Chemistry Journal of Moldova

Physical chemistry and chemical physics

Author(s):

Oleg Petuhov, Nina Timbaliuc, Irina Ceban (Ginsari), Silvia Cibotaru, Tudor Lupascu, Raisa Nastas


Field: Physical chemistry and chemical physics
Type: Research paper
Issue: 2024 Volume 19, no.1
Pages: 93-101
Keywords: activated carbon, adsorption, isotherm model, kinetic model, methylene blue.
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https://doi.org/10.19261/cjm.2024.897

Abstract (PDF)
Supplementary Material (PDF)
Graphycal Abstract: The purpose of this work was to compare the structural and sorption characteristics of local vegetal activated carbon obtained from apricot stones (AC-C, Republic of Moldova) with that of commercial activated carbons (Granucol® BI/GE/FA, Germany). According to the obtained results, the local vegetal activated carbon (AC-C) has proven to be comparatively effective with commercial ones (Granucol® type) in removing methylene blue dye from solutions.


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Author(s):

Zainab Jasim Khudair and Zeina Mohammad Kadam


Field: Physical chemistry and chemical physics
Type: Research paper
Issue: 2024 Volume 19, no.1
Pages: 84-92
Keywords: multi-walled carbon nanotubes, chitosan nanocomposite, adsorption, thermodynamic, ofloxacin drug.
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https://doi.org/10.19261/cjm.2024.1161

Abstract (PDF)
Supplementary Material (PDF)
Graphical Abstract:
A nanocomposite of chitosan and poly acrylic acid grafting multi-walled carbon nanotubesp (CS-co-AA)/MWCNTs was applied as adsorbent for Ofloxacin adsorption from water solutions. The isotherm constant (KF) of 0.218 and the separation factor (R2) of 0.956 indicate a strong and desirable adsorption of OFL on p(CS-co-AA)/MWCNTs with a concentration of 100 mg/L at a temperature of 293K and an acidic medium with pH of 7.0.




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Author(s):

Sri Wuryanti, Tina Mulya Gantina, Annisa Syafitri Kurniasetiawati


Field: Physical chemistry and chemical physics
Type: Research paper
Issue: 2024 Volume 19, no.1
Pages: 102-111
Keywords: TiO2 and ZnO fluorine-doped tin oxide, porphyrin, ZnO with Al doping.
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https://doi.org/10.19261/cjm.2024.1157

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Supplementary Material (PDF)
Graphical Abstract: This research systematically investigates the impact of porphyrin and chlorophyll dyes derived from Syzygium Paniculatum on Dye-Sensitized Solar Cells (DSSC) performance, aiming to achieve maximum solar cell efficiency. The investigation involves utilizing fluorine-doped tin oxide coating with a TiO2-ZnO composite. Results demonstrate that DSSCs based on TiO2-ZnO: Al + chlorophyll produce an efficiency of 13.32%, while porphyrin (2:2:0.1) and (2:2:0.2) produce efficiencies of 8.91% and 13.95%, respectively. These findings highlight the potential of utilizing natural dyes for enhancing DSSC performance.



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Author(s):

Ana Maria Toader, Maria Cristina Buta, Fanica Cimpoesu


Field: Physical chemistry and chemical physics
Type: Research paper
Issue: 2023 Volume 18, no.2
Pages: 78-86
Keywords: lanthanide ion, luminescence, spectral term, Slater-Condon parameter, ab initio calculation.
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https://doi.org/10.19261/cjm.2023.1146

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Supplementary Material (PDF)

Graphical Abstract: The ab initio account of f and d electrons in lanthanide ions is assessed taking the Pr(III) ion. This shows rich experimental data and analytical tractability of spectral terms. The calculations are reaching a moderate match to experiment, the analysis identifying the actual impediments and suggesting ways of possible improvement. 



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Author(s):

Tudor Spataru


Field: Physical chemistry and chemical physics
Type: Research paper
Issue: 2023 Volume 18, no.2
Pages: 96-104
Keywords: glutamate mutase, methylmalonyl-CoA mutase, adenosylcobalamin cofactor, vitamin B12, Pseudo-Jahn-Teller effect.
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https://doi.org/10.19261/cjm.2023.1087

Abstract (PDF)
Graphical Abstract: 
The Pseudo-Jahn-Teller-Effect governs the glutamate mutase and methylmalonate-CoA mutase preliminary step and provides insight into particular details of in vivo C-N bond cleavage reactions of the adenosylcobalamin cofactor. Multi-configurational self-consistent field (MCSCF) calculations show that the preliminary step reaction glutamate mutase and methylmalonate-CoA mutase processes occur in the absence of total energy barriers.





