Advances in Chemistry and Chemical Engineering

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Dear Colleagues,

The 22nd Romanian International Conference on Chemistry and Chemical Engineering (RICCCE22; https://riccce22.chimie.upb.ro/) is the main international scientific event held in Romania in the field of chemistry and chemical engineering. The aim of RICCCE 22 is to provide a forum for the presentation and discussion of the main scientific achievements made in chemistry and chemical engineering fields and to establish contacts between scientists as well as companies involved in research and development. Gathering in Sinaia, Romania, the conference brings together the most prominent scientists of the chemistry and chemical engineering research community. The 22th RICCCE conference will take place in September 2022 and, once again, will cover all major areas in chemistry and chemical engineering and feature the latest scientific results that are making an impact in fundamental research and applications. The Topics for original papers aim to cover all aspects of chemistry and include, but are not limited to, the following: 1. New developments in chemical synthesis and catalysis; 2. Biochemistry, food, and health; 3. Physical chemistry, electrochemistry, and corrosion; 4. New concepts in biochemical and chemical engineering; 5. Monitoring and environmental protection; 6. New materials and nanomaterials. We welcome you to share your up-to-date knowledge, developed by you and/or your research group, with the 22nd Romanian International Conference on Chemistry and Chemical Engineering, hoping that we will collect valuable contributions to create a unique Topic collection for MDPI journals.

Prof. Dr. Cristina Orbeci
Prof. Dr. Cristian Pirvu
Prof. Dr. Ileana Rau
Prof. Dr. Paul Octavian Stãnescu
Prof. Dr. Stefania Stoleriu
Dr. Maria-Cristina Todasca
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Participating Journals

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
ChemEngineering ChemEngineering	2.8	4.0	2017	29.6 Days	CHF 1600
Electrochem electrochem	-	6.3	2020	24 Days	CHF 1000
International Journal of Molecular Sciences ijms	4.9	8.1	2000	18.1 Days	CHF 2900
Molecules molecules	4.2	7.4	1996	15.1 Days	CHF 2700
Polymers polymers	4.7	8.0	2009	14.5 Days	CHF 2700
Separations separations	2.5	3.0	2014	12.4 Days	CHF 2600

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Published Papers (34 papers)

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13 pages, 1429 KiB  

Open AccessFeature PaperReview

An Arsenic Removal Technology and Its Application in Arsenic-Containing Copper

by Xiaowei Tang and Yuehui He

ChemEngineering 2024, 8(3), 56; https://doi.org/10.3390/chemengineering8030056 - 3 Jun 2024

Viewed by 1010

Abstract

The usage of copper (Cu) ores containing low or no arsenic (As) has reduced, and Cu ores containing high levels of As have emerged as vital mineral resources for Cu extraction and processing. The quality of the Cu ores has decreased from 1.6% [...] Read more.

The usage of copper (Cu) ores containing low or no arsenic (As) has reduced, and Cu ores containing high levels of As have emerged as vital mineral resources for Cu extraction and processing. The quality of the Cu ores has decreased from 1.6% to approximately 1.0%. The proportion of As to Cu in 15% of Cu resources currently reaches 1:5. However, during the extraction and processing of Cu ores, As presents significant environmental harm. Hence, safely and effectively removing As is paramount in Cu smelting and processing, holding substantial importance in fostering environmentally sustainable practices within the Cu extraction and processing industry. This article consolidates the resource distribution of As-containing Cu (ACC) ores, comprehensively and systematically evaluates the present advancements in extracting techniques for these minerals, and identifies the challenges inherent in pyrometallurgical and wet processes for treating ACC deposits. Pyrometallurgy is a simple primary roasting technique and has widespread applicability in the treatment of various ACC minerals. Its disadvantages are the emission of exhaust gas and the high treatment costs associated with it. The wet arsenic removal method boasts advantages including minimal air pollution and a high resource recovery rate, significantly aiding in Cu concentrate recovery; its major drawback is the production of As-containing wastewater. The hydrometallurgical removal of As from ACC mines involves extracting As through leaching. Recently, biometallurgy has presented innovative solutions using specialized microorganisms to bioleach or bioabsorb As, but large-scale industrial applications still lack specific practical implementation. This review explores the underlying causes of the challenges encountered in processing ACC minerals. Additionally, it highlights pyrometallurgical roasting coupled with high-temperature filtration as a pivotal advancement in the extraction and processing of ACC ores. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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25 pages, 14357 KiB  

Open AccessArticle

Study on the Effects of Wettability and Pressure in Shale Matrix Nanopore Imbibition during Shut-in Process by Molecular Dynamics Simulations

by Wen Jiang, Weifeng Lv, Ninghong Jia, Xiaoqing Lu, Lu Wang, Kai Wang and Yuhao Mei

Molecules 2024, 29(5), 1112; https://doi.org/10.3390/molecules29051112 - 1 Mar 2024

Cited by 5 | Viewed by 1306

Abstract

Shut-in after fracturing is generally adopted for wells in shale oil reservoirs, and imbibition occurring in matrix nanopores has been proven as an effective way to improve recovery. In this research, a molecular dynamics (MD) simulation was used to investigate the effects of [...] Read more.

Shut-in after fracturing is generally adopted for wells in shale oil reservoirs, and imbibition occurring in matrix nanopores has been proven as an effective way to improve recovery. In this research, a molecular dynamics (MD) simulation was used to investigate the effects of wettability and pressure on nanopore imbibition during shut-in for a typical shale reservoir, Jimsar. The results indicate that the microscopic advancement mechanism of the imbibition front is the competitive adsorption between “interfacial water molecules” at the imbibition front and “adsorbed oil molecules” on the pore wall. The essence of spontaneous imbibition involves the adsorption and aggregation of water molecules onto the hydroxyl groups on the pore wall. The flow characteristics of shale oil suggest that the overall push of the injected water to the oil phase is the main reason for the displacement of adsorbed oil molecules. Thus, shale oil, especially the heavy hydrocarbon component in the adsorbed layer, tends to slip on the walls. However, the weak slip ability of heavy components on the wall surface is an important reason that restricts the displacement efficiency of shale oil during spontaneous imbibition. The effectiveness of spontaneous imbibition is strongly dependent on the hydrophilicity of the matrix pore’s wall. The better hydrophilicity of the matrix pore wall facilitates higher levels of adsorption and accumulation of water molecules on the pore wall and requires less time for “interfacial water molecules” to compete with adsorbed oil molecules. During the forced imbibition process, the pressure difference acts on both the bulk oil and the boundary adsorption oil, but mainly on the bulk oil, which leads to the occurrence of wetting hysteresis. Meanwhile, shale oil still existing in the pore always maintains a good, stratified adsorption structure. Because of the wetting hysteresis phenomenon, as the pressure difference increases, the imbibition effect gradually increases, but the actual capillary pressure gradually decreases and there is a loss in the imbibition velocity relative to the theoretical value. Simultaneously, the decline in hydrophilicity further weakens the synergistic effect on the imbibition of the pressure difference because of the more pronounced wetting hysteresis. Thus, selecting an appropriate well pressure enables cost savings and maximizes the utilization of the formation’s natural power for enhanced oil recovery (EOR). Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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23 pages, 4038 KiB  

Open AccessArticle

The Effect of Bulk Modification of the MF-4SK Membrane with Phosphorylated Hyper-Branched Dendrimer Bolthorn H20 on the Mechanisms of Electroconvection/Dissociation of Water and Specific Selectivity to Divalent Ions

by Aslan Achoh, Denis Bondarev, Elena Nosova and Stanislav Melnikov

Electrochem 2024, 5(1), 84-106; https://doi.org/10.3390/electrochem5010006 - 20 Feb 2024

Cited by 2 | Viewed by 1257

Abstract

This study focuses on the modification of ion-exchange membranes by incorporating a phosphorylated dendrimer into sulfonated polytetrafluoroethylene membranes to enhance the specific selectivity between mono-/divalent ions, using the Ca²⁺/Na⁺ pair as an example. This research employs mechanical, physicochemical, and electrochemical [...] Read more.

