Journal Description
Physchem
Physchem
is an international, peer-reviewed, open access journal on science and technology in physical chemistry published quarterly online by MDPI.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, ESCI (Web of Science) and other databases.
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 20.6 days after submission; acceptance to publication is undertaken in 4.8 days (median values for papers published in this journal in the first half of 2024).
- Recognition of Reviewers: APC discount vouchers, optional signed peer review, and reviewer names published annually in the journal.
Latest Articles
Adsorptive Removal of Bisphenol A by Polyethylene Meshes Grafted with an Amino Group-Containing Monomer, 2-(Dimethylamino)ethyl Methacrylate
Physchem 2024, 4(4), 431-446; https://doi.org/10.3390/physchem4040030 (registering DOI) - 25 Oct 2024
Abstract
The adsorptive removal of Bisphenol A (BPA) with the PE meshes photografted with 2-(dimethylamino)ethyl methacrylate (DMAEMA) was performed by varying the grafted amount, pH value, BPA concentration, and temperature, and the adsorption performance was correlated by the equilibrium, kinetic, and isotherm models. In
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The adsorptive removal of Bisphenol A (BPA) with the PE meshes photografted with 2-(dimethylamino)ethyl methacrylate (DMAEMA) was performed by varying the grafted amount, pH value, BPA concentration, and temperature, and the adsorption performance was correlated by the equilibrium, kinetic, and isotherm models. In addition, the regeneration of DMAEMA-grafted PE (PE-g-PDMAEMA) meshes was discussed from the repetitive adsorption/desorption process. The adsorption capacity had the maximum value at the grafted amount of 2.6 mmol/g and at the initial pH value of 8.0. The increase in the protonation of dimethylamino groups on grafted PDMAEMA chains and the dissociation of phenol groups of BPA present in the outer solution during the adsorption process results in the increase in BPA adsorption. The adsorption process followed the pseudo second-order equation. The BPA adsorption was enhanced by increasing the BPA concentration and the equilibrium data fit to Langmuir equation. The adsorption capacity stayed almost constant with the increase in the temperature, whereas the k2 value increased against the temperature. These results comprehensively emphasized that BPA adsorption occurred through the chemical interaction or ionic bonding of a BPA anion to a terminal protonated dimethylamino group. Desorption of BPA increased by increasing the NaOH concentration and BPA was entirely desorbed at more than 20 mM. The cycle of adsorption at pH 8.0 and desorption in a NaOH solution at 100 mM was repeated five times without loss or structural damage. These results indicate PE-g-PDMAEMA meshes can be used as a regenerative adsorbent for BPA removal from aqueous medium.
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(This article belongs to the Section Surface Science)
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Deciphering the Coarse-Grained Model of Ionic Liquid by Tunning the Interaction Level and Bead Types of Martini 3 Force Field
by
Sukanya Konar, Arash Elahi and Santanu Chaudhuri
Physchem 2024, 4(4), 420-430; https://doi.org/10.3390/physchem4040029 - 23 Oct 2024
Abstract
In recent years, ionic liquids (ILs) have served as potential solvents to dissolve organic, inorganic, and polymer materials. A copolymer (for example, Pluronic) can undergo self-organization by forming a micelle-like structure in pure IL medium, and its assembly depends upon the composition of
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In recent years, ionic liquids (ILs) have served as potential solvents to dissolve organic, inorganic, and polymer materials. A copolymer (for example, Pluronic) can undergo self-organization by forming a micelle-like structure in pure IL medium, and its assembly depends upon the composition of IL. To evaluate the role of ILs, accurate coarse-grained (CG) modeling of IL is needed. Here, we modeled 1-ethyl-3-methylimidazolium dicyanamide ([EMIM][DCA]) ionic liquid (IL) using a CG framework. We optimized CG parameters for the [DCA]− anion by tuning the non-bonded parameters and selecting different kinds of beads. The molecular density (ρ) and radial distribution function (RDF) of our CG model reveal a good agreement with the all-atom (AA) simulation data. We further validated our model by choosing another imidazolium-based cation. Our modified CG model for the anion shows compatibility with the cation and the obtained density matches well with the experimental data. The strategies for developing the CG model will provide a guideline for accurate modeling of new types of ILs. Our CG model will be useful in studying the micellization of non-ionic Pluronic in the [EMIM][DCA] IL medium.
