ChemEngineering

20 pages, 6349 KiB

Open AccessArticle

Terephthalic-co-glycerol-g-fumaric Acid: A Promising Nanopolymer for Enhancing PPSU Membrane Properties

by Harith A. Alani, Qusay F. Alsalhy, Saad Al-Saadi, Faris H. Alani, Hicham Meskher, Raed A. Al-Juboori, Francesca Russo, Giampiero Chiappetta, Giuseppe Di Luca and Alberto Figoli

ChemEngineering 2025, 9(1), 12; https://doi.org/10.3390/chemengineering9010012 - 21 Jan 2025

Abstract

This study introduces an innovative approach to modifying polyphenylsulfone (PPSU) membranes for wastewater treatment applications. Terephthalic-co-glycerol-g-fumaric acid (TGF) was used as an innovative nanopolymer pore former. By incorporating TGF at varying concentrations, our research investigates its effects on the morphological and surface properties [...] Read more.

This study introduces an innovative approach to modifying polyphenylsulfone (PPSU) membranes for wastewater treatment applications. Terephthalic-co-glycerol-g-fumaric acid (TGF) was used as an innovative nanopolymer pore former. By incorporating TGF at varying concentrations, our research investigates its effects on the morphological and surface properties of PPSU membranes. Two different solvents were used to dissolve PPSU, optimizing the properties of the fabricated membranes. The resultant PPSU/TGF membranes were systematically characterized regarding topography, morphological changes, hydrophilicity, chemical composition, and performance against protein and synthetic dyes. Experimental results revealed that adding TGF resulted in a smoother membrane surface. With 6% TGF inclusion in the casting solution, a more porous structure was achieved, as confirmed by SEM analysis, along with significant improvements in porosity and a near doubling of pore size. Although the hydrophilicity of the membranes exhibited only minor enhancement, performance evaluation demonstrated a substantial increase in pure water flux, with an improvement of more than fourfold. Moreover, the retention of BSA and two synthetic dyes was found to be directly proportional to the concentration of the nanopolymer pore former used. These findings highlight the potential advantages of TGF/PPSU membranes for protein separation and synthetic dye separation applications, underscoring their viability for wastewater treatment. Full article

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14 pages, 1815 KiB

Open AccessArticle

Influence of Oil-Soluble Catalyst on Composition and Structure of Heavy Oil from Samara Region Field

by Mohammed O. N. Ali, Irek I. Mukhamatdinov, Boudkhil Affane, Rezeda E. Mukhamatdinova, Vladimir E. Katnov and Alexey V. Vakhin

ChemEngineering 2025, 9(1), 11; https://doi.org/10.3390/chemengineering9010011 - 20 Jan 2025

Abstract

In this study, an examination was conducted of the influence of iron tallate on the composition and properties of highly viscous oil from the Strelovskoye deposit in the Samara region under thermal–catalytic treatment (TCT). The research revealed that the dynamic viscosity of the [...] Read more.

In this study, an examination was conducted of the influence of iron tallate on the composition and properties of highly viscous oil from the Strelovskoye deposit in the Samara region under thermal–catalytic treatment (TCT). The research revealed that the dynamic viscosity of the oil following TCT at 300 °C, with a measurement temperature of 20 °C, decreased by a factor of 8 in comparison to the initial sample and nearly 4.5 times compared to the control sample at the 96-h mark. The most promising results in reducing the pour point temperature to 7 °C were identified following a 96-h TCT at 300 °C. This reduction was attributed to the decrease in paraffin content facilitated by the presence of the catalyst. According to the ICP-MS results, the extraction of the catalyst with the oil amounted to only 1%. This indicates that during the implementation of TCT within the reservoir, the catalyst is likely to adsorb onto the rock surfaces. Full article

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11 pages, 1557 KiB

Open AccessArticle

Engineering Calculations for Catalytic Hydrolysis of CF₄

by Robert Barat

ChemEngineering 2025, 9(1), 10; https://doi.org/10.3390/chemengineering9010010 - 20 Jan 2025

Abstract

Tetrafluoromethane (CF₄) is the simplest perfluorocarbon, a class of compounds with very high greenhouse gas potential. Catalytic hydrolysis offers an opportunity to convert these compounds to manageable CO₂ and HF. Recently published data showed the effectiveness of Ga-doping to overcome [...] Read more.