This study focuses on the modification of ion-exchange membranes by incorporating a phosphorylated dendrimer into sulfonated polytetrafluoroethylene membranes to enhance the specific selectivity between mono-/divalent ions, using the Ca²⁺/Na⁺ pair as an example. This research employs mechanical, physicochemical, and electrochemical analyses to explore the effects of P-H20 incorporation on membrane properties. Bulk modification significantly increases membrane selectivity towards calcium ions (the specific permselectivity coefficient rises from 1.5 to 7.2), while maintaining the same level of the limiting current density. Other findings indicate that bulk modification significantly changes the transport-channel structure of the membrane and alters the mechanism of over-limiting mass transfer. The over-limiting current for the pristine membrane is mainly due to non-equilibrium electroconvection, while modified membranes actively participate in the water-splitting reaction, leading to the suppression of the electroconvection. Despite this drawback, the decrease of the over-limiting potential drop results in a decrease in specific energy consumption from 0.11 to 0.07 kWh/mol. In the underlimiting current mode, the specific energy consumption for all studied membranes remains within the same limits of 0.02–0.03 kWh/mol. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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17 pages, 4728 KiB  

Open AccessArticle

Stability and Reactivity of Guaiacylglycerol-β-Guaiacyl Ether, a Compound Modeling β-O-4 Linkage in Lignin

by Zeinab Rabiei, Andrew Simons, Magdalena Folkmanova, Tereza Vesela, Ondrej Uhlik, Evguenii Kozliak and Alena Kubátová

Separations 2024, 11(2), 59; https://doi.org/10.3390/separations11020059 - 14 Feb 2024

Cited by 1 | Viewed by 1859

Abstract

Lignin, a complex and abundant biopolymer, is a major constituent of plant cell walls. Due to its chemical and structural complexity, lignin degradation is a challenging task for both natural and engineered systems. Therefore, investigation of lignin degradation using so called “model compounds” [...] Read more.

Lignin, a complex and abundant biopolymer, is a major constituent of plant cell walls. Due to its chemical and structural complexity, lignin degradation is a challenging task for both natural and engineered systems. Therefore, investigation of lignin degradation using so called “model compounds” has been the focus of many research efforts in recent years. This study addresses the utility of guaiacylglycerol-β-guaiacyl ether (Gβ2) as a model compound for evaluating the β-O-4 bond cleavage under diverse thermal and aqueous medium conditions. Experimental conditions included varied pH (3–10), microbial biodegradation, subcritical water environment (150–250 °C), and mild pyrolysis (150–250 °C). A high-performance liquid chromatography with high-resolution mass spectrometry was employed for accurate detection and quantification of both Gβ2 and its degradation/modification products in an aqueous environment. Pyrolysis experiments were performed using gas chromatography-mass spectrometry analysis with a pyrolyzer. The results showed that Gβ2 remained stable under exposure to moderate pH and several bacterial strains, which were successfully used previously for biodegradation of other recalcitrant pollutants. We report, for the first time, differing Gβ2 breakdown pathways for subcritical water treatment vs. pyrolysis under an inert atmosphere. The scientific novelty lies in the presentation of differences in the degradation pathways of Gβ2 during subcritical water treatment compared to pyrolysis in an inert atmosphere, with water playing a key role. The observed differences are ascribed to the suppression of homolytic reactions by water as a solvent. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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12 pages, 4482 KiB  

Open AccessBrief Report

Chemical Species Formed on FeB-Fe₂B Layers during Wet Sliding Wear Test

by Ricardo Andrés García-León and Nelson Afanador-García

ChemEngineering 2024, 8(1), 22; https://doi.org/10.3390/chemengineering8010022 - 9 Feb 2024

Viewed by 1711

Abstract

In the present work, X-ray photoelectron spectroscopy (XPS) survey spectra of borided AISI 316L for two different times (1 and 6 h) of exposure to simulated body fluid (SBF) were obtained after wet sliding wear. A borided layer of ~39 microns was obtained [...] Read more.

In the present work, X-ray photoelectron spectroscopy (XPS) survey spectra of borided AISI 316L for two different times (1 and 6 h) of exposure to simulated body fluid (SBF) were obtained after wet sliding wear. A borided layer of ~39 microns was obtained on the surface of the AISI 316L stainless steel using the thermochemical treatment of boriding. As part of the mechanical and chemical characterization of sliding wear, Berkovich nanoindentation and X-ray spectroscopy tests were used to determine the main properties of the borided layer. The results of the specific wear rate values were higher at 5 mm/s sliding speed than those recorded at 30 mm/s due to the influence of the exposure time of the sample and the complex combinations of chemical reactions with boron (e.g., B₂S₃, Cr₂O₃, and Fe₂O₃) on the surface during the sliding during 6 h of exposure in Hank’s solution due to the formation of the passive film. The knowledge of chemical species formed during wet sliding wear tests on borided AISI 316L is essential for understanding wear mechanisms and materials’ performance and optimizing material properties and materials’ and components’ reliability in the biomedical industry for screws and fastening plates. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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16 pages, 8047 KiB  

Open AccessArticle

Role of Alkyl Chain Length in Surfactant-Induced Precipitation of Reactive Brilliant Blue KN-R

by Hongyu Liu, Yunkang Chang, Yuhuan Li, Chengsong Cao and Rui Li

Molecules 2024, 29(3), 619; https://doi.org/10.3390/molecules29030619 - 28 Jan 2024

Cited by 1 | Viewed by 1206

Abstract

To develop a cost-effective method for the effective removal of reactive brilliant blue KN-R (RBB KN-R) from wastewater, we investigated the interactions between RBB KN-R and three cationic surfactants with different alkyl chain lengths, namely dodecyltrimethylammonium bromide (DTAB), tetradecyltrimethylammonium bromide (TTAB), and cetyltrimethylammonium [...] Read more.

To develop a cost-effective method for the effective removal of reactive brilliant blue KN-R (RBB KN-R) from wastewater, we investigated the interactions between RBB KN-R and three cationic surfactants with different alkyl chain lengths, namely dodecyltrimethylammonium bromide (DTAB), tetradecyltrimethylammonium bromide (TTAB), and cetyltrimethylammonium bromide (CTAB). Employing a conductivity analysis, surface tension analysis, ultraviolet-visible spectrophotometry, and molecular dynamics simulation, we ascertained that RBB KN-R formed a 1:1 molar ratio dye–surfactant complex with each surfactant through electrostatic attraction. Notably, an augmentation in alkyl chain length correlated with increased binding strength between RBB KN-R and the surfactant. The resulting dye–surfactant complex exhibited heightened surface activity, enabling interactions through hydrophobic forces to generate dye–surfactant aggregates when the molar ratio was below 1:1. Within these mixed aggregates, self-assembly of RBB KN-R molecules occurred, leading to the formation of dye aggregates. Due to the improved hydrophobicity with increased alkyl chain length, TTAB and CTAB could encapsulate dye aggregates within the mixed aggregates, but DTAB could not. The RBB KN-R aggregates tended to distribute on the surface of the RBB KN-R-DTAB mixed aggregates, resulting in low stability. Thus, at a DTAB concentration lower than CMC, insoluble particles readily formed and separated from surfactant aggregates at an RBB KN-R and DTAB molar ratio of 1:4. Analyzing the RBB KN-R precipitate through scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) and measuring the DTAB concentration in the supernate revealed that, at this molar ratio, all RBB KN-R precipitated from the dye–surfactant mixed solution, with only 7.5 ± 0.5% of DTAB present in the precipitate. Furthermore, the removal ratio of RBB KN-R reached nearly 100% within a pH range of 1.0 to 9.0 and standing time of 6 h. The salt type and concentration did not significantly affect the precipitation process. Therefore, this simultaneous achievement of successful RBB KN-R removal and effective separation from DTAB underscores the efficacy of the proposed approach. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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20 pages, 5539 KiB  

Open AccessArticle

Hydrophilic Reduction-Resistant Spin Labels of Pyrrolidine and Pyrroline Series from 3,4-Bis-hydroxymethyl-2,2,5,5-tetraethylpyrrolidine-1-oxyl

by Mikhail S. Usatov, Sergey A. Dobrynin, Yuliya F. Polienko, Denis A. Morozov, Yurii I. Glazachev, Sergey V. An’kov, Tatiana G. Tolstikova, Yuri V. Gatilov, Irina Yu. Bagryanskaya, Arthur E. Raizvikh, Elena G. Bagryanskaya and Igor A. Kirilyuk

Int. J. Mol. Sci. 2024, 25(3), 1550; https://doi.org/10.3390/ijms25031550 - 26 Jan 2024

Cited by 2 | Viewed by 1215

Abstract

Highly resistant to reduction nitroxides open new opportunities for structural studies of biological macromolecules in their native environment inside living cells and for functional imaging of pH and thiols, enzymatic activity and redox status in living animals. 3,4-Disubstituted nitroxides of 2,2,5,5-tetraethylpyrrolidine and pyrroline [...] Read more.