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Author(s):

Pedro Silva


Field: Physical chemistry and chemical physics
Type: Research paper
Issue: 2023 Volume 18, no.2
Pages: 87-95
Keywords: density-functional theory, reaction mechanisms, intra-molecular Williamson’s ether synthesis, epoxide, halohydrin.
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Abstract (PDF)
Graphical Abstract:
DFT computations identify the effects that enable the synthesis of geometrically-strained epoxide from deprotonated halohydrins. These computations also explain the preference for the formation of larger cyclic ethers with five-atom rings over six-atom-rings. Increased temperature favors elimination over SN2 only when the reacting moieties are part of separate molecules.




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Author(s):

Olga Chudinovych


Field: Physical chemistry and chemical physics
Type: Research paper
Issue: 2023 Volume 18, no.2
Pages: 69-77
Keywords: phase equilibria, lanthana, lutetia, erbia, lattice parameter.
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Abstract (PDF)
Graphical Abstract:
The isothermal section of the La2O3–Lu2O3–Er2O3 phase diagram at 1250°C has the characteristic three one-phase fields (A-La2O3, R, C-Lu2O3(Er2O3)) corresponding to solid solutions based on starting components and two two-phase fields (C + R, A + R) between them. 
 



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Author(s):

Isaac Bersuker


Field: Physical chemistry and chemical physics
Type: Invited paper
Issue: 2023 Volume 18, no.2
Pages: 7-14
Keywords: adiabatic potential, electronic degeneracy, Jahn-Teller effect, pseudo Jahn-Teller effect, spontaneous symmetry breaking.
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Abstract (PDF)
Graphical Abstract:
This paper discusses the notion of symmetry of polyatomic systems defined as invariance under transformations, and showes that this important property of atomic matter is extremely vulnerable, and may undergo internal breakdown, subject to the presence of electronic degeneracy or pseudodegeneracy. It is shown that electronic degeneracy and its extended form, called pseudodegeneracy, are actually the only source of spontaneous symmetry breaking (SSB) in nature, including all forms of matter, beginning with elementary particles, via nuclei, atoms, molecules, and solids. Theoretically, the vulnerability of the notion of symmetry is due to the fact that, following quantum mechanics, the separation of the motion of electrons and nuclei (and, similarly, the separation of motions of elementary particles) is approximate, and hence the classical notion of polyatomic space configuration is approximate too, with SSB as one of its main violation.


 


Downloads: 41

Author(s):

Luciano Nascimento, Adriano Lima da Silva, Ana Cristina Figueiredo de Melo Costa


Field: Physical chemistry and chemical physics
Type: Short communication
Issue: 2022 Volume 17, no.1
Pages: 120-124
Keywords: amorphous alloy Co69Nb25B6, high-energy ball milling, ferromagnetic phase.
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Abstract (PDF)
Graphical Abstract:
Amorphous alloy are materials have been around for some time and their applications can be found in many types of industrial products. Currently, the production of the amorphous alloy Co69Nb25B6 was obtained by high-energy ball milling which allows the formation of phases through solid state reaction through consolidation process. In addition, the effects of a 21:1 powder to ball mass ratio were used and the milling time during high energy milling was crucial for the formation of the amorphous and ferromagnetic phases. The characterization of the Co69Nb25B6 alloy was investigated by X-ray diffraction, scanning electron microscopy and by a vibrating sample magnetometer.


 


Downloads: 117

Author(s):

Anna Nazar, Tatyana Rakitskaya, Tatyana Kiose


Field: Physical chemistry and chemical physics
Type: Research paper
Issue: 2022 Volume 17, no.1
Pages: 47-55
Keywords: phlogopite, acid treatment, carbon monoxide, low temperature oxidation, Wacker-type catalyst.
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Abstract (PDF)
Graphical Abstract: The paper presents original results on the of nitric acid concentrations effect on structure, morphology, protolytic properties and the activity of low-temperature carbon monoxide oxidation catalysts based on acid-modified phlogopite (Н-Phl-1) and K2PdCl4, Cu(NO3)2, KBr base components. The obtained samples were characterized by XRD, SEM, FT-IR spectroscopy and pH metric method. The obtained catalyst Pd(II)-Cu(II)/8H-Phl-1 can be recommended for use in respiratory devices. 




Downloads: 164