Viorica Parvulescu

Prof. Viorica Parvulescu

Department Chemistry of Surface and Catalysis, “Ilie Murgulescu” Institute of Physical Chemistry, Romanian Academy, 060021 Bucharest, Romania

Research Focus & Metrics

Academic Career Length

18Years (2009-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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28 July 2023 in Nanomaterials
Verified
Journal Article
Open access
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Gabriela PetcuGabriela Petcu
Gabriela Petcu
Florica PapaFlorica Papa
Florica Papa
AIAtkinson Irina
Atkinson Irina
ABAdriana Baran
Adriana Baran
NANicoleta Apostol
Nicoleta Apostol
Viorica ParvulescuViorica Parvulescu
Viorica Parvulescu
Zeolite Y samples with microporous and hierarchical structures containing Ti–Ni and Ti–Co oxides were obtained as active photocatalysts. Different Ti amounts (5, 10% TiO2) were supported, followed by the loading of Ni or Co oxides (5%). X-ray diffraction evidenced the presence of TiO2 as an anatase. N2 adsorption–desorption results showed type IV isotherms for hierarchical zeolite Y samples, and a combination of type IV and I isotherms for zeolite Y samples. UV–Vis diffuse reflectance spectra showed a shift in the absorption band to visible with increasing Ti loading and especially after Co and Ni addition. A significant effect of the support was evidenced for Ti and its interaction with Co/Ni species. The zeolite Y support stabilized Ti in the 4+ oxidation state while hierarchical zeolite Y support favored the formation of Ti3+ species, Ni0 and Ni2+ and the oxidation of Co to 3+ oxidation state. Photocatalytic activity, under UV and visible light irradiation, was evaluated by the degradation of amoxicillin, used as a model test. The photocatalytic mechanism was investigated using ethanol, p-benzoquinone and KI as ·OH and ·O2− radicals and hole (h+) scavengers. The best results were obtained for the immobilized Ni-Ti species on the hierarchical zeolite Y support.

13 October 2022 in Journal of Alloys and Compounds
Verified
Journal Article
Closed access
DNDaniela Negoescu
Daniela Negoescu
IAIrina Atkinson
Irina Atkinson
MGMihaela Gherendi
Mihaela Gherendi
DCDaniela Culita
Daniela Culita
ABAdriana Baran
Adriana Baran
Viorica ParvulescuViorica Parvulescu
Viorica Parvulescu

Verified
Journal Article
Open access
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Gabriela PetcuGabriela Petcu
Gabriela Petcu
Elena Madalina CiobanuElena Madalina Ciobanu
Elena Madalina Ciobanu
GPGabriela Paun
Gabriela Paun
ENElena Neagu
Elena Neagu
ABAdriana Baran
Adriana Baran
Viorica ParvulescuViorica Parvulescu
Viorica Parvulescu
Ag nanoparticles (AgNPs) were biosynthesized using sage (Salvia officinalis L.) extract. The obtained nanoparticles were supported on SBA-15 mesoporous silica (S), before and after immobilization of 10% TiO2 (Degussa-P25, STp; commercial rutile, STr; and silica synthesized from Ti butoxide, STb). The formation of AgNPs was confirmed by X-ray diffraction. The plasmon resonance effect, evidenced by UV-Vis spectra, was preserved after immobilization only for the sample supported on STb. The immobilization and dispersion properties of AgNPs on supports were evidenced by TEM microscopy, energy-dispersive X-rays, dynamic light scattering, photoluminescence and FT-IR spectroscopy. The antioxidant activity of the supported samples significantly exceeded that of the sage extract or AgNPs. Antimicrobial tests were carried out, in conditions of darkness and white light, on Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Candida albicans. Higher antimicrobial activity was evident for SAg and STbAg samples. White light increased antibacterial activity in the case of Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa). In the first case, antibacterial activity increased for both supported and unsupported AgNPs, while in the second one, the activity increased only for SAg and STbAg samples. The proposed antibacterial mechanism shows the effect of AgNPs and Ag+ ions on bacteria in dark and light conditions.