Highly resistant to reduction nitroxides open new opportunities for structural studies of biological macromolecules in their native environment inside living cells and for functional imaging of pH and thiols, enzymatic activity and redox status in living animals. 3,4-Disubstituted nitroxides of 2,2,5,5-tetraethylpyrrolidine and pyrroline series with a functional group for binding to biomolecules and a polar moiety for higher solubility in water and for more rigid attachment via additional coordination to polar sites were designed and synthesized. The EPR spectra, lipophilicities, kinetics of the reduction in ascorbate-containing systems and the decay rates in liver homogenates were measured. The EPR spectra of all 3,4-disubstituted pyrrolidine nitroxides showed additional large splitting on methylene hydrogens of the ethyl groups, while the spectra of similar pyrroline nitroxides were represented with a simple triplet with narrow lines and hyperfine structure of the nitrogen manifolds resolved in oxygen-free conditions. Both pyrrolidine and pyrroline nitroxides demonstrated low rates of reduction with ascorbate, pyrrolidines being a bit more stable than similar pyrrolines. The decay of positively charged nitroxides in the rat liver homogenate was faster than that of neutral and negatively charged radicals, with lipophilicity, rate of reduction with ascorbate and the ring type playing minor role. The EPR spectra of N,N-dimethyl-3,4-bis-(aminomethyl)-2,2,5,5-tetraethylpyrrolidine-1-oxyl showed dependence on pH with pK_a = 3, Δa_N = 0.055 mT and Δa_H = 0.075 mT. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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14 pages, 1674 KiB  

Open AccessArticle

The Simulation and Optimization of the Tetrafluoroethylene Rectification Process

by Limin Yang, Yue Chen, Jinzhi Wang, Yongzhen Luo, Pengfei Zhou and Xiaolai Zhang

Separations 2024, 11(2), 37; https://doi.org/10.3390/separations11020037 - 25 Jan 2024

Cited by 1 | Viewed by 2201

Abstract

In the R22 (chlorodifuoromethane) steam-cracking process, which is used to produce a TFE (tetrafluoroethylene) monomer, distillation is employed to separate the high-purity TFE monomer from the cracked gas generated during this procedure. Traditionally, this distillation process is carried out using five towers. In [...] Read more.

In the R22 (chlorodifuoromethane) steam-cracking process, which is used to produce a TFE (tetrafluoroethylene) monomer, distillation is employed to separate the high-purity TFE monomer from the cracked gas generated during this procedure. Traditionally, this distillation process is carried out using five towers. In this study, the traditional five-tower distillation method was transformed into a four-tower distillation method through the Aspen Plus simulation software, and this process was simulated and optimized. Meanwhile, a double-effect distillation process was designed for the transformed four-tower distillation process. The transformed distillation process not only meets the requirements of 99.999% purity for the TFE monomer and 99.99% purity for R22 recycling, but it also reduces the footprint by eliminating one distillation tower and saves 112.9002 kW of tower load, thus reducing the operating costs. This research provides valuable guidance for practical production. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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17 pages, 2358 KiB  

Open AccessArticle

Surface-Active Ionic Liquids and Surface-Active Quaternary Ammonium Salts from Synthesis, Characterization to Antimicrobial Properties

by Marta Wojcieszak, Damian Krystian Kaczmarek, Maciej Karolak, Łukasz Pałkowski, Aneta Lewandowska, Agnieszka Marcinkowska, Katarzyna Dopierała and Katarzyna Materna

Molecules 2024, 29(2), 443; https://doi.org/10.3390/molecules29020443 - 16 Jan 2024

Viewed by 1454

Abstract

The present work provides new evidence of the ongoing potential of surface-active ionic liquids (SAILs) and surface-active quaternary ammonium salts (surface-active QASs). To achieve this, a series of compounds were synthesized with a yield of ≥85%, and their thermal analyses were studied. Additionally, [...] Read more.

The present work provides new evidence of the ongoing potential of surface-active ionic liquids (SAILs) and surface-active quaternary ammonium salts (surface-active QASs). To achieve this, a series of compounds were synthesized with a yield of ≥85%, and their thermal analyses were studied. Additionally, antimicrobial activity against both human pathogenic and soil microorganisms was investigated. Subsequently, their surface properties were explored with the aim of utilizing SAILs and surface-active QASs as alternatives to commercial amphiphilic compounds. Finally, we analyzed the wettability of the leaves’ surface of plants occurring in agricultural fields at different temperatures (from 5 to 25 °C) and the model plant membrane of leaves. Our results show that the synthesized compounds exhibit higher activity than their commercial analogues such as, i.e., didecyldimethylammonium chloride (DDAC) and dodecyltrimethylammonium bromide (C₁₂TAB), for which the CMC values are 2 mM and 15 mM. The effectiveness of the antimicrobial properties of synthesized compounds relies on their hydrophobic nature accompanied by a cut-off effect. Moreover, the best wettability of the leaves’ surface was observed at 25 °C. Our research has yielded valuable insights into the potential effectiveness of SAILs and surface-active QASs as versatile compounds, offering a promising alternative to established antimicrobials and crop protection agents, all the while preserving substantial surface activity. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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10 pages, 4972 KiB  

Open AccessCommunication

Heat-Induced Fragmentation and Adhesive Behaviour of Gold Nanowires for Surface-Enhanced Raman Scattering Substrates

by Annamarija Trausa, Ciro Federiko Tipaldi, Liga Ignatane, Boris Polyakov, Sven Oras, Edgars Butanovs, Edgars Vanags and Krisjanis Smits

ChemEngineering 2024, 8(1), 15; https://doi.org/10.3390/chemengineering8010015 - 9 Jan 2024

Cited by 3 | Viewed by 2336

Abstract

This study explores a novel approach to surface-enhanced Raman scattering (SERS) substrate fabrication through the heat-induced fragmentation of gold nanowires (Au NWs) and its impact on gold nanoparticle adhesion/static friction using atomic force microscopy manipulations. Controlled heating experiments and scanning electron microscopy measurements [...] Read more.

This study explores a novel approach to surface-enhanced Raman scattering (SERS) substrate fabrication through the heat-induced fragmentation of gold nanowires (Au NWs) and its impact on gold nanoparticle adhesion/static friction using atomic force microscopy manipulations. Controlled heating experiments and scanning electron microscopy measurements reveal significant structural transformations, with NWs transitioning into nanospheres or nanorods in a patterned fashion at elevated temperatures. These morphological changes lead to enhanced Raman signals, particularly demonstrated in the case of Rhodamine B molecules. The results underscore the critical role of NW shape modifications in augmenting the SERS effect, shedding light on a cost-effective and reliable method for producing SERS substrates. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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17 pages, 6779 KiB  

Open AccessArticle

Oxidation of Allura Red AC Using the NaHCO₃-activated H₂O₂ System Catalyzed with Cobalt Supported on Al-PILC

by Natalia Marín-González, Camila Giraldo-Loaiza, Iván F. Macías-Quiroga, Juan D. Rivera-Giraldo, Julio A. Cardona-Castaño and Nancy R. Sanabria-González

ChemEngineering 2024, 8(1), 14; https://doi.org/10.3390/chemengineering8010014 - 8 Jan 2024

Cited by 2 | Viewed by 2109

Abstract

The oxidation of aqueous solutions containing Allura Red AC (AR–AC) using bicarbonate-activated peroxide (BAP) and cobalt-impregnated pillared clay (Co/Al–PILC) as the catalyst was investigated. Using the CCD-RMS approach (central composite design–response surface methodology), the effects of dye, H₂O₂, and [...] Read more.

