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Physchem, Volume 3, Issue 1 (March 2023) – 13 articles

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12 pages, 2213 KiB  
Article
Additive Based on Synthetic Aluminosilicates for Dry Lime Construction Mixtures
by Valentina Ivanovna Loganina, Kristina Vladimirovna Zhegera and Maria Anatolyevna Svetalkina
Physchem 2023, 3(1), 198-209; https://doi.org/10.3390/physchem3010013 - 15 Mar 2023
Cited by 1 | Viewed by 1346
Abstract
The possibility of increasing the durability of coatings based on lime dry construction mix by introducing an additive containing synthetic aluminosilicates is substantiated. The regularities of the structure formation of the lime composite in the presence of an additive containing synthetic aluminosilicates, which [...] Read more.
The possibility of increasing the durability of coatings based on lime dry construction mix by introducing an additive containing synthetic aluminosilicates is substantiated. The regularities of the structure formation of the lime composite in the presence of an additive containing synthetic aluminosilicates, which additionally consists of a formation of calcium–sodium hydrosilicates and minerals of the zeolite group, an increase in the amount of chemically bound lime by 8.74%, are revealed. X-ray diffraction analysis and thermodynamic calculations have established that the mineralogical composition of the crystalline phase of the additive based on synthetic aluminosilicates is represented by thenardite, gibbsite, and the minerals of the zeolite group. It is shown that the content of the amorphous phase is 77.5%. It was found that the additive based on synthetic aluminosilicates is characterized by high activity, which is more than 350 mg/g. It was also found that the introduction of an additive based on synthetic aluminosilicates into the formulation of a lime dry mixture accelerates the curing of coatings and increases the compressive strength after 28 days of air-dry hardening by 1.9 times. Full article
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42 pages, 6472 KiB  
Article
Measurement Precision and Thermal and Absorption Properties of Nanostructures in Aqueous Solutions by Transient and Steady-State Thermal-Lens Spectrometry
by Vladislav R. Khabibullin, Liliya O. Usoltseva, Polina A. Galkina, Viktoriya R. Galimova, Dmitry S. Volkov, Ivan V. Mikheev and Mikhail A. Proskurnin
Physchem 2023, 3(1), 156-197; https://doi.org/10.3390/physchem3010012 - 9 Mar 2023
Cited by 5 | Viewed by 2748
Abstract
A simultaneous steady-state and transient photothermal-lens modality was used for both the thermal and optical parameters of aqueous dispersed systems (carbon and silica nanoparticles, metal iodides, surfactants, heme proteins, albumin, and their complexes). Heat-transfer parameters (thermal diffusivity and thermal effusivity), the temperature gradient [...] Read more.
A simultaneous steady-state and transient photothermal-lens modality was used for both the thermal and optical parameters of aqueous dispersed systems (carbon and silica nanoparticles, metal iodides, surfactants, heme proteins, albumin, and their complexes). Heat-transfer parameters (thermal diffusivity and thermal effusivity), the temperature gradient of the refractive index, light absorption, and concentration parameters were assessed. To simultaneously measure thermal and optical parameters, the time scale of thermal lensing (characteristic time, tc) should correspond to an excitation beam size of 60–300 µm, and the relative time intervals 0.5÷5tc and (5÷20)tc should be selected for transient and steady-state measurements, respectively. Dual-beam thermal-lens spectrometers in a mode-mismatched optical schematic at various excitation wavelengths were built. The spectrometers implement back-synchronized detection, providing different measurement conditions for the heating and cooling parts of the thermal-lens cycle. By varying the measurement parameters depending on the dispersed system, the conditions providing the suitable precision (replicability, repeatability, and reproducibility) of thermal-lens measurements were found; setups with a broad excitation beam (waist size, 150 and 300 μm) provide longer times to attain a thermal equilibrium and, thus, the better precision of measurements of thermal diffusivity. Full article
(This article belongs to the Section Application of Lasers to Physical Chemistry)
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9 pages, 761 KiB  
Communication
Biocide Coating from Polydiallyldimethylammonium Chloride—What Molecular Weight Should We Choose?