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(This article belongs to the Section Theoretical and Computational Chemistry)
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Green Silver Nanoparticles: Plant-Extract-Mediated Synthesis, Optical and Electrochemical Properties
by
Natalia Stozhko, Aleksey Tarasov, Viktoria Tamoshenko, Maria Bukharinova, Ekaterina Khamzina and Veronika Kolotygina
Physchem 2024, 4(4), 402-419; https://doi.org/10.3390/physchem4040028 - 16 Oct 2024
Abstract
Antioxidants of plant extract play an important role in the phytosynthesis of silver nanoparticles (phyto-AgNPs), providing the reduction of silver ions and capping and stabilization of nanoparticles. Despite the current progress in the studies of phytosynthesis, there is no approach to the selection
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Antioxidants of plant extract play an important role in the phytosynthesis of silver nanoparticles (phyto-AgNPs), providing the reduction of silver ions and capping and stabilization of nanoparticles. Despite the current progress in the studies of phytosynthesis, there is no approach to the selection of plant extract for obtaining phyto-AgNPs with desired properties. This work shows that antioxidant activity (AOA) of plant extracts is a key parameter for targeted phytosynthesis. In support of this fact, the synthesis of phyto-AgNPs was carried out using extracts of four plants with different AOA, increasing in the order Ribes uva-crispa < Lonicera caerulea < Fragaria vesca < Hippophae rhamnoides. Phyto-AgNPs have been characterized using Fourier-transform infrared spectroscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, selected area electron diffraction technique, ultraviolet–visible spectroscopy, electrochemical impedance spectroscopy and cyclic voltammetry. It was established that the change in the AOA of the plant extract is accompanied by a size-dependent change in the optical and electrochemical properties of phyto-AgNPs. In particular, an increase in the extract AOA leads to the formation of smaller phyto-AgNPs with higher electrochemical activity and low charge transfer resistance. A “blue shift” and an increase in the plasmon resonance band of silver sols are observed with an increase in the extract AOA. The obtained regularities prove the existence of the “AOA–size–properties” triad, which can be used for controlled phytosynthesis and prediction of phyto-AgNPs’ properties.
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(This article belongs to the Section Electrochemistry)
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Fitting Quality of NMR Relaxation Data to Differentiate Asphalt Binders
by
Rebecca M. Herndon, Kevin Lai, Magdy Abdelrahman and Klaus Woelk
Physchem 2024, 4(4), 389-401; https://doi.org/10.3390/physchem4040027 - 11 Oct 2024
Abstract
Asphalt binder performance grades (PGs) are important metrics in designing pavements for effective transportation infrastructure. The PG system relies on the binder’s stiffness and is determined through energy- and time-intensive physical testing. Physical properties, like stiffness, can also be determined by spin–lattice NMR
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Asphalt binder performance grades (PGs) are important metrics in designing pavements for effective transportation infrastructure. The PG system relies on the binder’s stiffness and is determined through energy- and time-intensive physical testing. Physical properties, like stiffness, can also be determined by spin–lattice NMR relaxometry, a non-destructive chemical method. NMR relaxometry can quantify the molecular mobility of materials by determining relaxation times from exponential decays of excited nuclear magnetization. While relaxation times have been used to determine physical properties of materials, a quantitative relation to the PG grades of asphalt binder is yet to be established. In this study, T1 NMR relaxation analyses were used to differentiate between solid asphalt binders and determine the fastest yet still-reliable method of modeling exponential decay data. Algorithms that fit exponential decay relaxation data using one, two, or three independent relaxation times were compared with a 128-coefficient discrete inverse Laplace transformation to determine the best mathematical fit for a comparative analysis. The number of data points was then reduced from 256 to 64 to 16 and finally to 8 data points on a relaxation curve to reduce the testing time and determine the minimum number of data points needed for comparison. Two batches of PG 64-22 asphalt binder, along with samples of PG 76-22 and 94-10 binders, were investigated. The best compromise between measuring time and data reliability was found by acquiring 64 data points and then using a biexponential model to fit the experimental data. The PG 64-22 sources provided similar results, indicating similar physical properties. The PG 64-22 and PG 76-22 binders could also be compared via monoexponential data fits, but the PG 94-10 samples required an additional relaxation parameter for comparison. To differentiate all three binder grades, the primary relaxation times, along with their relative ratios, were utilized.