The oxidation of aqueous solutions containing Allura Red AC (AR–AC) using bicarbonate-activated peroxide (BAP) and cobalt-impregnated pillared clay (Co/Al–PILC) as the catalyst was investigated. Using the CCD-RMS approach (central composite design–response surface methodology), the effects of dye, H₂O₂, and NaHCO₃ concentrations on AR–AC degradation were studied. The decolorization, total nitrogen (TN), and total carbon (TC) removals were the analyzed responses, and the experimental data were fitted to empirical quadratic equations for these responses, obtaining coefficients of determination R² and adjusted-R² higher than 0.9528. The multi-objective optimization conditions were [dye] = 21.25 mg/L, [H₂O₂] = 2.59 mM, [NaHCO₃] = 1.25 mM, and a catalyst loading of 2 g/L. Under these conditions, a decolorization greater than 99.43% was obtained, as well as TN and TC removals of 72.82 and 18.74%, respectively, with the added advantage of showing cobalt leaching below 0.01 mg/L. Chromatographic analyses (GC–MS and HPLC) were used to identify some reaction intermediates and by-products. This research showed that wastewater containing azo dyes may be treated using the cobalt-catalyzed BAP system in heterogeneous media. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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22 pages, 12388 KiB  

Open AccessArticle

Effect of Inserting Baffles on the Solid Particle Segregation Behavior in Fluidized Bed Reactor: A Computational Study

by Suchart Kreesaeng, Benjapon Chalermsinsuwan and Pornpote Piumsomboon

ChemEngineering 2024, 8(1), 7; https://doi.org/10.3390/chemengineering8010007 - 1 Jan 2024

Cited by 1 | Viewed by 2249

Abstract

In multi-solid, particle-size fluidized bed reactor systems, segregation is commonly observed. When segregation occurred, small solid particles were entrained to the top of the bed and escaped from the reactor. During the combustion process, the small solid particles that escaped from the boiler [...] Read more.

In multi-solid, particle-size fluidized bed reactor systems, segregation is commonly observed. When segregation occurred, small solid particles were entrained to the top of the bed and escaped from the reactor. During the combustion process, the small solid particles that escaped from the boiler were burned and subjected to damage around the cyclone separator. This study then employed a computational fluid dynamics approach to investigate solid particle behavior in the reactor using three different sizes of solid particles. The effects of baffle insertion, baffle angle, stage number, and its arrangement were examined. The percentage of segregation was calculated to compare behavior among different reactor systems. The insertion of 45-degree baffles resulted in reduced segregation behavior compared to cases without baffles and with 90-degree baffles, attributed to solid hindering and collision phenomena. Additionally, a double-stage baffle with any arrangement could reduce segregation behavior. The best arrangement was “above-arrangement” due to particles hindering, swirling, and accumulating between the baffle stages. Therefore, to diminish segregation behavior and enhance combustion chemical reactions, the insertion of baffles in the reactor zone is recommended. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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15 pages, 6399 KiB  

Open AccessArticle

Significant Progress of Initiated Chemical Vapor Deposition in Manufacturing Soft Non-spherical Nanoparticles: Upgrading to the Condensed Droplet Polymerization Approach and Key Technological Aspects

by Di Zhang

ChemEngineering 2024, 8(1), 2; https://doi.org/10.3390/chemengineering8010002 - 19 Dec 2023

Viewed by 2439

Abstract

Initiated chemical vapor deposition is a unique solvent-free and completely dry vapor-phase deposition technique used to synthesize organic polymer films. In this process, an activated initiator, monomer, and carrier gas are introduced into the reaction chamber simultaneously. This technique has been widely adopted. [...] Read more.

Initiated chemical vapor deposition is a unique solvent-free and completely dry vapor-phase deposition technique used to synthesize organic polymer films. In this process, an activated initiator, monomer, and carrier gas are introduced into the reaction chamber simultaneously. This technique has been widely adopted. However, if the monomer and initiator are introduced into the chamber in stages—allowing gas-phase monomer deposition and condensation first, followed by initiator introduction and controlling the monomer partial pressure to be higher than the saturated vapor pressure—non-spherical polymer nanoparticles with dome-like shapes can be obtained. This advanced iCVD technique is referred to as the “Condensed Droplet Polymerization Approach”. This high monomer partial pressure gas-phase deposition is not suitable for forming uniformly composed iCVD films; but interestingly, it can rapidly obtain polymer nanodomes (PNDs). Using CDP technology, Franklin polymerized multifunctional nanodomes in less than 45 s, demonstrating a wide range of continuous particle size variations, from sub-20 nanometers to over 1 micron. This rapid synthesis included a variety of functional polymer nanodomes in just a matter of seconds to minutes. This review discusses the crucial process conditions of the Condensed Droplet Polymerization (CDP) Approach for synthesizing PNDs. The main focus of the discussion was on the two-step method for synthesizing PNDs, where the nucleation mechanism of PNDs, factors influencing their size, and the effect of pressure on the distinct condensation of monomer vapor into polymer nanodomes and polymer films were extensively explored. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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10 pages, 1845 KiB  

Open AccessArticle

Enhancement of Electricity Production in Microbial Fuel Cells Using a Biosurfactant-Producing Co-Culture

by Carolina Montoya-Vallejo, Jorge Omar Gil Posada and Juan Carlos Quintero-Díaz

Molecules 2023, 28(23), 7833; https://doi.org/10.3390/molecules28237833 - 29 Nov 2023

Cited by 1 | Viewed by 1576

Abstract

Microbial fuel cells are bio-electrochemical devices that enable the conversion of chemical energy into bioelectricity. In this manuscript, the use of biosurfactants (Tween 80 and surfactin) and the effect of coculturing E. coli and L. plantarum were used to investigate the generation of [...] Read more.

Microbial fuel cells are bio-electrochemical devices that enable the conversion of chemical energy into bioelectricity. In this manuscript, the use of biosurfactants (Tween 80 and surfactin) and the effect of coculturing E. coli and L. plantarum were used to investigate the generation of bioelectricity coming from an H-type microbial fuel cell. In this setup, E. coli acts as an electron donor while L. plantarum acts as an in situ biosurfactant producer. It was observed that the use of exogenous surfactants enhanced electricity production compared to conventional E. coli cultures. The utilization of Tween 80 and surfactin increased the power generation from 204 µW m⁻² to 506 µW m⁻² and 577 µW m⁻², respectively. Furthermore, co-culturing E. coli and L. plantarum also resulted in a higher power output compared to pure cultures (132.8% more when compared to using E. coli alone and 68.1% more when compared to using L. plantarum alone). Due to the presence of surfactants, the internal resistance of the cell was reduced. The experimental evidence collected here clearly indicates that the production of endogenous surfactants, as well as the addition of exogenous surfactants, will enhance MFC electricity production. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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12 pages, 5415 KiB  

Open AccessArticle

Design of Hollow Porous P-NiCo₂O₄@Co₃O₄ Nanoarray and Its Alkaline Aqueous Zinc-Ion Battery Performance

by Zhe Liang, Chenmeng Lv, Luyao Wang, Xiran Li, Shiwen Cheng and Yuqiu Huo

Int. J. Mol. Sci. 2023, 24(21), 15548; https://doi.org/10.3390/ijms242115548 - 25 Oct 2023

Cited by 3 | Viewed by 1207

Abstract

Alkaline aqueous zinc-ion batteries possess a wider potential window than those in mildly acidic systems; they can achieve high energy density and are expected to become the next generation of energy storage devices. In this paper, a hollow porous P-NiCo₂O₄ [...] Read more.

Alkaline aqueous zinc-ion batteries possess a wider potential window than those in mildly acidic systems; they can achieve high energy density and are expected to become the next generation of energy storage devices. In this paper, a hollow porous P-NiCo₂O₄@Co₃O₄ nanoarray is obtained by ion etching and the calcination and phosphating of ZiF-67, which is directly grown on foam nickel substrate, as a precursor. It exhibits excellent performance as a cathode material for alkaline aqueous zinc-ion batteries. A high discharge specific capacity of 225.3 mAh g⁻¹ is obtained at 1 A g⁻¹ current density, and it remains 81.9% when the current density is increased to 10 A g⁻¹. After one thousand cycles of charging and discharging at 3 A g⁻¹ current density, the capacity retention rate is 88.8%. Even at an excellent power density of 25.5 kW kg⁻¹, it maintains a high energy density of 304.5 Wh kg⁻¹. It is a vital, promising high-power energy storage device for large-scale applications. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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13 pages, 2381 KiB  

Open AccessArticle

ClO₂-Mediated Oxidation of the TEMPO Radical: Fundamental Considerations of the Catalytic System for the Oxidation of Cellulose Fibers

by Laura Giraldo Isaza, Gérard Mortha, Nathalie Marlin, Florian Molton and Carole Duboc

Molecules 2023, 28(18), 6631; https://doi.org/10.3390/molecules28186631 - 15 Sep 2023

Cited by 3 | Viewed by 1846

Abstract

The reaction mechanism of ClO${}_2$-mediated TEMPO oxidation was investigated by EPR spectroscopy and UV–Vis spectroscopy in the context of an alternative TEMPO sequence for cellulose fiber oxidation. Without the presence of a cellulosic substrate, a reversibility between TEMPO and its oxidation [...] Read more.

