ChemEngineering

30 pages, 3084 KiB

Open AccessArticle

The Cascade Transformation of Furfural to Cyclopentanone: A Critical Evaluation Concerning Feasible Process Development

by Christian A. M. R. van Slagmaat

ChemEngineering 2025, 9(4), 74; https://doi.org/10.3390/chemengineering9040074 - 19 Jul 2025

Furfural is a fascinating bio-based platform molecule that can be converted into useful cyclic compounds, among others. In this work, the hydrogenative rearrangement-dehydration of furfural towards cyclopentanone using a commercially available Pt/C catalyst was investigated in terms of its reaction performance to assess [...] Read more.

Furfural is a fascinating bio-based platform molecule that can be converted into useful cyclic compounds, among others. In this work, the hydrogenative rearrangement-dehydration of furfural towards cyclopentanone using a commercially available Pt/C catalyst was investigated in terms of its reaction performance to assess its feasibility as an industrial process. However, acquiring an acceptable cyclopentanone yield proved very difficult, and the reaction was constrained by unforeseen parameters, such as the relative liquid volume in the reactor and the substrate concentration. Most strikingly, the sacrificial formation of furanoic oligomers that precipitated onto the catalyst’s surface was a troublesome key factor that mediated the product’s selectivity versus the carbon mass balance. By applying a biphasic water–toluene solvent system, the yield of cyclopentanone was somewhat improved to a middling 59%, while tentatively positive distributions of reaction components over these solvent phases were observed, which could be advantageous for anticipated down-stream processing. Overall, the sheer difficulty of controlling this one-pot cascade transformation towards a satisfactory product output under rather unfavorable reaction parameters renders it unsuitable for industrial process development, and a multi-step procedure for this chemical transformation might be considered instead. Full article

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18 pages, 5293 KiB

Open AccessArticle

Fluorescent Moieties Through Alkaline Treatment of Graphene Oxide: A Potential Substitute to Replace CRM in wLEDS

by Maria Lucia Protopapa, Emiliano Burresi, Martino Palmisano and Emanuela Pesce

ChemEngineering 2025, 9(4), 73; https://doi.org/10.3390/chemengineering9040073 - 18 Jul 2025

Abstract

White-light-emitting diodes (wLEDs) are central to next-generation lighting technologies, yet their reliance on critical raw materials (CRMs), such as rare-earth elements, raises concerns regarding sustainability and supply security. In this work, we present a simple, low-cost method to produce photoluminescent carbon-based nanostructures—known as [...] Read more.

White-light-emitting diodes (wLEDs) are central to next-generation lighting technologies, yet their reliance on critical raw materials (CRMs), such as rare-earth elements, raises concerns regarding sustainability and supply security. In this work, we present a simple, low-cost method to produce photoluminescent carbon-based nanostructures—known as oxidative debris (OD)—via alkaline treatment of graphene oxide (GO) using KOH solutions ranging from 0.04 M to 1.78 M. The resulting OD, isolated from the supernatant after acid precipitation, exhibits strong and tunable photoluminescence (PL) across the visible spectrum. Emission peaks shift from blue (~440 nm) to green (~500 nm) and yellow (~565 nm) as a function of treatment conditions, with excitation wavelengths between 300 and 390 nm. Optical, morphological. and compositional analyses were performed using UV-Vis, AFM, FTIR, and Raman spectroscopy, confirming the presence of highly oxidized aromatic domains. The blue-emitting (S2) and green/yellow-emitting (R2) fractions were successfully separated and characterized, demonstrating potential color tuning by adjusting KOH concentration and treatment time. This study highlights the feasibility of reusing GO-derived byproducts as sustainable phosphor alternatives in wLEDs, reducing reliance on CRMs and aligning with green chemistry principles. Full article

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12 pages, 1130 KiB

Open AccessArticle

Production of 2,2,3,3,4,4,4-Heptafluorobutyl Acetate from Acetic Acid and 2,2,3,3,4,4,4-Heptafluorobutan-1-ol by Batch Reactive Distillation

by Andrei V. Polkovnichenko, Egor V. Lupachev, Evgenia I. Kovaleva, Sergey Ya. Kvashnin, Tatiana V. Chelyuskina and Andrey A. Voshkin

ChemEngineering 2025, 9(4), 72; https://doi.org/10.3390/chemengineering9040072 - 11 Jul 2025

Abstract

In the present study, a process for the production of 2,2,3,3,4,4,4-heptafluorobutyl acetate (HFBAc) is proposed for the first time. The production process of HFBAc from acetic acid (AAc) and 2,2,3,3,4,4,4-heptafluorobutan-1-ol (HFBol) was carried out at laboratory scale using batch reactive distillation (BRD). The [...] Read more.

