Bulletin of the American Physical Society, Mar 18, 2009
metallic dopant ions into the titanium dioxide particles can influence the performance of these p... more metallic dopant ions into the titanium dioxide particles can influence the performance of these photocatalysts. This affects the dynamics of electron-ion recombination and interfacial charge transfer. In this paper it was synthesized undoped and doped TiO2 nanocrystals with metallic (Ag) and non-metallic (N) ions through sol-gel and hydrothermal methods. The materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX), diffuse reflectance UV-VIS, thermogravimetric analysis (TG) and differential thermal analysis (DTA).
In present work, nanocrystalline powders of TiO 2 undoped and doped with Pt and Au ions respectiv... more In present work, nanocrystalline powders of TiO 2 undoped and doped with Pt and Au ions respectively were synthesized. The synthesis was performed under hydrothermal conditions, at a temperature of 493 K for 5h. Obtained nanocrystalline powders were characterized by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). The citotoxic effect of TiO 2 nanoparticles undoped and doped with Pt and Au ions respectively on human eritroleukemia tumoral cell line (K562) was investigated.
ABSTRACT Undoped and Ag-doped TiO2 anatase nanocrystals were successfully prepared from titanium ... more ABSTRACT Undoped and Ag-doped TiO2 anatase nanocrystals were successfully prepared from titanium isopropoxide by a novel fast-hydrothermal method. The as-prepared TiO2 nanocrystals were characterized by XRD, DRUV–VIS spectroscopy and SEM/EDX. The results show that the anatase TiO2 has a particle size of around 4nm from SEM and XRD results.
The effect of a TiO 2 nanoparticle suspension (4 mg in 5 ml distilled water) doped or not with go... more The effect of a TiO 2 nanoparticle suspension (4 mg in 5 ml distilled water) doped or not with gold or iron, complexed or not with α-or β-cyclodextrin, on the mitotic division was studied. The treatment was performed in the M cellular mitotic cycle phase, in the meristematic tissue of Nigella damascena radicels, being analyzed the cytogenetic modifications. The cyclodextrin type and the ratio between cyclodextrin and titanium dioxide affect the percentage of normal cells and the chromosome aberration type. The TiO 2 complexed with α-cyclodextrin did not facilitate the reunion of the chromosome broken ends (absence of bridges in anaphase and in telophase). The titanium dioxide doped with iron, complexed with α-or β-cyclodextrin, also reduced the percentage of reunion of the broken ends of the chromosomes. These findings suggest the possibility of using doped or undoped TiO 2 , complexed with α-cyclodextrin, in the anticarcinogen therapy.
Curcuma is one of the most famous medicinal and tropical aromatic plants. Its health benefits hav... more Curcuma is one of the most famous medicinal and tropical aromatic plants. Its health benefits have been appreciated and exploited in traditional Asian medicine since ancient times. Various studies have investigated its complex chemical composition and demonstrated the remarkable therapeutic properties of curcuma’s phytoconstituents. Oxidative stress is a decisive driving factor triggering numerous pathologies (neurodegenerative, psychiatric and cardiovascular diseases; diabetes; tumors, etc.). Numerous recent studies have focused on the use of natural compounds and nanomaterials as innovative molecular targeting agents as effective therapeutic strategies. In this study, we report, for the first time, the development of a simple target phytocarrier system that capitalizes on the bioactive properties of curcuma and AgNPs. The complete metabolic profile of curcuma was determined based on gas chromatography-mass spectrometry (GC-MS) and electrospray ionization quadrupole time-of-flight ...
Sustainable waste and water management are key components of the newest EU policy regarding the c... more Sustainable waste and water management are key components of the newest EU policy regarding the circular economy. Simple, performant and inexpensive water treatment methods based on reusing waste are prerequisites for human health, sustainable development and environmental remediation. The design of performant, cost-effective absorbents represents a topical issue in wastewater treatment. This study aimed to investigate the development of a newly engineered adsorbent by functionalizing two different types of waste (industrial and food) with magnetic nanoparticles as environmentally friendly, highly efficient, cheap material for cadmium removal from aqueous solutions. This nano-engineered adsorbent (EFM) derived from waste eggshell and fly ash was used to remove the cadmium from the aqueous solution. SEM analysis has demonstrated that magnetite nanoparticles were successfully loaded with each waste. In addition, was obtained a double functionalization of the eggshell particles with as...
