Andrei Kanaev - Academia.edu (original) (raw)

2013 by Andrei Kanaev

Chemical Physics Letters, Feb 12, 2013

Kinetics of the amorphous–anatase phase transition in single immobilized 5-nm TiO2 nanoparticles ... more Kinetics of the amorphous–anatase phase transition in single immobilized 5-nm TiO2 nanoparticles has
been studied at temperatures between 400 and 1000 C at the DORIS-III synchrotron source of Hasylab.
The measurements indicate the anatase phase appearance at temperatures above 500 C. No formation of
rutile phase was observed. The transformation kinetics for each fixed temperature is rapid and completes
within 5 min. The crystalline mass progressively increases with temperature and the full transformation
into anatase polymorph is achieved above 800 C. The results suggest higher surface energy of the anatase
phase compared to amorphous one, which delays the crystallization process.

Papers by Andrei Kanaev

Journal of Chemical Physics, Nov 4, 2002

Cellulose

Due to its unique supramolecular structure, cellulose is widely used as a template agent, ensurin... more Due to its unique supramolecular structure, cellulose is widely used as a template agent, ensuring an easy structuring of anatase TiO2 particles with subsequent release after the organics burning. This work is devoted to the synthesis of microcrystalline cellulose-TiO2 (MCC-TiO2) composite photocatalyst by preserving the intermediate organic-inorganic structures. A series of the MCC-TiO2 materials were prepared via solvothermal sol-gel method in n-decane and caproic acid solvents and characterized by X-ray diffraction, transmission electron microscopy, IR spectroscopy, 1 Н NMR and TG/DSC methods. The photocatalytic activity of the prepared materials was evaluated by the decomposition of formic acid in aqueous solutions. The composites failed to be formed in n-decane, while in caproic acid, acting as solvent and reagent, anatase TiO2 nanoparticles were formed onto the crystalline domains of cellulose, tightly fixed due to covalent Ti-O-C bonds. The materials formed in caproic acid showed a higher photocatalytic activity, explained by a complementarity of the organic and inorganic components. The specific activity (normalized on TiO2 mass) of best synthetized composite materials was almost twice higher than that of Aeroxide P25 TiO 2 reference photocatalyst.

Journal of Materials Science

Catalysts

Over the past few decades, enzyme-based green and sustainable chemistry has attracted extensive r... more Over the past few decades, enzyme-based green and sustainable chemistry has attracted extensive research attention, which provides a promising alternative to the conventional treatment methods of recalcitrant micropollutants. However, enzyme denaturation and stability loss remain critical challenges for its potential applications in industrial wastewater treatment. In this study, laccase from Trametes versicolor (laccase T.) was cross-linked immobilized by ultraporous alumina (UPA) for the sustainable biodegradation of Remazol Brilliant Blue R (RBBR). Through sequential use of an aminosilane coupling agent (3-aminopropyl)triethoxysilane (APTES) and bifunctional cross-linker glutaraldehyde (GA), the synthesized biocatalysts showed better immobilization performances (about 4-fold to physical adsorption). The GA concentration considerably affected the laccase T. cross-linking degree, while the GA post-treatment protocol showed the highest laccase T. immobilization yield with lower acti...

Applied Surface Science, 2021

Reaction control by laser light is a unique method of the reaction dynamics mastery in the molecu... more Reaction control by laser light is a unique method of the reaction dynamics mastery in the molecular chemistry. We provide evidence of phase control processing with femtosecond lasers in macroscopic solids. Rutile TiO2 monocrystals with (001) and (100) surface orientations were irradiated with repetitive pulses of femtosecond KrF laser of variable fluences and a temporal delay between two superimposed linearly polarized beams. The appearance of three types of surface morphology was thoroughly analyzed: low-spatial frequency laser-induced periodic surface structures (LSFL), grooves and unusual featureless flat area (FFA). The interaction of light with the excited surface led to the onset or suppression of the subwavelength LSFL, depending on whether the temporal delay between laser beams is larger or smaller than the critical value of ~6 ps. By contrast, the suprawavelength grooves and FFA appeared at longer temporal delays. A strong decrease of the grooves onset energy was observed on the (001) oriented crystal after the delay of ~8 ps; the decrease of onset energy was also observed on the (100) oriented crystal, where FFA appeared instead of grooves. The critical delay is discussed in framework of a phenomenological model describing the energy evolution of excited transient states along the "reaction" coordinate.

