)

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18 pages, 1750 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Comparative Effects of Total, Water-Extractable, and Water-Unextractable Arabinoxylans from Wheat Bran on Dough and Noodle Properties

by Hyeonsu Han, Bomi Kim, Jaeha An and Meera Kweon

Processes 2025, 13(10), 3051; https://doi.org/10.3390/pr13103051 - 24 Sep 2025

Viewed by 563

Abstract

This study investigated the functional properties of arabinoxylan (AX) fractions—total (TAX), water-unextractable (WUAX), and water-extractable (WEAX)—isolated from three domestic wheat brans and their impact on flour functionality and noodle quality. WUAX was the predominant AX type, and it exhibited the highest water-absorption capacity, [...] Read more.

This study investigated the functional properties of arabinoxylan (AX) fractions—total (TAX), water-unextractable (WUAX), and water-extractable (WEAX)—isolated from three domestic wheat brans and their impact on flour functionality and noodle quality. WUAX was the predominant AX type, and it exhibited the highest water-absorption capacity, resulting in firmer dough and noodles but reduced visual and structural uniformity. By contrast, WEAX, characterized by a lower molecular weight and higher solubility, produced softer, more ductile dough and improved antioxidant properties, as indicated by elevated total phenolic content and scavenging activity against 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid radical. TAX demonstrated an intermediate behavior between that of WUAX and WEAX. AX addition produced no significant effect on gluten quality based on sodium dodecyl sulfate-sedimentation volume but substantially influenced the water solvent-retention capacity, dough development, and noodle texture. Functional differences were also observed among the wheat varieties, suggesting that both AX type and bran source affect performance. These findings demonstrate the potential for the targeted application of AX fractions to enhance the processing quality and nutritional value of wheat-based products, such as noodles, providing a basis for optimizing the use of functional ingredients in cereal food formulations. Full article

(This article belongs to the Special Issue Processing and Quality Control of Agro-Food Products)

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17 pages, 3106 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Effects of FPV Drone Frame Materials on Thermal Conditions of Motors Under Extreme Payloads: Experimental and Numerical Analysis

by Andrij Milenin

Processes 2025, 13(10), 3034; https://doi.org/10.3390/pr13103034 - 23 Sep 2025

Viewed by 992

Abstract

This study investigates the influence of frame material on the thermal behavior of motors and mechanical performance in First Person View (FPV) drones operating under extreme payloads. Two identical 7-inch quadcopters were constructed, differing only in the lower frame section material: carbon fiber-reinforced [...] Read more.

This study investigates the influence of frame material on the thermal behavior of motors and mechanical performance in First Person View (FPV) drones operating under extreme payloads. Two identical 7-inch quadcopters were constructed, differing only in the lower frame section material: carbon fiber-reinforced polymer (CF) or aluminum alloy 6061-T6 (AL). Both drones were subjected to 5-min hover tests with and without a 20 N payload, and their performance was assessed through infrared thermography, vibration analysis, flight log data, and finite element method (FEM) thermal simulations. Under no-load conditions, both frames showed comparable motor temperatures (37–44 °C). With payload CFframe motors exceeded 90 °C, indicating severe overheating, while ALframe motors remained below 60 °C, approximately 30 °C cooler, and demonstrated a more uniform temperature distribution between motors. Power analysis revealed higher consumption for the AL frame drone at no load due to its greater mass, but lower consumption under payload, likely because motor efficiency was maintained. Vibration analysis indicated fewer and lower-frequency resonances for the AL frame. FEM simulations, using boundary conditions from flight data, reproduced the experimental temperature distributions, confirming their reliability for predictive design. The overall results show that aluminum frames, although denser, enhance thermal regulation and dynamic stability in demanding UAV operations, providing practical guidance for defense, search-and-rescue, and other critical applications. Full article

(This article belongs to the Section Materials Processes)

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20 pages, 35510 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Effect of Glycerol Concentration on the Properties of Semolina- and Farina-Based Biodegradable Films

by Tomasz Tadeusz Murawski, Mikołaj Olczak, Szymon Mateusz Laskowski, Zuzanna Żołek-Tryznowska and Jerzy Szałapak

Processes 2025, 13(9), 3006; https://doi.org/10.3390/pr13093006 - 20 Sep 2025

Viewed by 655

Abstract

This study investigates the properties of biopolymer films derived from semolina and farina, focusing on the effect of varying concentrations of glycerol as a plasticizer. The research fills a gap in the study of grains such as semolina and farina, which have the [...] Read more.

This study investigates the properties of biopolymer films derived from semolina and farina, focusing on the effect of varying concentrations of glycerol as a plasticizer. The research fills a gap in the study of grains such as semolina and farina, which have the potential to expand the range of biodegradable materials. Mechanical tests revealed significant differences between the two film types. Farina-based films were notably more ductile, exhibiting an elongation at break of up to two times their original length, but with a low tensile strength of only 1–2 MPa. In contrast, semolina-based films were significantly stiffer, with a maximum elongation at break of 10%. A notable exception was the semolina film with a 25% glycerol concentration, which displayed an exceptionally high tensile strength of 17 MPa. This is a significant improvement over the typical potato starch-based film tested, which breaks at 5 MPa under static tearing. Furthermore, the study examined the films’ morphology, color, SFE, and surface roughness. Free surface energy ranged from 40 to 60 mJ/m² in the tests, where the influence of the plasticizer was significant. Color tests clearly show yellow discoloration. Full article

(This article belongs to the Section Materials Processes)

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16 pages, 2736 KB

Open AccessFeature PaperEditor’s ChoiceArticle

A Novel, Single-Step 3D-Printed Shadow Mask Fabrication Method for TFTs

by Kelsea A. Yarbrough, Makhes K. Behera, Sangram K. Pradhan and Messaoud Bahoura

Processes 2025, 13(9), 2976; https://doi.org/10.3390/pr13092976 - 18 Sep 2025

Viewed by 911

Abstract

This work presents a low-cost and scalable method for fabricating thin-film transistors (TFTs) using a single-step, 3D-printed shadow mask approach. Room temperature growth of both aluminum-doped zinc oxide (AZO) thin film was used as the semiconductor channel, and zirconium oxide (ZrO₂) [...] Read more.

This work presents a low-cost and scalable method for fabricating thin-film transistors (TFTs) using a single-step, 3D-printed shadow mask approach. Room temperature growth of both aluminum-doped zinc oxide (AZO) thin film was used as the semiconductor channel, and zirconium oxide (ZrO₂) as the high-k dielectric, and the films were never exposed to any post-annealing treatment. Structural and morphological characterization confirmed smooth, compact films with stable dielectric behavior. Electrical measurements revealed a field-effect mobility of 13.1 cm²/V·s, a threshold voltage of ~4.1 V, and an on/off ratio of ~10⁴, validating effective gate modulation and drain current saturation. The off-state current, estimated from AZO conductivity measurements, was ~10⁻¹⁰ A, while the on-state current reached ~10⁻⁶ A. Benchmarking against state-of-the-art devices shows that these transistors rival ALD-processed IGZO TFTs and significantly outperform reported indium-free ZnO/AZO devices, while avoiding scarce indium and costly high-temperature or photolithographic processing. These findings establish 3D-printed shadow masks as a practical alternative to conventional lithography for oxide TFT fabrication. The method offers high device performance with simplified, indium-free, and room-temperature processing, underscoring its potential for scalable, transparent, and flexible electronics. Full article

(This article belongs to the Special Issue Advanced Functionally Graded Materials)

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16 pages, 5313 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Upscaling of Toluene Oxidation Using Water-Sprinkled Pulsed Corona Discharge and Photocatalysis

by Daniel A. Teittinen, Sergei Preis and Juri Bolobajev

Processes 2025, 13(9), 2982; https://doi.org/10.3390/pr13092982 - 18 Sep 2025

Viewed by 506

Abstract

Advanced oxidation processes (AOPs) utilising a hydroxyl radical (•OH), a strong oxidant, are seen as a promising solution for removing hazardous and recalcitrant pollutants from waste streams. Among AOPs, non-thermal plasmas, especially pulsed corona discharge (PCD), enable the abatement of hazardous volatile organic [...] Read more.

Advanced oxidation processes (AOPs) utilising a hydroxyl radical (•OH), a strong oxidant, are seen as a promising solution for removing hazardous and recalcitrant pollutants from waste streams. Among AOPs, non-thermal plasmas, especially pulsed corona discharge (PCD), enable the abatement of hazardous volatile organic compounds (VOCs) with high energy efficiency. This study demonstrates the viability of upscaling PCD technology with water sprinkling in degrading the VOC toluene using a semi-pilot scale plasma reactor. A toluene–air mixture was treated with varying gas-phase toluene concentrations (30–100 ppm) and pulse repetition frequencies (25–800 pps), achieving toluene removal of 5–55% in PCD and an additional 10–18% in PCO, as well as excellent toluene removal energy efficiencies from 9.0 to 37.1 g kW⁻¹ h⁻¹. The process design with water sprinkling provides additional advantages compared to dry reactors—the water surface serves as a source of hydroxyl radicals and scrubs the air from degradation by-products resulting from the incomplete oxidation of target pollutants. Transformation products of toluene were identified, and an oxidation pathway via hydroxylation of the aromatic ring was suggested as the major route towards ring-opening reactions. A photocatalytic oxidation reactor with TiO₂ catalyst plates, following PCD as a post-treatment, enabled additional removal of residual contaminants, also converting residual ozone to oxygen. The PCD reactor with water sprinkling and post-plasma photocatalysis shows promising results for upscaling the process. Full article

(This article belongs to the Special Issue Mechanisms, Devices and Applications of Photocatalytic Processes)

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18 pages, 2421 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Operational Stress and Degradation of Inverters in Renewable and Industrial Power Systems

by Anna Jarosz-Kozyro and Jerzy Baranowski

Processes 2025, 13(9), 2987; https://doi.org/10.3390/pr13092987 - 18 Sep 2025

Viewed by 524

Abstract

The integration of photovoltaic (PV) systems into power grids has surged due to the global shift towards renewable energy, but this rapid adoption presents challenges like voltage regulation and inverter degradation. High PV penetration can lead to overvoltage conditions and transient voltage fluctuations, [...] Read more.

The integration of photovoltaic (PV) systems into power grids has surged due to the global shift towards renewable energy, but this rapid adoption presents challenges like voltage regulation and inverter degradation. High PV penetration can lead to overvoltage conditions and transient voltage fluctuations, which stress inverters and accelerate their degradation. To address these issues, advanced modeling techniques, particularly Bayesian modeling, are employed to predict and mitigate inverter failures by incorporating prior knowledge and real-world data. This approach enables probabilistic predictions of failure, improving maintenance scheduling and inverter design. By leveraging datasets from inverter operations with induction motors, this study aims to enhance the reliability of PV systems and optimize voltage regulation strategies for sustainable renewable energy growth. Full article

(This article belongs to the Special Issue Recent Advances in Renewable Energy Systems: Integration Challenges, Forecasting, and Grid Optimization for Sustainable Energy Management)

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23 pages, 4818 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Model Predictive Control of Common Ground PV Multilevel Inverter with Sliding Mode Observer for Capacitor Voltage Estimation

by Kelwin Silveira, Felipe B. Grigoletto, Fernanda Carnielutti, Mokhtar Aly, Margarita Norambuena and José Rodriguez

Processes 2025, 13(9), 2961; https://doi.org/10.3390/pr13092961 - 17 Sep 2025

Viewed by 826

Abstract

Transformerless inverters have received significant attention in solar photovoltaic (PV) applications. The absence of low-frequency transformers contributes to improved efficiency and reduced size compared to other topologies; however, there are concerns about leakage currents. The common ground (CG) connection in PV inverters is [...] Read more.