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(This article belongs to the Section Theoretical and Computational Chemistry)
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Open AccessArticle
Role of Multiple Intermolecular H-Bonding Interactions in Molecular Cluster of Hydroxyl-Functionalized Imidazolium Ionic Liquid: An Experimental, Topological, and Molecular Dynamics Study
by
Sumit Kumar Panja, Sumit Kumar, Boumediene Haddad, Abhishek R. Patel, Didier Villemin, Hakkoum-Mohamed Amine, Sayantan Bera and Mansour Debdab
Physchem 2024, 4(4), 369-388; https://doi.org/10.3390/physchem4040026 - 24 Sep 2024
Abstract
Multiple intermolecular H-bonding interactions play a pivotal role in determining the macroscopic state of ionic liquids (ILs). Hence, the relationship between the microscopic and the macroscopic properties is key for a rational design of new imidazolium ILs. In the present work, we investigated
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Multiple intermolecular H-bonding interactions play a pivotal role in determining the macroscopic state of ionic liquids (ILs). Hence, the relationship between the microscopic and the macroscopic properties is key for a rational design of new imidazolium ILs. In the present work, we investigated how the physicochemical property of hydroxyl-functionalized imidazolium chloride is connected to the molecular structure and intermolecular interactions. In the isolated ion pair, strong N-H···Cl H-bonding interactions are observed rather than H-bonding interactions at the acidic C2-H site and alkyl-OH···Cl of the hydroxyl-functionalized imidazolium chloride. However, the N-H···Cl H-bonding interaction of the cation plays a significant role in ion-pair formations and polymeric clusters. For 3-(2-Hydroxy)-1H-imidazolium chloride (EtOHImCl), the oxygen atom (O) engages in two significant interactions within its homodimeric ion-pair cluster: N-H···O and alkyl OH···Cl. Vibrational spectroscopy and DFT calculations reveal that the chloride ion (Cl−) forms a hydrogen bond with the C2-H group via a C2-H···Cl interaction site. Natural Bond Orbital (NBO) analysis indicates that the O-H···Cl hydrogen-bonding interaction is crucial for the stability of the IL, with a second-order perturbation energy of approximately 133.8 kJ/mol. Additional computational studies using Atoms in Molecules (AIMs), non-covalent interaction (NCI) analysis, Electron Localization Function (ELF), and Localized Orbital Locator (LOL) provide significant insights into the properties and nature of non-covalent interactions in ILs. Ab initio molecular dynamics (AIMD) simulations of the IL demonstrate its stable states with relatively low energy values around −1680.6510 atomic units (a.u.) at both 100 fs and 400 fs due to O-H···Cl and C-H···Cl interactions.
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(This article belongs to the Section Experimental and Computational Spectroscopy)
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Impact of Corn, Bean, and Semolina Flour Blends and Processing Methods on the Physical Properties and Antioxidant Activity of Instant Noodles
by
Diana Aviles-Simental, Jose Alberto Gallegos-Infante, Nuria Elizabeth Rocha-Guzmán, Alejandro Pérez-Lozano and Luz Araceli Ochoa-Martínez
Physchem 2024, 4(3), 356-368; https://doi.org/10.3390/physchem4030025 - 22 Sep 2024
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The main objective was to evaluate the use of common bean flour (CBF), corn flour, and semolina to obtain instant noodles by means of a hot dry and frying process. The hot drying process was conducted at 60 °C for 4 h, and
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The main objective was to evaluate the use of common bean flour (CBF), corn flour, and semolina to obtain instant noodles by means of a hot dry and frying process. The hot drying process was conducted at 60 °C for 4 h, and frying was conducted at 140 °C and 160 °C for 1 and 3 min. Proximate analysis, total phenolic content (TPC), the 2,2-diphenyl-1-picrylhydrazyl (DPPH) test, the oxygen radical absorbance capacity (ORAC) assay, phenolic acids and flavonoids profile by UPLC-ESI-MS/MS, the optimal cooking time (OCT), and color and texture analysis (TPA) were conducted. The general linear model and regression analysis were used. The incorporation of CBF resulted in an elevated protein content and TPC of the noodles. The noodles (hot dry) with CBF exhibited an enhanced antioxidant capacity. The adhesiveness has a direct correlation with the cinnamic, chlorogenic, and caffeic acid content (r2 = 0.95 or higher), as well as an inverse relationship with the vanillic, ferulic, and sinapic acids (r2 = −0.80 to −0.85). The dry hot noodles exhibited the lowest value of hardness (31.0 ± 1.5 N). The incorporation of common bean flour and corn flour enhances the nutritional profile of noodles. However, hot dry process affects their mechanical characteristics in comparison to the frying process.