Tetrafluoromethane (CF₄) is the simplest perfluorocarbon, a class of compounds with very high greenhouse gas potential. Catalytic hydrolysis offers an opportunity to convert these compounds to manageable CO₂ and HF. Recently published data showed the effectiveness of Ga-doping to overcome the fluorine poisoning of various Al₂O₃ catalysts at relatively modest temperatures. This prior work offered a partial catalytic mechanism together with kinetic and conversion data. The current paper completes the catalytic mechanism, and then analyzes it using the Langmuir–Hinshelwood algorithm for both the initial CF₄ conversion, and the catalyst site regeneration. The resulting derived rate expression, together with a catalyst activity coefficient expression, are then used in flow reactor configurations to simulate both relatively short exposure time runs with little loss of activity, as well as longer runs with severe activity loss. The reasonable agreement with the published laboratory data suggests that these expressions can be used for a larger-scale practical reactor design. Full article

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16 pages, 2585 KiB

Open AccessArticle

Development of Novel Monolithic Catalyst for BTEX Catalytic Oxidation Using 3D Printing Technology

by Filip Car, Vjeran Gomzi, Vesna Tomašić, Domagoj Vrsaljko and Stanislav Kurajica

ChemEngineering 2025, 9(1), 9; https://doi.org/10.3390/chemengineering9010009 - 13 Jan 2025

Abstract

Four differently shaped monolithic catalyst supports were made using 3D printing technology. Two catalytically active mixed oxides, MnFeO_x and MnCuO_x, were applied to the monolithic supports using the impregnation technique. Catalysts were characterized using an adhesion test, field emission scanning [...] Read more.

Four differently shaped monolithic catalyst supports were made using 3D printing technology. Two catalytically active mixed oxides, MnFeO_x and MnCuO_x, were applied to the monolithic supports using the impregnation technique. Catalysts were characterized using an adhesion test, field emission scanning electron microscopy, X-ray diffraction, and Raman spectroscopy in a manner similar to the density functional theory model. Excellent mechanical stability of the catalyst layer was obtained, with catalyst mass loss under 2% after 30 min of ultrasound exposure. SEM analysis revealed that the catalyst layer was rough but homogeneous in appearance and ~6 μm thick. The presence of double oxides—FeMnO₃ and CuMn₂O₄—as well as single oxides of Mn, Fe, and Cu was established via XRD and Raman spectroscopy. Additional theoretical calculations of Raman spectra for FeMnO₃ and CuMn₂O₄ were performed in order to aid in the interpretation of Raman spectra. The catalytic activity of the prepared catalysts for the catalytic oxidation of a gaseous mixture of benzene, toluene, ethylbenzene, and o-xylene (BTEX) was investigated. The monolithic support with the most complex shape and, consequently, the greatest surface area proved to enable the highest efficiency, while both catalysts performed well having similar conversions. Full article

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21 pages, 7204 KiB

Open AccessArticle

General Applicable Residence Time Distribution Model to Estimate Reaction Rates in a Rotor–Stator Spinning Disc Reactor

by Petra Meeuwse and Marit van Lieshout

ChemEngineering 2025, 9(1), 8; https://doi.org/10.3390/chemengineering9010008 - 10 Jan 2025

Abstract

Many designs of industrial reactors stem from designs from the 1960s–1970s. For a wide range of reactions, these designs lead to suboptimal reaction configurations due to limitations in heat- or mass-transfer. Process intensification has come up with a different approach, resulting in micro- [...] Read more.

Many designs of industrial reactors stem from designs from the 1960s–1970s. For a wide range of reactions, these designs lead to suboptimal reaction configurations due to limitations in heat- or mass-transfer. Process intensification has come up with a different approach, resulting in micro- and mini-reactors being safer and more cost-effective on a full industrial scale. However, based on the experience in the suboptimal reactor designs, the reaction rates of these reactions seem too low for full-scale reactions in a mini reactor. We suggest a test for the reaction rate based on a generalized model in combination with a specific type of mini-reactor: the rotor–stator spinning disc reactor. The generalized model is based on existing models on residence time distribution in such reactors. It does not need to be tailor-fitted for a specific rotor–stator spinning disc reactor that is used for the test, as is the case with current models. In this article, we show that our simplifications induce a difference in outcome in reaction rate of less than 10% with the existing models. Experiments with the well-studied chemical reaction of the hydrolysis of acetic anhydride show that the reaction rates calculated based on this scan fall within the range of reported data from the literature. Full article

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15 pages, 45229 KiB

Open AccessArticle

Effect of Alkyl Chain Length of Quaternary Ammonium Surfactant Corrosion Inhibitor on Fe (110) in Acetic Acid Media via Computer Simulation

by Mohd Sofi Numin, Khairulazhar Jumbri, Kee Kok Eng, Almila Hassan, Noorazlenawati Borhan, Nik M. Radi Nik M. Daud, Azmi M. Nor A, Firdaus Suhor and Nur Nadia Dzulkifli

ChemEngineering 2025, 9(1), 7; https://doi.org/10.3390/chemengineering9010007 - 8 Jan 2025

Abstract

Density functional theory (DFT) and molecular dynamics (MD) simulations were employed to investigate the inhibition mechanism of cationic quaternary ammonium surfactant corrosion inhibitors (CIs) with varying chain lengths in 1.0 M HCl and 500 ppm acetic acid on Fe (110) surfaces. DFT calculations [...] Read more.