Viscum is one of the most famous and appreciated medicinal plants in Europe and beyond. The symbi... more Viscum is one of the most famous and appreciated medicinal plants in Europe and beyond. The symbiotic relationship with the host tree and various endogenous and ecological aspects are the main factors on which the viscum metabolites’ profiles depend. In addition, European traditional medicine mentions that only in two periods of the year (summer solstice and winter solstice) the therapeutic potential of the plant is at its maximum. Many studies have investigated the phytotherapeutic properties of viscum grown on different species of trees. However, studies on Romanian viscum are relatively few and refer mainly to the antioxidant and antiproliferative activity of mistletoe grown on Acer campestre, Fraxinus excelsior, Populus nigra, Malus domestica, or Robinia pseudoacacia. This study reports the first complete low-molecular-weight metabolite profile of Romanian wild-grown European viscum. A total of 140 metabolites were identified under mass spectra (MS) positive mode from 15 seconda...
Amino Acid - New Insights and Roles in Plant and Animal
Currently, wide world research is focused on sustainable development and the demand for innovativ... more Currently, wide world research is focused on sustainable development and the demand for innovative clean technologies, nevertheless natural potential reconsideration could represent a viable solution for the identification and design of new pharmacological agents from renewable resources. The main reason consists of special properties of these natural derivates: immunomodulating activity with continuously perfectible selectivity and efficiency. Plants and herb extracts have been used for centuries as traditional medicines, throughout the entire world. Romanian phytotherapy represents practically a very important part of our traditional knowledge and heritage. Therapeutic properties of plant active principles still continue to be the subject of many researches. In this chapter, an overview of plant bioactive molecules from the perspective of modern phytochemistry is presented. A special part is devoted to a very special medicinal plant, Viscum album, in particular identification of amino acids and thionins from mistletoe.
Globally, the human population steady increase, expansion of urban areas, excessive industrializa... more Globally, the human population steady increase, expansion of urban areas, excessive industrialization including in agriculture, caused not only decrease to depletion of non-renewable resources, a rapid deterioration of the environment with negative impact on water quality, soil productivity and of course quality of life in general. This paper aims to prepare size controlled nanoparticles of aluminum oxide using a simple synthesis method. The morphology and dimensions of nanomaterial was investigated using modern analytical techniques: SEM/EDAX and XRD spectroscopy.
D. I. HĂDĂRUGĂ, N. G. HĂDĂRUGĂ, C. LĂZĂU, C. RAŢIU, C. CRĂCIUN, I. GROZESCU “Politehnica” Univers... more D. I. HĂDĂRUGĂ, N. G. HĂDĂRUGĂ, C. LĂZĂU, C. RAŢIU, C. CRĂCIUN, I. GROZESCU “Politehnica” University of Timişoara, Faculty of Industrial Chemistry and Environmental Engineering, Applied Chemistry and Organic-Natural Compounds Engineering, 300006-Timişoara, P-ţa Victoriei 2, Romania Banat’s University of Agricultural Sciences and Veterinary Medicine, Faculty of Food Processing Technology, Food Quality Department, 300645-Timişoara, C. Aradului 119, Romania National Institute for Research & Development in Electrochemistry and Condensed Matter, 300224-Timisoara, Plautius Andronescu 1, Romania “Babes Bolyai” University of Cluj Napoca, Faculty of Biology and Geology, 400015-Cluj Napoca, Gheorghe Bilascu 44, Romania
The term "tea" refers to the flavored beverage obtained by infusion of dried leaves, an... more The term "tea" refers to the flavored beverage obtained by infusion of dried leaves, and the popular name of the plant is Camellia sinensis. A series of tea from Camellia sinensis plant have been analyzed for caffeine content. In recent years, caffeine received increasing attention in food and pharmaceutical industries, due to its pharmacological properties which comprise stimulation of the central nervous system, peripheral vasoconstriction, relaxation of the smooth muscle and myocardial stimulation. The aim of this study was to determine the content of caffeine in different varieties of Camellia sinensis extract in aqueous, acid and alcoholic media. The content of caffeine was determined by using two methods: cyclic voltammetry and high-performance liquid chromatography (HPLC).