In the present study, a process for the production of 2,2,3,3,4,4,4-heptafluorobutyl acetate (HFBAc) is proposed for the first time. The production process of HFBAc from acetic acid (AAc) and 2,2,3,3,4,4,4-heptafluorobutan-1-ol (HFBol) was carried out at laboratory scale using batch reactive distillation (BRD). The process was conducted at atmospheric pressure in the presence of an acid catalyst, with an excess of AAc relative to HFBol (initial molar ratio of reagents HFBol/AAc is 45/55). During the BRD, the aqueous phase of the distillate was withdrawn from the system, while the organic phase of the distillate was returned as reflux. Since part of AAc is lost along with the aqueous phase of the distillate, a minor excess of AAc is reasonable for maximizing the conversion of the most expensive reagent—HFBol. The losses of AAc and HFBol with the aqueous phase of the distillate were less than 2 mole % and less than 0.5 mole % of the feed, respectively. The purity of HFBAc after BRD was 97.9 wt. %, and the conversion of HFBol exceeded 99 mole % of the feed. The purity of certain product fractions of HFBAc was greater than 99.6 wt. %. The obtained data can be used for industrial technology development to obtain HFBAc. Full article

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15 pages, 3671 KiB

Open AccessArticle

Improving the Water–Gas Shift Performance of a Co/CeO₂ Catalyst for Hydrogen Production

by Nipatta Chumanee and Pannipa Nachai

ChemEngineering 2025, 9(4), 71; https://doi.org/10.3390/chemengineering9040071 - 10 Jul 2025

Abstract

The aim of this study was to improve the water–gas shift efficiency of Co/CeO₂ catalyst by incorporating praseodymium and rhenium. The catalysts were synthesized via combustion method and characterized using X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) surface area analysis, Scanning Electron Microscope (SEM), [...] Read more.

The aim of this study was to improve the water–gas shift efficiency of Co/CeO₂ catalyst by incorporating praseodymium and rhenium. The catalysts were synthesized via combustion method and characterized using X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) surface area analysis, Scanning Electron Microscope (SEM), H₂-temperature programmed reduction (H₂-TPR), NH₃-temperature programmed desorption (NH₃-TPD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). These characterization techniques evaluate the increase of the surface acidity and oxygen vacancies in Co-based catalysts, which leads to an increase in water–gas shift performance because CO molecules prefer to react with surface oxygen, then followed by the production of CO₂ and oxygen vacancies which act as active sites for H₂O dissociation. The 1%Re4%Co/Ce-5%Pr-O catalyst exhibited a maximum CO conversion of 86% at 450 °C, substantially outperforming the 5%Co/Ce-5%Pr-O catalyst, which showed only 62% CO conversion at 600 °C. In addition, 1%Re4%Co/Ce-5%Pr-O catalyst is more resistant towards deactivation than 5%Co/Ce-5%Pr-O. The result presented that the catalytic activity of 1%Re4%Co/Ce-5%Pr-O catalyst was kept constant for the whole period of 50 h, while a 6% decrease in water–gas shift activity was found for the 5%Co/Ce-5%Pr-O catalyst. Moreover, the addition of rhenium into the Co/Ce-Pr-O catalyst reveals that the enhancement of oxygen vacancy concentration, oxygen mobility, and surface acidity, thereby enhances CO conversion efficiency. Full article

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19 pages, 1240 KiB

Open AccessArticle

Extending the Recovery Ratio of Brackish Water Desalination to Zero Liquid Discharge (>95%) Through Combination of Nanofiltration, 2-Stage Reverse-Osmosis, Silica Precipitation, and Mechanical Vapor Recompression

by Paz Nativ, Raz Ben-Asher, Yaron Aviezer and Ori Lahav

ChemEngineering 2025, 9(4), 70; https://doi.org/10.3390/chemengineering9040070 - 3 Jul 2025

Abstract

Extending the recovery ratio (RR) of brackish water reverse osmosis (RO) plants to zero liquid discharge (ZLD, i.e., ≥95%) is vital, particularly inland, where the cost of safe retentate disposal is substantial. Various suggestions appear in the literature; however, many of these are [...] Read more.