Transformerless inverters have received significant attention in solar photovoltaic (PV) applications. The absence of low-frequency transformers contributes to improved efficiency and reduced size compared to other topologies; however, there are concerns about leakage currents. The common ground (CG) connection in PV inverters is an attractive solution to this issue, as it generates a constant common-mode voltage and theoretically eliminates the leakage current. In this context, multilevel CG inverters can eliminate the leakage current while achieving high-quality output voltages. Nonetheless, achieving simultaneous control of the grid current and inner capacitor voltages can be challenging. Furthermore, controlling the capacitor voltages in multilevel inverters requires feedback from measurement sensors, which can increase the cost and may affect the overall reliability. To address these issues, this paper proposes a model predictive controller (MPC) for a CG multilevel inverter with a reduced number of sensors. While conventional MPC uses a classical multi-objective technique with a single cost function, the proposed method avoids the use of weighting factors in the cost function. Additionally, a sliding-mode observer is developed to estimate the capacitor voltages, and an incremental conductance-based maximum power point tracking (MPPT) algorithm is used to generate the current reference. Simulation and experimental results confirm the effectiveness of the proposed observer and MPC strategy. Full article

(This article belongs to the Special Issue Model Predictive Control of Electrical Systems: Methods, Results, and Challenges)

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21 pages, 1521 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Recovery of Carotenoids via Novel Extraction Technologies for the Valorization of Tomato By-Products

by Athina Ntzimani, Maria Tsevdou, Maria Katsouli, Ioanna Thanou, Dimitrios Tsimogiannis, Maria Giannakourou and Petros Taoukis

Processes 2025, 13(9), 2964; https://doi.org/10.3390/pr13092964 - 17 Sep 2025

Cited by 1 | Viewed by 586

Abstract

Tomato processing residues—including peels, seeds, and pomace—are rich in bioactive compounds, such as lycopene, β-carotene, cutin, pectin, and antioxidants, yet are often underutilized. This study evaluates microwave-assisted extraction (MAE) and high-pressure-assisted extraction (HPAE) for the recovery of carotenoids from TP, compared to [...] Read more.

Tomato processing residues—including peels, seeds, and pomace—are rich in bioactive compounds, such as lycopene, β-carotene, cutin, pectin, and antioxidants, yet are often underutilized. This study evaluates microwave-assisted extraction (MAE) and high-pressure-assisted extraction (HPAE) for the recovery of carotenoids from TP, compared to conventional extraction (CE) using ethyl acetate. Optimal MAE conditions (150 W, 50 °C, 20 min, solid/liquid ratio of 1:10 g/mL) yielded 592.5 mg carotenoids/kg dry weight (dw), exceeding CE yields (505.3 mg/kg dw), while significantly reducing extraction time (20 min vs. 120 min). By contrast, direct HPAE (650 MPa, ambient temperature, solid/liquid ratio of 1:10 g/mL) resulted in lower carotenoid yields (ca. 84 mg/kg dw), but when used as a pre-treatment followed by stirring for 24 h, HPAE enhanced carotenoids extractability to 277.0 mg/kg dw, recovering 55% of carotenoids extracted by CE. Bioaccessibility studies showed low lycopene bioaccessibility across all methods (3.9% for HPAE, 3.4% for MAE, and 1.6% for CE). Incorporation into oils significantly improved bioaccessibility, with olive pomace oil (OPO) achieving 28.1%, compared to 8.1% in corn oil (CO). Overall, MAE and HPAE (as pre-treatment) present efficient strategies that reduce solvent usage and processing time, though they still rely on organic solvents, while strategies to enhance bioaccessibility should further be explored for effective functional ingredient development. Full article

(This article belongs to the Special Issue Technologies for Production, Processing, and Extraction of Natural Products, 3rd Edition)

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26 pages, 2688 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Investigation of the Influencing Parameters of the H₂O₂-Assisted Photochemical Treatment of Waste Liquid from the Hydrothermal Carbonization Process in a Microreactor Flow System

by Aleksandra Petrovič, Tjaša Cenčič Predikaka, Silvo Hribernik and Andreja Nemet

Processes 2025, 13(9), 2934; https://doi.org/10.3390/pr13092934 - 14 Sep 2025

Viewed by 556

Abstract

Due to its complex composition and toxicity, the waste liquid from hydrothermal carbonization (HTC) poses a serious environmental challenge that must be addressed before disposal. In this study, the photochemical treatment of HTC liquid in a microreactor flow system was investigated. The effects [...] Read more.

Due to its complex composition and toxicity, the waste liquid from hydrothermal carbonization (HTC) poses a serious environmental challenge that must be addressed before disposal. In this study, the photochemical treatment of HTC liquid in a microreactor flow system was investigated. The effects of wavelength, the presence of atmospheric oxygen, oxidizing agent (H₂O₂) and catalyst (FeSO₄), residence time and pH on the efficiency of the photo-treatment were investigated. In addition, the influence of the addition of deep eutectic solvent (DES) on photo-treatment was studied. The results showed that the photochemical treatment was more efficient at 365 nm than at 420 nm, and that the acidic conditions gave better results than the basic ones. UV₃₆₅ treatment in the presence of H₂O₂ (at a dosage of 1 vol%) resulted in removal efficiencies of 31.6% for COD, 17.6% for TOC, 16.9% for NH₄-N and 17.2% for PO₄-P. The addition of FeSO₄ caused coagulation/flocculation effects, but improved phosphorus removal. The addition of DES resulted in slight discolouration of the liquid and proved unsuccessful in COD removal. The GC-MS analysis and 3D-EEM spectra showed significant changes in the fate of organics and in the fluorescence intensity of aromatic proteins and humic acid-like substances. Photochemical treatment in a microreactor flow system in the presence of H₂O₂ under the selected operating conditions reduced the content of organics and nutrients in the HTC liquid, but the process liquids still showed toxic effects on the organisms V. fischeri and Daphnia magna. Full article

(This article belongs to the Special Issue Chemical and Microbiological Analyses of Wastes, Effluents and Materials)

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27 pages, 6729 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Process Route for Electric Arc Furnace Dust (EAFD) Rinse Wastewater Desalination

by Hedviga Horváthová, Eduardo Henrique Rotta, Tatiane Benvenuti, Andréa Moura Bernardes, Andrea Miskufova and Zita Takáčová

Processes 2025, 13(9), 2919; https://doi.org/10.3390/pr13092919 - 12 Sep 2025

Viewed by 466

Abstract

This study introduces a two-step treatment method for synthetic and real electric arc furnace dust (EAFD) wastewater, integrating sorption with Mg–Al layered double hydroxides (LDHs) and electrodialysis (ED). The hydrotalcite (LDH), mainly Mg₆Al₂(CO₃)OH₁₆·4H₂O [...] Read more.

This study introduces a two-step treatment method for synthetic and real electric arc furnace dust (EAFD) wastewater, integrating sorption with Mg–Al layered double hydroxides (LDHs) and electrodialysis (ED). The hydrotalcite (LDH), mainly Mg₆Al₂(CO₃)OH₁₆·4H₂O (hydrotalcite-2H), was characterized by XRD, FTIR, SEM, and EDX, confirming its layered structure and ion-exchange capacity. Calcination at 550 °C was identified as optimal, enhancing sorption efficiency while retaining rehydration potential. Sorption tests demonstrated high effectiveness in removing multivalent ions, achieving over 99% elimination of Ca²⁺, SO₄²⁻, and Pb²⁺ ions and Cr from both synthetic and real wastewater. In contrast, monovalent ions such as Na⁺ and K⁺ were not effectively removed, except for partial removal of Cl⁻. To overcome this limitation, electrodialysis was applied in the second step, successfully targeting the remaining monovalent ions and achieving more than 95% conductivity reduction. A key challenge of ED, salt precipitation caused by calcium and sulphate in the concentrate, was effectively mitigated by the prior LDH treatment. The combined process minimized scaling risks, improved overall ion removal (above 97% for Na⁺ and K⁺), and produced low-salinity effluents (0.84 mS cm⁻¹), suitable for reuse in hydrometallurgical operations. These findings demonstrate that coupling LDH sorption with electrodialysis provides a sustainable and efficient strategy for treating high-salinity industrial wastewaters, particularly those originating from EAFD processes. Full article

(This article belongs to the Topic Advanced Processes and Technologies for Wastewater: Collection, Treatment, and Resource)

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29 pages, 7233 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Exposing Vulnerabilities: Physical Adversarial Attacks on AI-Based Fault Diagnosis Models in Industrial Air-Cooling Systems

by Stavros Bezyrgiannidis, Ioannis Polymeropoulos, Eleni Vrochidou and George A. Papakostas

Processes 2025, 13(9), 2920; https://doi.org/10.3390/pr13092920 - 12 Sep 2025

Viewed by 1126

Abstract

Although neural network-based methods have significantly advanced the field of machine fault diagnosis, they remain vulnerable to physical adversarial attacks. This work investigates such attacks in the physical context of a real production line. Attacks simulate failures or irregularities arising from the maintenance [...] Read more.

Although neural network-based methods have significantly advanced the field of machine fault diagnosis, they remain vulnerable to physical adversarial attacks. This work investigates such attacks in the physical context of a real production line. Attacks simulate failures or irregularities arising from the maintenance or production department during the production process, a scenario commonly encountered in industrial environments. The experiments are conducted using data from vibration signals and operational parameters of a motor installed in an industrial air-cooling system used for staple fiber production. In this context, we propose the Mean Confusion Impact Index (MCII), a novel and simple robustness metric that measures the average misclassification confidence of models under adversarial physical attacks. By performing a series of hardware-level interventions, this work aims to demonstrate that even minor physical disturbances can lead to a significant reduction in the model’s diagnostic accuracy. Additionally, a hybrid defense approach is proposed, which leverages deep feature representations extracted from the original classification model and integrates them with lightweight classifiers retrained on adversarial labeled data. Research findings underscore an important limitation in existing industrial artificial intelligence (AI)-based monitoring systems and introduce a practical, scalable framework for improving the physical resilience of machine fault diagnosis in real-world environments. Full article

(This article belongs to the Special Issue Application of Artificial Intelligence in Industrial Process Modelling and Optimization (2nd Edition))

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15 pages, 1698 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Fluorescence Spectroscopy Applied to Thermal Conversion of Bitumen

by Raj Divyajeetsinh, Lina M. Yañez Jaramillo, Priscila T. H. Nascimento and Arno de Klerk

Processes 2025, 13(9), 2901; https://doi.org/10.3390/pr13092901 - 11 Sep 2025

Viewed by 408

Abstract

Phase instability that develops during thermal conversion of heavy oils and bitumen limits the extent of conversion in processes such as visbreaking. It was postulated that aromatic species with conjugated unsaturated systems extending beyond the aromatic rings likely contributed to reactions leading to [...] Read more.