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Open AccessArticle
Nuclear Magnetic Resonance (NMR) Assessment of Bio and Crude Oil-Based Rejuvenation
by
Rebecca M. Herndon, Jay Balasubramanian, Magdy Abdelrahman and Klaus Woelk
Physchem 2024, 4(3), 344-355; https://doi.org/10.3390/physchem4030024 - 14 Sep 2024
Cited by 1
Abstract
Asphalt binders in pavements lose their stability through aging and eventually fail in the field. Using nuclear magnetic resonance (NMR) to monitor the primary longitudinal relaxation time of asphalt samples and the ratio of material that carries this primary relaxation time has been
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Asphalt binders in pavements lose their stability through aging and eventually fail in the field. Using nuclear magnetic resonance (NMR) to monitor the primary longitudinal relaxation time of asphalt samples and the ratio of material that carries this primary relaxation time has been shown to indicate the impact of ultraviolet (UV) radiation on the aging of asphalt pavements. Longitudinal NMR relaxation was used to investigate two types of proposed asphalt rejuvenators, a bio-oil-based rejuvenator and a crude-oil-based rejuvenator. Two different binders with the performance grades (PG) 64-22 and 76-22 were considered for their interactions with the rejuvenators. After 72 h of exposure to intense UV radiation, specifically designed NMR relaxometry experiments were applied to compare the rejuvenation capabilities of the two rejuvenator samples. The crude oil-based rejuvenator was found to exhibit relaxation times similar to the binder samples while the bio-based material showed relaxation times that pointed to different nuclear hydrogen environments. Both rejuvenators reduced the primary relaxation time of the PG 76-22 binder, which indicates that their stiffness was reduced. Both types of rejuvenators also seemed to prevent the effects of UV aging. Two mechanisms of rejuvenation were identified by NMR relaxometry. The primary relaxation time can be used to indicate a change in stiffness while the primary ratio of the material is tied to oxidative aging. Oxidative aging creates distinct hydrogen environments due to asphaltene aggregation. The bio-based rejuvenator only reduced the binder’s stiffness, while the crude oil-based rejuvenator also reduced the aggregation of asphaltenes. Consequently, the bio-based rejuvenator could be classified as an asphalt softener, while the oil-based material acted like a true rejuvenator.
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(This article belongs to the Section Solid-State Chemistry and Physics)
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Exploring the Distribution of Low Molecular Weight Compounds in Water-Based Two-Phase Systems with Various Salt Additives
by
Margarida Costa, Pedro P. Madeira, Vladimir N. Uversky and Boris Y. Zaslavsky
Physchem 2024, 4(3), 334-343; https://doi.org/10.3390/physchem4030023 - 9 Sep 2024
Abstract
The partition coefficients of seven low molecular weight compounds were tested in different aqueous two-phase systems. The ionic composition of each system included specific salt additives, and it was found that there is a linear relationship between the solute partition coefficients and the
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The partition coefficients of seven low molecular weight compounds were tested in different aqueous two-phase systems. The ionic composition of each system included specific salt additives, and it was found that there is a linear relationship between the solute partition coefficients and the presence of different salt additives. The study suggests that the solute structure and the type of ions influence the solute response to the ionic environment. Additionally, it was observed that the solutes’ polar surface area and the solvent-accessible surface area are the essential structural features governing partitioning in aqueous two-phase systems.
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(This article belongs to the Section Biophysical Chemistry)
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Exploring the Diversity and Dehydration Performance of New Mixed Tutton Salts (K2V1−xM’x(SO4)2(H2O)6, Where M’ = Co, Ni, Cu, and Zn) as Thermochemical Heat Storage Materials
by
João G. de Oliveira Neto, Jacivan V. Marques, Jayson C. dos Santos, Adenilson O. dos Santos and Rossano Lang
Physchem 2024, 4(3), 319-333; https://doi.org/10.3390/physchem4030022 - 26 Aug 2024
Abstract
Tutton salts form an isomorphic crystallographic family that has been intensively investigated in recent decades due to their attractive thermal and optical properties. In this work, we report four mixed Tutton crystals (obtained by the slow solvent evaporation method) with novel chemical compositions
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Tutton salts form an isomorphic crystallographic family that has been intensively investigated in recent decades due to their attractive thermal and optical properties. In this work, we report four mixed Tutton crystals (obtained by the slow solvent evaporation method) with novel chemical compositions based on K2V1−xM’x(SO4)2(H2O)6, where M’ represents Co, Ni, Cu, and Zn, aiming at thermochemical energy storage applications. Their structural and thermal properties were correlated with theoretical studies. The crystal structures were solved by powder X-ray diffraction using the Rietveld method with similar compounds. All of the samples crystallized in monoclinic symmetry with the P21/a-space group. A detailed study of the intermolecular interactions based on Hirshfeld surfaces and 2D fingerprint mappings showed that the main interactions arise from hydrogen bonds (H∙∙∙O/O∙∙∙H) and dipole–ion (K∙∙∙O/O∙∙∙K). On the other hand, free space percentages in the unit cells determined by electron density isosurfaces presented low values ranging from 0.53 (V–Ni) to 0.81% (V–Cu). The thermochemical findings from thermogravimetry, a differential thermal analysis, and differential scanning calorimetry indicate that K2V0.47Ni0.53(SO4)2(H2O)6 salt is the most promising among mixed salts (K2V1−xM’x(SO4)2(H2O)6) for heat storage potential, achieving a low dehydration temperature (≈85 °C), high dehydration enthalpy (≈360 kJ/mol), and high energy storage density (≈1.84 GJ/m3).