Density functional theory (DFT) and molecular dynamics (MD) simulations were employed to investigate the inhibition mechanism of cationic quaternary ammonium surfactant corrosion inhibitors (CIs) with varying chain lengths in 1.0 M HCl and 500 ppm acetic acid on Fe (110) surfaces. DFT calculations demonstrated that all surfactant CI molecules possess favorable inhibition properties, with the cationic quaternary ammonium groups (N⁺) and alpha carbon serving as electron-donating reactive centers, characterized by a low band-gap energy of 1.26 eV. MD simulations highlighted C12, with a 12-alkyl chain length, as the most promising CI molecule, exhibiting high adsorption and binding energies, a low diffusion coefficient, and a random distribution at low concentrations, thereby facilitating optimal adsorption onto the Fe (110) metal surface. The insights gained from computational modeling regarding the influence of alkyl chain length on inhibition efficiency, coupled with the comprehensive theoretical understanding of cationic quaternary ammonium surfactant CI molecules in acidic corrosion systems, can serve as a foundation for the future development of innovative surfactant CI molecules incorporating ammonium-based functional groups. Full article

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21 pages, 10370 KiB

Open AccessArticle

Optimizing Chloride and Calcium Ion Extraction from Municipal Solid Waste Incineration Fly Ash from Zhoushan, China: Effects of Leaching Conditions and Industrial Applications

by Kaicheng Zhang, Yecheng Xue, Dongyan Liu, Jianfu Zhao, Marta Sibhat and Yang Tong

ChemEngineering 2025, 9(1), 6; https://doi.org/10.3390/chemengineering9010006 - 6 Jan 2025

Abstract

Municipal solid waste incineration (MSWI) fly ash, containing substantial amounts of calcium (Ca), chloride (Cl), and other valuable elements, offers promising potential as a raw material for carbon capture, utilization (CCU), and alkali production. Despite numerous approaches being explored to enhance calcium ion [...] Read more.

Municipal solid waste incineration (MSWI) fly ash, containing substantial amounts of calcium (Ca), chloride (Cl), and other valuable elements, offers promising potential as a raw material for carbon capture, utilization (CCU), and alkali production. Despite numerous approaches being explored to enhance calcium ion leaching from fly ash, the combined effects of salt and leaching conditions on ion extraction have not been thoroughly investigated. This study provides a comprehensive examination of various leaching conditions, including primary leaching—optimal for efficiency—secondary leaching, which achieved the highest leaching rate, and reverse secondary leaching, focusing on their impact on calcium extraction efficiency. Considering optimal leaching efficiency and resource utilization, this study identifies the most favorable industrial conditions as a 15 min leaching time, a stirring speed of 200 rpm, a temperature of 25 °C, and a 1:10 liquid-to-solid ratio (L/S ratio). The application of a 6% NaCl solution in salt-assisted leaching elevated the calcium ion concentration from 4101.5 mg/L to 4662.6 mg/L, indicating a substantial improvement in leaching performance. Additionally, in carbonate-assisted and ultrasound-assisted leaching, the introduction of CO₂ further increased calcium extraction amounts, but it did not enhance efficiency, while ultrasonic intervention had minimal impact. This research investigates enhanced efficiencies through multiple optimized and assisted leaching conditions, advancing MSWI fly ash utilization in carbon capture applications while paving new pathways for sustainable industrial practices that could revolutionize waste management and support global environmental objectives. Full article

(This article belongs to the Special Issue Innovative Approaches for the Environmental Chemical Engineering)

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26 pages, 7027 KiB

Open AccessArticle

Parametric CFD Study of Spray Drying Chamber Geometry: Part I—Effects on Airflow Dynamics

by Jairo Andrés Gutiérrez Suárez, Carlos Humberto Galeano Urueña and Alexánder Gómez Mejía

ChemEngineering 2025, 9(1), 5; https://doi.org/10.3390/chemengineering9010005 - 4 Jan 2025

Abstract

Internal airflow dynamics play a crucial role in spray drying engineering by governing particle transport and, consequently, the quality of dried products. For this application, airflow dynamics represent short- and long-timescale behaviors across the main jet and recirculation regions and have been related, [...] Read more.