Phase instability that develops during thermal conversion of heavy oils and bitumen limits the extent of conversion in processes such as visbreaking. It was postulated that aromatic species with conjugated unsaturated systems extending beyond the aromatic rings likely contributed to reactions leading to phase instability, fouling, and coking. Many fluorophores have such conjugated π-electron systems. Three case studies were presented where products from thermal conversion were analyzed by fluorescence spectroscopy: (i) Cold Lake bitumen converted at 150–300 °C; (ii) asphaltenes depleted and enriched Athabasca bitumen converted at 380 °C; and (iii) Athabasca bitumen converted at 400 °C and 0.5–4.0 MPa. It was found that the fluorescence intensity of bitumen increased on thermal conversion. Fluorescence intensity increased in relation to reaction time for conversion at 150–300 °C, but it had a weak relationship with temperature. At 380 and 400 °C, this monotonic relationship was no longer apparent. There was no relationship with refractive index. Despite some overlap in fluorescence intensity values, 400 °C converted products obtained at 2.5–4.0 MPa had lower fluorescence intensity than products obtained at 0.5–2.0 MPa. Tentative explanations were offered for these observations. The change in fluorescence intensity with operating conditions and nature of the feed was consistent with the expected free radical concentration associated with the operating conditions and extent of hydrogen transfer. Although the study did not provide proof for the relationship between the fluorescence intensity and the concentration of aromatic species with conjugated unsaturated systems, the experimental observations were congruent with it. Full article

(This article belongs to the Special Issue Petroleum Characterization and Bioprocesses: Numerical and Experimental Investigation (2nd Edition))

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17 pages, 1832 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Comparison of Active and Passive Grid Coupling in Distribution Grids Using Particle Swarm Optimization

by Frederik Gielnik, Sebastian Hormel, Michael Suriyah and Thomas Leibfried

Processes 2025, 13(9), 2905; https://doi.org/10.3390/pr13092905 - 11 Sep 2025

Viewed by 607

Abstract

Distribution networks are facing increasing challenges due to the growing share of renewable energy sources (RESs), particularly because of the volatile nature of the available power. In addition to targeted grid expansion measures, the concept of a dynamic grid topology offers an additional [...] Read more.

Distribution networks are facing increasing challenges due to the growing share of renewable energy sources (RESs), particularly because of the volatile nature of the available power. In addition to targeted grid expansion measures, the concept of a dynamic grid topology offers an additional layer of flexibility in the power system. Furthermore, there are concepts to use active coupling methods in distribution grids, such as medium-voltage direct current (MVDC) systems, which enable horizontal power flows between distribution grids and thus active control. This paper investigates the potential of combining dynamic passive and active coupling between two distribution grids. Particle swarm optimization (PSO) is used to determine both an optimized operating point of two MVDC interconnections as well as the most efficient switch configuration within both networks. The goal of the optimization is to reduce both network losses and power exchange between the different voltage levels. To evaluate its potential, various use cases are simulated using a representative feed-in of photovoltaics while considering grid constraints. Individual and combined impacts of dynamic AC switching and DC coupling are compared using a modified IEEE-123 test feeder. The results show a significant optimization potential, especially with an increase in RES penetration within the grid. In the best scenarios, the power losses can be decreased by 33.73% and the power transfer can be reduced by 8.75%. Full article

(This article belongs to the Special Issue AI-Based Modelling and Control of Power Systems)

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39 pages, 2107 KB

Open AccessFeature PaperEditor’s ChoiceReview

A Comparative Review on Dry Ice Production Methods: Challenges, Sustainability and Future Directions

by Jean Claude Assaf, Christina Issa, Tony Flouty, Lea El Marji and Mantoura Nakad

Processes 2025, 13(9), 2848; https://doi.org/10.3390/pr13092848 - 5 Sep 2025

Viewed by 1819

Abstract

Dry ice, the solid form of carbon dioxide (CO₂), is widely used in cold chain logistics, industrial cleaning, and biomedical preservation. Its production, however, is closely linked to carbon capture, energy-intensive liquefaction, and solidification processes. This review critically evaluates and compares [...] Read more.

Dry ice, the solid form of carbon dioxide (CO₂), is widely used in cold chain logistics, industrial cleaning, and biomedical preservation. Its production, however, is closely linked to carbon capture, energy-intensive liquefaction, and solidification processes. This review critically evaluates and compares the existing methods of CO₂ capture, including chemical absorption, physical absorption, adsorption, and membrane-based separation as they pertain to dry ice production. This study further assesses liquefaction cycles using refrigerants such as ammonia and R744, highlighting thermodynamic and environmental trade-offs. Solidification techniques are examined in the context of energy consumption, process integration, and product quality. The comparative analysis is supported by extensive tabulated data on operating conditions, CO₂ purity, and sustainability metrics. This review identifies key technical and environmental challenges, such as solvent regeneration, CO₂ leakage, and energy recovery. Thus, it also explores emerging innovations, including hybrid cycles and renewable energy integration, to advance the sustainability of dry ice production. This, in turn, offers strategic insight for optimizing dry ice manufacturing in alignment with low-carbon industrial goals. Full article

(This article belongs to the Section Chemical Processes and Systems)

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24 pages, 2087 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Towards Surrogate Modeling for Adsorption Processes Using Physics-Informed Neural Networks

by Mattia Galanti, Mik Janssen, Ivo Roghair, Jean-Yves Dieulot, Pejman Shoeibi Omrani, Jurriaan Boon and Martin van Sint Annaland

Processes 2025, 13(9), 2824; https://doi.org/10.3390/pr13092824 - 3 Sep 2025

Viewed by 1728

Abstract

Physics-informed neural networks (PINNs) have emerged as a promising alternative to purely data-driven neural networks (NNs) for surrogate modeling, particularly in data-scarce scenarios. This study evaluates the performance of hybrid-PINNs against traditional NNs for modeling the adsorption step of a Direct Air Capture [...] Read more.

Physics-informed neural networks (PINNs) have emerged as a promising alternative to purely data-driven neural networks (NNs) for surrogate modeling, particularly in data-scarce scenarios. This study evaluates the performance of hybrid-PINNs against traditional NNs for modeling the adsorption step of a Direct Air Capture (DAC) process. As the complexity of the modeled system increases, larger datasets and longer computational times are required for numerical methods. Therefore, the study aims to develop approaches that minimize data requirements while maintaining accuracy, which is crucial for efficient modeling of complex physical systems. While both AI models can achieve high accuracy with abundant data, the advantages of hybrid-PINNs become more evident as data becomes scarce. In the intermediate and low-data regimes, the physics constraints embedded in hybrid-PINNs significantly improve generalization and predictive accuracy. For extreme low-data conditions, a curriculum learning strategy is implemented, progressively enforcing physics constraints to mitigate underfitting and enhance model stability. Despite these benefits, hybrid-PINNs exhibit a computational cost approximately one order of magnitude higher than traditional NNs as enforcing physics constraints increases training complexity. The results suggest that PINNs hold potential for modeling complex multi-physics problems in DAC and beyond, provided challenges related to gradient balancing and computational efficiency are addressed. Full article

(This article belongs to the Section Environmental and Green Processes)

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26 pages, 2161 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Mining and Processing of Mineral Resources: A Comparative Study of Simulated and Operational Processes

by Radim Rybár, Martin Beer and Lucia Bednárová

Processes 2025, 13(9), 2823; https://doi.org/10.3390/pr13092823 - 3 Sep 2025

Viewed by 1876

Abstract

The aim of this study is to analyze the representation of geological, mining, processing, and environmental processes in platform Minecraft. Based on a methodological comparison of in-platform mechanics with technological and geoscientific procedures, the article assesses the degree of accuracy, simplification, and didactic [...] Read more.

The aim of this study is to analyze the representation of geological, mining, processing, and environmental processes in platform Minecraft. Based on a methodological comparison of in-platform mechanics with technological and geoscientific procedures, the article assesses the degree of accuracy, simplification, and didactic applicability of individual processes related to the extraction and use of mineral resources. The analysis is structured into seven main thematic areas covering the entire resource value chain—from geological exploration through mining, ore beneficiation and processing, to quantitative indicators (e.g., waste-to-ore ratio), fluid resources, and environmental impacts. Special attention is given to the potential of modifications that significantly enhance the complexity and accuracy of simulated processes. The results show that Minecraft, enriched with thematic mods, can serve as an accessible and flexible tool for the popularization and education of industrial and geoscientific processes, while engaging a wide range of audiences. Full article

(This article belongs to the Special Issue Advances in Coal Processing, Utilization, and Process Safety)

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16 pages, 9259 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Computational Analysis of Two Micro-Vortex Generator Configurations for Supersonic Boundary Layer Flow Control

by Yong Yang, Caixia Chen, Yonghua Yan and Mai Al Shaaban

Processes 2025, 13(9), 2818; https://doi.org/10.3390/pr13092818 - 3 Sep 2025

Viewed by 699

Abstract

The increasing demand for effective flow control in supersonic boundary layers, particularly for mitigating shock-wave boundary-layer interactions, underscores the need to explore optimized micro-vortex generator (MVG) configurations. This study investigates the aerodynamic performance of two different MVG configurations: a two-MVG setup with a [...] Read more.

The increasing demand for effective flow control in supersonic boundary layers, particularly for mitigating shock-wave boundary-layer interactions, underscores the need to explore optimized micro-vortex generator (MVG) configurations. This study investigates the aerodynamic performance of two different MVG configurations: a two-MVG setup with a pair of close parallel-positioned MVGs and a three-MVG arrangement that includes an additional upstream unit. Both are examined within a Mach 2.5 flow regime, aiming to improve mixing and energize the boundary layer. Large Eddy Simulations (LES) were performed using high-order numerical schemes. A newly developed vortex identification method was utilized to characterize vortex structures, while turbulent kinetic energy (TKE) metrics were integrated to quantify turbulence. Findings reveal that the two-MVG configuration produces regular, symmetric vortex pairs with limited interaction. This results in a steady increase in TKE and a thickened momentum boundary layer—indicative of notable energy loss. In contrast, the three-MVG setup generates more intricate and interactive vortex formations that significantly elevate TKE levels, rapidly expand the turbulent region, and reduce energy loss downstream. The peak TKE occurs before tapering slightly. Instantaneous flow analysis further highlights chaotic, hairpin-dominated vortex structures in the three-MVG case, compared to the more orderly ones observed in the two-MVG case. Overall, the three-MVG configuration demonstrates superior mixing and boundary-layer energization potential, albeit with greater structural complexity. Full article

(This article belongs to the Special Issue Transport Processes in Single- and Multi-Phase Flow Systems)

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12 pages, 1252 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Microparticle Production of Mefenamic Acid Using the Continuous Antisolvent Sonocrystallization Process

by Salal Hasan Khudaida, Chia-Yi Lee and Chie-Shaan Su

Processes 2025, 13(9), 2813; https://doi.org/10.3390/pr13092813 - 2 Sep 2025

Viewed by 974

Abstract

Continuous crystallizations have promising potential for effectively controlling and modifying the crystal properties of active pharmaceutical ingredients (APIs). In this study, a continuous antisolvent sonocrystallization process was developed to recrystallize a poorly water-soluble API, mefenamic acid, for microparticle production. This method offers advantages [...] Read more.