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(This article belongs to the Section Solid-State Chemistry and Physics)
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Open AccessReview
The Theories of Rubber Elasticity and the Goodness of Their Constitutive Stress–Strain Equations
by
Vincenzo Villani and Vito Lavallata
Physchem 2024, 4(3), 296-318; https://doi.org/10.3390/physchem4030021 - 22 Aug 2024
Abstract
One of the most important challenges in polymer science is a rigorous understanding of the molecular mechanisms of rubber elasticity by relating macroscopic deformation to molecular changes and deriving the constitutive stress–strain equation for the elastomeric network. The models developed from the last
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One of the most important challenges in polymer science is a rigorous understanding of the molecular mechanisms of rubber elasticity by relating macroscopic deformation to molecular changes and deriving the constitutive stress–strain equation for the elastomeric network. The models developed from the last century to today describe many aspects of the physics of rubber elasticity; although these theories are successful, they are not complete. In this review we analyze the main theoretical and phenomenological models of rubber elasticity, including their assumptions, main characteristics, and stress–strain equations. Then, we compare the predictions of the theories to our experimental data of polydimethylsiloxane (PDMS) rubber, in order to highlight the goodness of the reviewed models. The nonaffine and phenomenological deformation models verify the experimental curves in tension and compression in the whole investigated deformation range . On the contrary, the affine deformation hypothesis is rigorously verified only in the deformation range .
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(This article belongs to the Section Theoretical and Computational Chemistry)
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Open AccessArticle
Asphalt-Binder Mixtures Evaluated by T1 NMR Relaxometry
by
Rebecca M. Herndon, Jay Balasubramanian, Magdy Abdelrahman and Klaus Woelk
Physchem 2024, 4(3), 285-295; https://doi.org/10.3390/physchem4030020 - 13 Aug 2024
Cited by 2
Abstract
Asphalt pavements make up a majority of the essential transportation systems in the US. Asphalt mixtures age and degrade over time, reducing the pavement performance. Pavement performance critically depends on the aging of asphalt binder. The aging of asphalt binder during construction is
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Asphalt pavements make up a majority of the essential transportation systems in the US. Asphalt mixtures age and degrade over time, reducing the pavement performance. Pavement performance critically depends on the aging of asphalt binder. The aging of asphalt binder during construction is traditionally modeled by rolling thin film oven (RTFO) testing, while aging during service life is modeled by pressure aging vessel (PAV) testing. Comparing these models to the aging of binders in actual pavements is limited because, to be used for current testing, binders must be separated from the pavement’s aggregate by solvent extraction. Solvent extraction will, at least in part, compromise the structural integrity of asphalt binder samples. Spin-lattice NMR relaxometry has been shown to nondestructively evaluate asphalt properties in situ through the analysis of hydrogen environments. The molecular mobility of hydrogen environments and with it the stiffness of asphalt binder samples can be determined by characteristic T1 relaxation times, indicating the complexity of asphalt-binder aging. In this study, two laboratory-generated asphalt mixtures, a failed field sample, and several laboratory-aged binder samples are compared by NMR relaxometry. NMR relaxometry was found to be able to differentiate between asphalt samples based on their binder percentage. According to the relaxometry findings, the RTFO binder aging compared favorably to the 6% laboratory-mixed sample. The PAV aging, however, did not compare well to the relaxometry results found for the field-aged sample. The amount of aggregate was found to have an influence on the relaxation times of the binder in the mixed samples and an inverse proportionality of the binder content to the primary NMR relaxation time was detected. It is concluded that molecular water present in the pores of the aggregate material gives rise to such a relationship. The findings of this study lay the foundation for nondestructive asphalt performance evaluation by NMR relaxometry.
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(This article belongs to the Section Solid-State Chemistry and Physics)
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Open AccessArticle
Polyvinyl Alcohol Coatings Containing Lamellar Solids with Antimicrobial Activity
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Maria Bastianini, Michele Sisani, Raúl Escudero García, Irene Di Guida, Carla Russo, Donatella Pietrella and Riccardo Narducci
Physchem 2024, 4(3), 272-284; https://doi.org/10.3390/physchem4030019 - 1 Aug 2024
Abstract
The design of an antimicrobial coating material has become important in the prevention of infections caused by the transmission of pathogens coming from human contact with contaminated surfaces. With that aim, layered single hydroxides (LSHs) and layered double hydroxides (LDHs) containing Zn and
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The design of an antimicrobial coating material has become important in the prevention of infections caused by the transmission of pathogens coming from human contact with contaminated surfaces. With that aim, layered single hydroxides (LSHs) and layered double hydroxides (LDHs) containing Zn and Cu intercalated with antimicrobial molecules were synthesized and characterized. Cinnamate and salicylate anions were chosen because of their well-known antimicrobial activity. Several coatings based on polyvinyl alcohol (PVA) and LDHs or LSHs with increasing amounts of filler were prepared and filmed on a polyethylene terephthalate (PET) substrate. The coatings were characterized, and their antimicrobial activity was evaluated against several pathogens that are critical in nosocomial infections, showing a synergistic effect between metal ions and active molecules and the ability to inhibit their growth.