Internal airflow dynamics play a crucial role in spray drying engineering by governing particle transport and, consequently, the quality of dried products. For this application, airflow dynamics represent short- and long-timescale behaviors across the main jet and recirculation regions and have been related, among other factors, to spray chamber design. This study examines the parametric effects of key geometrical design parameters on internal airflow dynamics using Design of Experiments (DOE) methodologies and 3D Computational Fluid Dynamics (CFD) simulations. The CFD model adopts a cost-efficient approach, including adaptive mesh refinement (AMR) methods, enabling running multiple simulation cases while retaining turbulence-resolving capabilities. The results provide quantitative parameter–response relationships, offering insights into the impact of chamber geometry on complex airflow behaviors. Among the parameters studied, the chamber aspect ratio strongly influences the strength of external recirculation flows. The inlet swirl primarily governs the stability of central and recirculating flows, while the conical–cylindrical section topology, in conjunction with the jet Reynolds number, affects flow impingement on walls, predominantly caused by the precession and reversal of the central jet. This methodology demonstrates significant potential for future studies on particle drying, equipment, process scale-up, and alternative chamber configurations in spray drying systems. Full article

(This article belongs to the Special Issue The Applications of Computational Fluid Dynamics in Transport Phenomena)

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17 pages, 5962 KiB

Open AccessArticle

A Case Study on Integrating an AI System into the Fuel Blending Process in a Chemical Refinery

by Abdul Gani Abdul Jameel

ChemEngineering 2025, 9(1), 4; https://doi.org/10.3390/chemengineering9010004 - 3 Jan 2025

Abstract

Fuel blending plays a very important role in petroleum refineries, because it directly affects the quality of the end products, as well as the overall profitability of the refinery. This process of blending involves a combination of various hydrocarbon streams to make fuels [...] Read more.

Fuel blending plays a very important role in petroleum refineries, because it directly affects the quality of the end products, as well as the overall profitability of the refinery. This process of blending involves a combination of various hydrocarbon streams to make fuels that meet specific performance standards and comply with regulatory guidelines. For many decades, most refineries have been dependent on linear programming (LP) models for developing recipes for blending optimization. However, most LP models normally fail to capture the complex nonlinear interaction of blend components with fuel properties, leading to off-specification products that may necessitate re-blending. This work discusses a case study of a hybrid artificial intelligence (AI)-based method for gasoline blending based on a genetic algorithm (GA) combined with an artificial neural network (ANN). AI-based blending systems are more flexible and will enable the refineries to meet the product specifications regularly and result in cost reduction owing to the fall in quality giveaways. The AI-powered process discussed can predict, with much better accuracy, critical combustion properties of gasoline such as the Research Octane Number (RON), Motor Octane Number (MON), and Antiknock Index (AKI), compared to the classical LP models, with the added advantage of optimization of the blend ratio in real time. The results showed that the AI-integrated fuel blending system was able to produce fuel recipes with a mean absolute error (MAE) of 1.4 for the AKI. The obtained MAE is close to the experimental uncertainty of 0.5 octane. A high coefficient of determination (R²) of 0.99 was also obtained when the system was validated with a new set of 57 fuels comprising primary reference fuels and real gasoline blends. The study highlights the potential of AI-integrated systems in transforming traditional fuel blending practices towards sustainable and economically viable refinery operations. Full article

(This article belongs to the Special Issue New Advances in Chemical Engineering)

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16 pages, 1544 KiB

Open AccessArticle

Statistical Correlations Between Various Drivers of Energy Demand in Post-Combustion Carbon Capture Retrofitted Power Plants

by Dalal Alalaiwat and Ezzat Khan

ChemEngineering 2025, 9(1), 3; https://doi.org/10.3390/chemengineering9010003 - 2 Jan 2025

Abstract

Power plants are one of the main sources emitting the CO₂ that is responsible for climate change consequences. Post-combustion carbon capture (PCC), particularly using an aqueous solution, is highly recommended to be used as a mitigation solution to reduce the emissions of [...] Read more.

Power plants are one of the main sources emitting the CO₂ that is responsible for climate change consequences. Post-combustion carbon capture (PCC), particularly using an aqueous solution, is highly recommended to be used as a mitigation solution to reduce the emissions of CO₂ from power plants. Although PCC is a promising solution, the process still needs further development to reduce the energy demand for solvent regeneration. This paper reviews the challenges related to the post-combustion processes and finds the correlations between selected variables addressed by several researchers. Moreover, this study provides valuable insights into the factors influencing the reduction in energy demand and efficiency penalties. The research findings highlight the importance of considering two key drivers during the design of the PCC process. These are the absorber temperature and the type and amount of the selected solvent. Indeed, statistical analyses show that there is a correlation between the identified drivers’ values and the energy demand of solvent regeneration. Full article

(This article belongs to the Special Issue Innovative Approaches for the Environmental Chemical Engineering)

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21 pages, 4425 KiB

Open AccessArticle

Mechanical Properties of Faecal Sludge and Its Influence on Moisture Retention

by Arun Kumar Rayavellore Suryakumar, Sergio Luis Parra-Angarita, Angélique Léonard, Jonathan Pocock and Santiago Septien

ChemEngineering 2025, 9(1), 2; https://doi.org/10.3390/chemengineering9010002 - 30 Dec 2024

Abstract

The mechanical properties of faecal sludge (FS) influence its moisture retention characteristics to a greater extent than other properties. A comprehensive fundamental characterisation of the mechanical properties is scarcely discussed in the literature. This research focused on bulk and true densities, porosity, particle [...] Read more.

