Irina Petreanu - Academia.edu (original) (raw)

Papers by Irina Petreanu

A facile, solvent-deficient, one-pot synthesis of a thermally stable silica-doped alumina, having... more A facile, solvent-deficient, one-pot synthesis of a thermally stable silica-doped alumina, having high surface area, large pore volume and uniquely large pores, has been developed. Silica-doped alumina (SDA) was synthesized by adding 5 wt% silica from tetraethyl orthosilicate (TEOS) to aluminum isoproxide (AIP), a 1:5 mol ratio AIP to water, and a 1:2 mol ratio TEOS to water in the absence of a template. The structure of silica-doped alumina was studied by in situ high-temperature powder XRD, nitrogen adsorption, thermogravimetric analysis, solid-state NMR, and TEM. The addition of silica significantly increases the stability of c-Al 2 O 3 phase to 1200°C while maintaining a high surface area, a large pore volume and a large pore diameter. After calcination at 1100°C for 2 h, a surface area of 160 m 2 /g, pore volume of 0.99 cm 3 /g, and a bimodal pore size distribution of 23 and 52 nm are observed. Compared to a commercial silica-doped alumina, after calcination for 24 h at 1100°C, the surface area, pore volume, and pore diameter SDA are higher by 46, 155, and 94 %, respectively. Results reveal that Si stabilizes the porous structure of c-Al 2 O 3 up to 1200°C, while unstabilized alumina is stable to only 900°C. From our data, we infer that Si enters tetrahedral vacancies in the defect spinel structure of alumina without moving Al from tetrahedral positions and forms a silica-alumina interface.

Journal of Porous Materials, 2015

A facile, solvent-deficient, one-pot synthesis of a thermally stable silica-doped alumina, having... more A facile, solvent-deficient, one-pot synthesis of a thermally stable silica-doped alumina, having high surface area, large pore volume and uniquely large pores, has been developed. Silica-doped alumina (SDA) was synthesized by adding 5 wt% silica from tetraethyl orthosilicate (TEOS) to aluminum isoproxide (AIP), a 1:5 mol ratio AIP to water, and a 1:2 mol ratio TEOS to water in the absence of a template. The structure of silica-doped alumina was studied by in situ high-temperature powder XRD, nitrogen adsorption, thermogravimetric analysis, solid-state NMR, and TEM. The addition of silica significantly increases the stability of c-Al 2 O 3 phase to 1200°C while maintaining a high surface area, a large pore volume and a large pore diameter. After calcination at 1100°C for 2 h, a surface area of 160 m 2 /g, pore volume of 0.99 cm 3 /g, and a bimodal pore size distribution of 23 and 52 nm are observed. Compared to a commercial silica-doped alumina, after calcination for 24 h at 1100°C, the surface area, pore volume, and pore diameter SDA are higher by 46, 155, and 94 %, respectively. Results reveal that Si stabilizes the porous structure of c-Al 2 O 3 up to 1200°C, while unstabilized alumina is stable to only 900°C. From our data, we infer that Si enters tetrahedral vacancies in the defect spinel structure of alumina without moving Al from tetrahedral positions and forms a silica-alumina interface.

Book of Abstracts SIMI 2022

Progress of Cryogenics and Isotopes Separation, 2018

Progress of Cryogenics and Isotopes Separation, 2017

Progress of Cryogenics and Isotopes Separation, 2017

SMART ENERGY AND SUSTAINABLE ENVIRONMENT, 2021

The efficient use of renewable energy resources is one of the most important elements of energy s... more The efficient use of renewable energy resources is one of the most important elements of energy sustainability at the European Union level. The growing demand for energy will continue to support the use of other materials as resources of energy than conventional ones, coal, crude oil and natural gas. This paper investigates the feasibility of valorizing wastes with energetic potential in a multi-component alternative solid fuel. Biomass - vegetable waste (BW), meat and bone meal (MBM) and slag/bottom ash from lignite combustion, in combination with a low-rank, lignite, was used to prepare tri-component mixtures (MBM+Lignite +Slag and MBM+BW+Lignite) indifferent variable proportions, and further characterized to assess their potential for use as energy source. The thermal behavior of the mixtures was assessed by thermogravimetric analysis; the resulting ashes were characterized by scanning electron microscopy.Also, the environmental impact as emissions level after their combustion wa...