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(This article belongs to the Section Surface Science)
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Thermodynamic Equilibrium Analysis of CO2 Methanation through Equilibrium Constants: A Comparative Simulation Study
by
Bruno Varandas, Miguel Oliveira, Carlos Andrade and Amadeu Borges
Physchem 2024, 4(3), 258-271; https://doi.org/10.3390/physchem4030018 - 23 Jul 2024
Abstract
In this study, a steady-state thermodynamic equilibrium evaluation of CO2 methanation was conducted. Calculations were performed by solving the material balance equations using the equilibrium constants of CO2 methanation and reverse water–gas shift reactions. Results obtained from an analytical method developed
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In this study, a steady-state thermodynamic equilibrium evaluation of CO2 methanation was conducted. Calculations were performed by solving the material balance equations using the equilibrium constants of CO2 methanation and reverse water–gas shift reactions. Results obtained from an analytical method developed with the aid of the Microsoft Excel platform were compared to simulations conducted using the commercially available free software COCO and DWSIM. The effects of temperature, pressure, and H2/CO2 ratio on CH4 yield, carbon oxide formation, and heat balance were investigated. The results indicate that the methanation process is highly favored by low temperatures and higher pressures with a stoichiometric H2/CO2 ratio. Under these conditions, CH4 output increases, and carbon formation is reduced, resulting in better performance. Simulations from all three models are in agreement, with minor differences noted in the DWSIM software.
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(This article belongs to the Section Thermochemistry)
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Open AccessReview
Development and Characterisation of Functional Bakery Products
by
Raquel P. F. Guiné and Sofia G. Florença
Physchem 2024, 4(3), 234-257; https://doi.org/10.3390/physchem4030017 - 17 Jul 2024
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This review focuses on a set of studies about functional bakery products. The literature search was performed on scientific databases ScienceDirect, PubMed, MDPI, BOn, and SciELO, based on some eligibility criteria, and a total of 102 original research articles about functional bakery products
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This review focuses on a set of studies about functional bakery products. The literature search was performed on scientific databases ScienceDirect, PubMed, MDPI, BOn, and SciELO, based on some eligibility criteria, and a total of 102 original research articles about functional bakery products were selected. The studies were analysed according to the types of products, functional properties, functional ingredients, their sources, and the types of measurements described. Results showed that breads were the most frequently analysed products. Most of the products were rich in fibre and antioxidants or were gluten-free. Of the 102 studies, 92 analysed physical properties, 81 involved chemical analyses, 50 involved sensorial analyses, and eight reported microbiological analyses. The most frequent physical properties were texture and colour, while the most frequent chemical components were fibre and minerals. For sensorial properties, colour and texture were particularly evaluated, which were also the most frequently measured physical properties. The studies presented various successful strategies for the fortification of bakery products with functional components, demonstrating their ability to meet consumer needs and potentiate industry growth. This review highlights the relevance of functional bakery products in the current food panorama, contributing to increased knowledge and stimulating discussions about the impact of functional bakery products in promoting healthier eating.
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Grafting of Polyethyleneimines on Porous Silica Beads and Their Use for Adsorptive Removal of Cr(VI) from Aqueous Medium
by
Ayane Taki, Kouta Morioka, Keiko Noguchi, Hiromichi Asamoto, Hiroaki Minamisawa and Kazunori Yamada
Physchem 2024, 4(3), 214-233; https://doi.org/10.3390/physchem4030016 - 14 Jul 2024
Abstract
Porous silica-based adsorbents for hexavalent chromium (Cr(VI)) ion removal were prepared by the combined use of functionalization with (3-glycidyloxypropyl)trimethoxysilane and the grafting of branched and linear polyethyleneimine (BPEI and LPEI). LPEI was prepared from polyethyloxazolin by hydrolysis with HCl. The preparation of LPEI
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Porous silica-based adsorbents for hexavalent chromium (Cr(VI)) ion removal were prepared by the combined use of functionalization with (3-glycidyloxypropyl)trimethoxysilane and the grafting of branched and linear polyethyleneimine (BPEI and LPEI). LPEI was prepared from polyethyloxazolin by hydrolysis with HCl. The preparation of LPEI was identified by NMR measurements and the grafting of BPEI and LPEI on the silica beads was confirmed by an XPS analysis. The Cr(VI) ion adsorption of the obtained BPEI-grafted silica beads (BPEI–silica beads) was investigated as a function of the pH value, the content of amino groups, the temperature, the Cr(VI) ion concentration, and the molecular mass of the grafted BPEI chains. The Cr(VI) ion adsorption at pH 3.0 increased with an increase in the content of amino groups, and the maximum adsorption capacity of 1.06 mmol/g was obtained when the content of amino groups was at 2.17 mmol/g. This value corresponds to 589 mg/g−1.8KPEI, and the adsorption ratio of about 0.5 is a noteworthy result. The data fit to the pseudo-second-order kinetic model, and the suitability of this fitting was supported by the results that the adsorption capacity and initial rate of adsorption increased with the temperature. In addition, the equilibrium data followed the Langmuir isotherm model. These results clearly demonstrate that the Cr(VI) adsorption occurred chemically, or through the electrostatic interaction of protonated amino groups on the grafted BPEI chains with hydrochromate ( ) ions. A higher adsorption capacity was obtained for the silica beads grafted with shorter BPEI chains, and the adsorption capacity of BPEI–silica beads is a little higher than that of linear PEI-grafted silica beads, suggesting that the Cr(VI) ion adsorption is affected by the chain isomerism of PEI (linear and branched) as well as the molecular mass of the grafted PEI chains, in addition to the content of amino groups. The experimental and analytical results derived from this study emphasize that the BPEI–silica beads can be used as an adsorbent for the removal of Cr(VI) ions from an aqueous medium.