Journal of Optoelectronics and Advanced Materials, 2009
Bioactive compounds encapsulating for controlled protection and release is an actuality field, wi... more Bioactive compounds encapsulating for controlled protection and release is an actuality field, with involved in supramolecular chemistry, biochemistry, drugs products, cosmetics and food-processing fields. The controlled protection and release of bio-molecules represent a large and actuality field, with application, especially in drugs, cosmetics and food-processing industries. Cyclodextrins were the first studying compounds regarding to complexing behavior and catalytic properties, in order to copy the enzymes. In this paper it was achieved the synthesis of titanium dioxide undoped and doped with metallic ions, silver and iron, through sol-gel method, and also their complexation with α- / β-cyclodextrins through co-crystallization method. The obtained nanomaterials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), thermogravimetry (TG) and Fourier transform infrared spectroscopy (FT-IR).
The paper presents the obtaining of liposomes containing titanium dioxide nanoparticles by using ... more The paper presents the obtaining of liposomes containing titanium dioxide nanoparticles by using the ultrasonication method. Natural lecithin and titanium dioxide doped with Au+ ions were used for obtaining the liposome micro/nanocapsules and these were analyzed by scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. Generally, the liposomes have not a higher uniformity, being formed by agglomerated capsules with various diameters up to 500 nm, as is revealed by SEM and TEM analyses. These liposomes contain titanium dioxide nanoparticles as is demonstrated by EDS analysis. The composition of liposomes containing titanium dioxide was: 25.5-49% lecithin, 1.3-2% TiO2, and 48.8-73.2% water (on the basis of EDS analysis).
Reducing the costs associated with water management, improving water quality and the environment ... more Reducing the costs associated with water management, improving water quality and the environment are fundamental requirements of sustainable development. Maintaining the optimal level of phosphorus has a direct impact on water quality and the biological system. Current methods used in tertiary wastewater treatment for phosphorus removal present several disadvantages that influence the final water processing cost. Therefore, it is essential for water quality and food safety to develop ecological, cheap and highly efficient materials. This study reported the first comparative assessment of three different types of materials (magnetic, semiconductors and composite) as environmentally friendly, cheap adsorbents for phosphorus removal from wastewater. Several experiments were done to investigate the influence of adsorbent type, dosage and contact time on the efficiency of the processes. The adsorption process was fast and equilibrium was reached within 150 min. We found that the phosphor...
Truffles are the rarest species and appreciated species of edible fungi and are well-known for th... more Truffles are the rarest species and appreciated species of edible fungi and are well-known for their distinctive aroma and high nutrient content. However, their chemical composition largely depends on the particularities of their grown environment. Recently, various studies investigate the phytoconstituents content of different species of truffles. However, this research is still very limited for Romanian truffles. This study reports the first complete metabolites profiles identification based on gas chromatography-mass spectrometry (GC-MS) and electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-QTOF-MS) of two different types of Romania truffles: Tuber magnatum pico and Tuber brumale. In mass spectra (MS) in positive mode, over 100 metabolites were identified from 14 secondary metabolites categories: amino acids, terpenes, alkaloids, flavonoids, organic acids, fatty acids, phenolic acids, sulfur compounds, sterols, hydrocarbons, etc. Additionally, the biologica...