SMART ENERGY AND SUSTAINABLE ENVIRONMENT, 2020

Article info: Carbon nanofibers are very stiff, strong and light materials composed from tightly ... more Article info: Carbon nanofibers are very stiff, strong and light materials composed from tightly packed layers of graphite sheets stacked parallel one near the other in a regular pattern and aligned along the fiber axis. This study presents a facile approach to prepare composite Ni/C nanofibers through electrospinning of polymer solution. A mixed solution of polyacrylonitrile (PAN) in dimethylformamide (DMF) solvent along with Ni(CH 3 COO) 2 was the precursor solution used to obtain composite Ni/C nanofibers. The amount of Ni salt was varied in order to study the influence of Ni percent on the composite fibers properties, particularly the pores dimension and the specific surface area. The composition and the structure of materials were investigated through elemental analysis and scanning electron microscopy (SEM). In addition, thermal gravimetric analysis (TGA) was performed to complete the composition study and the thermal degradation profile.

Materials Research Bulletin, 2018

Corrigendum to "Synthesis and testing of a composite membrane based on sulfonated polyphenylene o... more Corrigendum to "Synthesis and testing of a composite membrane based on sulfonated polyphenylene oxide and silica compounds as proton exchange membrane for PEM fuel cells" Mater. Res. Bull., 96, (December (Part 3)), (2017), 136-142

Materials Research Bulletin, 2017

The present work is an attempt to improve the usseful properties of sulfonated polyphenylene oxid... more The present work is an attempt to improve the usseful properties of sulfonated polyphenylene oxide in order to obtain a proton exchange membrane (PEM) for proton exchange membrane fuel cells(PEMFC). Formation of siloxane compounds inside the polymer matrix through an in situ sol-gel process improves properties of the composite membrane: water retention, tensile strength and dimensional stability of the membrane. The presence of the silicone atoms inside the polymer matrix is highlited in the X-ray fluorescence spectra. Parameters related to water absorbtion and proton transport inside the membrane such as: water uptake, hydration number (l), dimensional expansion by hydration, ion exchange capacity and sulfonation degree show an optimization of the composite membrane compared to the polymeric one. Furthermore, the tensile strength of the composite membranes is better than the polymeric one when both samples are fully hydrated.

Reaction Kinetics, Mechanisms and Catalysis, 2017

Adsorbent materials based on apatites (non-substituted and substituted with Sr and Ba) were used ... more Adsorbent materials based on apatites (non-substituted and substituted with Sr and Ba) were used for the adsorption of phenol from aqueous solution at 10, 20 and 30°C and three pH values (3, 6 and 10.5). Structural studies show the formation of the apatite materials and the replacement of Ca by Sr and Ba. The adsorption isotherms of phenol were determined and modelled with two parameter equations (Langmuir, Freundlich and Temkin) or with three parameter equations (Sips and Dubinin-Radushkevich). Taking into account the Sips isotherm, the maximum amount of phenol uptake was 220 mg g-1 for Ba based adsorbent. Thermodynamic parameters were calculated and indicated that the adsorption of phenol onto prepared apatites was spontaneous and exothermic. The DRIFTS studies detected both phenol and phenolate species adsorbed on the surface. It was also shown that phenol molecules were adsorbed by hydrogen bonding between apatite metal ion or oxygen atom from P-O group and the hydrogen of the phenol Irina Fierascu, Sorin Marius Avramescu, and Radu Claudiu Fierascu have contributed equally to the manuscript.

Journal of Thermal Analysis and Calorimetry, 2012

An aromatic polymer, poly(2,6-dimethyl-1,4phenylene oxide) (PPO) was sulfonate with different sul... more An aromatic polymer, poly(2,6-dimethyl-1,4phenylene oxide) (PPO) was sulfonate with different sulfonation degrees (30, 50, and 75 % theoretical degree) to obtain an electrolytic polymer suitable as proton exchange membrane for fuel cells. Thermal behaviors of sulfonated PPO were tested by differential scanning calorimetry and thermogravimetry. The sulfonation degrees were correlated with glass transitions temperatures (T g) and the percent of weight loss. One notices a good fitting between sulfonation degree and the percent of weight loss thanks splitting of sulfonic moieties but it is not the same for glass transition temperatures that have a random variation.

Thermodynamics and Energy Engineering, 2020

This paper presents a classification and also an overview of fuel cells, including the working pr... more This paper presents a classification and also an overview of fuel cells, including the working principles, the equations of the governing reactions, and the main applications. A brief exposure of thermodynamics and electrochemical theory describe the functioning of the fuel cells. Further, the proton exchange membrane fuel cells assembly, starting with the schematic presentation of the main components, the role of each component in fuel cell, the specific materials and their requested properties, and the way of assembling the components into device will be detailed. In conclusion, the challenges related to reliability and the cost and the targets for future development of the proton exchange membrane fuel cells for mobile and stationary applications will be presented.