The reaction mechanism of ClO${}_2$-mediated TEMPO oxidation was investigated by EPR spectroscopy and UV–Vis spectroscopy in the context of an alternative TEMPO sequence for cellulose fiber oxidation. Without the presence of a cellulosic substrate, a reversibility between TEMPO and its oxidation product, TEMPO${}^{+}$, was displayed, with an effect of the pH and reagent molar ratios. The involvement of HOCl and Cl${}^{-}$, formed as byproducts in the oxidation mechanism, was also evidenced. Trapping HOCl partly inhibits the reaction, whereas adding methylglucoside, a cellulose model compound, inhibits the reversibility of the reaction to TEMPO. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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15 pages, 3563 KiB  

Open AccessArticle

Bicarbonate-Activated Hydrogen Peroxide for an Azo Dye Degradation: Experimental Design

by Karla Y. Mora-Bonilla, Iván F. Macías-Quiroga, Nancy R. Sanabria-González and María T. Dávila-Arias

ChemEngineering 2023, 7(5), 86; https://doi.org/10.3390/chemengineering7050086 - 14 Sep 2023

Cited by 6 | Viewed by 1845

Abstract

The present study investigated the degradation of an aqueous Allura Red AC (AR–AC) solution by activating hydrogen peroxide with bicarbonate using cobalt ion (Co²⁺) as the catalyst. Four independent variables (H₂O₂, NaHCO₃, Co²⁺, [...] Read more.

The present study investigated the degradation of an aqueous Allura Red AC (AR–AC) solution by activating hydrogen peroxide with bicarbonate using cobalt ion (Co²⁺) as the catalyst. Four independent variables (H₂O₂, NaHCO₃, Co²⁺, and dye concentrations) were analyzed in the composite central design (CCD). AR–AC degradation was optimized using the response surface methodology (RSM). Under optimal degradation conditions (41.86 mg/L AR–AC, 5.58 mM H₂O₂, 2.00 mM NaHCO₃, and 9.00 µM Co²⁺), decolorization > 99.86%, mineralization (CO₂ to conversion) of 12.99%, and total nitrogen removal of 51.97% were achieved. The predicted values for the three response variables were consistent with the experimental values, with determination coefficients (R²) greater than 0.9053. Because cobalt ions (Co²⁺) are a source of water pollution, after oxidation, these were adsorbed on sodium bentonite (Na–Bent), obtaining a final concentration of <0.01 mg/L. Bicarbonate-activated hydrogen peroxide is a potential technology for dye wastewater treatment that operates at an alkaline pH and at ambient temperature. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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13 pages, 2558 KiB  

Open AccessFeature PaperArticle

The Competitive Adsorption of Water and Methanol on a Hybrid Silica Stationary Phase in Supercritical Fluid Chromatography

by Muhamad Yahia Kazmouz and Attila Felinger

Separations 2023, 10(9), 492; https://doi.org/10.3390/separations10090492 - 11 Sep 2023

Cited by 1 | Viewed by 1234

Abstract

This study investigates the adsorption of methanol, water, and their mixture in a hybrid silica stationary phase with supercritical carbon dioxide as a mobile phase in supercritical fluid chromatography (SFC). The adsorption isotherms of methanol and water were determined by two dynamic methods: [...] Read more.

This study investigates the adsorption of methanol, water, and their mixture in a hybrid silica stationary phase with supercritical carbon dioxide as a mobile phase in supercritical fluid chromatography (SFC). The adsorption isotherms of methanol and water were determined by two dynamic methods: the elution by characteristic point (ECP) method and the inverse method (IM). Both the single-component and competitive bi-Langmuir models were pre-selected for the inverse method. The initial parameters of the single-component isotherm for both methanol and water were estimated with the ECP method by fitting the experimental data to the bi-Langmuir isotherm model. Then, using the inverse method, we refined the single-component isotherm parameter values, which were then further used for determining the competitive isotherm of the methanol–water mixture. The elution profile of the (methanol–water) mixture sample was calculated by the equilibrium-dispersive (ED) model. The results indicated that there is a good agreement between the experimental band profile and the calculated band profile, which was obtained from the parameters of the competitive bi-Langmuir isotherm model, revealing a competition between methanol and water to reach the adsorption sites. Furthermore, the saturation capacity of the adsorption sites in the stationary phase decreased in the case of the mixture sample compared to those for the single-component sample. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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22 pages, 67123 KiB  

Open AccessArticle

Morphology of Particulate Structures on a Fiber Array before and at Clogging Point of an Aerosol Filtration Process

by Lukas Poggemann, Benedikt King, Jörg Meyer and Achim Dittler

Separations 2023, 10(9), 462; https://doi.org/10.3390/separations10090462 - 23 Aug 2023

Cited by 2 | Viewed by 1451

Abstract

Fundamental microscopic investigations are based on the interaction between filter fiber and particles. The fibrous filter theory is based on a single fiber of a fiber array, and experiments focus either on a single fiber or a fiber array. This study investigates the [...] Read more.

Fundamental microscopic investigations are based on the interaction between filter fiber and particles. The fibrous filter theory is based on a single fiber of a fiber array, and experiments focus either on a single fiber or a fiber array. This study investigates the particle loading process of a fiber array and focuses on the microscopic development of particle structures on the fiber array. Gravimetric measurements and image analysis of the array were used to study the development of the particle structure and morphology. Microscopic analysis of the video data focused on the evolution of particle accumulation within the fiber spacing, the development of boundary lines of the particle structure, and the number/size of bridges and pores within the particle structure. For the tested flow velocities, an increase in mass was observed to increase the duration of the filtration process. An extreme increase in deposited mass was observed at the moment of complete blocking (clogging) of the fiber spacing at flow velocities of 0.65 m/s. The size of pores (hydraulic diameter) increased with the flow velocity during the loading procedure. However, the total number of pores was higher in tests with lower Stokes numbers due to the dendritic and more porous structure. This work provides insights into the growth kinetics and structural setup of the particle structure (on a microscopic level). This will improve the understanding of the change of the filtration process from the transition phase to the clogging phase in fibrous filters. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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13 pages, 3176 KiB  

Open AccessArticle

In-Line Measurement of Extraction Process by Slug Flow and Determination of Mass Transfer Parameters

by Takamichi Okamoto and Akinori Muto

Separations 2023, 10(8), 443; https://doi.org/10.3390/separations10080443 - 8 Aug 2023

Viewed by 1607

Abstract

The primary objective of this study was to pragmatically implement an extraction process using slug flow, wherein two immiscible phases, aqueous and oil, are alternatively channeled through a conduit to encourage mass exchange across the interface. To facilitate this, we introduced and empirically [...] Read more.

The primary objective of this study was to pragmatically implement an extraction process using slug flow, wherein two immiscible phases, aqueous and oil, are alternatively channeled through a conduit to encourage mass exchange across the interface. To facilitate this, we introduced and empirically validated an in-line technique to precisely quantify the length of the slug and the potential extraction concentration of the two aforementioned phases. The length of the slug and its concentration were ascertained through conductivity, utilizing platinum wire as the electrode. This method consistently produced results with a maximum error margin of ±5%. Using this apparatus, we determined key mass transfer parameters, including the overall mass transfer coefficient. Notably, as the linear velocity amplified, so did the extraction rate. These findings present a significant opportunity for enhancing the efficiency of the extraction process and enabling its optimization. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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33 pages, 13851 KiB  

Open AccessArticle

Enhancing ASP Flooding by Using Special Combinations of Surfactants and Starch Nanoparticles

by Hasanain A. Al-Jaber, Agus Arsad, Sulalit Bandyopadhyay, Muslim Abdurrahman, Mohammad Yasin Abdulfatah, Augustine Agi, Suriatie Mat Yusuf, Abdulmunem R. Abdulmunem, Muhammad Tahir and Mustafa Jawad Nuhma

Molecules 2023, 28(15), 5770; https://doi.org/10.3390/molecules28155770 - 31 Jul 2023

Cited by 7 | Viewed by 1703

Abstract

This study aimed to address the challenges faced by mature oilfields in extracting substantial oil quantities. It focused on improving the efficiency of alkaline–surfactant–polymer (ASP) flooding technique, which is a proven tertiary recovery technology, to overcome scaling issues and other hindrances in its [...] Read more.