Environmental Engineering and Management Journal, 2012
The purpose of the present work was to study comparatively the sorption of humic acids from water... more The purpose of the present work was to study comparatively the sorption of humic acids from water on Ag doped natural and synthetic zeolite envisaging the advanced drinking water treatment. Synthetic zeolite ZA nanoparticles were synthesized from natural clinoptilolite as Si source and sodium aluminate as Al source. The silver doped natural and synthetic zeolites were characterized by instrumental analysis methods, i.e., X-ray diffraction (XRD), scanning electron microscopy (SEM/EDX) and FT-IR spectroscopy. The equilibrium adsorption studies for humic acid allowed to assess the sorption capacity of the each zeolite, described by the adsorption isotherms, which informs about the surface properties and affinity of the material for the investigated pollutant. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) adsorption isotherms were used to determine the equilibrium constants for the adsorption of the humic acid on the zeolite for various conditions, e.g., humic acid concentrations and zeolite amount. Also, adsorption kinetics has been studied in terms of pseudo-first-order and pseudo-second-order to elucidate some sorption mechanistic aspects. All determined equilibrium and kinetic parameters showed that silver doped synthetic zeolite exhibited better adsorptive affinity and capacity for humic acid removal from aqueous solutions, in comparison with the silver doped natural zeolite.
Environmental Engineering and Management Journal, 2009
This paper presents the preliminary results of photocatalytic oxidation of humic acid from water ... more This paper presents the preliminary results of photocatalytic oxidation of humic acid from water using two types of catalysts, i.e., TiO 2 and Ag-doped TiO 2 modified zeolite (TMZ and Ag-TMZ). TMZ and Ag-TMZ, with zeolite granulation of 315-500 µm was synthesized by sol-gel method, and the morphology and composition of the unmodified/modified zeolite were characterized by BET (Brunauer-Emmet-Teller) method, X-ray Diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX). The sorption process played a major role in photoxidation process, and a slight higher photodegradation rate of humic acid from water was obtained for TiO 2 modified zeolite. The photodegradation process of humic acid from water by using catalysts of TiO 2 and Ag-doped TiO 2 led to a complete mineralization.
Two samples of Na-Ta oxides were synthesized by the hydrothermal method at reaction temperatures ... more Two samples of Na-Ta oxides were synthesized by the hydrothermal method at reaction temperatures of 160 • C (sample A) and 200 • C (sample B). For reference, a third sample of pure NaTaO3 was prepared by the sol-gel method (sample C). Using X-ray diffraction, scanning electron microscopy, UV-vis diffuse reflectance spectra and electric measurements, structural, morphologic, spectroscopic and electric properties of samples were investigated. The structural characterization by X-ray diffraction revealed that samples A and B are mixtures of Na-Ta oxides (including NaTaO3 and other compounds), whilst sample C is pure NaTaO3. UV-vis diffuse reflectance spectra allowed evaluation of the band gap energy (Eg), resulting in 3.88 eV for sample A, 3.93 eV for sample B and 4.1 eV for sample C. Electrical resistivity measurements, over the temperature range 300-450 K, showed a typical semiconductor behavior of the investigated samples, with the effective activation energy, Ea of 0.47 eV (sample A), 0.45 eV (sample B) and 0.82 eV (sample C). Based on the Mott variable range hopping model, the conductivity mechanism in the investigated samples was analyzed. The results shown that the density of states at the Fermi-level, N (EF) is constant in the investigated temperature range and the typical values of N (EF) are 0.713×10 18 eV −1 cm −3 (sample A), 0.621 × 10 18 eV −1 cm −3 (sample B) and 0.855 × 10 17 eV −1 cm −3 (sample C). Other parameters of VRH model such as the hopping distance R and the hopping energy W have also been computed and the following values at the room temperature were obtained: R = 15.7 nm and W = 86 meV (for sample A); R = 16.3 nm and W = 89 meV (for sample B) and R = 26.7 nm and W = 147 meV (for sample C).
Annals of West University of Timisoara - Physics, 2015
Two samples of NaTaOUsing X-ray diffraction (XRD), it shows that samples S1 and S2 are mixtures o... more Two samples of NaTaOUsing X-ray diffraction (XRD), it shows that samples S1 and S2 are mixtures of Na-Ta oxides (TaThe frequency (f) dependencies of complex impedance, Z(f) = Z’(f) - i Z’’(f) of the samples, over the frequency range 20 Hz - 2 MHz, at room temperature are presented. The real component Z’ of the complex impedance decreases with increasing frequency and the imaginary component Z’’ has two maximum corresponding to two relaxation processes.The results obtained from the complex impedance spectroscopy, Z’’(Z’) showed the appearance of two semicircles, corresponding to grain and grain boundary mechanism. Experimental results have been fitted with two parallel RC equivalent circuits connected in series and the parameters R and C have been evaluated.