Extending the recovery ratio (RR) of brackish water reverse osmosis (RO) plants to zero liquid discharge (ZLD, i.e., ≥95%) is vital, particularly inland, where the cost of safe retentate disposal is substantial. Various suggestions appear in the literature; however, many of these are impractical in the real world. Often, the limiting parameter that determines the maximal recovery is the SiO₂ concentration that develops in the RO retentate and the need to further desalinate the high osmotic pressure retentates produced in the process. This work combines well-proven treatment schemes to attain RR ≥ 95% at a realistic cost. The raw brackish water undergoes first a 94% recovery nanofiltration (NF) step, whose permeate undergoes a further 88-RR RO step. To increase the overall RR, the retentate of the 1st RO step undergoes SiO₂ removal performed via iron electro-dissolution and then a 2nd, 43% recovery, RO pass. The retentate of this step is combined with the NF retentate, and the mix is treated with mechanical vapor recompression (MVR) (RR = 62.7%). The results show that >95% recovery can be attained by the suggested process at an overall cost of ~USD 0.70/m³. This is ~60% higher than the USD 0.44/m³ calculated for the baseline operation (RR = 82.7%), making the concept feasible when either the increase in the plant’s capacity is regulatorily requested, or when the available retentate discharge method is very costly. The cost assessment accuracy was approximated at >80%. Full article

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12 pages, 3309 KiB

Open AccessArticle

A Study on the Effects of Solvent and Temperature on 2-Amino-7-Nitro-Fluorene (ANF) Using Synchronous Fluorescence

by Suresh Sunuwar, Miguel Rodriguez-Escalante, Priscila Blanco-Cortés and Carlos E. Manzanares

ChemEngineering 2025, 9(4), 69; https://doi.org/10.3390/chemengineering9040069 - 27 Jun 2025

Abstract

Synchronous fluorescence spectra are presented to investigate solute–solvent interactions in liquids. To this end, the spectra of 2-amino-7-nitro-fluorene (ANF) in six different solvents—acetic anhydride, acetone, acetonitrile, benzene, chlorobenzene, and ethyl acetate—are presented. The study also examines ANF’s synchronous fluorescence signals at five temperatures [...] Read more.

Synchronous fluorescence spectra are presented to investigate solute–solvent interactions in liquids. To this end, the spectra of 2-amino-7-nitro-fluorene (ANF) in six different solvents—acetic anhydride, acetone, acetonitrile, benzene, chlorobenzene, and ethyl acetate—are presented. The study also examines ANF’s synchronous fluorescence signals at five temperatures from 25 °C to 5 °C, providing a comprehensive analysis of its fluorescence characteristics in different environments and temperatures. An ANF sample dissolved in benzene at 5 °C produced a synchronous band with the largest intensity and smallest frequency shift. The results show that higher-intensity peaks are obtained at lower temperatures with solvents with a small dipole moment and dielectric constant. This suggest that the best conditions to detect ANF and similar molecules at very low concentrations are with non-polar solvents at low temperatures. Full article

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17 pages, 3372 KiB

Open AccessArticle

Combustion Air Humidifier for a Biomass Boiler with Flue Gas Condensation

by Jan Havlík and Tomáš Dlouhý

ChemEngineering 2025, 9(4), 68; https://doi.org/10.3390/chemengineering9040068 - 25 Jun 2025

Abstract

This paper deals with combustion air humidification for application with a biomass boiler and a spray flue gas condenser. The use of a combustion air humidifier increases the dew point temperature of the flue gas, thereby increasing the potential for heat recovery in [...] Read more.

This paper deals with combustion air humidification for application with a biomass boiler and a spray flue gas condenser. The use of a combustion air humidifier increases the dew point temperature of the flue gas, thereby increasing the potential for heat recovery in the flue gas condenser and increasing the amount of heat supplied to the thermal system. The air humidification process in a counter current spray humidifier was experimentally analysed under conditions corresponding to the use before a biomass boiler with a flue gas condenser. For air heating and humidification, temperature factor values of up to 0.90 can be obtained; this value is mainly influenced by the ratio of the spray water and humidified air flow rates. The volumetric heat transfer coefficient is significantly affected by the humidified air velocity, although this velocity is negligible compared to the counter current spray water velocity. The volumetric heat transfer coefficient reaches higher values at higher spray water temperatures and therefore higher air heating. The whole process is also affected by the saturation of the incoming air, where the dew point temperature of the air drawn in from the surroundings is lower than its temperature. These results can be used as basic information for the design of combustion air humidifiers, for the selection of their operating parameters, and for a basic balancing of the energy contribution of the combustion air humidifier before a more detailed design of the whole system. Full article

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11 pages, 1639 KiB

Open AccessArticle

New Approach to the Combined Removal of NO_x and SO₂ for Circulating Fluidized Beds

by Chao Wang and Qinggang Lyu

ChemEngineering 2025, 9(4), 67; https://doi.org/10.3390/chemengineering9040067 - 25 Jun 2025

Abstract

Post-combustion technology is a new kind of low-nitrogen combustion technology. To achieve the combined removal of nitrogen oxides (NO_x) and sulfur dioxide (SO₂) emissions, the post-combustion technology combined with the sorbent injection in the furnace and post-combustion chamber is [...] Read more.