An aromatic polymer, poly(2,6-dimethyl-1,4- phenylene oxide) (PPO) was sulfonate with different s... more An aromatic polymer, poly(2,6-dimethyl-1,4- phenylene oxide) (PPO) was sulfonate with different sulfonation degrees (30, 50, and 75 % theoretical degree) to obtain an electrolytic polymer suitable as proton exchange membrane for fuel cells. Thermal behaviors of sulfonated PPO were tested by differential scanning calorimetry and thermogravimetry. The sulfonation degrees were correlated with glass transitions temperatures (Tg) and the percent of weight loss. One notices a good fitting between sulfonation degree and the percent of weight loss thanks splitting of sulfonic moieties but it is not the same for glass transition temperatures that have a random variation.

NATO Science for Peace and Security Series B: Physics and Biophysics, 2008

This paper deals with preparation of PEM, based on commercial block copolymer of the styrene-buta... more This paper deals with preparation of PEM, based on commercial block copolymer of the styrene-butadiene. The copolymer was structurally changed by sulfonation followed by cross linking, in order to design a Proton Exchange Membrane for Fuel Cells. The membranes were structural tested by FTIR Spectroscopy and Scanning Electron Microscopy. Ionic Exchange Capacity (IEC) and thermal behavior by Differential Scanning Calorimetry

Journal of Fuel Cell Science and Technology, 2014

An aromatic polymer, poly(2,6-dimethyl-1,4phenylene oxide) (PPO) was sulfonate with different sul... more An aromatic polymer, poly(2,6-dimethyl-1,4phenylene oxide) (PPO) was sulfonate with different sulfonation degrees (30, 50, and 75 % theoretical degree) to obtain an electrolytic polymer suitable as proton exchange membrane for fuel cells. Thermal behaviors of sulfonated PPO were tested by differential scanning calorimetry and thermogravimetry. The sulfonation degrees were correlated with glass transitions temperatures (T g ) and the percent of weight loss. One notices a good fitting between sulfonation degree and the percent of weight loss thanks splitting of sulfonic moieties but it is not the same for glass transition temperatures that have a random variation.

A facile, solvent-deficient, one-pot synthesis of a thermally stable silica-doped alumina, having... more A facile, solvent-deficient, one-pot synthesis of a thermally stable silica-doped alumina, having high surface area, large pore volume and uniquely large pores, has been developed. Silica-doped alumina (SDA) was synthesized by adding 5 wt% silica from tetraethyl orthosilicate (TEOS) to aluminum isoproxide (AIP), a 1:5 mol ratio AIP to water, and a 1:2 mol ratio TEOS to water in the absence of a template. The structure of silica-doped alumina was studied by in situ high-temperature powder XRD, nitrogen adsorption, thermogravimetric analysis, solid-state NMR, and TEM. The addition of silica significantly increases the stability of c-Al 2 O 3 phase to 1200°C while maintaining a high surface area, a large pore volume and a large pore diameter. After calcination at 1100°C for 2 h, a surface area of 160 m 2 /g, pore volume of 0.99 cm 3 /g, and a bimodal pore size distribution of 23 and 52 nm are observed. Compared to a commercial silica-doped alumina, after calcination for 24 h at 1100°C, the surface area, pore volume, and pore diameter SDA are higher by 46, 155, and 94 %, respectively. Results reveal that Si stabilizes the porous structure of c-Al 2 O 3 up to 1200°C, while unstabilized alumina is stable to only 900°C. From our data, we infer that Si enters tetrahedral vacancies in the defect spinel structure of alumina without moving Al from tetrahedral positions and forms a silica-alumina interface.