Continuous crystallizations have promising potential for effectively controlling and modifying the crystal properties of active pharmaceutical ingredients (APIs). In this study, a continuous antisolvent sonocrystallization process was developed to recrystallize a poorly water-soluble API, mefenamic acid, for microparticle production. This method offers advantages such as efficient sonication, enhanced heat removal, and potential for scalability. The effects of operating parameters, such as sonication intensity, crystallization temperature, antisolvent flow rate, and solution flow rate, were investigated and compared. Using continuous antisolvent sonocrystallization, the particle size of mefenamic acid was controlled within the range of 2.6–3.5 μm, achieving a narrower particle size distribution compared to the unprocessed sample. In addition, scanning electron microscopy (SEM) analysis confirmed that the sonocrystallized mefenamic acid exhibited an improved crystal shape. Analytical results from powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC) showed that the crystal structure, spectroscopic characteristics, and thermal behavior of mefenamic acid remained unchanged after the sonocrystallization process. Full article

(This article belongs to the Special Issue 2nd Edition of Green Particle Technologies: Processes and Applications)

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19 pages, 2366 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Characterization of Cadmium Removal Processes from Seawater by the Living Biomass of Three Microalgae with Different Tolerance to This Metal

by Julio Abalde and Enrique Torres

Processes 2025, 13(9), 2804; https://doi.org/10.3390/pr13092804 - 1 Sep 2025

Viewed by 657

Abstract

Pollution of the marine environment is a current problem. One of the main pollutants is cadmium. This heavy metal is toxic for living beings. For this reason, the removal of cadmium from seawater solutions is a relevant problem. However, there are few studies [...] Read more.

Pollution of the marine environment is a current problem. One of the main pollutants is cadmium. This heavy metal is toxic for living beings. For this reason, the removal of cadmium from seawater solutions is a relevant problem. However, there are few studies on the elimination of this metal in seawater. Biosorption is a technique that uses the properties of living or dead biomass to remove pollutants from solutions in an efficient and environmentally friendly way. Microalgal biomass has shown good results in this field. In this work, the ability of the living biomass of three species of marine microalgae (Phaeodactylum tricornutum, Tetraselmis suecica and Dunaliella salina) to remove cadmium from seawater was studied. Growth, kinetics, equilibrium isotherms, cadmium adsorbed to the cell surface and intracellular cadmium were studied. The efficiency of the three species in removing cadmium was compared, showing significant differences both in kinetics and in amount of cadmium removed. After 96h P. tricornutum was able to remove 27.48 ± 1.05 milligrams of cadmium per gram of biomass, T. suecica 78.11 ± 2.08 and D. salina 10.72 ± 0.28. The percentage of cadmium removed by adsorption was higher than the intracellular, except for the lowest cadmium concentrations in P. tricornutum and T. suecica. Full article

(This article belongs to the Special Issue Microbial Bioremediation of Environmental Pollution (2nd Edition))

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27 pages, 6026 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Application of an Automated Machine Learning-Driven Grid Block Classification Framework to a Realistic Deep Saline Aquifer Model for Accelerating Numerical Simulations of CO₂ Geological Storage

by Eirini Maria Kanakaki, Sofianos Panagiotis Fotias and Vassilis Gaganis

Processes 2025, 13(8), 2658; https://doi.org/10.3390/pr13082658 - 21 Aug 2025

Cited by 2 | Viewed by 670

Abstract

Numerical simulations are essential for optimizing CO₂ geological storage in deep saline aquifers; however, their substantial computational demands pose a significant challenge. This study introduces an automated machine learning (ML)-driven grid block classification framework applied to a realistic deep saline aquifer model [...] Read more.

Numerical simulations are essential for optimizing CO₂ geological storage in deep saline aquifers; however, their substantial computational demands pose a significant challenge. This study introduces an automated machine learning (ML)-driven grid block classification framework applied to a realistic deep saline aquifer model to accelerate numerical simulations while maintaining accuracy. The methodology employs an ML and interquartile range-based classifier to distinguish grid blocks as either fast- or slow-varying. ML-based proxy models are applied exclusively to slow-varying regions, while traditional iterative methods handle dynamic, fast-varying regions. Results confirm a considerable reduction in computational costs without compromising predictive accuracy. Validated under realistic reservoir conditions, the approach demonstrates scalability and robustness, supporting efficient, accurate large-scale CO₂ storage simulations and advancing sustainable subsurface sequestration strategies. Full article

(This article belongs to the Special Issue 2nd Edition of Artificial Intelligent Techniques in the Optimal Operation of Oil and Gas Production Systems)

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29 pages, 5893 KB

Open AccessFeature PaperEditor’s ChoiceReview

Solid Oxide Electrolyzers Process Integration: A Comprehensive Review

by Fernando Ferrete, Ana Molina, Gracia María Cabello González, Ángeles Moreno-Racero, Henar Olmedo and Alfredo Iranzo

Processes 2025, 13(8), 2656; https://doi.org/10.3390/pr13082656 - 21 Aug 2025

Cited by 1 | Viewed by 2762

Abstract

Solid oxide electrolysis (SOEL) has emerged as a promising technology for efficient hydrogen production. Its main advantages lie in the high operating temperatures, which enhance thermodynamic efficiency, and in the ability to supply part of the required energy in the form of heat. [...] Read more.

Solid oxide electrolysis (SOEL) has emerged as a promising technology for efficient hydrogen production. Its main advantages lie in the high operating temperatures, which enhance thermodynamic efficiency, and in the ability to supply part of the required energy in the form of heat. Nevertheless, improving the long-term durability of stack materials remains a key challenge. Thermal energy can be supplied by dedicated integration with different industrial processes, where the main challenge lies in the elevated stack operating temperature (700–900 °C). This review provides a comprehensive analysis of the integration of solid oxide electrolysis cells (SOECs) into different industrial applications. Main processes cover methanol production, methane production, Power-to-Hydrogen systems, or the use of reversible solid oxide electrolysis cell (rSOEC) stacks that can operate in both electrolysis and fuel cell mode. The potential of co-electrolysis to increase process flexibility and broaden application areas is also analyzed. The aim is to provide a comprehensive analysis of the integration strategies, identify the main technical and economic challenges, and highlight recent developments and future trends in the field. A detailed comparison assessment of the different processes is being discussed in terms of electrical and thermal efficiencies and operating parameters, as well as Key Performance Indicators (KPIs) for each process. Technical-economic challenges that are currently a barrier to their implementation in industry are also analyzed. Full article

(This article belongs to the Special Issue Sustainable and Intelligent Energy Systems and Processes: Recent Advances and Challenges (2nd Edition))

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25 pages, 5337 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Development of a CFD Model to Study the Fundamental Phenomena Associated with Biomass Combustion in a Grate-Fired Boiler

by João Pedro Silva, Senhorinha Teixeira and José Carlos Teixeira

Processes 2025, 13(8), 2617; https://doi.org/10.3390/pr13082617 - 18 Aug 2025

Cited by 1 | Viewed by 1100

Abstract

Usually, biomass combustion in grate-fired boilers presents significant challenges due to the heterogeneous nature of the fuel, chemical composition variability, and complex thermal and chemical conversion processes along the grate. Accurate modeling of the fuel bed conversion is critical for optimizing combustion performance [...] Read more.

Usually, biomass combustion in grate-fired boilers presents significant challenges due to the heterogeneous nature of the fuel, chemical composition variability, and complex thermal and chemical conversion processes along the grate. Accurate modeling of the fuel bed conversion is critical for optimizing combustion performance and reducing emissions. However, detailed bed models are often computationally intensive and time-consuming. To address this issue, the present work details a simplified empirical bed model that is integrated into a 3D computational fluid dynamics (CFD) simulation of a 35 MW industrial grate-fired boiler. The model successfully reproduced the flue gas mass flow rate, temperature, and chemical composition across different grate sections, predicting an average furnace outlet temperature of 994 °C, CO mass fraction of 779 mg/m³, CO₂ concentration of 12 vol.%, and O₂ concentration of 9.5 vol.%. These results fall within the range reported in recent CFD studies of similar systems and are consistent with operational monitoring data from the same plant. Sensitivity analyses showed that modifying the primary-to-secondary-air split ratio from 79/21 to 40/60 reduced the average CO mass fraction at the furnace outlet by more than 50%. Additionally, the average furnace temperature increased up to 1050 °C, enhancing combustion efficiency. The CFD model also demonstrated that relocating char combustion to later grate sections led to temperature imbalances near the boiler walls, emphasizing the importance of grate-specific conversion profiles. These results underscore the model’s ability to guide air distribution optimization, improve combustion performance, and reduce pollutant emissions in biomass boilers. Full article

(This article belongs to the Special Issue Applications of Computational Fluid Dynamics (CFD) in Chemical Process Simulations)

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23 pages, 313 KB

Open AccessFeature PaperEditor’s ChoiceReview

Valorization of Food Industry Waste for Biodegradable Biopolymer-Based Packaging Films

by Kristina Cvetković, Ivana Karabegović, Simona Dordevic, Dani Dordevic and Bojana Danilović

Processes 2025, 13(8), 2567; https://doi.org/10.3390/pr13082567 - 14 Aug 2025

Cited by 2 | Viewed by 1094

Abstract

In recent years, food waste management has become one of the key challenges faced by modern society. The significant ecological footprint left by this type of waste can be mitigated through proper valorization. Directing food waste towards the production of biopolymers has attracted [...] Read more.

In recent years, food waste management has become one of the key challenges faced by modern society. The significant ecological footprint left by this type of waste can be mitigated through proper valorization. Directing food waste towards the production of biopolymers has attracted considerable attention from researchers. Plant- and animal-based by-products from the food industry are the valuable materials which can be utilized for the production of biopolymer-based films. Although the use of food waste in biopolymer film production holds great potential, various factors such as the type of source and extraction methods significantly affect the physicochemical properties of the films. With the addition of various compounds that enhance their antioxidant and antimicrobial effects, these films can prolong the freshness and safety of packaged products, making them comparable to plastic derived from fossil fuels. This review highlights the potential of biopolymers from food waste for the production of biopolymer-based films and the possibilities of their modification in order to improve their properties for use in the food packaging industry. Full article

(This article belongs to the Special Issue Resource Utilization of Food Industry Byproducts)

19 pages, 539 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Drying Kinetics and Physicochemical Characteristics of Dehydrated Jerusalem Artichoke (Helianthus tuberosus L.)

by Stanisław Rudy, Dariusz Dziki, Beata Biernacka, Renata Polak, Andrzej Krzykowski, Marek Domin, Grzegorz Rudzki and Magdalena Kachel-Górecka

Processes 2025, 13(8), 2553; https://doi.org/10.3390/pr13082553 - 13 Aug 2025

Cited by 1 | Viewed by 716

Abstract

Jerusalem artichoke (Helianthus tuberosus L.) is a valuable source of inulin and fructooligosaccharides—compounds with well-documented prebiotic and functional food properties. However, its high moisture content significantly limits storage stability. This study aimed to assess the effects of drying method and process temperature [...] Read more.