Post-combustion technology is a new kind of low-nitrogen combustion technology. To achieve the combined removal of nitrogen oxides (NO_x) and sulfur dioxide (SO₂) emissions, the post-combustion technology combined with the sorbent injection in the furnace and post-combustion chamber is proposed. Experiments investigating the effects of the sorbent addition in a post-combustion chamber and post-combustion air arrangement on NO_x and SO₂ emissions were conducted in a 0.1 MWth circulating fluidized bed test platform. In addition, a comparative analysis of the NO_x and SO₂ emissions under both combined removal methods was also performed. The results indicated that adding sorbent to the post-combustion chamber can reduce SO₂ emissions, but further increasing the amount of sorbent will not significantly improve the desulfurization effect. The injection position of the post-combustion air will affect the emissions of NO_x and SO₂ in the flue gas. When the three-stage distribution of post-combustion air is adopted, the further back the third nozzle is distributed, the lower the temperature in the post-combustion chamber, which is beneficial to the control of NO_x and SO₂ emissions. Compared with the conventional combined removal method, the NO_x emissions were significantly reduced under the new combined removal method. Through secondary desulfurization in the furnace and post-combustion chamber, oxygen-deficient combustion in the furnace can achieve the combined removal of NO_x and SO₂. Full article

(This article belongs to the Special Issue Fuel Engineering and Technologies)

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17 pages, 5119 KiB

Open AccessArticle

Anode-Supported SOFCs with a Bi₂O₃-Doped NiO–ScSZ Anode and ScSZ Electrolyte: Low-Temperature Co-Sintering and High Performance

by Shang Peng, Zhao Liu, Pairuzha Xiaokaiti, Tiancheng Fang, Jiwei Wang, Guoqing Guan and Abuliti Abudula

ChemEngineering 2025, 9(4), 66; https://doi.org/10.3390/chemengineering9040066 - 24 Jun 2025

Abstract

In this study, a novel anode-supported solid oxide fuel cell (SOFC) comprising a Bi₂O₃-doped NiO-ScSZ anode and an ScSZ electrolyte was successfully fabricated via a low-temperature co-sintering process at 1300 °C. The incorporation of 3 wt% Bi₂O [...] Read more.

In this study, a novel anode-supported solid oxide fuel cell (SOFC) comprising a Bi₂O₃-doped NiO-ScSZ anode and an ScSZ electrolyte was successfully fabricated via a low-temperature co-sintering process at 1300 °C. The incorporation of 3 wt% Bi₂O₃ effectively promoted the sintering of both the anode support and electrolyte layer, resulting in a dense, gas-tight electrolyte and a mechanically robust porous anode support. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses confirmed the formation of phase-pure, highly crystalline ScSZ with an optimized microstructure. Electrochemical performance measurements demonstrated that the fabricated cells achieved excellent power density, reaching a peak value of 0.861 W cm⁻² at 800 °C under humidified hydrogen fuel conditions. The cells maintained stable performance under dry methane operation, with a maximum power density of 0.624 W cm⁻² at 800 °C, indicating resistance to carbon deposition. Gas chromatographic analyses further revealed that the Bi₂O₃-doped NiO-ScSZ anode facilitated earlier and more stable electrochemical oxidation of methane-derived species compared with the conventional NiO-YSZ system, even under conditions of an elevated methane partial pressure. These findings demonstrate that Bi₂O₃ co-doping, combined with low-temperature co-sintering, provides an effective approach for fabricating high-performance intermediate-temperature SOFCs with enhanced structural integrity and electrochemical stability. The developed methodology presents a promising pathway toward achieving cost-effective and durable SOFC technologies. Full article

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18 pages, 6497 KiB

Open AccessArticle

Characterization of HFE 7500 Refrigerant Suspensions Containing Oxide and Nitride Nanoparticles: Thermal, Rheological, and Electrokinetic Insights

by Serdar Ozturk and Keagan Schmidt

ChemEngineering 2025, 9(4), 65; https://doi.org/10.3390/chemengineering9040065 - 24 Jun 2025

Abstract

Nanofluids—engineered suspensions of nanometer-sized particles—have attracted significant attention due to their reportedly enhanced thermal properties, making them promising candidates for advanced heat transfer applications. However, despite extensive studies, uncertainties remain regarding the magnitude and origin of these effects, limiting their practical implementation. To [...] Read more.