This study aimed to address the challenges faced by mature oilfields in extracting substantial oil quantities. It focused on improving the efficiency of alkaline–surfactant–polymer (ASP) flooding technique, which is a proven tertiary recovery technology, to overcome scaling issues and other hindrances in its large-scale implementation. Appropriate materials and their suitable concentrations were selected to enhance the ASP flooding technique. Special surfactants from Indonesia were introduced to improve the interfacial tension reduction and wettability alteration. Reservoir rock model that resembling Langgak oilfield in Sumatra was utilized, and low-salinity water was employed to mimic the oilfield conditions. Starches derived from cassava nanoparticles (CSNPs) and purple yam nanoparticles (PYNPs) were combined separately with conventional hydrolyzed polyacrylamide (HPAM) polymer to enhance its performance. Sodium hydroxide and sodium carbonate were used as alkaline in final ASP formula. It was demonstrated from this research that only two combinations of ASP formulations have led to improved oil recovery. One combination utilizing PYNPs resulted in 39.17% progressive recovery, while the other combination incorporating CSNPs achieved 35% incremental oil recovery. The ASP combination that resulted in recovery rate of 39.17% was composed of sodium hydroxide (NaOH) at a concentration of 1.28 wt.%, PSC EOR 2.2 (0.98 wt.%), and a combined polymer consisting of HPAM (0.2 wt.%) and PYNPs nano-starch (0.6 wt.%). The second combination led to 35% recovery rate and involved NaOH also at concentration 1.28 wt.%, PSC HOMF (0.63 wt.%), and a combined polymer comprising from HPAM (0.2 wt.%) and CSNPs nano-starch (0.8 wt.%). These findings of this study highlighted the potential of this modified ASP flooding to enhance oil recovery in mature oilfields, thereby offering valuable insights for oil industry. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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24 pages, 8601 KiB  

Open AccessReview

Advanced Development of Molecularly Imprinted Membranes for Selective Separation

by Jiahe Chen, Maobin Wei and Minjia Meng

Molecules 2023, 28(15), 5764; https://doi.org/10.3390/molecules28155764 - 30 Jul 2023

Cited by 8 | Viewed by 1910

Abstract

Molecularly imprinted membranes (MIMs), the incorporation of a given target molecule into a membrane, are generally used for separating and purifying the effective constituents of various natural products. They have been in use since 1990. The application of MIMs has been studied in [...] Read more.

Molecularly imprinted membranes (MIMs), the incorporation of a given target molecule into a membrane, are generally used for separating and purifying the effective constituents of various natural products. They have been in use since 1990. The application of MIMs has been studied in many fields, including separation, medicine analysis, solid-phase extraction, and so on, and selective separation is still an active area of research. In MIM separation, two important membrane performances, flux and permselectivities, show a trade-off relationship. The enhancement not only of permselectivity, but also of flux poses a challenging task for membranologists. The present review first describes the recent development of MIMs, as well as various preparation methods, showing the features and applications of MIMs prepared with these different methods. Next, the review focuses on the relationship between flux and permselectivities, providing a detailed analysis of the selective transport mechanisms. According to the majority of the studies in the field, the paramount factors for resolving the trade-off relationship between the permselectivity and the flux in MIMs are the presence of effective high-density recognition sites and a high degree of matching between these sites and the imprinted cavity. Beyond the recognition sites, the membrane structure and pore-size distribution in the final imprinted membrane collectively determine the selective transport mechanism of MIM. Furthermore, it also pointed out that the important parameters of regeneration and antifouling performance have an essential role in MIMs for practical applications. This review subsequently highlights the emerging forms of MIM, including molecularly imprinted nanofiber membranes, new phase-inversion MIMs, and metal–organic-framework-material-based MIMs, as well as the construction of high-density recognition sites for further enhancing the permselectivity/flux. Finally, a discussion of the future of MIMs regarding breakthroughs in solving the flux–permselectivity trade-off is offered. It is believed that there will be greater advancements regarding selective separation using MIMs in the future. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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21 pages, 3852 KiB  

Open AccessArticle

Upgrading Pyrolytic Oil via Catalytic Co-Pyrolysis of Beechwood and Polystyrene

by Yehya Jaafar, Gian Carlos Arias Ramirez, Lokmane Abdelouahed, Antoine El Samrani, Roland El Hage and Bechara Taouk

Molecules 2023, 28(15), 5758; https://doi.org/10.3390/molecules28155758 - 30 Jul 2023

Cited by 2 | Viewed by 1326

Abstract

This study aims to investigate the catalytic co-pyrolysis of beech wood with polystyrene as a synergic and catalytic effect on liquid oil production. For this purpose, a tubular semi-continuous reactor under an inert nitrogen atmosphere was used. Several zeolite catalysts were modified via [...] Read more.

This study aims to investigate the catalytic co-pyrolysis of beech wood with polystyrene as a synergic and catalytic effect on liquid oil production. For this purpose, a tubular semi-continuous reactor under an inert nitrogen atmosphere was used. Several zeolite catalysts were modified via incipient wetness impregnation using iron and/or nickel. The liquid oil recovered was analyzed using GC-MS for the identification of the liquid products, and GC-FID was used for their quantification. The effects of catalyst type, beechwood-to-polystyrene ratio, and operating temperature were investigated. The results showed that the Fe/Ni-ZSM-5 catalyst had the best deoxygenation capability. The derived oil was mainly constituted of aromatics of about 92 wt.% for the 1:1 mixture of beechwood and polystyrene, with a remarkably high heating value of around 39 MJ/kg compared to 18 MJ/kg for beechwood-based bio-oil. The liquid oil experienced a great reduction in oxygen content of about 92% for the polystyrene–beechwood 50-50 mixture in comparison to beechwood alone. The catalytic and synergetic effects were more realized for high beechwood percentages as a 75-25 beechwood–polystyrene mix. Regarding the temperature variation between 450 and 600 °C, the catalyst seemed to deactivate faster at higher temperatures, thus constituting a quality reduction in the pyrolytic oil in high-temperature ranges. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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17 pages, 911 KiB  

Open AccessArticle

Droplet Evaporation Process of a Fluorobenzene + n-Octane + Polystyrene Mixture

by Wei Wang, Zhendong Zhou and Bo Zhou

Molecules 2023, 28(15), 5659; https://doi.org/10.3390/molecules28155659 - 26 Jul 2023

Cited by 1 | Viewed by 1220

Abstract

The vapor–liquid equilibrium of the fluorobenzene–polystyrene binary polymer solution at 303.15 K was measured using a static pressure device. The vapor–liquid equilibrium of the fluorobenzene–n-octane–polystyrene ternary solution in a partial concentration range under normal pressure was determined using an improved Othmer equilibrium still, [...] Read more.

The vapor–liquid equilibrium of the fluorobenzene–polystyrene binary polymer solution at 303.15 K was measured using a static pressure device. The vapor–liquid equilibrium of the fluorobenzene–n-octane–polystyrene ternary solution in a partial concentration range under normal pressure was determined using an improved Othmer equilibrium still, in which the octane concentration was low. Three activity coefficient models, poly-NRTL, UNIQUAC, and M-UNIQUAC-LBY, were utilized to correlate the experimental data of binary and ternary solutions, and the component activities of the fluorobenzene–n-octane–polystyrene solution at 303.15 K were predicted. A mathematical model based on the Stefan flow was developed to simulate the evaporation process of composite spherical droplets. The activity predicted by the activity coefficient model was used for numerical simulations, and compared with simulations using the activity following Raoult’s law. The comparative analysis revealed that simulations based on Raoult’s law and activity coefficient models yielded similar results when the mass fraction of fluorobenzene exceeded 0.6. However, in the later stages of evaporation, the calculations based on Raoult’s law predicted a 10% shorter drying time for fluorobenzene. The activity coefficient models provided a better approximation and exhibited similar droplet diameter shrinking behaviors to the actual evaporation process. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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11 pages, 1647 KiB  

Open AccessArticle

DNA–CTMA Matrix Influence on Rhodamine 610 Light Emission in Thin Films

by Adrian Petris, Petronela Gheorghe and Ileana Rău

Polymers 2023, 15(14), 3105; https://doi.org/10.3390/polym15143105 - 21 Jul 2023

Cited by 1 | Viewed by 1005

Abstract

Due to the increased application of lasers in different fields (industry, medicine, etc.), there is a growing need for new laser sources with good beam quality and variable emission wavelength. At the same time, for environmental reasons, the obtaining of novel eco-friendly active [...] Read more.