Jerusalem artichoke (Helianthus tuberosus L.) is a valuable source of inulin and fructooligosaccharides—compounds with well-documented prebiotic and functional food properties. However, its high moisture content significantly limits storage stability. This study aimed to assess the effects of drying method and process temperature on the drying kinetics and selected physicochemical properties of Jerusalem artichoke. Convective drying (AD) and combined convective–microwave drying (AMD), using a microwave power of 100 W, were employed. Drying was conducted at air temperatures of 40 °C, 60 °C, and 80 °C. Among the mathematical models evaluated, the Page model provided the best fit to the experimental drying data for both methods. Samples dried at 80 °C using the AMD technique exhibited the most pronounced changes in color, significant polyphenol losses, and a substantial reduction in antioxidant capacity compared to the fresh material. The lowest polyphenol degradation and the highest retention were observed in products dried at 40 °C using both AD and AMD methods. Notably, the AMD method significantly reduced drying time and improved the grindability of the dried Jerusalem artichoke samples. Although AMD contributed to certain quality deterioration, it also promoted a higher degree of particle size reduction. However, this increased degree of particle size reduction had only a limited effect on the extraction efficiency of fructooligosaccharides and inulin. The results of the present study suggest that AMD may serve as a competitive alternative to AD for drying Jerusalem artichoke, particularly when processing time and grindability are critical considerations. Full article

(This article belongs to the Special Issue Drying Kinetics and Quality Control in Food Processing, 2nd Edition)

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20 pages, 3853 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Immobilized Pseudomonas fluorescens Lipase on Eggshell Membranes for Sustainable Lipid Structuring in Cocoa Butter Substitute

by Marta Ostojčić, Marija Stjepanović, Blanka Bilić Rajs, Ivica Strelec, Natalija Velić, Mirna Brekalo, Volker Hessel and Sandra Budžaki

Processes 2025, 13(8), 2548; https://doi.org/10.3390/pr13082548 - 12 Aug 2025

Cited by 1 | Viewed by 663

Abstract

As the supply of cocoa becomes increasingly volatile, biotechnological innovations such as lipid engineering with lipases play a crucial role in supporting more stable, ethical, and sustainable chocolate production systems. This study explores the potential of Pseudomonas fluorescens lipase immobilized on eggshell membrane-based [...] Read more.

As the supply of cocoa becomes increasingly volatile, biotechnological innovations such as lipid engineering with lipases play a crucial role in supporting more stable, ethical, and sustainable chocolate production systems. This study explores the potential of Pseudomonas fluorescens lipase immobilized on eggshell membrane-based carriers for the synthesis of a cocoa butter substitute (CBS). The carriers were prepared by treating eggshells with different acids to generate chemically distinct support materials. Lipase immobilization was performed using both adsorption and covalent binding techniques. All resulting biocatalysts were characterized and compared to the free enzyme with respect to pH and temperature optima, as well as thermal and solvent stability. Immobilization caused shifts in the enzyme’s optimal operating conditions and significantly improved its stability at elevated temperatures and in the presence of organic solvents. Among the tested systems, the lipase immobilized by adsorption onto a hydrochloric acid-treated carrier exhibited the best performance. Using this biocatalyst, a CBS containing 93.54 ± 0.16% of the target triacylglycerols (POP, POS, and SOS) was successfully synthesized and reused over five consecutive synthesis cycles without significant loss of activity. These findings demonstrate the potential of waste-derived biomaterials for the development of efficient, stable, and reusable biocatalysts in the enzymatic production of functional lipids. Full article

(This article belongs to the Section Biological Processes and Systems)

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28 pages, 2321 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Effect of Different Amine Solutions on Performance of Post-Combustion CO₂ Capture

by Sara Elmarghni, Meisam Ansarpour and Tohid N. Borhani

Processes 2025, 13(8), 2521; https://doi.org/10.3390/pr13082521 - 10 Aug 2025

Cited by 1 | Viewed by 3616

Abstract

Carbon dioxide (CO₂) is the primary component contributing to anthropogenic greenhouse gas emissions, necessitating the adoption of effective mitigation strategies to promote environmental sustainability. Among the various carbon capture methodologies, chemical absorption is acknowledged as the most scalable solution for post-combustion [...] Read more.

Carbon dioxide (CO₂) is the primary component contributing to anthropogenic greenhouse gas emissions, necessitating the adoption of effective mitigation strategies to promote environmental sustainability. Among the various carbon capture methodologies, chemical absorption is acknowledged as the most scalable solution for post-combustion applications. This investigation presents a thorough, comparative, and scenario-based evaluation of both singular and blended amine solvents for CO₂ capture within packed absorption–desorption columns. A validated rate-based model employing monoethanolamine (MEA) functions as the benchmark for executing process simulations. Three sequential scenarios are meticulously examined to switch the solvents and see the results. In the preliminary scenario, baseline performance is assessed by applying MEA to achieve the designated 73% removal target. Then the implementation of alternative solvents is examined—piperazine (PZ), a combination of methyldiethanolamine (MDEA) and PZ, and a blend of MEA and PZ—under uniform design parameters to ascertain their relative effectiveness and performance. In the second scenario, the design of the system is changed to reach a CO₂ removal efficiency for MEA of 90%, and then MEA is switched to other solvents. In the final scenario, critical design parameters, including column height and diameter, are adjusted for each solvent system that did not meet the 90% capture efficiency in Scenario 2 to achieve 90% CO₂ capture. A comprehensive sensitivity analysis is subsequently conducted on the adjusted systems to evaluate the influence of critical operational variables such as temperature, flue gas and solvent flow rates, and concentrations. Importantly, the MEA + PZ blend also demonstrated the lowest specific reboiler duty, as low as 4.28 MJ/kg CO₂, highlighting its superior energy efficiency compared to other solvents in the condition that the system in this study is pilot-scale, not commercial-scale, and due to this reason, the energy consumption of the system is slightly higher than the reported value for the commercial-scale systems. The results yield invaluable insights into the performance trade-offs between singular and blended amines, thereby facilitating the development of more efficient CO₂ capture systems that function within practical constraints. Full article

(This article belongs to the Section Chemical Processes and Systems)

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11 pages, 1278 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Investigation of Low-Toxicity Azoic Direct Dyes Synthesized from 4,4′-Diaminobenzanilide

by Maria Elena Radulescu-Grad, Simona Popa, Giannin Mosoarca and Vasile Daniel Gherman

Processes 2025, 13(8), 2505; https://doi.org/10.3390/pr13082505 - 8 Aug 2025

Viewed by 526

Abstract

In this paper, a toxicological investigation was carried out on a series of azoic direct dyes generally with an affinity for cellulosic fibers, presenting symmetrical and asymmetrical structures having as a central component a non-carcinogenic, mutagenic, or teratogenic and accessible precursor potential substitute [...] Read more.

In this paper, a toxicological investigation was carried out on a series of azoic direct dyes generally with an affinity for cellulosic fibers, presenting symmetrical and asymmetrical structures having as a central component a non-carcinogenic, mutagenic, or teratogenic and accessible precursor potential substitute for benzidine, namely 4,4′-diaminobenzanilide, and, as coupling components, 2-hydroxybenzoic acid, 2-hydroxy-3,6-naphthalenesulfonic acid, 2-amino-8-hydroxynaphthalene-6-sulfonic acid, 1-amino-8-hydroxynaphthalene-3,6-disulfonic acid, 1-(4′-sulfophenyl)-3-methyl-5-pyrazolone, and 2-hydroxy-6-naphthalenesulfonic acid, respectively. For the purpose of their safe use, this study shows the results regarding the toxicity of the above-mentioned dyes, obtained through biological tests on colonies of Hydractinia echinata (H. echinata). The toxicity tests were performed on heterotrophic bacteria cultures obtained from the Bega River. The minimum toxic concentration was monitored using the dilutions 0.6 g/L, 24 g/L, and 48 g/L, obtained by dilution of a stock solution of 60 g/L. The symmetric dye with the coupling component 2-hydroxybenzoic acid presents the highest degree of toxicity, the lowest being shown by dyes with symmetric and asymmetric structures with the following coupling components: 2-amino-8-hydroxynaphthalene-6-sulfonic acid, 1-amino-8-hydroxynaphthalene-3,6-disulfonic acid, 1-(4′-sulfophenyl)-3-methyl-5-pyrazolone, and 2-hydroxy-6-naphthalenesulfonic acid. Full article

(This article belongs to the Section Biological Processes and Systems)

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23 pages, 2823 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Thermodynamic Analysis of Biomass Pyrolysis in an Auger Reactor Coupled with a Fluidized-Bed Reactor for Catalytic Deoxygenation

by Balkydia Campusano, Michael Jabbour, Lokmane Abdelouahed and Bechara Taouk

Processes 2025, 13(8), 2496; https://doi.org/10.3390/pr13082496 - 7 Aug 2025

Viewed by 1159

Abstract

This research contributes to advance the sustainable production of biofuels and provides insights into the energy and exergy assessment of bio-oil, which is essential for developing environmentally friendly energy production solutions. Energy and exergy analyses were performed to evaluate the pyrolysis of beech [...] Read more.

This research contributes to advance the sustainable production of biofuels and provides insights into the energy and exergy assessment of bio-oil, which is essential for developing environmentally friendly energy production solutions. Energy and exergy analyses were performed to evaluate the pyrolysis of beech wood biomass at 500 °C in an Auger reactor. To improve the quality of the obtained bio-oil, its catalytic deoxygenation was performed within an in-line fluidized catalytic bed reactor using a catalyst based on HZSM5 zeolite modified with 5 wt.% Iron (5%FeHZSM-5). A thermodynamic analysis of the catalytic and non-catalytic pyrolysis system was carried out, as well as a comparative study of the calculation methods for the energy and exergy evaluation for bio-oil. The required heat for pyrolysis was found to be 1.2 MJ/kg_biomass in the case of non-catalytic treatment and 3.46 MJ/kg_biomass in the presence of the zeolite-based catalyst. The exergy efficiency in the Auger reactor was 90.3%. Using the catalytic system coupled to the Auger reactor, this efficiency increased to 91.6%, leading to less energy degradation. Calculating the total energy and total exergy of the bio-oil using two different methods showed a difference of 6%. In the first method, only the energy contributions of the model compounds, corresponding to the major compounds of each chemical family of bio-oil, were considered. In contrast, in the second method, all molecules identified in the bio-oil were considered for the calculation. The second method proved to be more suitable for thermodynamic analysis. The novelties of this work concern the thermodynamic analysis of a coupled system of an Auger biomass pyrolysis reactor and a fluidized bed catalytic deoxygenation reactor on the one hand, and the use of all the molecules identified in the oily phase for the evaluation of energy and exergy on the other hand. Full article

(This article belongs to the Section Chemical Processes and Systems)

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21 pages, 8315 KB

Open AccessFeature PaperEditor’s ChoiceArticle

The Influence of the Geometric Configuration of the Drive System on the Motion Dynamics of Jaw Crushers

by Emilian Mosnegutu, Claudia Tomozei, Oana Irimia, Vlad Ciubotariu, Diana Mirila, Mirela Panainte-Lehadus, Marcin Jasiński, Nicoleta Sporea and Ivona Camelia Petre

Processes 2025, 13(8), 2498; https://doi.org/10.3390/pr13082498 - 7 Aug 2025

Viewed by 498

Abstract

This study presents a comparative analysis of two double-toggle drive systems for jaw crushers that are tension based and compression based (this refers to the way in which the connecting rod is mechanically stressed within the drive mechanism), with the objective of identifying [...] Read more.