Nanofluids—engineered suspensions of nanometer-sized particles—have attracted significant attention due to their reportedly enhanced thermal properties, making them promising candidates for advanced heat transfer applications. However, despite extensive studies, uncertainties remain regarding the magnitude and origin of these effects, limiting their practical implementation. To address this, we present a comprehensive study on nanofluid formulations based on the commercial refrigerant HFE-7500, incorporating surfactant-stabilized dispersions of several metal oxide and nitride nanoparticles. We measured key physicochemical properties, including zeta potential, particle size, viscosity, and thermal conductivity. Our results show that while the nanofluids exhibited high stability, their particle sizes in suspension were significantly larger than the primary nanoparticle sizes measured by TEM. Notably, alumina-based suspensions demonstrated the greatest enhancement, exhibiting approximately 10–15% increases in thermal conductivity as a function of volume percentage. These surpassed the 5–10% improvements observed with other metal oxides, an effect that may be linked to their comparatively larger particle sizes. However, the observed enhancements were lower than some previously reported values that claimed anomalously high thermal conductivity increases. Furthermore, steady shear viscosity increased with particle concentration, showing enhancements of 10–20%, which suggests a potential trade-off for practical implementation. Our findings refine the understanding of nanofluid behavior in refrigerants and establish a foundation for optimizing their performance in thermal management applications. However, viscosity increases must be carefully considered when designing next-generation nanofluids for real-world use. Full article

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15 pages, 2424 KiB

Open AccessArticle

Kinetic and Thermodynamic Study of Cationic Dye Removal Using Activated Biochar Synthesized from Prosopis juliflora Waste

by Andrés Abuabara, Carlos Diaz-Uribe, William Vallejo, Freider Duran and Edgar Mosquera-Vargas

ChemEngineering 2025, 9(3), 64; https://doi.org/10.3390/chemengineering9030064 - 19 Jun 2025

Abstract

In this study, we synthesized an activated biochar using Prosopis juliflora waste as a carbon source. Citric acid (CA) was used as the chemical agent for biochar activation. The removal of methylene blue (MB) using the fabricated biochar was investigated. A response surface [...] Read more.

In this study, we synthesized an activated biochar using Prosopis juliflora waste as a carbon source. Citric acid (CA) was used as the chemical agent for biochar activation. The removal of methylene blue (MB) using the fabricated biochar was investigated. A response surface methodology (RSM) experimental design was employed to evaluate the effects of synthesis parameters, including the temperature and the CA/biochar mass ratio, on the biochar’s MB removal efficiency. The impact of adsorption parameters, such as the biochar dosage, pH, MB concentration, and ionic strength, was also examined. Kinetic and isothermal adsorption studies were conducted to assess the efficacy of the activated biochar. The kinetic study revealed a maximum adsorption capacity (q_e) of 37.6 mg/g and a rate constant of 0.0022 g mg⁻¹ min⁻¹, with the pseudo-second-order model providing the best fit. The isotherm study indicated that the Freundlich model best described the data, with K_F = 37.8 mg/g and 1/n_f = 0.498. Thermodynamic analysis showed that the MB adsorption onto the biochar was spontaneous (ΔG = −9.14 kJ/mol), endothermic (ΔH = 17.87 kJ/mol), and driven by an entropy increase (ΔS = 89.20 J/mol·K). Full article

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16 pages, 1557 KiB

Open AccessTechnical Note

Growth of a Single Bubble Due to Super-Saturation: Comparison of Correlation-Based Modelling with CFD Simulation

by Johannes Manthey, Wei Ding, Hossein Mehdipour, Montadhar Guesmi, Simon Unz, Uwe Hampel and Michael Beckmann

ChemEngineering 2025, 9(3), 63; https://doi.org/10.3390/chemengineering9030063 - 17 Jun 2025

Abstract

This paper investigates and assesses the potential applicability of global mass transfer coefficients derived from large-scale experiments to the bubble growth of a single bubble in a super-saturated flow

(σ = 9)

. Therefore, it presents, for a specific flow velocity [...] Read more.

This paper investigates and assesses the potential applicability of global mass transfer coefficients derived from large-scale experiments to the bubble growth of a single bubble in a super-saturated flow

(σ = 9)

. Therefore, it presents, for a specific flow velocity

(u = 1 \frac{m}{s}, R e = 10,678)

, a comparison between correlation-based modelling and 3D Large Eddy Simulation–Volume of Fluid (LES-VOF) Computational Fluid Dynamics (CFD) simulations (minimum cell size of 10 µm, Δt = 10 µs). After the verification of the CFD with pool nucleation bubbles, two cases are regarded: (1) the bubble flowing in the bulk and (2) a bubble on a wall with a crossflow. The correlation-based modelling results in a nearly linear relationship between bubble radius and time; meanwhile, theoretically, the self-similarity rule offers

r ~ {B t}^{0.5}

. The Avdeev correlation gives the best agreement with the CFD simulation for a bubble in the flow bulk (case 1), while the laminar approach for calculation of the exposure time of the penetration theory shows good agreement with the CFD simulation for the bubble growth at the wall (case 2). This preliminary study provides the first quantitative validation of global mass transfer coefficient correlations at the single-bubble scale, suggesting that computationally intensive CFD simulations may be omitted for rapid estimations. Future work will extend the analysis to a wider range of flow velocities and bubble diameters to further validate these findings. Full article