by Vladislava A. Pigareva, Valeria I. Marina and Andrey V. Sybachin
Physchem 2023, 3(1), 147-155; https://doi.org/10.3390/physchem3010011 - 2 Mar 2023
Cited by 1 | Viewed by 1635
Abstract
Biocidal compositions based on interpolyelectrolyte complexes and a low molecular weight antibiotic can become a promising material for creating biocidal coatings, as they combine wash-off resistance and dual biocidal action due to the biocide and the polycation. Molecular mass characteristics of polymers play [...] Read more.
Biocidal compositions based on interpolyelectrolyte complexes and a low molecular weight antibiotic can become a promising material for creating biocidal coatings, as they combine wash-off resistance and dual biocidal action due to the biocide and the polycation. Molecular mass characteristics of polymers play an essential role in the physics and mechanical properties of the coatings. In this work, the properties of polydiallyldimethylammonium chloride (PDADMAC) coatings of various molecular weights are investigated and assumptions are made about the optimal molecular weight needed to create antibacterial compositions. To study the resistance to washing off and moisture saturation of the coatings, the gravimetric method was used, and the adhesive properties of the coatings were studied by dynamometry. It has been established that an increase in molecular weight affects the wash-off resistance of coatings, but does not affect moisture absorption and adhesion mechanics of coatings. All samples of PDADMAC were demonstrated to exhibit the same antibacterial activity. Thus, when developing systems for creating antibacterial coatings, it must be taken into account that in order to create stable coatings, the requirement to use PDADMAC with a high degree of polymerization is necessary for the coating desorption control during wash off-but not mandatory for the control of mechanical and antibacterial properties of the coating. Full article
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22 pages, 7582 KiB  
Article
An Investigation of Antimicrobial Activity for Plant Pathogens by Green-Synthesized Silver Nanoparticles Using Azadirachta indica and Mangifera indica
by Archana Rana, Anjali Kumari, Amit Kumar Chaudhary, Ritu Srivastava, Deeba Kamil, Parth Vashishtha and Shailesh Narain Sharma
Physchem 2023, 3(1), 125-146; https://doi.org/10.3390/physchem3010010 - 15 Feb 2023
Cited by 8 | Viewed by 3616
Abstract
Photo-microbes are well known to demolish rice and fruits, as farmers use chemical pesticides to overcome agricultural problems and economic damage. The use of pesticides in agriculture fails to protect crops in lower concentrations and increases the intake of chemicals that cause many [...] Read more.
Photo-microbes are well known to demolish rice and fruits, as farmers use chemical pesticides to overcome agricultural problems and economic damage. The use of pesticides in agriculture fails to protect crops in lower concentrations and increases the intake of chemicals that cause many human ailments. The sophisticated nanotechnology approach used in agriculture for antimicrobial activities offers several advantages for growth and improves nutrient absorption in plants. We report the green synthesis of silver nanoparticles (AgNPs) using Azadirachta indica (A. indica) and Mangifera indica (M. indica) tree leaf extract that contains antioxidants to treat numerous diseases. AgNPs tested against three plant pathogens, fungi Alternaria alternata (A. alternata), Sclerotium rolfsii (A. rolfsii), and bacteria Xanthomonas oryzae (X. oryzae), which leads to agricultural problems. The experiment was performed with different concentrations of AgNPs in μL/mL prepared using two