This study presents a comparative analysis of two double-toggle drive systems for jaw crushers that are tension based and compression based (this refers to the way in which the connecting rod is mechanically stressed within the drive mechanism), with the objective of identifying the optimal configuration from both kinematic and functional perspectives. Jaw crushers play a critical role in the extractive industry, and their performance is strongly influenced by the geometry and positioning of the drive mechanism. A theoretical approach based on mathematical modeling and numerical simulation was applied to a real constructive model (SMD-117), assessing variations in the linear velocity of the moving links as a function of mechanism placement. The study employed Mathcad 15, Roberts Animator, and GIM (Graphical Interactive Mechanisms) 2025.4 software to perform calculations and simulate motion. Results revealed a sinusoidal velocity pattern with significant differences between the two systems: the tension-based drive achieves peak velocities at the beginning of the angular variation interval, while the compression-based system reaches its maximum toward the end. Link C consistently exhibits higher velocities than link E, indicating increased mechanical stress. Polar graphic analysis identified critical velocity angles, and simulations confirmed the model’s validity with a maximum error of just 1.79%. The findings emphasize the importance of selecting an appropriate drive system to enhance performance, durability, and energy efficiency, offering concrete recommendations for equipment design and operation. Full article

(This article belongs to the Section Manufacturing Processes and Systems)

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19 pages, 1976 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Eudragit^® S 100 Coating of Lipid Nanoparticles for Oral Delivery of RNA

by Md. Anamul Haque, Archana Shrestha and George Mattheolabakis

Processes 2025, 13(8), 2477; https://doi.org/10.3390/pr13082477 - 5 Aug 2025

Cited by 1 | Viewed by 2363

Abstract

Lipid nanoparticle (LNP)-based delivery systems are promising tools for advancing RNA-based therapies. However, there are underlying challenges for the oral delivery of LNPs. In this study, we optimized an LNP formulation, which we encapsulated in a pH-sensitive Eudragit^® S 100 (Eu) coating. [...] Read more.

Lipid nanoparticle (LNP)-based delivery systems are promising tools for advancing RNA-based therapies. However, there are underlying challenges for the oral delivery of LNPs. In this study, we optimized an LNP formulation, which we encapsulated in a pH-sensitive Eudragit^® S 100 (Eu) coating. LNPs were prepared using the DLin-MC3-DMA ionizable lipid, cholesterol, DMG-PEG, and DSPC at a molar ratio of 50:38.5:10:1.5. LNPs were coated with 1% Eu solution via nanoprecipitation using 0.25% acetic acid to get Eu-coated LNPs (Eu-LNPs). Particle characteristics of LNPs were determined by using dynamic light scattering (DLS). Ribogreen and agarose gel retardation assays were used to evaluate nucleic acid entrapment and stability. LNPs and Eu-LNPs were ~120 nm and 4.5 μm in size, respectively. Eu-LNPs decrease to an average size of ~191 ± 22.9 nm at a pH of 8. Phosphate buffer (PB)-treated and untreated Eu-LNPs and uncoated LNPs were transfected in HEK-293 cells. PB-treated Eu-LNPs showed significant transfection capability compared to their non-PB-treated counterparts. Eu-LNPs protected their nucleic acid payloads in the presence of a simulated gastric fluid (SGF) with pepsin and maintained transfection capacity following SGF or simulated intestinal fluid. Hence, Eu coating is a potentially promising approach for the oral administration of LNPs. Full article

(This article belongs to the Special Issue Drug Carriers Production Processes for Innovative Human Applications (2nd Edition))

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21 pages, 1360 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Design and Characterization of Mn(II), Co(II), and Zn(II) Complexes with Chrysin: Spectroscopic, Antibacterial, and Anti-Biofilm Insights

by Elżbieta Woźnicka, Anna Miłoś, Lidia Zapała, Małgorzata Kosińska-Pezda, Katarzyna Lecka-Szlachta and Łukasz Byczyński

Processes 2025, 13(8), 2468; https://doi.org/10.3390/pr13082468 - 4 Aug 2025

Cited by 1 | Viewed by 1179

Abstract

This study presents the synthesis and physicochemical characterization of coordination compounds formed between chrysin, a natural flavonoid, and transition metal ions: Mn(II), Co(II), and Zn(II). The complexes were obtained under mildly basic conditions and analyzed using elemental analysis, thermogravimetric analysis (TGA), silver-assisted laser [...] Read more.

This study presents the synthesis and physicochemical characterization of coordination compounds formed between chrysin, a natural flavonoid, and transition metal ions: Mn(II), Co(II), and Zn(II). The complexes were obtained under mildly basic conditions and analyzed using elemental analysis, thermogravimetric analysis (TGA), silver-assisted laser desorption/ionization mass spectrometry (SALDI-MS), FT-IR spectroscopy, and ¹H NMR. The spectroscopic data confirm that chrysin coordinates as a bidentate ligand through the 5-hydroxyl and 4-carbonyl groups, with structural differences depending on the metal ion involved. The mass spectrometry results revealed distinct stoichiometries: 1:2 metal-to-ligand ratios for Mn(II) and Co(II), and 1:1 for Zn(II), with additional hydroxide coordination. Biological assays demonstrated that Co(II) and Mn(II) complexes exhibit enhanced antibacterial and anti-biofilm activity compared to free chrysin, particularly against drug-resistant Staphylococcus epidermidis, whereas the Zn(II) complex showed negligible biological activity. Full article

(This article belongs to the Special Issue Metal Complexes: Design, Properties and Applications)

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32 pages, 10052 KB

Open AccessFeature PaperEditor’s ChoiceArticle

A Study on Large Electric Vehicle Fires in a Tunnel: Use of a Fire Dynamics Simulator (FDS)

by Roberto Dessì, Daniel Fruhwirt and Davide Papurello

Processes 2025, 13(8), 2435; https://doi.org/10.3390/pr13082435 - 31 Jul 2025

Cited by 1 | Viewed by 1569

Abstract

Internal combustion engine vehicles damage the environment and public health by emitting toxic fumes, such as CO₂ or CO and other trace compounds. The use of electric cars helps to reduce the emission of pollutants into the environment due to the use [...] Read more.

Internal combustion engine vehicles damage the environment and public health by emitting toxic fumes, such as CO₂ or CO and other trace compounds. The use of electric cars helps to reduce the emission of pollutants into the environment due to the use of batteries with no direct and local emissions. However, accidents of battery electric vehicles pose new challenges, such as thermal runaway. Such accidents can be serious and, in some cases, may result in uncontrolled overheating that causes the battery pack to spontaneously ignite. In particular, the most dangerous vehicles are heavy goods vehicles (HGVs), as they release a large amount of energy that generate high temperatures, poor visibility, and respiratory damage. This study aims to determine the potential consequences of large BEV fires in road tunnels using computational fluid dynamics (CFD). Furthermore, a comparison between a BEV and an ICEV fire shows the differences related to the thermal and the toxic impact. Furthermore, the adoption of a longitudinal ventilation system in the tunnel helped to mitigate the BEV fire risk, keeping a safer environment for tunnel users and rescue services through adequate smoke control. Full article

(This article belongs to the Special Issue Research on New Energy Carriers in Vehicles: Safety and Green Transition)

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21 pages, 3300 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Catalytic Ozonation of Nitrite in Denitrification Wastewater Based on Mn/ZSM-5 Zeolites: Catalytic Performance and Mechanism

by Yiwei Zhang, Yulin Sun, Yanqun Zhu, Wubin Weng, Yong He and Zhihua Wang

Processes 2025, 13(8), 2387; https://doi.org/10.3390/pr13082387 - 27 Jul 2025

Viewed by 779

Abstract

In wet flue gas desulfurization and denitrification processes, nitrite accumulation inhibits denitrification efficiency and induces secondary pollution due to its acidic disproportionation. This study developed a Mn-modified ZSM-5 zeolite catalyst, achieving efficient resource conversion of nitrite in nitrogen-containing wastewater through an O₃ [...] Read more.

In wet flue gas desulfurization and denitrification processes, nitrite accumulation inhibits denitrification efficiency and induces secondary pollution due to its acidic disproportionation. This study developed a Mn-modified ZSM-5 zeolite catalyst, achieving efficient resource conversion of nitrite in nitrogen-containing wastewater through an O₃ + Mn/ZSM-5 catalytic system. Mn/ZSM-5 catalysts with varying SiO₂/Al₂O₃ ratios (prepared by wet impregnation) were characterized by BET, XRD, and XPS. Experimental results demonstrated that Mn/ZSM-5 (SiO₂/Al₂O₃ = 400) exhibited a larger specific surface area, enhanced adsorption capacity, abundant surface Mn³⁺/Mn⁴⁺ species, hydroxyl oxygen species, and chemisorbed oxygen, leading to superior oxidation capability and catalytic activity. Under the optimized conditions of reaction temperature = 40 °C, initial pH = 4, Mn/ZSM-5 dosage = 1 g/L, and O₃ concentration = 100 ppm, the

N O_{2}^{-}

oxidation efficiency reached 94.33%. Repeated tests confirmed that the Mn/ZSM-5 catalyst exhibited excellent stability and wide operational adaptability. The synergistic effect between Mn species and the zeolite support significantly improved ozone utilization efficiency. The O₃ + Mn/ZSM-5 system required less ozone while maintaining high oxidation efficiency, demonstrating better cost-effectiveness. Mechanism studies revealed that the conversion pathway of

N O_{2}^{-}

followed a dual-path catalytic mechanism combining direct ozonation and free radical chain reactions. Practical spray tests confirmed that coupling the Mn/ZSM-5 system with ozone oxidation flue gas denitrification achieved over 95% removal of liquid-phase

N O_{2}^{-}

byproducts without compromising the synergistic removal efficiency of NO_x/SO₂. This study provided an efficient catalytic solution for industrial wastewater treatment and the resource utilization of flue gas denitrification byproducts. Full article

(This article belongs to the Special Issue Processes in 2025)

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25 pages, 2550 KB

Open AccessFeature PaperEditor’s ChoiceReview

Graphene Oxide Aerogels: From Synthesis Pathways to Mechanical Performance and Applications

by Mayur B. Wakchaure and Pradeep L. Menezes

Processes 2025, 13(8), 2375; https://doi.org/10.3390/pr13082375 - 26 Jul 2025

Viewed by 3070

Abstract

Graphene oxide (GO) aerogels were discovered as lightweight, highly porous materials with exceptional mechanical, electrical, and thermal properties. These properties make them suitable for a wide range of advanced applications. This paper discusses GO aerogel synthesis processes, characterization, mechanical properties, applications, and future [...] Read more.