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(This article belongs to the Section Surface Science)
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Geopolymers for Space Applications
by
D. Mendoza-Cachú, J. B. Rojas-Trigos, J. Hernández-Wong, T. J. Madera-Santana and E. A. Franco-Urquiza
Physchem 2024, 4(3), 197-213; https://doi.org/10.3390/physchem4030015 - 5 Jul 2024
Abstract
Geopolymers are cementitious materials with exceptional mechanical and physical properties, making them suitable for aerospace applications. Considering their excellent performance, the present investigation aims to develop geopolymers with designed physical properties to address some issues in the aerospace industry. In this sense, the
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Geopolymers are cementitious materials with exceptional mechanical and physical properties, making them suitable for aerospace applications. Considering their excellent performance, the present investigation aims to develop geopolymers with designed physical properties to address some issues in the aerospace industry. In this sense, the influence of the alkaline activator on the final properties was evaluated. For the development of the geopolymers, sodium hydroxide and sodium metasilicate solutions were preparedto obtain the alkaline activator. The synthesis process also consisted of a mixing stage using a mixer to obtain a homogenous paste. After mixing, the curing process consisted of a first thermal treatment at 60 °C for 4 h to evaporate the excess water, avoid excessive contraction, and promote strength at early ages. Subsequently, the geopolymers were left at rest for 28 days until the final properties were achieved. The influence of the solid-to-liquidratio (S/L) on the microstructure of the geopolymers was evaluated. For this purpose, X-ray fluorescence spectrometry, X-ray diffraction, and infrared spectrometry analyses were performed. The results show that the content of the alkaline activator promotes variations inthe presence of different crystalline phases, which is more noticeable as the S/L ratio increases. Likewise, the infrared spectra display peaks at different wavelengths regarding the variations in elemental composition, which are more evident with the changes in the S/L ratio. In addition, physical studies, such as thermal conductivity and resistance to gamma radiation were conducted for different geopolymer compositions. The results indicate that changes in properties are not too sensitive to compositional variations, although slight modifications exist. Finally, these studies are significant as aerospace-focused materials are directly exposed to this kind of phenomena. The designed geopolymers have to be able to resist and maintain their properties through exposure to any energy.
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(This article belongs to the Section Solid-State Chemistry and Physics)
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Facile Fabrication of Pd-Doped CuO-ZnO Composites for Simultaneous Photodegradation of Anionic and Neutral Dyes
by
Sumalatha Bonthula, Muna Farah Ibrahim, Aisha Omar Al-Jaber, Al-Dana Faisal Al-Siddiqi, Ramyakrishna Pothu, Tauqeer Chowdhury, Yusuf Siddiqui, Rajender Boddula, Ahmed Bahgat Radwan and Noora Al-Qahtani
Physchem 2024, 4(3), 181-196; https://doi.org/10.3390/physchem4030014 - 27 Jun 2024
Abstract
This study explores the synthesis and application of Pd-doped CuO-ZnO composites for the simultaneous photodegradation of anionic and neutral dyes. The nanocomposite was synthesized using a hydrothermal technique and characterized using XRD, FTIR, and UV-Vis absorption spectra. Photocatalytic degradation experiments were conducted with
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This study explores the synthesis and application of Pd-doped CuO-ZnO composites for the simultaneous photodegradation of anionic and neutral dyes. The nanocomposite was synthesized using a hydrothermal technique and characterized using XRD, FTIR, and UV-Vis absorption spectra. Photocatalytic degradation experiments were conducted with varying catalyst loadings, revealing optimal conditions for enhanced degradation performance. The nanocomposite exhibited a synergistic effect on the degradation of the dye mixture, following pseudo-first-order kinetics with significant efficiency under sunlight exposure. Moreover, the study evaluated the influence of pH on the degradation process, showing improved efficiency in neutral and basic conditions. Overall, the findings highlight the efficacy of the Pd-doped CuO-ZnO catalyst in degrading complex dye mixtures, offering potential applications for wastewater treatment in various industrial settings.