other plants extract against fungi and bacteria during summer. The results expose the importance of plant extract in synthesizing silver nanoparticles (AgNPs) and their efficacy for microbes. A comparison among different concentrations of AgNPs (4 μL/mL, 6 μL/mL, and 10 μL/mL) was performed for two fungi (tomato disease) and bacteria (rice leaf blight disease). A-AgNPs (A. indica-AgNPs) demonstrate a greater zone of inhibition than M-AgNPs (M. indica-AgNPs), further highlighting the dependence of plants. Under in vitro conditions, the results of the antifungal activity showed zones of inhibition of 21 mm against A. alternata and 17 mm against A. rolfsii, while antibacterial activity against X. oryzae bacteria showed a 15 mm zone of inhibition at 10 mg/mL for A-AgNPs, and less for M-AgNPs. For AgNPs, the antifungal activity was characterized bya more significant area of inhibition than antibacterial activity was. The current study indicates that AgNPs with lower concentrations exhibitsuperior toxicity to microbes and may be able to manage diseases in rice and tomato, and increase plant growth. Full article
(This article belongs to the Section Biophysical Chemistry)
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15 pages, 2118 KiB  
Article
Near-Infrared Transitions from the Singlet Excited States to the Ground Triplet State of the S2 Molecule
by Lidan Xiao, Bing Yan and Boris F. Minaev
Physchem 2023, 3(1), 110-124; https://doi.org/10.3390/physchem3010009 - 10 Feb 2023
Cited by 3 | Viewed by 1694
Abstract
Intensity of transitions from the b1g+  and a1Δg states to the ground state X3g  in the near IR emission spectrum of the S2 molecule has been calculated by the [...] Read more.
Intensity of transitions from the b1g+  and a1Δg states to the ground state X3g  in the near IR emission spectrum of the S2 molecule has been calculated by the multireference configuration interaction method taking into account spin-orbit coupling (SOC). The intensity of the b1g+ X3g,Ms=±1 transition is largely determined by the spin interaction with the electromagnetic wave, which comes from the zero-field splitting of the ground X multiplet and the SOC-induced mixing between b and X3g,0 states. The Einstein coefficients for the experimentally detected 0−0, 0−1, 1−1 bands of the b1g+X3g,Ms=±1 emission system are calculated in good agreement with observations. The Einstein coefficient of the a1gX3g,Ms=±1 magnetic dipole transition is very low, being equal to 0.0014 s−1. Nonetheless, the weakest of all experimentally observed bands (the 0−0 band of the a-XMs=±1 transition) qualitatively corresponds to this calculation. Most importantly, we provide many other IR bands for magnetic dipole b1g+ X3g,Ms=±1 and a1gX3g,Ms=±1 transitions, which could be experimentally observable in the S2 transparency windows from a theoretical point of view. We hope that these results will contribute to the further experimental exploration of the magnetic infrared bands in the S2 dimer. Full article
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18 pages, 5034 KiB  
Article
Optical and Sensing Properties of Carbon Colloidal Particles Based on (Thio)urea and Citric Acid: Effect of the Components Ratio
by Evgeny Karpushkin, Ekaterina Kharochkina, Ekaterina Mesnyankina, Olga Zaborova and Vladimir Sergeyev
Physchem 2023, 3(1), 92-109; https://doi.org/10.3390/physchem3010008 - 26 Jan 2023
Cited by 2 | Viewed by 1695
Abstract
Changing the composition of a precursors mixture is a powerful tool to tune the structure and properties of carbonaceous nanoparticles synthesized via the solvothermal route. We have addressed the influence of the ratio of urea or thiourea to citric acid during their solvothermal [...] Read more.