Journal of Porous Materials, 2015

A facile, solvent-deficient, one-pot synthesis of a thermally stable silica-doped alumina, having... more A facile, solvent-deficient, one-pot synthesis of a thermally stable silica-doped alumina, having high surface area, large pore volume and uniquely large pores, has been developed. Silica-doped alumina (SDA) was synthesized by adding 5 wt% silica from tetraethyl orthosilicate (TEOS) to aluminum isoproxide (AIP), a 1:5 mol ratio AIP to water, and a 1:2 mol ratio TEOS to water in the absence of a template. The structure of silica-doped alumina was studied by in situ high-temperature powder XRD, nitrogen adsorption, thermogravimetric analysis, solid-state NMR, and TEM. The addition of silica significantly increases the stability of c-Al 2 O 3 phase to 1200°C while maintaining a high surface area, a large pore volume and a large pore diameter. After calcination at 1100°C for 2 h, a surface area of 160 m 2 /g, pore volume of 0.99 cm 3 /g, and a bimodal pore size distribution of 23 and 52 nm are observed. Compared to a commercial silica-doped alumina, after calcination for 24 h at 1100°C, the surface area, pore volume, and pore diameter SDA are higher by 46, 155, and 94 %, respectively. Results reveal that Si stabilizes the porous structure of c-Al 2 O 3 up to 1200°C, while unstabilized alumina is stable to only 900°C. From our data, we infer that Si enters tetrahedral vacancies in the defect spinel structure of alumina without moving Al from tetrahedral positions and forms a silica-alumina interface.

Book of Abstracts SIMI 2022

Progress of Cryogenics and Isotopes Separation, 2018

Progress of Cryogenics and Isotopes Separation, 2017

Progress of Cryogenics and Isotopes Separation, 2017

SMART ENERGY AND SUSTAINABLE ENVIRONMENT, 2021

The efficient use of renewable energy resources is one of the most important elements of energy s... more The efficient use of renewable energy resources is one of the most important elements of energy sustainability at the European Union level. The growing demand for energy will continue to support the use of other materials as resources of energy than conventional ones, coal, crude oil and natural gas. This paper investigates the feasibility of valorizing wastes with energetic potential in a multi-component alternative solid fuel. Biomass - vegetable waste (BW), meat and bone meal (MBM) and slag/bottom ash from lignite combustion, in combination with a low-rank, lignite, was used to prepare tri-component mixtures (MBM+Lignite +Slag and MBM+BW+Lignite) indifferent variable proportions, and further characterized to assess their potential for use as energy source. The thermal behavior of the mixtures was assessed by thermogravimetric analysis; the resulting ashes were characterized by scanning electron microscopy.Also, the environmental impact as emissions level after their combustion wa...

SMART ENERGY AND SUSTAINABLE ENVIRONMENT, 2020

Article info: Carbon nanofibers are very stiff, strong and light materials composed from tightly ... more Article info: Carbon nanofibers are very stiff, strong and light materials composed from tightly packed layers of graphite sheets stacked parallel one near the other in a regular pattern and aligned along the fiber axis. This study presents a facile approach to prepare composite Ni/C nanofibers through electrospinning of polymer solution. A mixed solution of polyacrylonitrile (PAN) in dimethylformamide (DMF) solvent along with Ni(CH 3 COO) 2 was the precursor solution used to obtain composite Ni/C nanofibers. The amount of Ni salt was varied in order to study the influence of Ni percent on the composite fibers properties, particularly the pores dimension and the specific surface area. The composition and the structure of materials were investigated through elemental analysis and scanning electron microscopy (SEM). In addition, thermal gravimetric analysis (TGA) was performed to complete the composition study and the thermal degradation profile.

Materials Research Bulletin, 2018

Corrigendum to "Synthesis and testing of a composite membrane based on sulfonated polyphenylene o... more Corrigendum to "Synthesis and testing of a composite membrane based on sulfonated polyphenylene oxide and silica compounds as proton exchange membrane for PEM fuel cells" Mater. Res. Bull., 96, (December (Part 3)), (2017), 136-142

Materials Research Bulletin, 2017

The present work is an attempt to improve the usseful properties of sulfonated polyphenylene oxid... more The present work is an attempt to improve the usseful properties of sulfonated polyphenylene oxide in order to obtain a proton exchange membrane (PEM) for proton exchange membrane fuel cells(PEMFC). Formation of siloxane compounds inside the polymer matrix through an in situ sol-gel process improves properties of the composite membrane: water retention, tensile strength and dimensional stability of the membrane. The presence of the silicone atoms inside the polymer matrix is highlited in the X-ray fluorescence spectra. Parameters related to water absorbtion and proton transport inside the membrane such as: water uptake, hydration number (l), dimensional expansion by hydration, ion exchange capacity and sulfonation degree show an optimization of the composite membrane compared to the polymeric one. Furthermore, the tensile strength of the composite membranes is better than the polymeric one when both samples are fully hydrated.