The effect of UV light intensity on the kinetics of free radical polymerization 2-hydoxyethyl met... more The effect of UV light intensity on the kinetics of free radical polymerization 2-hydoxyethyl methacrylate (HEMA) triggered with phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO) photoinitiator was investigated experimentally and theoretically. The temporal evolution of the conversion yield and polymerization rate was followed by Raman spectroscopy. The experimental data were treated with a kinetic model, which takes into account significant diffusion controlled processes and termination pathways including bimolecular reaction and primary radical termination. This model showed a very good agreement with the experiment in a large range of the UV light intensities and shed light on the termination process. In particular, it was show that the primary radical termination is dominant for relatively low light intensities below 1 mW/cm², when the photoinitiator is weakly consumed during the polymerization process.

Journal of the Optical Society of America B, 2018

Laser-based surface patterning of rutile TiO 2 monocrystals with (001) and (100) surface orientat... more Laser-based surface patterning of rutile TiO 2 monocrystals with (001) and (100) surface orientation is investigated following irradiation by a femtosecond KrF laser (248 nm) with variable fluences and multiple linearly polarized beams. Different types of structures were observed: volcano-like craters, nanoparticle-covered structures, ripples, and grooves. Furthermore, two kinds of distinct laser-induced periodic structures, 1D and 2D patterns, were observed. Morphological maps of characteristic surface morphologies were produced for each crystalline orientation, which indicate the significant influence of the crystalline anisotropy.

Microporous and Mesoporous Materials, 2019

A straightforward and facile procedure for the fabrication of superhydrophobic luminescent 3D nan... more A straightforward and facile procedure for the fabrication of superhydrophobic luminescent 3D nanomaterials was developed. Chemical modification of ultra-lightweight highly porous nanostructured aluminum oxyhydroxide (NOA) monoliths in 8-hydroxyquinoline vapors resulted in the formation of tris(8-hydroxyquinoline)aluminum on the surface of NOA nanofibrils. The original shape and size of the initial NOA monolith and its internal 3D nanostructure were completely preserved during the modification. Surface modified NOA samples demonstrated intense green luminescence as well as superhydrophobicity, the water contact angle being ~153°.

Materials Science and Engineering: C, 2019

This is a report on the antibacterial activity of ZnO and CuO nanoparticles synthesized via sol-g... more This is a report on the antibacterial activity of ZnO and CuO nanoparticles synthesized via sol-gel method. The studies were performed on Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli and Pseudomonas aeruginosa bacteria using disc and well diffusion methods, bioluminescence and optical density analysis. The results show a strong decline of bacterial strains after a short contact with nanoparticles. The modelling allowed clarifying the bacterial sensitivity of toxic agents at different stages of their population evolution kinetics. It was concluded that the bacterial suppression is most effective at the exponential growth phase while it is of a lower effectiveness at the lag and stationary phases. The CuO and ZnO nanoparticles showed comparable effectiveness at the exponential growth phase. In the same time, ZnO was almost inactive at the lag phase and of lower effectiveness at the stationary phase, at which CuO conserved a significant activity.

Ceramics International, 2019

Spark plasma sintering cycles were applied to a commercial magnesium aluminate spinel powder to e... more Spark plasma sintering cycles were applied to a commercial magnesium aluminate spinel powder to evaluate its suitability for producing small-grained optical ceramics. Translucent stoichiometric samples with a crystalline grain size as small as ~0.5 µm

Chemical Engineering Journal, 2018

Different sizes of gold nanoparticles were obtained by photocatalytic reduction. • Au/TiO 2 is su... more Different sizes of gold nanoparticles were obtained by photocatalytic reduction. • Au/TiO 2 is suitable catalyst for acetaldehyde removal in term of energy yield. • Plasma treatment doesn't influence the surface Au atoms density. • The reaction mechanism of acetaldehyde decomposition by Au/TiO 2 was proposed.

CrystEngComm, 2017

We describe the preparation of mixed metal oxide nanoparticles of a desirable composition and the... more We describe the preparation of mixed metal oxide nanoparticles of a desirable composition and their transformation to the crystalline solids ZrxTi1−xO2 (0.0 ≤ x ≤ 1.0) after heat treatment.

The Journal of Supercritical Fluids, 2016

Highlights  High yield (97.45 %) of ethyl esters are obtained by using ZnO/Al2O3 (5 wt %) under ... more Highlights  High yield (97.45 %) of ethyl esters are obtained by using ZnO/Al2O3 (5 wt %) under SCF conditions (T=623 K, P =30 MPa, molar ratio ethanol/oil-12:1).  A comparable yield (97.46 %) are obtained under the same conditions with the SrO/Al2O3 (2 wt %) catalyst.  SrO/Al2O3 was found to be the best candidate for biodiesel production.