Changing the composition of a precursors mixture is a powerful tool to tune the structure and properties of carbonaceous nanoparticles synthesized via the solvothermal route. We have addressed the influence of the ratio of urea or thiourea to citric acid during their solvothermal treatment in dimethylformamide on the optical and sensing properties of the obtained colloidal product. It has been found that the urea-derived products are more diverse in comparison with the thiourea-based ones. The excitation-dependent fluorescence of the products and their sensitivity to mercury(II) ions have been investigated; one to three types of fluorophores have been observed in the products depending on the composition. The nanoparticles prepared in excess of urea have been found more sensitive to the heavy metal, with the sensitivity of the long-wave emission band being superior. Full article
(This article belongs to the Section Nanoscience)
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14 pages, 3548 KiB  
Article
Non-Conventional Hybrid Microporous Layers for Enhanced Performance and Durability of PEM Fuel Cells
by Saverio Latorrata, Marco Mariani, Andrea Basso Peressut, Riccardo Balzarotti and Giovanni Dotelli
Physchem 2023, 3(1), 78-91; https://doi.org/10.3390/physchem3010007 - 22 Jan 2023
Viewed by 1871
Abstract
In this work, novel microporous layers (MPLs) were developed based on fluorinated ethylene propylene (FEP), as a hydrophobic agent, and carboxymethylcellulose (CMC), as a wettability modulator and rheology controller for the inks, which were deposited onto pre-hydrophobized macroporous gas diffusion layers (GDLs). Higher [...] Read more.
In this work, novel microporous layers (MPLs) were developed based on fluorinated ethylene propylene (FEP), as a hydrophobic agent, and carboxymethylcellulose (CMC), as a wettability modulator and rheology controller for the inks, which were deposited onto pre-hydrophobized macroporous gas diffusion layers (GDLs). Higher CMC amounts led to higher dynamic viscosities of the inks, which induced the formation of a more compact and less cracked MPL surface. Different concentrations of CMC were tested and the experimental measurements showed a threshold limit pointing out an optimal composition that positively affected the electrochemical performances at medium-low relative humidity (RH), which is important to mitigate the need of saturating inlet gases. Durability of the best performing samples was assessed by means of an ad hoc developed accelerated stress test (AST) and compared to one of the conventional FEP-based GDMs. It was found that a lower decrement of both the output power density and the overall cell efficiency can be obtained upon the ASTs with the novel samples. Full article
(This article belongs to the Section Electrochemistry)
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1 pages, 133 KiB  
Editorial
Acknowledgment to the Reviewers of Physchem in 2022
by Physchem Editorial Office
Physchem 2023, 3(1), 77; https://doi.org/10.3390/physchem3010006 - 17 Jan 2023
Viewed by 1111
Abstract
High-quality academic publishing is built on rigorous peer review [...] Full article
16 pages, 3647 KiB  
Article
Quaternization of Porous Cellulose Beads and Their Use for Removal of Humic Acid from Aqueous Medium
by Kana Uchiyama, Hiromichi Asamoto, Hiroaki Minamisawa and Kazunori Yamada
Physchem 2023, 3(1), 61-76; https://doi.org/10.3390/physchem3010005 - 10 Jan 2023
Cited by 4 | Viewed by 1816
Abstract
Porous cellulose beads were quaternized with glycidyltrimethylammonium chloride (GTMAC) to explore a potential use of them as an adsorbent for removal of humic acid (HA) from aqueous medium. The introduction of quaternary ammonium groups was confirmed by FT-IR and XPS analysis. The content [...] Read more.