Reaction Kinetics, Mechanisms and Catalysis, 2017

Adsorbent materials based on apatites (non-substituted and substituted with Sr and Ba) were used ... more Adsorbent materials based on apatites (non-substituted and substituted with Sr and Ba) were used for the adsorption of phenol from aqueous solution at 10, 20 and 30°C and three pH values (3, 6 and 10.5). Structural studies show the formation of the apatite materials and the replacement of Ca by Sr and Ba. The adsorption isotherms of phenol were determined and modelled with two parameter equations (Langmuir, Freundlich and Temkin) or with three parameter equations (Sips and Dubinin-Radushkevich). Taking into account the Sips isotherm, the maximum amount of phenol uptake was 220 mg g-1 for Ba based adsorbent. Thermodynamic parameters were calculated and indicated that the adsorption of phenol onto prepared apatites was spontaneous and exothermic. The DRIFTS studies detected both phenol and phenolate species adsorbed on the surface. It was also shown that phenol molecules were adsorbed by hydrogen bonding between apatite metal ion or oxygen atom from P-O group and the hydrogen of the phenol Irina Fierascu, Sorin Marius Avramescu, and Radu Claudiu Fierascu have contributed equally to the manuscript.

Journal of Thermal Analysis and Calorimetry, 2012

An aromatic polymer, poly(2,6-dimethyl-1,4phenylene oxide) (PPO) was sulfonate with different sul... more An aromatic polymer, poly(2,6-dimethyl-1,4phenylene oxide) (PPO) was sulfonate with different sulfonation degrees (30, 50, and 75 % theoretical degree) to obtain an electrolytic polymer suitable as proton exchange membrane for fuel cells. Thermal behaviors of sulfonated PPO were tested by differential scanning calorimetry and thermogravimetry. The sulfonation degrees were correlated with glass transitions temperatures (T g) and the percent of weight loss. One notices a good fitting between sulfonation degree and the percent of weight loss thanks splitting of sulfonic moieties but it is not the same for glass transition temperatures that have a random variation.

Thermodynamics and Energy Engineering, 2020

This paper presents a classification and also an overview of fuel cells, including the working pr... more This paper presents a classification and also an overview of fuel cells, including the working principles, the equations of the governing reactions, and the main applications. A brief exposure of thermodynamics and electrochemical theory describe the functioning of the fuel cells. Further, the proton exchange membrane fuel cells assembly, starting with the schematic presentation of the main components, the role of each component in fuel cell, the specific materials and their requested properties, and the way of assembling the components into device will be detailed. In conclusion, the challenges related to reliability and the cost and the targets for future development of the proton exchange membrane fuel cells for mobile and stationary applications will be presented.

An aromatic polymer, poly(2,6-dimethyl-1,4- phenylene oxide) (PPO) was sulfonate with different s... more An aromatic polymer, poly(2,6-dimethyl-1,4- phenylene oxide) (PPO) was sulfonate with different sulfonation degrees (30, 50, and 75 % theoretical degree) to obtain an electrolytic polymer suitable as proton exchange membrane for fuel cells. Thermal behaviors of sulfonated PPO were tested by differential scanning calorimetry and thermogravimetry. The sulfonation degrees were correlated with glass transitions temperatures (Tg) and the percent of weight loss. One notices a good fitting between sulfonation degree and the percent of weight loss thanks splitting of sulfonic moieties but it is not the same for glass transition temperatures that have a random variation.

NATO Science for Peace and Security Series B: Physics and Biophysics, 2008

This paper deals with preparation of PEM, based on commercial block copolymer of the styrene-buta... more This paper deals with preparation of PEM, based on commercial block copolymer of the styrene-butadiene. The copolymer was structurally changed by sulfonation followed by cross linking, in order to design a Proton Exchange Membrane for Fuel Cells. The membranes were structural tested by FTIR Spectroscopy and Scanning Electron Microscopy. Ionic Exchange Capacity (IEC) and thermal behavior by Differential Scanning Calorimetry

Journal of Fuel Cell Science and Technology, 2014

An aromatic polymer, poly(2,6-dimethyl-1,4phenylene oxide) (PPO) was sulfonate with different sul... more An aromatic polymer, poly(2,6-dimethyl-1,4phenylene oxide) (PPO) was sulfonate with different sulfonation degrees (30, 50, and 75 % theoretical degree) to obtain an electrolytic polymer suitable as proton exchange membrane for fuel cells. Thermal behaviors of sulfonated PPO were tested by differential scanning calorimetry and thermogravimetry. The sulfonation degrees were correlated with glass transitions temperatures (T g ) and the percent of weight loss. One notices a good fitting between sulfonation degree and the percent of weight loss thanks splitting of sulfonic moieties but it is not the same for glass transition temperatures that have a random variation.