Graphene oxide (GO) aerogels were discovered as lightweight, highly porous materials with exceptional mechanical, electrical, and thermal properties. These properties make them suitable for a wide range of advanced applications. This paper discusses GO aerogel synthesis processes, characterization, mechanical properties, applications, and future directions. The synthesis methods discussed include hydrothermal reduction, chemical reduction, crosslinking methods, and 3D printing, with major emphasis on their effects on the aerogel’s structural and functional attributes. A detailed analysis of mechanical characterization techniques is elaborated upon, along with highlighting the effects of parameters such as porosity, crosslinking, and graphene concentration on mechanical strength, elasticity, and stability. Research has been carried out to find GO aerogel applications in various sectors, such as energy storage, environmental remediation, sensors, and thermal management, showcasing their versatility and potential. Additionally, the combination of nanoparticles and doping strategies to improve specific properties is addressed. The review concludes by identifying current challenges in scalability, brittleness, and property optimization and proposes future directions for synthesis innovations. This work will be helpful for researchers and engineers exploring new possibilities for GO aerogels in both academic and industrial areas. Full article

(This article belongs to the Special Issue Advanced Functionally Graded Materials)

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16 pages, 5026 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Insulation Ability and Morphological Effect of ZrO₂ Spacer Layer in Carbon-Based Multiporous Layered Electrode Perovskite Solar Cells

by Takaya Shioki, Naonari Izumoto, Fumitaka Iwakura, Ryuki Tsuji and Seigo Ito

Processes 2025, 13(7), 2264; https://doi.org/10.3390/pr13072264 - 16 Jul 2025

Viewed by 942

Abstract

Fully printable carbon-based multiporous layered electrode perovskite solar cells (MPLE−PSCs) are close to being commercialized due to their excellent stability, their ability to easily be scaled up, and their amenability to mass production via non-vacuum fabrication processes. To improve their efficiency, it is [...] Read more.

Fully printable carbon-based multiporous layered electrode perovskite solar cells (MPLE−PSCs) are close to being commercialized due to their excellent stability, their ability to easily be scaled up, and their amenability to mass production via non-vacuum fabrication processes. To improve their efficiency, it is important that detailed studies of the morphologies of mesoporous electrodes be carried out. In this study, we prepared five types of ZrO₂ spacer layers for MPLE−PSCs, and the morphology of ZrO₂ and device performance were evaluated using a scanning electron microscope, nitrogen adsorption/desorption measurements, electrode resistance measurements, UV-visible light reflectance measurements, and current density–voltage measurements. The results reveal that the adequate specific surface area and pore size distribution of mesoporous ZrO₂ provided high insulation ability when used as spacers between electrodes and light absorbance, resulting in a 10.92% photoelectric conversion efficiency with a 23.22 mA cm⁻² short-circuit current density. This information can serve as a guideline for designing morphologies useful for producing high-efficiency devices. Full article

(This article belongs to the Special Issue Sustainability of Perovskite Solar Cells)

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20 pages, 2869 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Influence of Polyester and Denim Microfibers on the Treatment and Formation of Aerobic Granules in Sequencing Batch Reactors

by Victoria Okhade Onyedibe, Hassan Waseem, Hussain Aqeel, Steven N. Liss, Kimberley A. Gilbride, Roxana Sühring and Rania Hamza

Processes 2025, 13(7), 2272; https://doi.org/10.3390/pr13072272 - 16 Jul 2025

Cited by 1 | Viewed by 1022

Abstract

This study examines the effects of polyester and denim microfibers (MFs) on aerobic granular sludge (AGS) over a 42-day period. Treatment performance, granulation, and microbial community changes were assessed at 0, 10, 70, 210, and 1500 MFs/L. Reactors with 70 MFs/L achieved rapid [...] Read more.

This study examines the effects of polyester and denim microfibers (MFs) on aerobic granular sludge (AGS) over a 42-day period. Treatment performance, granulation, and microbial community changes were assessed at 0, 10, 70, 210, and 1500 MFs/L. Reactors with 70 MFs/L achieved rapid granulation and showed improved settling by day 9, while 0 and 10 MFs/L reactors showed delayed granule formation, which was likely due to limited nucleation and weaker shear conditions. Severe clogging and frequent maintenance occurred at 1500 MFs/L. Despite > 98% MF removal in all reactors, treatment performance declined at higher MF loads. Nitrogen removal dropped from 93% to 68%. Phosphate removal slightly increased in reactors with no or low microfiber loads (96–99%), declined in reactors with 70 or 210 MFs/L (92–91%, 89–88%), and dropped significantly in the reactor with1500 MFs/L (86–70%, p < 0.05). COD removal declined with increasing MF load. Paracoccus (denitrifiers) dominated low-MF reactors; Acinetobacter (associated with complex organic degradation) and Nitrospira (nitrite-oxidizing genus) were enriched at 1500 MFs/L. Performance decline likely stemmed from nutrient transport blockage and toxic leachates, highlighting the potential threat of MFs to wastewater treatment and the need for upstream MF control. Full article

(This article belongs to the Special Issue State-of-the-Art Wastewater Treatment Techniques)

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26 pages, 871 KB

Open AccessFeature PaperEditor’s ChoiceReview

Addressing Challenges in Large-Scale Bioprocess Simulations: A Circular Economy Approach Using SuperPro Designer

by Juan Silvestre Aranda-Barradas, Claudia Guerrero-Barajas and Alberto Ordaz

Processes 2025, 13(7), 2259; https://doi.org/10.3390/pr13072259 - 15 Jul 2025

Cited by 1 | Viewed by 1750

Abstract

Bioprocess simulation is a powerful tool for leveraging circular economy principles in the analysis of large-scale bioprocesses, enhancing decision-making for efficient and sustainable production. By simulating different process scenarios, researchers and engineers can evaluate the techno-economic feasibility of different approaches. This approach enables [...] Read more.

Bioprocess simulation is a powerful tool for leveraging circular economy principles in the analysis of large-scale bioprocesses, enhancing decision-making for efficient and sustainable production. By simulating different process scenarios, researchers and engineers can evaluate the techno-economic feasibility of different approaches. This approach enables the identification of cost-effective and sustainable solutions, optimizing resource use and minimizing waste, thereby enhancing the overall efficiency and viability of bioprocesses within a circular economy framework. In this review, we provide an overview of circular economy concepts and trends before discussing design methodologies and challenges in large-scale bioprocesses. The analysis highlights the application and advantages of using process simulators like SuperPro Designer v.14 in bioprocess development. Process design methodologies have evolved to use specialized software that integrates chemical and biochemical processes, physical properties, and economic and environmental considerations. By embracing circular economy principles, these methodologies evaluate projects that transform waste into valuable products, aiming to reduce pollution and resources use, thereby shifting from a linear to a circular economy. In process engineering, exciting perspectives are emerging, particularly in large-scale bioprocess simulations, which are expected to contribute to the improvement of bioprocess technology and computer applications. Full article

(This article belongs to the Special Issue Trends in Biochemical Processing Techniques)

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23 pages, 7174 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Enhancing Wastewater Treatment Through Python ANN-Guided Optimization of Photocatalysis with Boron-Doped ZnO Synthesized via Mechanochemical Route

by Vladan Nedelkovski, Milan Radovanović, Dragana Medić, Sonja Stanković, Iosif Hulka, Dejan Tanikić and Milan Antonijević

Processes 2025, 13(7), 2240; https://doi.org/10.3390/pr13072240 - 14 Jul 2025

Cited by 3 | Viewed by 1018

Abstract

This study explores the enhanced photocatalytic performance of boron-doped zinc oxide (ZnO) nanoparticles synthesized via a scalable mechanochemical route. Utilizing X-ray diffraction (XRD) and scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS), the structural and morphological properties of these nanoparticles were assessed. Specifically, nanoparticles [...] Read more.

This study explores the enhanced photocatalytic performance of boron-doped zinc oxide (ZnO) nanoparticles synthesized via a scalable mechanochemical route. Utilizing X-ray diffraction (XRD) and scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS), the structural and morphological properties of these nanoparticles were assessed. Specifically, nanoparticles with 1 wt%, 2.5 wt%, and 5 wt% boron doping were analyzed after calcination at temperatures of 500 °C, 600 °C, and 700 °C. The obtained results indicate that 1 wt% B-ZnO nanoparticles calcined at 700 °C show superior photocatalytic efficiency of 99.94% methyl orange degradation under UVA light—a significant improvement over undoped ZnO. Furthermore, the study introduces a predictive model using the artificial neural network (ANN) technique, developed in Python, which effectively forecasts photocatalytic performance based on experimental conditions with R² = 0.9810. This could further enhance wastewater treatment processes, such as heterogeneous photocatalysis, through ANN-guided optimization. Full article

(This article belongs to the Special Issue Metal Oxides and Their Composites for Photocatalytic Degradation)

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19 pages, 3865 KB

Open AccessFeature PaperEditor’s ChoiceArticle

The Voltage Regulation of Boost Converters via a Hybrid DQN-PI Control Strategy Under Large-Signal Disturbances

by Pengqiang Nie, Yanxia Wu, Zhenlin Wang, Song Xu, Seiji Hashimoto and Takahiro Kawaguchi

Processes 2025, 13(7), 2229; https://doi.org/10.3390/pr13072229 - 12 Jul 2025

Cited by 1 | Viewed by 832

Abstract

The DC-DC boost converter plays a crucial role in interfacing low-voltage sources with high-voltage DC buses in DC microgrid systems. To enhance the dynamic response and robustness of the system under large-signal disturbances and time-varying system parameters, this paper proposes a hybrid control [...] Read more.

The DC-DC boost converter plays a crucial role in interfacing low-voltage sources with high-voltage DC buses in DC microgrid systems. To enhance the dynamic response and robustness of the system under large-signal disturbances and time-varying system parameters, this paper proposes a hybrid control strategy that integrates proportional–integral (PI) control with a deep Q-network (DQN). The proposed framework leverages the advantages of PI control in terms of steady-state regulation and a fast transient response, while also exploiting the capabilities of the DQN agent to learn optimal control policies in dynamic and uncertain environments. To validate the effectiveness and robustness of the proposed hybrid control framework, a detailed boost converter model was developed in the MATLAB 2024/Simulink environment. The simulation results demonstrate that the proposed framework exhibits a significantly faster transient response and enhanced robustness against nonlinear disturbances compared to the conventional PI and fuzzy controllers. Moreover, by incorporating PI-based fine-tuning in the steady-state phase, the framework effectively compensates for the control precision limitations caused by the discrete action space of the DQN algorithm, thereby achieving high-accuracy voltage regulation without relying on an explicit system model. Full article

(This article belongs to the Special Issue Challenges and Advances of Process Control Systems)

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31 pages, 5892 KB

Open AccessFeature PaperEditor’s ChoiceArticle

RANS Simulation of Turbulent Flames Under Different Operating Conditions Using Artificial Neural Networks for Accelerating Chemistry Modeling

by Tobias Reiter, Jonas Volgger, Manuel Früh, Christoph Hochenauer and Rene Prieler

Processes 2025, 13(7), 2220; https://doi.org/10.3390/pr13072220 - 11 Jul 2025

Viewed by 1091

Abstract

Combustion modeling using computational fluid dynamics (CFD) offers detailed insights into the flame structure and thermo-chemical processes. Furthermore, it has been extensively used in the past to optimize industrial furnaces. Despite the increasing computational power, the prediction of the reaction kinetics in flames [...] Read more.