Porous cellulose beads were quaternized with glycidyltrimethylammonium chloride (GTMAC) to explore a potential use of them as an adsorbent for removal of humic acid (HA) from aqueous medium. The introduction of quaternary ammonium groups was confirmed by FT-IR and XPS analysis. The content of introduced quaternary ammonium groups increased with an increase in the GTMAC concentration. The adsorption capacity increased with a decrease in the initial pH value and attained the maximum value at pH 3 and increased with an increase in the content of quaternary ammonium groups. The removal % increased with the dose of quaternized cellulose beads at both pH 3.0 and 6.0. The adsorption process obeyed the pseudo-second order kinetic model and exhibited a better fit to the Langmuir isotherm model, suggesting that the adsorption of HA is accomplished through the electrostatic interaction between a quaternary ammonium group introduced and a dissociated carboxy group of a HA molecule. The maximum adsorption capacity obtained in this study is comparable to or higher than those published by other articles. HA loaded was completely released to NaOH solutions at higher than 100 mM to regenerate the quaternized cellulose beads. The above-mentioned results clearly show that the quaternized cellulose beads prepared in this study can be used as a regenerable adsorbent with high capacity for removal of HA from aqueous medium. Full article
(This article belongs to the Section Surface Science)
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27 pages, 9442 KiB  
Article
A “Zero-Cost” Adsorbing Hydroxyapatite-Based Material from Amazon Fishery Waste for Water Remediation and Nutrient Release for Agriculture
by Carmen Greice Renda, Thamara Machado de Oliveira Ruellas, João Otávio Donizette Malafatti, Carla Suellem Sousa Araújo, Gabriela Leite da Silva, Bruno Apolo Miranda Figueira, Simone Quaranta and Elaine Cristina Paris
Physchem 2023, 3(1), 34-60; https://doi.org/10.3390/physchem3010004 - 1 Jan 2023
Cited by 3 | Viewed by 2386
Abstract
This paper puts forward the use of “low-cost/low-end” hydroxyapatite-based adsorbing materials prepared from Tambaqui fish cleaning residues (i.e., bones) by grinding and/or thermal annealing. The nature of raw materials and treatments practically resulted in a “zero-cost” adsorbent for atrazine pesticide and Co2+ [...] Read more.
This paper puts forward the use of “low-cost/low-end” hydroxyapatite-based adsorbing materials prepared from Tambaqui fish cleaning residues (i.e., bones) by grinding and/or thermal annealing. The nature of raw materials and treatments practically resulted in a “zero-cost” adsorbent for atrazine pesticide and Co2+ ion remediation in an aqueous solution. Despite the distinctive character of the two contaminants, all adsorptions were found to follow pseudo-second order kinetics and Freundlich isotherm models. Pristine hydroxyapatite proved to be more effective in adsorbing atrazine at low concentrations due to interactions with collagen residues. Conversely, heat-treated materials demonstrated better adsorption performances for cobalt due to the removal of organic residues hindering access to the surface. On the other hand, lower adsorption affinities resulted into a faster and more efficient Co2+ release into water. The different behavior in terms of phosphate and cobalt release shown by the three hydroxyapatite-based absorbents can be exploited for differential liberation of targeted nutrients, with high seed germination rates. Considering circular economic principles, waste-derived hydroxyapatites may be potentially attractive for removing ionic species, minimizing water pollution stemming from heavy industry, and for their subsequent targeted release to edible plants, enhancing agricultural availability of mineral nutrients for soil fertilization. Full article
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12 pages, 3811 KiB  
Article
The Effect of Infrared Laser Irradiation on the Surface Morphology and Electrical Properties of Zinc Metal
by Muhammad Asif, Anwar Latif, Ahsan Ali, Muhammad Shahid Rafique, Shakeel Ahmad Khan, Abdul Haseeb and Muhammad Kashif Shahid
Physchem 2023, 3(1), 22-33; https://doi.org/10.3390/physchem3010003 - 31 Dec 2022
Cited by 2 | Viewed by 2450
Abstract
This study details the irradiation of pure (99.995%) and immaculate metallic Zinc using Nd: YAG laser (1064 nm, 10 mJ, 9–14 ns). The influence and impact of multiple laser shots on the formation of microstructures and crystal structure orientations is assessed. Arrays of [...] Read more.