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(This article belongs to the Section Catalysis)
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The Surprising Role of Endogenous Calcium Carbonate in Crab Shell-Mediated Biosorption of Pb (II)
by
Carolina Londoño-Zuluaga, Hasan Jameel, Ronalds W. Gonzalez, Guihua Yang and Lucian Lucia
Physchem 2024, 4(2), 167-180; https://doi.org/10.3390/physchem4020013 - 20 Jun 2024
Abstract
Crustacean shells, waste from the seafood industry, have been identified as a potential sustainable material for the adsorption of lead, a potent heavy metal found in the discharge of industrial processes. The dynamics and kinetics of its performance were evaluated in batch experiments
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Crustacean shells, waste from the seafood industry, have been identified as a potential sustainable material for the adsorption of lead, a potent heavy metal found in the discharge of industrial processes. The dynamics and kinetics of its performance were evaluated in batch experiments under pH, temperature, time, and initial concentration. A unique and non-intuitive key finding was that among the native components of the crab shell matrix, i.e., chitin, protein, and calcium carbonate, calcium carbonate was instrumental in sequestration. The role of protein was minimal, whereas the efficiency of chitin in lead complexation was linked to the lead atomic radius, which, of the crab shell components, we determined was very prone to interacting with chitin.
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(This article belongs to the Section Physical Organic Chemistry)
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Fast Recombination of Free Radicals in Solution and Microviscosity
by
Igor V. Khudyakov
Physchem 2024, 4(2), 157-166; https://doi.org/10.3390/physchem4020012 - 27 May 2024
Abstract
Rates of fast reactions are inversely proportional to the solvent viscosity (η). However, a quantitative study demonstrates that dynamic viscosity η is often a crude reflection of a viscous drug exerted on a molecule or radical. This paper aims to present an accurate
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Rates of fast reactions are inversely proportional to the solvent viscosity (η). However, a quantitative study demonstrates that dynamic viscosity η is often a crude reflection of a viscous drug exerted on a molecule or radical. This paper aims to present an accurate dependence of the rates of fast bi- and monomolecular reactions upon the viscous drug of a media. Different correction coefficients fmicro are discussed, which should lead to a dependence rate ∝ (fmicroη)−1. Microviscosity is viscosity, leading to the expected rate dependence upon shear viscosity. In many cases, experimentally measured diffusion coefficients of molecules of a similar structure to the reactive radicals lead to the correct prediction of radicals’ diffusion coefficients and the rate constants of radicals recombination. Microviscosity of complex non-Newtonian liquids (biological liquids, polymeric solutions) can be measured using low MW molecular probes. Usually, the measured ηmicro is much lower than the shear η of complex biological or polymeric liquids. Cis–trans isomerization of bulky groups in monomolecular reactions is often described with Kramers’ theory. An example of such isomerization of a cyanine dye studied experimentally and theoretically is presented. It is demonstrated in the selected case that Kramers’ theory adequately describes the dependence of cis–trans isomerization of organic compounds upon η.
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(This article belongs to the Section Kinetics and Thermodynamics)
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A Computational Study of the Mechanism and Kinetics of the 4-Methyl Aniline Reaction with OH Radicals
by
Tien V. Pham
Physchem 2024, 4(2), 146-156; https://doi.org/10.3390/physchem4020011 - 26 May 2024
Abstract
In this study, the mechanism of the reaction between 4-methyl aniline and hydroxyl free radicals was computed using the M06-2X and CCSD(T) methods, along with the 6-311++G(3df,2p) basis set. The kinetics of the reaction were calculated utilizing the transition state theory and the
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In this study, the mechanism of the reaction between 4-methyl aniline and hydroxyl free radicals was computed using the M06-2X and CCSD(T) methods, along with the 6-311++G(3df,2p) basis set. The kinetics of the reaction were calculated utilizing the transition state theory and the microcanonical Rice–Ramsperger–Kassel–Marcus theory. The calculated results revealed that NH-C6H4-CH3 was the key product of the system. The total rate coefficient of the system, k_total = 2.04 × 10−18 T2.07 exp[(11.2 kJ/mol)/RT] cm3/s, was found under the 300–2000 K interval, with P = 760 Torr. At the ambient conditions, the velocity of this reaction was about ten times larger than that of the reaction between C6H5CH3 and hydroxyl free radicals, but it was smaller than the aniline + OH rate.
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(This article belongs to the Section Theoretical and Computational Chemistry)
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