The mechanical properties of faecal sludge (FS) influence its moisture retention characteristics to a greater extent than other properties. A comprehensive fundamental characterisation of the mechanical properties is scarcely discussed in the literature. This research focused on bulk and true densities, porosity, particle size distribution and zeta-potential, extracellular polymeric substances, rheology and dilatancy, microstructure analysis, and compactibility in the context of using the FS as a substitute for soil in land reclamation and bioremediation processes. FSs from different on-site sanitation systems were collected from around Durban, South Africa. The porosity of the FSs varied between 42% and 63%, with the zeta-potential being negative, below 10 mV. Over 95% of the particles were <1000 µm. With its presence in the inner part of the solid particles, tightly bound extra-cellular polymeric substances (TB-EPSs) influenced the stability of the sludge by tightly attaching to the cell walls, with the highest being in the septic tank with the greywater sample. More proteins than carbohydrates also confirmed characterised the anaerobic nature of the sludge. The results of the textural properties using a penetrometer showed that the initial slope of the positive part of the penetration curve was related to the stiffness of the sludge sample and similar to that of sewage sludge. The dynamic oscillatory measurements exhibited a firm gel-like behaviour with a linear viscoelastic behaviour of the sludges due to the change in EPSs because of anaerobicity. The high-TS samples exhibited the role of moisture as a lubricating agent on the motion of solid particles, leading to dilatancy with reduced moisture, where the yield stress was no longer associated with the viscous forces but with the frictional contacts of solid–solid particle interactions. The filtration–compression cell test showed good compactibility, but the presence of unbound moisture even at a high pressure of 300 kPa meant that not all unbound moisture was easily removable. The moisture retention behaviour of FS was influenced by its mechanical properties, and any interventional changes to these properties can result in the release of the bound moisture of FS. Full article

(This article belongs to the Special Issue Innovative Approaches for the Environmental Chemical Engineering)

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24 pages, 7920 KiB

Open AccessArticle

Investigation of the Tribological Effects of Nano-Sized Transition Metal Oxides on a Base Oil Containing Pour Point Depressant and Viscosity Modifier

by Ádám István Szabó, Kevin Szabó and Hajnalka Hargitai

ChemEngineering 2025, 9(1), 1; https://doi.org/10.3390/chemengineering9010001 - 27 Dec 2024

Abstract

This study investigates the tribological effects of nano-sized metal oxides (ZrO₂, CuO, Y₂O₃ and TiO₂) in Group III type base oil containing 0.3% pour point depressant (PPD) and 5% viscosity modifier (VM) to enhance friction and [...] Read more.

This study investigates the tribological effects of nano-sized metal oxides (ZrO₂, CuO, Y₂O₃ and TiO₂) in Group III type base oil containing 0.3% pour point depressant (PPD) and 5% viscosity modifier (VM) to enhance friction and wear performance. The homogenized lubricant samples with varying concentrations of oxide nanoparticles (0.1–0.5 wt%) on a linear oscillating tribometer performed static and dynamic frictional tests. Optical and confocal microscopy surface analysis evaluated the wear of the specimen, and SEM and EDX analyses characterized the wear tracks, nanoparticle distributions, and quantification. The cooperation between PPD and nanoparticles significantly improved friction and wear values; however, the worn surface suffered extensively from fatigue wear. The collaboration between VM and nanoparticles resulted in a nanoparticle-rich tribofilm on the contact surface, providing excellent wear resistance that protects the component while also favorably impacting friction reduction. This study found CuO reduced wear volume by 85% with PPD and 43% with VM at 0.5 wt%, while ZrO₂ achieved 80% and 63% reductions, respectively. Y₂O₃ reduced wear volume by 82% with PPD, and TiO₂ reduced friction by 20% with VM. These nanoparticles enhanced tribological performance at optimal concentrations, but high concentrations caused tribofilm instability, highlighting the need for precise optimization. Full article

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19 pages, 3279 KiB

Open AccessArticle

Optimization of Spray Drying Conditions for a Capsicum chinense Leaf Extract Rich in Polyphenols Obtained by Ultrasonic Probe/NADES

by Kevin Alejandro Avilés-Betanzos, Juan Valerio Cauich-Rodríguez, Manuel Octavio Ramírez-Sucre and Ingrid Mayanin Rodríguez-Buenfil

ChemEngineering 2024, 8(6), 131; https://doi.org/10.3390/chemengineering8060131 - 23 Dec 2024

Abstract

Habanero pepper (Capsicum chinense) is known for its heat and culinary uses, especially in Mexico’s Yucatán Peninsula. Its leaves, rich in bioactive compounds like polyphenols with antioxidants and anti-inflammatory properties, have been traditionally used in medicinal practices and are gaining interest [...] Read more.