Chemical Physics Letters, 2017

The nucleation-growth of titanium oxo-alkoxy (TOA) nanoparticles was studied in n-propanol and is... more The nucleation-growth of titanium oxo-alkoxy (TOA) nanoparticles was studied in n-propanol and isopropanol solvents. A common feature is quasi-instantaneous appearance of stable clusters with the hydrodynamic radius 1.6 nm, which form nanoparticles aggregated during the induction period. In contrast to clusters, the nanoparticle size and growth kinetics were affected by solvent: their size was 3.8 nm in n-propanol and 5.2 nm in isopropanol and the growth kinetics in isopropanol was significantly faster. The results suggest that the stability of the growing TOA units decreases with an increase of size, supporting the hierarchical model of the sol-gel growth.

Ceramics International, 2016

Nanocrystalline gamma alumina (γ-Al 2 O 3) powder with a crystallite size of $ 10 nm was synthesi... more Nanocrystalline gamma alumina (γ-Al 2 O 3) powder with a crystallite size of $ 10 nm was synthesized by oxidation of high purity aluminium plate in a humid atmosphere followed by annealing in air. Spark plasma sintering (SPS) at different sintering parameters (temperature, dwell time, heating rate, pressure) were studied for this highly porous γ-Al 2 O 3 in correlation with the evolution in microstructure and density of the ceramics. SPS sintering cycles using different heating rates were carried out at 1050-1550°C with dwell times of 3 min and 20 min under uniaxial pressure of 80 MPa. Alumina sintered at 1550°C for 20 min reached 99% of the theoretical density and average grain size of 8.5 mm. Significant grain growth was observed in ceramics sintered at temperatures above 1250°C.

Chemical Physics Letters, Feb 12, 2013

Kinetics of the amorphous–anatase phase transition in single immobilized 5-nm TiO2 nanoparticles ... more Kinetics of the amorphous–anatase phase transition in single immobilized 5-nm TiO2 nanoparticles has
been studied at temperatures between 400 and 1000 C at the DORIS-III synchrotron source of Hasylab.
The measurements indicate the anatase phase appearance at temperatures above 500 C. No formation of
rutile phase was observed. The transformation kinetics for each fixed temperature is rapid and completes
within 5 min. The crystalline mass progressively increases with temperature and the full transformation
into anatase polymorph is achieved above 800 C. The results suggest higher surface energy of the anatase
phase compared to amorphous one, which delays the crystallization process.

Journal of Chemical Physics, Nov 4, 2002

Cellulose

Due to its unique supramolecular structure, cellulose is widely used as a template agent, ensurin... more Due to its unique supramolecular structure, cellulose is widely used as a template agent, ensuring an easy structuring of anatase TiO2 particles with subsequent release after the organics burning. This work is devoted to the synthesis of microcrystalline cellulose-TiO2 (MCC-TiO2) composite photocatalyst by preserving the intermediate organic-inorganic structures. A series of the MCC-TiO2 materials were prepared via solvothermal sol-gel method in n-decane and caproic acid solvents and characterized by X-ray diffraction, transmission electron microscopy, IR spectroscopy, 1 Н NMR and TG/DSC methods. The photocatalytic activity of the prepared materials was evaluated by the decomposition of formic acid in aqueous solutions. The composites failed to be formed in n-decane, while in caproic acid, acting as solvent and reagent, anatase TiO2 nanoparticles were formed onto the crystalline domains of cellulose, tightly fixed due to covalent Ti-O-C bonds. The materials formed in caproic acid showed a higher photocatalytic activity, explained by a complementarity of the organic and inorganic components. The specific activity (normalized on TiO2 mass) of best synthetized composite materials was almost twice higher than that of Aeroxide P25 TiO 2 reference photocatalyst.

Journal of Materials Science

Catalysts

Over the past few decades, enzyme-based green and sustainable chemistry has attracted extensive r... more Over the past few decades, enzyme-based green and sustainable chemistry has attracted extensive research attention, which provides a promising alternative to the conventional treatment methods of recalcitrant micropollutants. However, enzyme denaturation and stability loss remain critical challenges for its potential applications in industrial wastewater treatment. In this study, laccase from Trametes versicolor (laccase T.) was cross-linked immobilized by ultraporous alumina (UPA) for the sustainable biodegradation of Remazol Brilliant Blue R (RBBR). Through sequential use of an aminosilane coupling agent (3-aminopropyl)triethoxysilane (APTES) and bifunctional cross-linker glutaraldehyde (GA), the synthesized biocatalysts showed better immobilization performances (about 4-fold to physical adsorption). The GA concentration considerably affected the laccase T. cross-linking degree, while the GA post-treatment protocol showed the highest laccase T. immobilization yield with lower acti...