Bulletin of the American Physical Society, Mar 18, 2009
metallic dopant ions into the titanium dioxide particles can influence the performance of these p... more metallic dopant ions into the titanium dioxide particles can influence the performance of these photocatalysts. This affects the dynamics of electron-ion recombination and interfacial charge transfer. In this paper it was synthesized undoped and doped TiO2 nanocrystals with metallic (Ag) and non-metallic (N) ions through sol-gel and hydrothermal methods. The materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX), diffuse reflectance UV-VIS, thermogravimetric analysis (TG) and differential thermal analysis (DTA).
In present work, nanocrystalline powders of TiO 2 undoped and doped with Pt and Au ions respectiv... more In present work, nanocrystalline powders of TiO 2 undoped and doped with Pt and Au ions respectively were synthesized. The synthesis was performed under hydrothermal conditions, at a temperature of 493 K for 5h. Obtained nanocrystalline powders were characterized by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). The citotoxic effect of TiO 2 nanoparticles undoped and doped with Pt and Au ions respectively on human eritroleukemia tumoral cell line (K562) was investigated.
ABSTRACT Undoped and Ag-doped TiO2 anatase nanocrystals were successfully prepared from titanium ... more ABSTRACT Undoped and Ag-doped TiO2 anatase nanocrystals were successfully prepared from titanium isopropoxide by a novel fast-hydrothermal method. The as-prepared TiO2 nanocrystals were characterized by XRD, DRUV–VIS spectroscopy and SEM/EDX. The results show that the anatase TiO2 has a particle size of around 4nm from SEM and XRD results.
The effect of a TiO 2 nanoparticle suspension (4 mg in 5 ml distilled water) doped or not with go... more The effect of a TiO 2 nanoparticle suspension (4 mg in 5 ml distilled water) doped or not with gold or iron, complexed or not with α-or β-cyclodextrin, on the mitotic division was studied. The treatment was performed in the M cellular mitotic cycle phase, in the meristematic tissue of Nigella damascena radicels, being analyzed the cytogenetic modifications. The cyclodextrin type and the ratio between cyclodextrin and titanium dioxide affect the percentage of normal cells and the chromosome aberration type. The TiO 2 complexed with α-cyclodextrin did not facilitate the reunion of the chromosome broken ends (absence of bridges in anaphase and in telophase). The titanium dioxide doped with iron, complexed with α-or β-cyclodextrin, also reduced the percentage of reunion of the broken ends of the chromosomes. These findings suggest the possibility of using doped or undoped TiO 2 , complexed with α-cyclodextrin, in the anticarcinogen therapy.
Curcuma is one of the most famous medicinal and tropical aromatic plants. Its health benefits hav... more Curcuma is one of the most famous medicinal and tropical aromatic plants. Its health benefits have been appreciated and exploited in traditional Asian medicine since ancient times. Various studies have investigated its complex chemical composition and demonstrated the remarkable therapeutic properties of curcuma’s phytoconstituents. Oxidative stress is a decisive driving factor triggering numerous pathologies (neurodegenerative, psychiatric and cardiovascular diseases; diabetes; tumors, etc.). Numerous recent studies have focused on the use of natural compounds and nanomaterials as innovative molecular targeting agents as effective therapeutic strategies. In this study, we report, for the first time, the development of a simple target phytocarrier system that capitalizes on the bioactive properties of curcuma and AgNPs. The complete metabolic profile of curcuma was determined based on gas chromatography-mass spectrometry (GC-MS) and electrospray ionization quadrupole time-of-flight ...