Habanero pepper (Capsicum chinense) is known for its heat and culinary uses, especially in Mexico’s Yucatán Peninsula. Its leaves, rich in bioactive compounds like polyphenols with antioxidants and anti-inflammatory properties, have been traditionally used in medicinal practices and are gaining interest for health benefits. Efficient green extraction methods, such as natural deep eutectic solvents (NADES), combined with microencapsulation, can improve the stability and application of these compounds in functional foods and nutraceuticals. This study aimed to determine the optimal microencapsulation parameters using response surface methodology, implementing a 2² central composite design with 4 central points of habanero leaf extracts obtained by sonic probe with NADES. The factors evaluated were the percentage of guar gum (5%, 7.5%, and 10%) and the drying temperature (80 °C, 90 °C, and 100 °C). The extracts were spray-dried with maltodextrin (DE17-20), guar gum, and modified starch as encapsulating agents. The total polyphenol content (TPC), polyphenol profile, and antioxidant capacity methods like 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) or ABTS were analyzed. The best results for TPC and ABTS antioxidant capacity were achieved using 7.5% guar gum (GG) at 90 °C. At 104 °C, with the same GG concentration, the microcapsules maintained a high antioxidant capacity. Optimal conditions for TPC, DPPH, and neohesperidin were identified as 7.8% GG/89.4 °C, 8.06% GG/104.1 °C, and 4% GG/75.85 °C, respectively. The resulting powder exhibited high polyphenol content and antioxidant capacity, highlighting successful microencapsulation. Full article

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25 pages, 8553 KiB

Open AccessArticle

Employment of Fe₃O₄/Fe₂TiO₅/TiO₂ Composite Made Using Ilmenite for Elimination of Methylene Blue

by Himasha Gunathilaka and Charitha Thambiliyagodage

ChemEngineering 2024, 8(6), 130; https://doi.org/10.3390/chemengineering8060130 - 18 Dec 2024

Abstract

A novel material was created from natural ilmenite sand, and methylene blue (MB) was used to test the material’s capacity to remove colors from wastewater. The material was synthesized by neutralizing the acid leachate obtained by Ilmenite sand digestion, followed by drying at [...] Read more.

A novel material was created from natural ilmenite sand, and methylene blue (MB) was used to test the material’s capacity to remove colors from wastewater. The material was synthesized by neutralizing the acid leachate obtained by Ilmenite sand digestion, followed by drying at 180 °C. It was characterized by XRD, Raman, TEM, SEM, XPS, XRF, and BET techniques. The crystal nature of the composite is Fe₃O₄/Fe₂TiO₅/TiO₂. The surface area, average pore size and total pore volume of the composite are 292.18 m²/g, 1.53 nm, and 0.202 cc/g, respectively. At pH 10, 10 mg/L MB, and 10 mg of the material resulted in a maximum adsorption capacity of 24.573 mg/g. Using 5 mg/L increments, the dye concentration was adjusted between 10 and 25 mg/L, yielding equilibrium adsorption capacities of 24.573, 31.012, 41.443, and 52.259 mg/g with 10, 15, 20, and 25 mg/L, respectively. The greatest adsorbent capacity of 24.573 mg/g was achieved with 10 mg of the adsorbent and 10 mg/L MB. The adsorbent dosage ranged from 10, 25, 45, 65, and 100 mg. MB was adsorbed via pseudo-second-order kinetics with an adsorption capacity of 24.863 mg/g. The intraparticle diffusion model showed that MB adsorption occurs in three stages, with intra-particle diffusion constants of 1.50, 2.71, 3.38, and 4.41 g/mg min^1/2. Adsorption followed the Langmuir isotherm model. The obtained thermodynamic parameters ΔG, ΔH, and ΔS were −27.5521 kJ/mol at 298 K, 2.571 kJ/mol, and 0.101 kJ/mol, respectively. Regeneration studies of the adsorbent were carried out for five cycles, indicating some activity loss after each cycle. Full article

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21 pages, 1755 KiB

Open AccessReview

Amine-Based Solvents and Additives to Improve the CO₂ Capture Processes: A Review

by Dennis Loachamin, Jordan Casierra, Verónica Calva, Alex Palma-Cando, Edward E. Ávila and Marvin Ricaurte

ChemEngineering 2024, 8(6), 129; https://doi.org/10.3390/chemengineering8060129 - 13 Dec 2024

Abstract

The use of amine-based solvents for carbon dioxide (CO₂) capture has shown significant promise; however, operational challenges such as high energy requirements, solvent degradation, and equipment corrosion highlight the need for enhanced solutions. This review focuses on identifying amine-based solvents and [...] Read more.