Combustion modeling using computational fluid dynamics (CFD) offers detailed insights into the flame structure and thermo-chemical processes. Furthermore, it has been extensively used in the past to optimize industrial furnaces. Despite the increasing computational power, the prediction of the reaction kinetics in flames is still related to high calculation times, which is a major drawback for large-scale combustion systems. To speed-up the simulation, artificial neural networks (ANNs) were applied in this study to calculate the chemical source terms in the flame instead of using a chemistry solver. Since one ANN may lack accuracy for the entire input feature space (temperature, species concentrations), the space is sub-divided into four regions/ANNs. The ANNs were tested for different fuel mixtures, degrees of turbulence, and air-fuel/oxy-fuel combustion. It was found that the shape of the flame and its position were well predicted in all cases with regard to the temperature and CO. However, at low temperature levels (<800 K), in some cases, the ANNs under-predicted the source terms. Additionally, in oxy-fuel combustion, the temperature was too high. Nevertheless, an overall high accuracy and a speed-up factor for all simulations of 12 was observed, which makes the approach suitable for large-scale furnaces. Full article

(This article belongs to the Special Issue Data-Driven Modeling and Applications for Flow, Heat Transfer, and Combustion)

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24 pages, 13675 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Microscopic Investigation of the Effect of Different Wormhole Configurations on CO₂-Based Cyclic Solvent Injection in Post-CHOPS Reservoirs

by Sepideh Palizdan, Farshid Torabi and Afsar Jaffar Ali

Processes 2025, 13(7), 2194; https://doi.org/10.3390/pr13072194 - 9 Jul 2025

Viewed by 520

Abstract

Cyclic Solvent Injection (CSI), one of the most promising solvent-based enhanced oil recovery (EOR) methods, has attracted the oil industry’s interest due to its energy efficiency, produced oil quality, and environmental suitability. Previous studies revealed that foamy oil flow is considered as one [...] Read more.

Cyclic Solvent Injection (CSI), one of the most promising solvent-based enhanced oil recovery (EOR) methods, has attracted the oil industry’s interest due to its energy efficiency, produced oil quality, and environmental suitability. Previous studies revealed that foamy oil flow is considered as one of the main mechanisms of the CSI process. However, due to the presence of complex high-permeable channels known as wormholes in Post-Cold Heavy Oil Production with Sands (Post-CHOPS) reservoirs, understanding the effect of each operational parameter on the performance of the CSI process in these reservoirs requires a pore-scale investigation of different wormhole configurations. Therefore, in this project, a comprehensive microfluidic experimental investigation into the effect of symmetrical and asymmetrical wormholes during the CSI process has been conducted. A total of 11 tests were designed, considering four different microfluidic systems with various wormhole configurations. Various operational parameters, including solvent type, pressure depletion rate, and the number of cycles, were considered to assess their effects on foamy oil behavior in post-CHOPS reservoirs in the presence of wormholes. The finding revealed that the wormhole configuration plays a crucial role in controlling the oil production behavior. While the presence of the wormhole in a symmetrical design could positively improve oil production, it would restrict oil production in an asymmetrical design. To address this challenge, we used the solvent mixture containing 30% propane that outperformed CO₂, overcame the impact of the asymmetrical wormhole, and increased the total recovery factor by 14% under a 12 kPa/min pressure depletion rate compared to utilizing pure CO₂. Moreover, the results showed that applying a lower pressure depletion rate at 4 kPa/min could recover a slightly higher amount of oil, approximately 2%, during the first cycle compared to tests conducted under higher pressure depletion rates. However, in later cycles, a higher pressure depletion rate at 12 kPa/min significantly improved foamy oil flow quality and, subsequently, heavy oil recovery. The interesting finding, as observed, is the gap difference between the total recovery factor at the end of the cycle and the recovery factor after the first cycle, which increases noticeably with higher pressure depletion rate, increasing from 9.5% under 4 kPa/min to 16% under 12 kPa/min. Full article

(This article belongs to the Special Issue Flow Mechanisms and Enhanced Oil Recovery)

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11 pages, 2217 KB

Open AccessFeature PaperEditor’s ChoiceArticle

One-Pot Improvement of Stretchable PEDOT/PSS Alginate Conductivity for Soft Sensing Biomedical Processes

by Somayeh Zanganeh, Alberto Ranier Escobar, Hung Cao and Peter Tseng

Processes 2025, 13(7), 2173; https://doi.org/10.3390/pr13072173 - 8 Jul 2025

Viewed by 1192

Abstract

Hydrogels have immense potential in soft electronics due to their similarity to biological tissues. However, for applications in fields like tissue engineering and wearable electronics, hydrogels must obtain electrical conductivity, stretchability, and implantability. This article explores recent advancements in the development of electrically [...] Read more.

Hydrogels have immense potential in soft electronics due to their similarity to biological tissues. However, for applications in fields like tissue engineering and wearable electronics, hydrogels must obtain electrical conductivity, stretchability, and implantability. This article explores recent advancements in the development of electrically conductive hydrogel composites with high conductivity, low Young’s modulus, and remarkable stretchability. By incorporating conductive particles into hydrogels, such as poly(3,4-ethylenedioxythiophene)/poly (styrenesulfonate) (PEDOT/PSS) researchers have enhanced their conductivity. This study presents a one-pot synthesis method for creating electrically conductive hydrogel composites by combining PEDOT/PSS with alginate. The hydrogel reveals changes in chemical composition upon treatment with dimethyl sulfoxide (DMSO). Additionally, surface morphology analysis via Field Emission Scanning Electron Microscopy (FESEM) and Atomic Force Microscopy (AFM) demonstrate the impact of DMSO treatment on PEDOT/PSS/alginate films. Furthermore, electrical conductivity measurements highlighted the effectiveness of the conductive hydrogels in Electromyography (EMG) and human motion detection. This study offers insights into the fabrication and characterization of stretchable, conductive hydrogels, advancing their potential for various soft sensing biomedical applications. The optimized PDOT/PSS/alginate composite under dry condition shows a conductivity of 0.098 S/cm and can be stretched without significant loss in conductivity or mechanical stability. This one-pot method provides a simple and effective way to improve the properties of conductive hydrogel-based sensors. Full article

(This article belongs to the Special Issue Application of Artificial Intelligence in Industrial Process Modelling and Optimization)

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42 pages, 13901 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Hybrid Explainable AI for Machine Predictive Maintenance: From Symbolic Expressions to Meta-Ensembles

by Nikola Anđelić, Sandi Baressi Šegota and Vedran Mrzljak

Processes 2025, 13(7), 2180; https://doi.org/10.3390/pr13072180 - 8 Jul 2025

Viewed by 1609

Abstract

Machine predictive maintenance plays a critical role in reducing unplanned downtime, lowering maintenance costs, and improving operational reliability by enabling the early detection and classification of potential failures. Artificial intelligence (AI) enhances these capabilities through advanced algorithms that can analyze complex sensor data [...] Read more.

Machine predictive maintenance plays a critical role in reducing unplanned downtime, lowering maintenance costs, and improving operational reliability by enabling the early detection and classification of potential failures. Artificial intelligence (AI) enhances these capabilities through advanced algorithms that can analyze complex sensor data with high accuracy and adaptability. This study introduces an explainable AI framework for failure detection and classification using symbolic expressions (SEs) derived from a genetic programming symbolic classifier (GPSC). Due to the imbalanced nature and wide variable ranges in the original dataset, we applied scaling/normalization and oversampling techniques to generate multiple balanced dataset variations. Each variation was used to train the GPSC with five-fold cross-validation, and optimal hyperparameters were selected using a Random Hyperparameter Value Search (RHVS) method. However, as the initial Threshold-Based Voting Ensembles (TBVEs) built from SEs did not achieve a satisfactory performance for all classes, a meta-dataset was developed from the outputs of the obtained SEs. For each class, a meta-dataset was preprocessed, balanced, and used to train a Random Forest Classifier (RFC) with hyperparameter tuning via RandomizedSearchCV. For each class, a TBVE was then constructed from the saved RFC models. The resulting ensemble demonstrated a near-perfect performance for failure detection and classification in most classes (0, 1, 3, and 5), although Classes 2 and 4 achieved a lower performance, which could be attributed to an extremely low number of samples and a hard-to-detect type of failure. Overall, the proposed method presents a robust and explainable AI solution for predictive maintenance, combining symbolic learning with ensemble-based meta-modeling. Full article

(This article belongs to the Special Issue Applications of Artificial Intelligence Technologies in Energy, Manufacturing and Automatic Control Processes)

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15 pages, 2832 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Processing of Low-Grade Cu–Pb–Zn Sulfide Polymetallic Ore Stockpiles for Sustainable Raw Material Recovery by Froth Flotation

by Michal Marcin, Martin Sisol, Martina Laubertová, Dominika Marcin Behunová and Igor Ďuriška

Processes 2025, 13(7), 2158; https://doi.org/10.3390/pr13072158 - 7 Jul 2025

Viewed by 1518

Abstract

This study demonstrated the successful recovery of zinc, lead, and copper collective concentrates from historical metal-bearing mine tailings (sulfide–polymetallic ore with a composition of 7.38% Zn, 1.45% Pb, and 0.49% Cu) using froth flotation techniques, which were originally developed during uranium ore mining. [...] Read more.

This study demonstrated the successful recovery of zinc, lead, and copper collective concentrates from historical metal-bearing mine tailings (sulfide–polymetallic ore with a composition of 7.38% Zn, 1.45% Pb, and 0.49% Cu) using froth flotation techniques, which were originally developed during uranium ore mining. Froth flotation techniques were used to justify suitability for recovering metals. The effects of a dosage of the foaming agent Polyethylene glycol (PEG 600) at 50 and 100 g t⁻¹, collector types Aerophine 3418A (AERO), Danafloat 067 (DF), and potassium ethyl xanthate (KEX) at 50 and 80 g t⁻¹, and a suspension density of 300 and 500 g L⁻¹ on froth flotation collective concentrates were investigated. The final collective concentrate achieved recoveries exceeding 91% for lead (Pb), 88% for copper (Cu), and 87% for zinc (Zn). The obtained concentrates were analyzed using Atomic Absorption Spectroscopy (AAS) and X-ray Fluorescence Spectrometry (XRF), while selected samples were further examined via Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray Spectroscopy (EDS). The resulting sulfide concentrates can subsequently be treated using suitable hydrometallurgical techniques. The application of these concentrates in metal production would help reduce the environmental burden of mining activities. Full article

(This article belongs to the Special Issue Non-ferrous Metal Metallurgy and Its Cleaner Production)

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32 pages, 1477 KB

Open AccessFeature PaperEditor’s ChoiceReview

Photochemical Catalysts for Hydrocarbons and Biomass Derivates Reforming in Intensified Processes

by Mattia Boscherini and Francesco Miccio

Processes 2025, 13(7), 2150; https://doi.org/10.3390/pr13072150 - 6 Jul 2025

Viewed by 1291

Abstract

Photocatalysts for applications in different sectors, e.g., civil and environmental, are already developed to a mature extent and allow, for example, the purification of gaseous and liquid streams or the self−cleaning surfaces. The application of photocatalysts in the industrial sector is, however, quite [...] Read more.

Photocatalysts for applications in different sectors, e.g., civil and environmental, are already developed to a mature extent and allow, for example, the purification of gaseous and liquid streams or the self−cleaning surfaces. The application of photocatalysts in the industrial sector is, however, quite limited. The review addresses the specific topic of the photocatalytic reforming of methane and biomass derivates. In this regard, recent advances in materials science are reported and discussed, in particular regarding doped and modified oxides (TiO₂ and ZrO₂) or non−oxidic ceramics. Concerning process integration, a comparison between traditional two−dimensional photoreactors and fluidized bed systems is proposed and design guidelines are drawn, with indications of the possible benefits. Photocatalytic fluidized beds appear more suitable for small− and medium−scale integrated processes of reforming, operating at lower temperatures than traditional ones for distributed hydrogen generation. Full article

(This article belongs to the Special Issue Mechanisms, Devices and Applications of Photocatalytic Processes)

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