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24 pages, 7924 KiB

Open AccessArticle

Mechanisms and Optimization of Foam Flooding in Heterogeneous Thick Oil Reservoirs: Insights from Large-Scale 2D Sandpack Experiments

by Qingchun Meng, Hongmei Wang, Weiyou Yao, Yuyang Han, Xianqiu Chao, Tairan Liang, Yongxian Fang, Wenzhao Sun and Huabin Li

ChemEngineering 2025, 9(3), 62; https://doi.org/10.3390/chemengineering9030062 - 4 Jun 2025

Abstract

To address the challenges of low displacement efficiency and gas channeling in the Lukqin thick oil reservoir, characterized by high viscosity (286 mPa·s) and strong heterogeneity (permeability contrast 5–10), this study systematically investigated water flooding and foam flooding mechanisms using a large-scale 2D [...] Read more.

To address the challenges of low displacement efficiency and gas channeling in the Lukqin thick oil reservoir, characterized by high viscosity (286 mPa·s) and strong heterogeneity (permeability contrast 5–10), this study systematically investigated water flooding and foam flooding mechanisms using a large-scale 2D sandpack model (5 m × 1 m × 0.04 m). Experimental results indicate that water flooding achieves only 30% oil recovery due to a mobility ratio imbalance (M = 128) and preferential channeling. In contrast, foam flooding enhances recovery by 15–20% (final recovery: 45%) through synergistic mechanisms of dynamic high-permeability channel plugging and mobility ratio optimization. By innovatively integrating electrical resistivity tomography with HSV color mapping, this work achieves the first visualization of foam migration pathways in meter-scale heterogeneous reservoirs at a spatial resolution of ≤0.5 cm, reducing monitoring costs by approximately 30% compared to conventional CT techniques. Key controlling factors for gas channeling (injection rate, foam quality, permeability contrast) are identified, and a nonlinear predictive model for plugging strength ((S = 0.70C^0.6 k_r^−0.28) (R² = 0.91)) is established. A composite optimization strategy—combining high-concentration slugs (0.7% AOS), salt-resistant polymer-enhanced foaming, and multi-round profile control—achieves a 67% reduction in gas channeling. This study elucidates the dynamic plugging mechanisms of foam flooding in heterogeneous thick oil reservoirs through large-scale physical simulations and data fusion, offering direct technical guidance for optimizing foam flooding operations in the Lukqin Oilfield and analogous reservoirs. Full article

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19 pages, 1656 KiB

Open AccessArticle

Optimizing Biomethane Production from Industrial Pig Slurry and Wine Vinasse: A Mathematical Approach

by Belén Cañadas, Juana Fernández-Rodríguez, Rosario Solera and Montserrat Pérez

ChemEngineering 2025, 9(3), 61; https://doi.org/10.3390/chemengineering9030061 - 3 Jun 2025

Abstract

Pig slurry (PS) and wine vinasse (WV) pose environmental risks if not properly managed. Their composition makes them suitable for anaerobic co-digestion (AcoD), enhancing biomethane production and improving organic matter degradation efficiency. This research applies an innovative Design of Experiments (DoE) approach—specifically the [...] Read more.

Pig slurry (PS) and wine vinasse (WV) pose environmental risks if not properly managed. Their composition makes them suitable for anaerobic co-digestion (AcoD), enhancing biomethane production and improving organic matter degradation efficiency. This research applies an innovative Design of Experiments (DoE) approach—specifically the Box–Behnken design (BBD)—to systematically optimize the AcoD process, surpassing traditional single-factor methods by efficiently evaluating the interactions. Variables such as temperature (35 °C, 52.5 °C, 70 °C), substrate ratio (25PS:75WV, 50PS:50WV, 75PS:25WV) and pH (7, 7.5, 8) were tested using a Box–Behnken design which studied the correlations between the experimental data and the model. In fact, the results showed that temperature, ratio, and their interaction significantly influenced biomethane production, being the pH the factor with the least influence on the response. Optimal conditions—pH of 8, temperature of 35 °C and a 50:50 substrate ratio—achieved a biomethane yield of 487.94 CH₄/gVS (Volatile Solids). These results demonstrate the effectiveness of the DoE methodology in maximizing biomethane production and represent a significant advancement in valorizing wastes from pig farms and wineries, promoting a circular and sustainable economy. Full article

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16 pages, 706 KiB

Open AccessArticle

The Re-Modeling of a Polymeric Drug Delivery System Using Smart Response Surface Designs: A Sustainable Approach for the Consumption of Fewer Resources

by Magdy M. Aly, Shaimaa S. Ibrahim and Rania M. Hathout

ChemEngineering 2025, 9(3), 60; https://doi.org/10.3390/chemengineering9030060 - 1 Jun 2025

Abstract

Introduction: The use of response surface designs for drug formulation is highly warranted nowadays. Such smart designs reduce the number of required experiments compared to full-factorial designs, while providing highly accurate and reliable results. Aim: This study compares the effectiveness of [...] Read more.