Applied Surface Science, 2021

Reaction control by laser light is a unique method of the reaction dynamics mastery in the molecu... more Reaction control by laser light is a unique method of the reaction dynamics mastery in the molecular chemistry. We provide evidence of phase control processing with femtosecond lasers in macroscopic solids. Rutile TiO2 monocrystals with (001) and (100) surface orientations were irradiated with repetitive pulses of femtosecond KrF laser of variable fluences and a temporal delay between two superimposed linearly polarized beams. The appearance of three types of surface morphology was thoroughly analyzed: low-spatial frequency laser-induced periodic surface structures (LSFL), grooves and unusual featureless flat area (FFA). The interaction of light with the excited surface led to the onset or suppression of the subwavelength LSFL, depending on whether the temporal delay between laser beams is larger or smaller than the critical value of ~6 ps. By contrast, the suprawavelength grooves and FFA appeared at longer temporal delays. A strong decrease of the grooves onset energy was observed on the (001) oriented crystal after the delay of ~8 ps; the decrease of onset energy was also observed on the (100) oriented crystal, where FFA appeared instead of grooves. The critical delay is discussed in framework of a phenomenological model describing the energy evolution of excited transient states along the "reaction" coordinate.

The effect of UV light intensity on the kinetics of free radical polymerization 2-hydoxyethyl met... more The effect of UV light intensity on the kinetics of free radical polymerization 2-hydoxyethyl methacrylate (HEMA) triggered with phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO) photoinitiator was investigated experimentally and theoretically. The temporal evolution of the conversion yield and polymerization rate was followed by Raman spectroscopy. The experimental data were treated with a kinetic model, which takes into account significant diffusion controlled processes and termination pathways including bimolecular reaction and primary radical termination. This model showed a very good agreement with the experiment in a large range of the UV light intensities and shed light on the termination process. In particular, it was show that the primary radical termination is dominant for relatively low light intensities below 1 mW/cm², when the photoinitiator is weakly consumed during the polymerization process.

Journal of the Optical Society of America B, 2018

Laser-based surface patterning of rutile TiO 2 monocrystals with (001) and (100) surface orientat... more Laser-based surface patterning of rutile TiO 2 monocrystals with (001) and (100) surface orientation is investigated following irradiation by a femtosecond KrF laser (248 nm) with variable fluences and multiple linearly polarized beams. Different types of structures were observed: volcano-like craters, nanoparticle-covered structures, ripples, and grooves. Furthermore, two kinds of distinct laser-induced periodic structures, 1D and 2D patterns, were observed. Morphological maps of characteristic surface morphologies were produced for each crystalline orientation, which indicate the significant influence of the crystalline anisotropy.

Microporous and Mesoporous Materials, 2019

A straightforward and facile procedure for the fabrication of superhydrophobic luminescent 3D nan... more A straightforward and facile procedure for the fabrication of superhydrophobic luminescent 3D nanomaterials was developed. Chemical modification of ultra-lightweight highly porous nanostructured aluminum oxyhydroxide (NOA) monoliths in 8-hydroxyquinoline vapors resulted in the formation of tris(8-hydroxyquinoline)aluminum on the surface of NOA nanofibrils. The original shape and size of the initial NOA monolith and its internal 3D nanostructure were completely preserved during the modification. Surface modified NOA samples demonstrated intense green luminescence as well as superhydrophobicity, the water contact angle being ~153°.

Materials Science and Engineering: C, 2019

This is a report on the antibacterial activity of ZnO and CuO nanoparticles synthesized via sol-g... more This is a report on the antibacterial activity of ZnO and CuO nanoparticles synthesized via sol-gel method. The studies were performed on Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli and Pseudomonas aeruginosa bacteria using disc and well diffusion methods, bioluminescence and optical density analysis. The results show a strong decline of bacterial strains after a short contact with nanoparticles. The modelling allowed clarifying the bacterial sensitivity of toxic agents at different stages of their population evolution kinetics. It was concluded that the bacterial suppression is most effective at the exponential growth phase while it is of a lower effectiveness at the lag and stationary phases. The CuO and ZnO nanoparticles showed comparable effectiveness at the exponential growth phase. In the same time, ZnO was almost inactive at the lag phase and of lower effectiveness at the stationary phase, at which CuO conserved a significant activity.