7 April 2009 in Topics in Catalysis
Verified
Journal Article
Closed access
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FVFlorin Vasiliu
Florin Vasiliu
LDLucian DIAMANDESCU
Lucian DIAMANDESCU
DMD. Macovei
D. Macovei
Cristian-Mihail TeodorescuCristian-Mihail Teodorescu
Cristian-Mihail Teodorescu
DTD. Tarabasanu-Mihaila
D. Tarabasanu-Mihaila
Viorica ParvulescuViorica Parvulescu
Viorica Parvulescu

4 July 2022 in Membranes
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GPGabriela Paun
Gabriela Paun
ENElena Neagu
Elena Neagu
Viorica ParvulescuViorica Parvulescu
Viorica Parvulescu
Mihai AnastasescuMihai Anastasescu
Mihai Anastasescu
SPsimona petrescu
simona petrescu
GRGabriel Lucian Radu
Gabriel Lucian Radu
This study presents the preparation of hybrid nanofiltration membranes based on poly(1,4-phenylene ether ether sulfone), polyacrylonitrile, poly(vinyl pyrrolidone), and SBA-15 mesoporous silica. Laser treatment of polymeric solutions to enhance the hydrophilicity and performance of membranes was investigated. The membranes’ structure was characterized using scanning electron (SEM) and atomic force (AFM) microscopy and contact angle measurements. The addition of PAN in the casting solution produced significant changes in the membrane structure, from finger-like porous structures to sponge-like porous structures. Increased PAN concentration in the membrane composition enhanced the hydrophilicity of the membrane surface, which also accounted for the improvement in the antifouling capabilities. The permeation of apple pomace extract and the content of polyphenols and flavonoids were used to evaluate the efficacy of the hybrid membranes created. The results showed that the hybrid nanofiltration membranes based on PPEES/PAN/PVP/SBA-15: 15/5/1/1 and 17/3/1/1 exposed to laser for 5 min present a higher rejection coefficient to total polyphenols (78.6 ± 0.7% and 97.8 ± 0.9%, respectively) and flavonoids (28.7 ± 0.2% and 50.3 ± 0.4%, respectively) and are substantially better than a commercial membrane with MWCO 1000 Da or PPEES-PVP-based membrane.

28 September 2022 in Catalysts
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Journal Article
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Gabriela PetcuGabriela Petcu
Gabriela Petcu
EAElena Maria Anghel
Elena Maria Anghel
ÈBÈlena Buixaderas
Èlena Buixaderas
AIAtkinson Irina
Atkinson Irina
SSSimona Somacescu
Simona Somacescu
Viorica ParvulescuViorica Parvulescu
Viorica Parvulescu
New photocatalysts were obtained by immobilization of titanium and gold species on zeolite Y, hierarchical zeolite Y, MCM-48 and KIT-6 supports with microporous, hierarchical and mesoporous cubic structure. The obtained samples were characterized by X-ray diffraction (XRD), N2-physisorption, scanning and transmission electron microscopy (SEM/TEM), diffuse reflectance UV–Vis spectroscopy (DRUV-Vis), X-ray photoelectron spectroscopy (XPS), Raman and photoluminescence spectroscopy. The photocatalytic properties were evaluated in degradation of amoxicillin (AMX) from water, under UV (254 nm) and visible light (532 nm) irradiation. The higher degradation efficiency and best apparent rate constant were obtained under UV irradiation for Au-TiO2-KIT-6, while in the visible condition for the Au-TiO2-MCM-48 sample containing anatase, rutile and the greatest percent of Au metallic clusters were found (evidenced by XPS). Although significant values of amoxicillin degradation were obtained, total mineralization was not achieved. These results were explained by different reaction mechanisms, in which Au species act as e− trap in UV and e− generator in visible light.