Introduction: The use of response surface designs for drug formulation is highly warranted nowadays. Such smart designs reduce the number of required experiments compared to full-factorial designs, while providing highly accurate and reliable results. Aim: This study compares the effectiveness of two of the most commonly used response surface designs—Central Composite Design (CCD) and D-optimal Design (DOD)—in modeling a polymer-based drug delivery system. The performance of the two designs was further evaluated under a challenging scenario where a central point was deliberately converted into an outlier. Methods: Both methods were assessed using ANOVA, R-squared values, and adequate precision, and were assessed through an experimental validation point. Results: Both models demonstrated statistical significance (p-value < 0.05), confirming their ability to describe the relationships between formulation variables and critical quality attributes (CQAs). CCD achieved higher R-squared and predicted R-squared values compared to DOD (0.9977 and 0.9846 vs. 0.8792 and 0.7858, respectively), rendering it as the superior approach in terms of modeling complex variables’ interactions. However, DOD proved to be more predictive as it scored a lower percentage relative error. Conclusion: The demonstrated resilience of both models, despite the introduction of an outlier, further validates their utility in real-world applications, instead of the exhaustive full-factorial design. Full article

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15 pages, 2555 KiB

Open AccessArticle

Solving a Challenge in the Tequila Industry: A New Continuous Rectification Process for Reducing Higher Alcohols and Obtaining Products Within the Official Tequila Standard

by Héctor Flores-Martínez, Isaac Guadalupe Tejeda-Arandas, Mirna Estarrón-Espinosa and José Daniel Padilla-de la Rosa

ChemEngineering 2025, 9(3), 59; https://doi.org/10.3390/chemengineering9030059 - 1 Jun 2025

Abstract

This work is the first to study the effect of residence time on the volatile composition of distilled fractions of ordinario using a horizontal continuous distiller of our own manufacture. The ordinario used in this research had a high amount of higher alcohols, [...] Read more.

This work is the first to study the effect of residence time on the volatile composition of distilled fractions of ordinario using a horizontal continuous distiller of our own manufacture. The ordinario used in this research had a high amount of higher alcohols, so its adequate distillation is complicated. The fractions rectified by continuous distillation were compared with those obtained by batch distillation. Five distilled fractions were collected, and their combined volume was subjected to gas chromatography (GC) analysis to determine the principal volatile compounds (furfural, aldehyde, higher alcohols, methanol, and ester contents). A variance analysis of each group of volatile compounds was conducted to evaluate the effect of residence time (2 and 4 h) in continuous distillation compared to batch distillation (4 h). Continuous rectification allowed for obtaining a distillate within the permissible limits specified by the Official Mexican Standard (NOM-006-SCFI-2012). For the continuous 2 h, continuous 4 h, and batch 4 h processes, the higher alcohols, esters, and aldehydes showed a decreasing pattern, while methanol and furfural showed an increasing pattern in relation to the fraction number. An analysis of variance showed no statistically significant differences in terms of the regulated volatile composition (higher alcohols, esters, methanol, and furfural) according to process type (continuous 2 h, continuous 4 h, and batch 4 h), except for aldehydes, which presented differences. This new continuous rectification process increases productivity while reducing the processing time by 50%, keeping the composition and volume of the heart fraction. Full article

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22 pages, 1013 KiB

Open AccessSystematic Review

Valorization of Lignocellulosic Biomass to Biofuel: A Systematic Review

by Mbuyu Germain Ntunka, Siphesihle Mangena Khumalo, Thobeka Pearl Makhathini, Sphesihle Mtsweni, Marc Mulamba Tshibangu and Joseph Kapuku Bwapwa

ChemEngineering 2025, 9(3), 58; https://doi.org/10.3390/chemengineering9030058 - 29 May 2025

Abstract

Lignocellulosic biomass, derived from plant materials, represents a renewable alternative to fossil fuels and plays a crucial role in advancing environmental sustainability. This systematic review investigates recent developments in the conversion of lignocellulosic biomass into biofuels, with a focus on pre-treatment technologies that [...] Read more.