Due to the increased application of lasers in different fields (industry, medicine, etc.), there is a growing need for new laser sources with good beam quality and variable emission wavelength. At the same time, for environmental reasons, the obtaining of novel eco-friendly active optical materials, such as those based on the deoxyribonucleic acid (DNA) biopolymer, with optimal light emission properties, is of high interest. The results obtained in this study of the temporal dependence of the transmittance and of the light emission in thin films of DNA–CTMA–Rhodamine 610 (at different Rhodamine concentrations) (DNA–CTMA–Rh610), when they are illuminated with continuous wave laser light at 532 nm (frequently used in the optical pumping of dye lasers), are presented and discussed. The transmittance results obtained for thin film samples are compared to those obtained for the DNA–CTMA–Rh610 solutions in butanol, from which the films have been made, and also with those obtained for Rh610 solutions in butanol with the same concentrations. The investigation was performed in order to assess the influence of the DNA-CTMA and of the green laser light at 532 nm wavelength on relevant chromophore properties such as light transmission and fluorescence emission. The results obtained revealed that the DNA–CTMA matrix has an active influence on the Rhodamine 610 emission, in the whole range of concentrations of the investigated samples. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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12 pages, 2109 KiB  

Open AccessArticle

Design Strategy for Performance Enhancement of Vertical Plate Microdistillators

by Yosuke Muranaka, Taisuke Maki, Kosuke Nishigaya and Kazuhiro Mae

Separations 2023, 10(7), 404; https://doi.org/10.3390/separations10070404 - 14 Jul 2023

Cited by 1 | Viewed by 1181

Abstract

Microdevices have been actively implemented in chemical processes, such as in mixing and reactions. However, microseparation devices, excluding extraction devices, are still under development. In distillation, the use of microdevices has been expected to improve separation performance, as their large specific surface area [...] Read more.

Microdevices have been actively implemented in chemical processes, such as in mixing and reactions. However, microseparation devices, excluding extraction devices, are still under development. In distillation, the use of microdevices has been expected to improve separation performance, as their large specific surface area enables a rapid vapor–liquid equilibrium and for large temperature gradients to be easily realized. In this study, improvements in throughput and product purities in microdistillation devices were achieved for ethyl acetate–toluene distillation. At low feedstock flow rates, ethyl acetate was successfully purified to 99.5 wt%. Although the performance decreased with increasing feedstock flow rate, by increasing the channel length, this performance decrease was suppressed even at high flow rates. The thickness of the channel was also important, and the highest performance was observed at the lowest thickness of 0.5 mm. A performance evaluation using the HETP showed that the efficiency was seven times higher than that of conventional packed column distillators. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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25 pages, 2194 KiB  

Open AccessArticle

Optimizing the Sulfates Content of Cement Using Neural Networks and Uncertainty Analysis

by Dimitris C. Tsamatsoulis, Christos A. Korologos and Dimitris V. Tsiftsoglou

ChemEngineering 2023, 7(4), 58; https://doi.org/10.3390/chemengineering7040058 - 21 Jun 2023

Cited by 1 | Viewed by 1968

Abstract

This study aims to approximate the optimum sulfate content of cement, applying maximization of compressive strength as a criterion for cement produced in industrial mills. The design includes tests on four types of cement containing up to three main components and belonging to [...] Read more.

This study aims to approximate the optimum sulfate content of cement, applying maximization of compressive strength as a criterion for cement produced in industrial mills. The design includes tests on four types of cement containing up to three main components and belonging to three strength classes. We developed relationships correlating to 7- and 28-day strength with the sulfate and clinker content of the cement (CL), as well as the clinker mineral composition (tricalcium silicate, C₃S, tricalcium aluminate, C₃A). We correlated strength with the ratio %SO₃/CL and the molecular ratios MSO₃/C₃S and MSO₃/C₃A. The data processing stage proved that artificial neural networks (ANNs) fit the results’ distribution better than a parabolic function, providing reliable models. The optimal %SO₃/CL value for 7- and 28-day strength was 2.85 and 3.00, respectively. Concerning the ratios of SO₃ at the mineral phases for 28-day strength, the best values were MSO₃/C₃S = 0.132–0.135 and MSO₃/C₃A = 1.55. We implemented some of the ANNs to gain a wide interval of input variables’ values. Thus, the approximations of SO₃ optimum using ANNs had a relatively broad application in daily plant quality control, at least as a guide for experimental design. Finally, we investigated the impact of SO₃ uncertainty on the 28-day strength variance using the error propagation method. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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24 pages, 7562 KiB  

Open AccessArticle

Enhancing Oil Recovery by Polymeric Flooding with Purple Yam and Cassava Nanoparticles

by Hasanain A. Al-Jaber, Agus Arsad, Muhammad Tahir, Mustafa Jawad Nuhma, Sulalit Bandyopadhyay, Abdulmunem R. Abdulmunem, Anis Farhana Abdul Rahman, Zakiah binti Harun and Augustine Agi

Molecules 2023, 28(12), 4614; https://doi.org/10.3390/molecules28124614 - 7 Jun 2023

Cited by 8 | Viewed by 1835

Abstract

Significant amounts of oil remain in the reservoir after primary and secondary operations, and to recover the remaining oil, enhanced oil recovery (EOR) can be applied as one of the feasible options remaining nowadays. In this study, new nano-polymeric materials have been prepared [...] Read more.

Significant amounts of oil remain in the reservoir after primary and secondary operations, and to recover the remaining oil, enhanced oil recovery (EOR) can be applied as one of the feasible options remaining nowadays. In this study, new nano-polymeric materials have been prepared from purple yam and cassava starches. The yield of purple yam nanoparticles (PYNPs) was 85%, and that of cassava nanoparticles (CSNPs) was 90.53%. Synthesized materials were characterized through particle size distribution (PSA), Zeta potential distribution, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and transmission electron microscopy (TEM). The performance of PYNPs in recovering oil was better than CSNPs, as found from the recovery experiments. Zeta potential distribution results confirmed the stability of PYNPs over CSNPs (−36.3 mV for PYNPs and −10.7 mV for CSNPs). The optimum concentration for these nanoparticles has been found from interfacial tension measurements and rheological properties, and it was 0.60 wt.% for PYNPs and 0.80 wt.% for CSNPs. A more incremental recovery (33.46%) was achieved for the polymer that contained PYNPs in comparison to the other nano-polymer (31.3%). This paves the way for a new technology for polymer flooding that may replace the conventional method, which depends on partially hydrolyzed polyacrylamide (HPAM). Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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12 pages, 2266 KiB  

Open AccessArticle

Improved Synthesis of Deoxyadenosine Triphosphate by Saccharomyces cerevisiae Using an Efficient ATP Regeneration System: Optimization of Response Surface Analysis

by Jian Xiong, Hanghang Xu, Qi Wang and Wenyuan Sun

Molecules 2023, 28(10), 4029; https://doi.org/10.3390/molecules28104029 - 11 May 2023

Viewed by 1909

Abstract

Deoxyadenosine triphosphate (dATP) is an important biochemical molecule. In this paper, the synthesis of dATP from deoxyadenosine monophosphate (dAMP), catalyzed by Saccharomyces cerevisiae, was studied. By adding chemical effectors, an efficient ATP regeneration and coupling system was constructed to achieve efficient synthesis of [...] Read more.

Deoxyadenosine triphosphate (dATP) is an important biochemical molecule. In this paper, the synthesis of dATP from deoxyadenosine monophosphate (dAMP), catalyzed by Saccharomyces cerevisiae, was studied. By adding chemical effectors, an efficient ATP regeneration and coupling system was constructed to achieve efficient synthesis of dATP. Factorial and response surface designs were used to optimize process conditions. Optimal reaction conditions were as follows: dAMP 1.40 g/L, glucose 40.97 g/L, MgCl₂·6H₂O 4.00 g/L, KCl 2.00 g/L, NaH₂PO₄ 31.20 g/L, yeast 300.00 g/L, ammonium chloride 0.67 g/L, acetaldehyde 11.64 mL/L, pH 7.0, temperature 29.6 °C. Under these conditions, the substrate conversion was 93.80% and the concentration of dATP in the reaction system was 2.10 g/L, which was 63.10% higher than before optimization, and the concentration of product was 4 times higher than before optimization. The effects of glucose, acetaldehyde, and temperature on the accumulation of dATP were analyzed. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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12 pages, 2624 KiB  

Open AccessArticle

High-Contrast Visualization Chemiluminescence Based on AIE-Active and Base-Sensitive Emitters

by Xiao-Wen Zhang, Xu-Lin Chen and Can-Zhong Lu

Molecules 2023, 28(9), 3976; https://doi.org/10.3390/molecules28093976 - 8 May 2023

Viewed by 1857

Abstract

Peroxyoxalate chemiluminescence (PO-CL) is one of the most popular cold light sources, yet the drawback of aggregation-caused quenching limits their use. Here, we report a new kind of efficient bifunctional emitter derived from salicylic acid, which not only exhibits typical aggregation-induced emission (AIE) [...] Read more.