The use of amine-based solvents for carbon dioxide (CO₂) capture has shown significant promise; however, operational challenges such as high energy requirements, solvent degradation, and equipment corrosion highlight the need for enhanced solutions. This review focuses on identifying amine-based solvents and additives that can improve CO₂ capture efficiency while minimizing costs and avoiding substantial modifications to existing industrial facilities. Specifically, the study emphasizes the development of a comprehensive database of additives to optimize CO₂ capture processes. A detailed analysis of recent advancements in amine-based solvents was conducted, with a focus on (i) process optimization strategies, (ii) sector-specific CO₂ emission profiles, and (iii) equipment issues associated with conventional chemical solvents. The study evaluates these solvents’ kinetic and thermodynamic properties and their potential to address critical operational challenges, including reducing corrosion, solvent viscosity, and evaporation rates. The findings highlight the pivotal role of amino group-containing compounds, particularly alkanolamines, in enhancing CO₂ capture performance. The structural versatility of these compounds, characterized by the presence of hydroxyl groups, facilitates aqueous dissolution while offering kinetic and thermodynamic benefits. This review underscores the importance of continued innovation in solvent chemistry and the integration of amine-based solvents with emerging technologies to overcome current limitations and advance the implementation of efficient and sustainable CO₂ capture technologies. Full article

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31 pages, 9106 KiB

Open AccessArticle

Thermodynamic Analysis of Cyclic Operation of On-Board Nanoporous Carbon-Based Adsorbed Methane Storage Tank with Various Thermal Control Systems

by Sergey S. Chugaev, Ilya E. Men’shchikov, Igor D. Shelyakin, Evgeny M. Strizhenov, Alexander E. Grinchenko, Andrey V. Shkolin and Anatoly A. Fomkin

ChemEngineering 2024, 8(6), 128; https://doi.org/10.3390/chemengineering8060128 - 10 Dec 2024

Abstract

Thermal effects of adsorption and desorption, leading to temperature fluctuations and losses of adsorption storage systems capacity in the processes of gas charging and discharging, are the main obstacle to the wide practical application of adsorbed natural gas (ANG) technology. This work presents [...] Read more.

Thermal effects of adsorption and desorption, leading to temperature fluctuations and losses of adsorption storage systems capacity in the processes of gas charging and discharging, are the main obstacle to the wide practical application of adsorbed natural gas (ANG) technology. This work presents a numerical simulation of heat and mass transfer processes under various cyclic operation modes of a full-scale adsorption storage tank with various thermal control systems. The high-density monolithic adsorbent KS-HAM, obtained on the basis of industrial activated carbon KS-HA, was used as the adsorption material. The phase composition, surface morphology, and porous structure of the sorbents were studied. The adsorption of methane on the KS-HA adsorbent was measured. It is shown that increasing the duration of charging leads to obtaining additional capacity of the ANG system; however, the final efficiency and benefit at the end of the charging–discharging cycle are determined by the efficiency of the thermal control system and the gas-discharging mode. It has been shown that the presence of a finned thermal control system allows for charging the adsorption storage tank 3–8 times faster and provides an 8–24% greater amount of gas discharged at the discharging stage compared to the ANG system without fins. Full article

(This article belongs to the Special Issue Recent Advances in Applied Activated Carbon Research)

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26 pages, 4959 KiB

Open AccessArticle

Plantwide Control for the Separation of THF-H₂O in an Azeotropic Distillation Process

by Moises Ramos-Martinez, Gerardo Ortiz-Torres, Felipe D. J. Sorcia-Vázquez, Carlos Alberto Torres-Cantero, Manuela Calixto-Rodriguez, Mayra G. Mena-Enriquez, Jorge Salvador Valdez Martínez, Estela Sarmiento-Bustos, Alan Cruz Rojas and Jesse Y. Rumbo-Morales

ChemEngineering 2024, 8(6), 127; https://doi.org/10.3390/chemengineering8060127 - 9 Dec 2024

Abstract

This paper presents a plantwide control strategy for optimizing a pressure-swing azeotropic distillation process used in tetrahydrofuran dehydration. Leveraging Skogestad’s methodology, this strategy focused on two distillation columns: a low-pressure column for water recovery at 20 psia and a high-pressure column that achieved [...] Read more.