Lignocellulosic biomass, derived from plant materials, represents a renewable alternative to fossil fuels and plays a crucial role in advancing environmental sustainability. This systematic review investigates recent developments in the conversion of lignocellulosic biomass into biofuels, with a focus on pre-treatment technologies that enhance enzymatic hydrolysis, a critical step in efficient biofuel production. This review addresses two primary questions: (1) What are the most effective pre-treatment methods for enhancing enzymatic hydrolysis in lignocellulosic biomass conversion? (2) How do these pre-treatment methods compare in terms of efficiency, environmental impact, and economic feasibility? Consequently, studies were selected based on inclusion criteria that focus on research investigating these pre-treatment methods and their comparative performance. A structured search of original studies was applied across databases such as Crossref, Google Scholar, Scopus, PubMed, and Semantic Scholar, resulting in the inclusion of 17 peer-reviewed articles published between 2019 and 2024. The findings highlight effective pre-treatment methods that significantly improve enzymatic accessibility and bioethanol yields. However, ongoing challenges such as feedstock variability, process efficiency, and cost-effectiveness remain. These results highlight the need for further research and development to optimize conversion technologies and identify new areas for exploration. Full article

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14 pages, 2322 KiB

Open AccessArticle

Effect of Rotation Speed and Powder Bed Volume on Powder Flowability Measured by a Powder Rheometer: Evaluation of the Humidity Effect on Lactose Powder Flowability

by Takamasa Mori, Kanaho Sakurada and Kenta Kitamura

ChemEngineering 2025, 9(3), 57; https://doi.org/10.3390/chemengineering9030057 - 29 May 2025

Abstract

Relative humidity during storage is known to affect powder flowability, although its effect on powder flowability remains unclear. Various techniques have been used to evaluate powder flowability, including measurement of the rotational torque of the powder bed, which is a novel method. However, [...] Read more.

Relative humidity during storage is known to affect powder flowability, although its effect on powder flowability remains unclear. Various techniques have been used to evaluate powder flowability, including measurement of the rotational torque of the powder bed, which is a novel method. However, studies investigating the effect of relative humidity on powder flowability using rotational torque measurements are limited. Therefore, this study aimed to examine the influence of relative humidity during storage on the flowability of lactose powder through rotational torque measurement of the powder bed using an Anton Paar powder rheometer. Rotation speed had a minimal effect, except when the powder was stored at a high relative humidity of 99%. The effect of relative humidity was more pronounced at a smaller powder volume (30 mL) than that at the other volumes tested. Of the techniques employed, including the angle of repose and bulk density measurements, the rotational torque measurement of the powder rheometer exhibited the highest sensitivity to variations in relative humidity. It was also found that the measured rotation torque hardly changed when the rotation speed was below a critical value, indicating that the optimal rotation speed exists to measure the representative rotation torque of each powder. Full article

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20 pages, 1490 KiB

Open AccessReview

Liposome-Based Drug Delivery Systems: From Laboratory Research to Industrial Production—Instruments and Challenges

by Suman Basak and Tushar Kanti Das

ChemEngineering 2025, 9(3), 56; https://doi.org/10.3390/chemengineering9030056 - 27 May 2025

Cited by 2

Abstract

Liposome-based drug delivery systems have revolutionized modern pharmaceutics, offering unparalleled versatility and precision in therapeutic delivery. These lipid vesicles, capable of encapsulating hydrophilic, hydrophobic, and amphiphilic drugs, have demonstrated significant potential in addressing pharmacokinetic challenges such as poor solubility, systemic toxicity, and rapid [...] Read more.

Liposome-based drug delivery systems have revolutionized modern pharmaceutics, offering unparalleled versatility and precision in therapeutic delivery. These lipid vesicles, capable of encapsulating hydrophilic, hydrophobic, and amphiphilic drugs, have demonstrated significant potential in addressing pharmacokinetic challenges such as poor solubility, systemic toxicity, and rapid clearance. This review provides a comprehensive exploration of the evolution of liposomes from laboratory models to clinically approved therapeutics, highlighting their structural adaptability, functional tunability, and transformative impact on modern medicine. We discuss pivotal laboratory-scale preparation techniques, including thin-film hydration, ethanol injection, and reverse-phase evaporation, along with their inherent advantages and limitations. The challenges of transitioning to industrial-scale production are examined, with emphasis on achieving batch-to-batch consistency, scalability, regulatory compliance, and cost-effectiveness. Innovative strategies, such as the incorporation of microfluidic systems and advanced process optimization, are explored to address these hurdles. The clinical success of Food and Drug Administration (FDA)-approved liposomal formulations such as Doxil^® and AmBisome^® underscores their efficacy in treating conditions ranging from cancer to fungal infections. Furthermore, this review delves into emerging trends, including stimuli-responsive and hybrid liposomes, as well as their integration with nanotechnology for enhanced therapeutic precision. As liposomes continue to expand their role in gene therapy, theranostics, and personalized medicine, this review highlights their potential to redefine pharmaceutical applications. Despite existing challenges, ongoing advancements in formulation techniques and scalability underscore the bright future of liposome-based therapeutics in addressing unmet medical needs. Full article

(This article belongs to the Special Issue New Trends in (Bio)chemical Engineering: Biobased Pharmaceutical Processes)

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