Peroxyoxalate chemiluminescence (PO-CL) is one of the most popular cold light sources, yet the drawback of aggregation-caused quenching limits their use. Here, we report a new kind of efficient bifunctional emitter derived from salicylic acid, which not only exhibits typical aggregation-induced emission (AIE) character but also has the ability to catalyze the CL process under basic conditions based on base sensitivity. By taking advantage of these unique features, we successfully confine the CL process on the surface of solid bases and provide a high-contrast visualization of CL emission. This method allows most of the common basic salts like sodium carbonate to be invisible encryption information ink and PO-CL solution to be a decryption tool to visualize the hidden information. The current study opens up an appealing way for the development of multifunction CL emitters for information encryption and decryption applications. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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9 pages, 1746 KiB  

Open AccessArticle

Supercritical Fluid Extraction of Essential Oil and Sclareol from a Clary Sage Concrete

by Alessandra Zanotti, Lucia Baldino, Mariarosa Scognamiglio and Ernesto Reverchon

Molecules 2023, 28(9), 3903; https://doi.org/10.3390/molecules28093903 - 5 May 2023

Cited by 2 | Viewed by 2129

Abstract

Clary Sage extracts are of industrial interest: in particular, sclareol shows a strong pharmaceutical potential. Supercritical fluid extraction was used to recover compounds of interest from a Salvia sclarea L. waxy n-hexane extract (“concrete”), using semi-continuous fractionation and a multi-step extraction strategy. [...] Read more.

Clary Sage extracts are of industrial interest: in particular, sclareol shows a strong pharmaceutical potential. Supercritical fluid extraction was used to recover compounds of interest from a Salvia sclarea L. waxy n-hexane extract (“concrete”), using semi-continuous fractionation and a multi-step extraction strategy. Multi-step extraction experiments were carried out in two phases: the first one operated at 90 bar and 50 °C; the second one at 100 bar and 40 °C. GC-MS traces showed that during the first extraction step, only lighter compounds (e.g., monoterpenes, sesquiterpenes, and derivatives) were collected, whereas, in the second step, only sclareol and related compounds were recovered. By adjusting operating conditions (temperature and pressure), selective extraction of different families of compounds was accomplished, with no further need for post-processing of the products. Moreover, using two separators in series, the compounds of interest were fractionated from paraffins and, by changing the operating conditions, the extraction yield increased from about 6.0% to 9.3% w/w as CO₂ density increased. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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16 pages, 1841 KiB  

Open AccessArticle

Isolation and Purification of Single Gold Nanoclusters by Alternate Pumping Chromatography

by Malvina Supper, Virginia Birner, Lukas Gromotka, Wolfgang Peukert and Malte Kaspereit

Separations 2023, 10(3), 214; https://doi.org/10.3390/separations10030214 - 18 Mar 2023

Viewed by 1831

Abstract

Alternate pumping chromatography is applied to obtain atomically precise glutathione-stabilized gold nanoclusters in high purity from synthesized mixtures. On the basis of anion exchange chromatography, the feasibility of isolating a single cluster, Au${}_{10}$GSH${}_{10}$, as well as two different clusters [...] Read more.

Alternate pumping chromatography is applied to obtain atomically precise glutathione-stabilized gold nanoclusters in high purity from synthesized mixtures. On the basis of anion exchange chromatography, the feasibility of isolating a single cluster, Au${}_{10}$GSH${}_{10}$, as well as two different clusters simultaneously (Au${}_{25}$GSH${}_{18}$ and Au${}_{29}$GSH${}_{20}$) is demonstrated. In addition, Au${}_{18}$GSH${}_{14}$, which is present only in trace amounts, is successfully enriched. A simple design procedure is proposed that allows using columns with different retention behavior. Successful experiments with large injection amounts confirm the potential of the concept for preparative-scale productions of high-quality nanoparticulate products. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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17 pages, 4420 KiB  

Open AccessArticle

Effect of Gold Nanoparticles on the Physical Properties of an Epoxy Resin

by F. Fraga-López, Lisbeth Jiménez Carrillo, María Pilar Vázquez-Tato, Julio A. Seijas, Francisco Meijide, José Vázquez Tato and Aida Jover

Int. J. Mol. Sci. 2023, 24(6), 5638; https://doi.org/10.3390/ijms24065638 - 15 Mar 2023

Cited by 1 | Viewed by 1960

Abstract

The effect of doping the bisphenol A diglycidyl ether (DGEBA)/m-xylylenediamine (mXDA) system with gold nanoparticles (AuNP) has been studied with differential scanning calorimetry (DSC), thermogravimetric analysis, dynamic mechanical analysis (DMA), and dielectric analysis (DEA). The evolved heat (ΔH_t), the glass [...] Read more.

The effect of doping the bisphenol A diglycidyl ether (DGEBA)/m-xylylenediamine (mXDA) system with gold nanoparticles (AuNP) has been studied with differential scanning calorimetry (DSC), thermogravimetric analysis, dynamic mechanical analysis (DMA), and dielectric analysis (DEA). The evolved heat (ΔH_t), the glass transition temperature (T_g), and the associated activation energies of this relaxation process have been determined. Below a certain concentration of AuNPs (=8.5%, in mg AuNP/g epoxy matrix), T_g decreases linearly with the concentration of AuNPs, but above it, T_g is not affected. The degree of conversion α of this epoxy system was analyzed by the semiempirical Kamal’s model, evidencing that diffusion correction is required at high values of α. Activation energy values suggest that AuNPs can cause some impediments at the beginning of the crosslinking process (n-order mechanism). The slight difference between the initial decomposition temperature, as well as the temperature for which the degradation rate is at a maximum, for both systems can be accepted to be within experimental error. Mechanical properties (tension, compression, and bending tests) are not affected by the presence of AuNPs. Dielectric measurements show the existence of a second T_g at high temperatures, which was analyzed using the Tsagarapoulos and Eisenberg model of the mobility restrictions of network chains bound to the filler. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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13 pages, 522 KiB  

Open AccessArticle

Effect of 1,2-propanediol on the Critical Micelle Concentration of Decyltrimethylammonium Bromide at Temperatures from 293.15 K to 308.15 K

by Carmen M. Romero, Andrea P. Escamilla, Ana C. F. Ribeiro and Miguel A. Esteso

Int. J. Mol. Sci. 2022, 23(24), 15884; https://doi.org/10.3390/ijms232415884 - 14 Dec 2022

Cited by 5 | Viewed by 2091

Abstract

It is well known that polar organic compounds, such as alcohols and polyols, exert an appreciable influence on water structure and thus have important effects on surfactant micellization. These substances are often used to modify the properties of surfactants in aqueous solutions, increasing [...] Read more.

It is well known that polar organic compounds, such as alcohols and polyols, exert an appreciable influence on water structure and thus have important effects on surfactant micellization. These substances are often used to modify the properties of surfactants in aqueous solutions, increasing the practical applications they have in diverse industries. In this work, the critical micelle concentration (CMC) of decyltrimethylammonium bromide (C₁₀TAB) in water and in 1,2-propanediol aqueous solutions was determined from both sound velocity and surface tension measurements as a function of surfactant concentration in the temperature range of (293.15 to 308.15) K. The critical micelle concentration of the surfactant increases as the concentration of 1,2-propanediol becomes higher, while the effect on temperature does not show important changes within the range considered. At the selected temperatures, the standard thermodynamic parameters of micellization suggests that the addition of 1,2-propanediol makes the micellization process less favorable. Thermodynamic analysis suggests that the micelle formation of C₁₀TAB is an entropy-driven process at the temperatures considered in this study. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

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