This study details the irradiation of pure (99.995%) and immaculate metallic Zinc using Nd: YAG laser (1064 nm, 10 mJ, 9–14 ns). The influence and impact of multiple laser shots on the formation of microstructures and crystal structure orientations is assessed. Arrays of ablated craters are machined on the whole surface of the target to probe the electrical and topographical characteristics of laser-treated surfaces. Irradiated samples are examined by multiple characterizing techniques such as scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and a four-point probe for electrical conductivity measurements. SEM and AFM analysis exhibited the formation of laser-induced ripple structures with periodicity sheerly dependent on laser shots. A comparison of surface topography of the virgin and treated samples disclosed a pronounced modification in surface texture. The XRD patterns of laser shined targets indicate no momentous structural change in the crystal structure, whereas the measurements on the electrical conductivity of the irradiated surfaces exhibit an exponential descending trend with an augmentation in laser shots. Full article
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9 pages, 1917 KiB  
Article
Fabrication and Characterization of Pre-Defined Few-Layer Graphene
by Tingting Wang, Liangguang Jia, Quanzhen Zhang, Ziqiang Xu, Zeping Huang, Peiwen Yuan, Baofei Hou, Xuan Song, Kaiqi Nie, Chen Liu, Jiaou Wang, Huixia Yang, Liwei Liu, Teng Zhang and Yeliang Wang
Physchem 2023, 3(1), 13-21; https://doi.org/10.3390/physchem3010002 - 21 Dec 2022
Cited by 2 | Viewed by 1668
Abstract
Graphene is one of the most well-known two-dimensional (2D) materials that has attracted significant interest due to its unique electrical and optical properties. Being a van der Waals substrate, the fabrication of few-layered graphene by stacking a pre-defined number of graphene monolayers is [...] Read more.
Graphene is one of the most well-known two-dimensional (2D) materials that has attracted significant interest due to its unique electrical and optical properties. Being a van der Waals substrate, the fabrication of few-layered graphene by stacking a pre-defined number of graphene monolayers is essential in the field. The thickness can influence the interface interaction and therefore tune the surface electronic properties. In the study, we demonstrate a bottom-up synthesis of pre-defined few-layer graphene on SiC substrate using the thermal decomposition method and carefully characterize its thickness by the non-damageable synchrotron-radiation-based X-ray photo-electron spectroscopy (SR-XPS). By varying the photon energy, we acquire different probe depths, resulting in the different intensity ratios of graphene to SiC substrate, which is then used to estimate the thickness of the few-layer graphene. Our calculation demonstrates that the thermal decomposition method in the study can repeatedly fabricate graphene samples with expected thickness. We further compare the obtained few-layer graphene to the single-layer graphene and HOPG using the scanning tunneling microscopy (STM) technique. Our work provides accurate methods for fabricating and characterizing pre-defined few-layer graphene, providing essential knowledge in future graphene-based thin film electronics. Full article
(This article belongs to the Section Surface Science)
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12 pages, 476 KiB  
Article
Role of the Number of Adsorption Sites and Adsorption Dynamics of Diffusing Particles in a Confined Liquid with Langmuir Kinetics
by Renato F. de Souza, Roberta R. Ribeiro de Almeida, Eric K. Omori, Rodolfo T. de Souza, Ervin K. Lenzi, Luiz R. Evangelista and Rafael S. Zola
Physchem 2023, 3(1), 1-12; https://doi.org/10.3390/physchem3010001 - 20 Dec 2022
Viewed by 1485
Abstract
In this work, we investigate the effect of the number of available adsorption sites for diffusing particles in a liquid confined between walls where the adsorption (desorption) phenomena occur. We formulate and numerically solve a model for particles governed by Fickian’s law of [...] Read more.
In this work, we investigate the effect of the number of available adsorption sites for diffusing particles in a liquid confined between walls where the adsorption (desorption) phenomena occur. We formulate and numerically solve a model for particles governed by Fickian’s law of diffusion, where the dynamics at the surfaces obey the Langmuir kinetic equation. The ratio between the available number of adsorption sites and the number of total particles are used as a control parameter. The investigation is carried out in terms of characteristic times of the system for different initial configurations, as well as the cases of identical or non-identical surfaces. We calculate the bulk and surface densities dynamics, as well as the variance of the system, and demonstrate that the number of sites affects the bulk, surface distributions, and diffusive regimes. Full article
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