This paper presents a plantwide control strategy for optimizing a pressure-swing azeotropic distillation process used in tetrahydrofuran dehydration. Leveraging Skogestad’s methodology, this strategy focused on two distillation columns: a low-pressure column for water recovery at 20 psia and a high-pressure column that achieved 0.99 molar fraction purity of tetrahydrofuran at 115 psia. This study identified critical control variables through plant analysis by implementing PI controllers in the regulatory control layer to stabilize flows and pressures. In the supervisory control layer, a PI controller combined with MIMO MPC effectively enhanced the product purity and reduced the energy consumption by 36%. Stable inlet and outlet flow conditions (100 lbmol/hr inlet, 29.59 lbmol/hr outlet) were maintained without compromising the equipment integrity. The operational ranges for the process included variations in the tetrahydrofuran mole fraction from 0.25 to 0.35 at the inlet, which demonstrated a robust performance across perturbations. These achievements signify significant advancements in process efficiency and sustainability, offering substantial reductions in energy usage while ensuring consistent high purity levels in tetrahydrofuran production. The developed control structure sets a new standard for efficient azeotropic distillation processes, with implications for enhancing operational performance across industrial applications. Full article

(This article belongs to the Special Issue Green and Sustainable Separation and Purification Technologies)

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9 pages, 10341 KiB

Open AccessCommunication

One-Stage Aqueous Colloid Process: From the Synthesis of Few-Layer Graphene–PVA Colloids to Efficient Electrospun Nanofibers

by Kamel Shoueir, Emeline Lobry, Guy Schlatter and Izabela Janowska

ChemEngineering 2024, 8(6), 126; https://doi.org/10.3390/chemengineering8060126 - 9 Dec 2024

Abstract

Sustainability requirements must be met by the appropriate selection of efficient and environmentally friendly materials and processes. We present materials obtained via all-in-water methods: first, few-layer graphene (FLG)–polyvinyl alcohol (PVA) colloids and then electrospun PVA-FLG fibers. The effects of the FLG concentration, and [...] Read more.

Sustainability requirements must be met by the appropriate selection of efficient and environmentally friendly materials and processes. We present materials obtained via all-in-water methods: first, few-layer graphene (FLG)–polyvinyl alcohol (PVA) colloids and then electrospun PVA-FLG fibers. The effects of the FLG concentration, and indirectly of ultrasound, are reflected via the modification of the structural and physical properties, including the microstructure, viscosity, thermal degradation and mechanical properties, of colloids and fiber mats. The primary results are highly encouraging for further optimization and the development of conductive, and mechanically resistant, materials. Full article

(This article belongs to the Collection Green and Environmentally Sustainable Chemical Processes)

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19 pages, 3704 KiB

Open AccessArticle

Catalytic Reduction of the Compounds Generated When Heating Heet Tobacco in Presence of USY and Beta Zeolites and Silica Lovel 6000 and SBA-15 Silicate in Oxidative and Inert Atmospheres: Effect of Temperature and Catalyst Content

by Antonio Marcilla, Deseada Berenguer, María Isabel Beltrán and Catalina Farcas

ChemEngineering 2024, 8(6), 125; https://doi.org/10.3390/chemengineering8060125 - 6 Dec 2024

Abstract

The thermal decomposition of a heat-not-burn (HNB) tobacco at four temperatures (250–400 °C) was studied via thermogravimetric analysis (TGA) and Multi-shot pyrolizer experiments (Py-GC/MS), and the effect of four potential additives, USY Beta and beta zeolites and Silica Lovel 6000 and SBA-15 silicates [...] Read more.

The thermal decomposition of a heat-not-burn (HNB) tobacco at four temperatures (250–400 °C) was studied via thermogravimetric analysis (TGA) and Multi-shot pyrolizer experiments (Py-GC/MS), and the effect of four potential additives, USY Beta and beta zeolites and Silica Lovel 6000 and SBA-15 silicates at three concentrations (5, 15 and 25% w/w) under an inert and oxidative atmosphere was analyzed. Different techniques were applied showing that the presence of the additives modifies the decomposition processes (TGA). Py-GC/MS showed that these tobaccos generate large amounts of Nicotine and Glycerine. Acid compounds are the most abundant compounds under an inert atmosphere, while Oxygenated compounds predominate under an oxidative atmosphere. In both atmospheres, Furans and Aromatics present in a significant abundance at high temperatures. The additives used reduce both the number and the concentration of most of the compounds generated, especially at high temperatures and concentrations. Moreover, SBA-15 shows good aptitudes to reduce the formation of some individual compounds included in the FDA’s HPHC list, such as Acetone and Acetaldehyde. Finally, smoking experiments corroborated that all additives produce marked reductions in TPM, i.e., the majority fraction obtained, and in practically all the compounds generated. Phenol, a toxicant compound that was detected in a significant amount, is also markedly reduced. SBA-15 is the material that presents a major reduction in the TPM and the principal compounds generated. These results may be of great interest for further reducing the toxicity of smoking this type of heat-not-burn tobacco product. Full article

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