Ceramics International, 2019

Spark plasma sintering cycles were applied to a commercial magnesium aluminate spinel powder to e... more Spark plasma sintering cycles were applied to a commercial magnesium aluminate spinel powder to evaluate its suitability for producing small-grained optical ceramics. Translucent stoichiometric samples with a crystalline grain size as small as ~0.5 µm

Chemical Engineering Journal, 2018

Different sizes of gold nanoparticles were obtained by photocatalytic reduction. • Au/TiO 2 is su... more Different sizes of gold nanoparticles were obtained by photocatalytic reduction. • Au/TiO 2 is suitable catalyst for acetaldehyde removal in term of energy yield. • Plasma treatment doesn't influence the surface Au atoms density. • The reaction mechanism of acetaldehyde decomposition by Au/TiO 2 was proposed.

CrystEngComm, 2017

We describe the preparation of mixed metal oxide nanoparticles of a desirable composition and the... more We describe the preparation of mixed metal oxide nanoparticles of a desirable composition and their transformation to the crystalline solids ZrxTi1−xO2 (0.0 ≤ x ≤ 1.0) after heat treatment.

The Journal of Supercritical Fluids, 2016

Highlights  High yield (97.45 %) of ethyl esters are obtained by using ZnO/Al2O3 (5 wt %) under ... more Highlights  High yield (97.45 %) of ethyl esters are obtained by using ZnO/Al2O3 (5 wt %) under SCF conditions (T=623 K, P =30 MPa, molar ratio ethanol/oil-12:1).  A comparable yield (97.46 %) are obtained under the same conditions with the SrO/Al2O3 (2 wt %) catalyst.  SrO/Al2O3 was found to be the best candidate for biodiesel production.

Chemical Physics Letters, 2017

The nucleation-growth of titanium oxo-alkoxy (TOA) nanoparticles was studied in n-propanol and is... more The nucleation-growth of titanium oxo-alkoxy (TOA) nanoparticles was studied in n-propanol and isopropanol solvents. A common feature is quasi-instantaneous appearance of stable clusters with the hydrodynamic radius 1.6 nm, which form nanoparticles aggregated during the induction period. In contrast to clusters, the nanoparticle size and growth kinetics were affected by solvent: their size was 3.8 nm in n-propanol and 5.2 nm in isopropanol and the growth kinetics in isopropanol was significantly faster. The results suggest that the stability of the growing TOA units decreases with an increase of size, supporting the hierarchical model of the sol-gel growth.

Ceramics International, 2016

Nanocrystalline gamma alumina (γ-Al 2 O 3) powder with a crystallite size of $ 10 nm was synthesi... more Nanocrystalline gamma alumina (γ-Al 2 O 3) powder with a crystallite size of $ 10 nm was synthesized by oxidation of high purity aluminium plate in a humid atmosphere followed by annealing in air. Spark plasma sintering (SPS) at different sintering parameters (temperature, dwell time, heating rate, pressure) were studied for this highly porous γ-Al 2 O 3 in correlation with the evolution in microstructure and density of the ceramics. SPS sintering cycles using different heating rates were carried out at 1050-1550°C with dwell times of 3 min and 20 min under uniaxial pressure of 80 MPa. Alumina sintered at 1550°C for 20 min reached 99% of the theoretical density and average grain size of 8.5 mm. Significant grain growth was observed in ceramics sintered at temperatures above 1250°C.

CLEAN – Soil, Air, Water, 2016

Effects of some characteristics of alumina as material adsorbent on arsenic removal from water ar... more Effects of some characteristics of alumina as material adsorbent on arsenic removal from water are presented. In particular, the effect of the alumina particle size has been firstly experimentally observed, then studied by means of a diffusive model. The effects of pH and other contaminants in the aqueous solution have been also measured. Finally, an improvement of the arsenic adsorption performances has been attempted by using a TiO2 coating of commercial alumina. The characterization of alumina in the different forms has been done by X‐ray diffraction, Brunauer–Emmett–Teller specific area measurement and scanning electron microscopy. The kinetics and equilibrium experiments of arsenic(V) removal by the adsorbent materials were studied in a batch mode. The alumina particulate size showed to play a key role in the adsorption process. In fact, among the tested adsorbent types, that material with the lowest particle size (i.e., 20 μm) showed the maximum arsenic(V) uptake capacity, whi...