Sustainable waste and water management are key components of the newest EU policy regarding the c... more Sustainable waste and water management are key components of the newest EU policy regarding the circular economy. Simple, performant and inexpensive water treatment methods based on reusing waste are prerequisites for human health, sustainable development and environmental remediation. The design of performant, cost-effective absorbents represents a topical issue in wastewater treatment. This study aimed to investigate the development of a newly engineered adsorbent by functionalizing two different types of waste (industrial and food) with magnetic nanoparticles as environmentally friendly, highly efficient, cheap material for cadmium removal from aqueous solutions. This nano-engineered adsorbent (EFM) derived from waste eggshell and fly ash was used to remove the cadmium from the aqueous solution. SEM analysis has demonstrated that magnetite nanoparticles were successfully loaded with each waste. In addition, was obtained a double functionalization of the eggshell particles with as...
Viscum is one of the most famous and appreciated medicinal plants in Europe and beyond. The symbi... more Viscum is one of the most famous and appreciated medicinal plants in Europe and beyond. The symbiotic relationship with the host tree and various endogenous and ecological aspects are the main factors on which the viscum metabolites’ profiles depend. In addition, European traditional medicine mentions that only in two periods of the year (summer solstice and winter solstice) the therapeutic potential of the plant is at its maximum. Many studies have investigated the phytotherapeutic properties of viscum grown on different species of trees. However, studies on Romanian viscum are relatively few and refer mainly to the antioxidant and antiproliferative activity of mistletoe grown on Acer campestre, Fraxinus excelsior, Populus nigra, Malus domestica, or Robinia pseudoacacia. This study reports the first complete low-molecular-weight metabolite profile of Romanian wild-grown European viscum. A total of 140 metabolites were identified under mass spectra (MS) positive mode from 15 seconda...
Amino Acid - New Insights and Roles in Plant and Animal
Currently, wide world research is focused on sustainable development and the demand for innovativ... more Currently, wide world research is focused on sustainable development and the demand for innovative clean technologies, nevertheless natural potential reconsideration could represent a viable solution for the identification and design of new pharmacological agents from renewable resources. The main reason consists of special properties of these natural derivates: immunomodulating activity with continuously perfectible selectivity and efficiency. Plants and herb extracts have been used for centuries as traditional medicines, throughout the entire world. Romanian phytotherapy represents practically a very important part of our traditional knowledge and heritage. Therapeutic properties of plant active principles still continue to be the subject of many researches. In this chapter, an overview of plant bioactive molecules from the perspective of modern phytochemistry is presented. A special part is devoted to a very special medicinal plant, Viscum album, in particular identification of amino acids and thionins from mistletoe.
Globally, the human population steady increase, expansion of urban areas, excessive industrializa... more Globally, the human population steady increase, expansion of urban areas, excessive industrialization including in agriculture, caused not only decrease to depletion of non-renewable resources, a rapid deterioration of the environment with negative impact on water quality, soil productivity and of course quality of life in general. This paper aims to prepare size controlled nanoparticles of aluminum oxide using a simple synthesis method. The morphology and dimensions of nanomaterial was investigated using modern analytical techniques: SEM/EDAX and XRD spectroscopy.
D. I. HĂDĂRUGĂ, N. G. HĂDĂRUGĂ, C. LĂZĂU, C. RAŢIU, C. CRĂCIUN, I. GROZESCU “Politehnica” Univers... more D. I. HĂDĂRUGĂ, N. G. HĂDĂRUGĂ, C. LĂZĂU, C. RAŢIU, C. CRĂCIUN, I. GROZESCU “Politehnica” University of Timişoara, Faculty of Industrial Chemistry and Environmental Engineering, Applied Chemistry and Organic-Natural Compounds Engineering, 300006-Timişoara, P-ţa Victoriei 2, Romania Banat’s University of Agricultural Sciences and Veterinary Medicine, Faculty of Food Processing Technology, Food Quality Department, 300645-Timişoara, C. Aradului 119, Romania National Institute for Research & Development in Electrochemistry and Condensed Matter, 300224-Timisoara, Plautius Andronescu 1, Romania “Babes Bolyai” University of Cluj Napoca, Faculty of Biology and Geology, 400015-Cluj Napoca, Gheorghe Bilascu 44, Romania
The term "tea" refers to the flavored beverage obtained by infusion of dried leaves, an... more The term "tea" refers to the flavored beverage obtained by infusion of dried leaves, and the popular name of the plant is Camellia sinensis. A series of tea from Camellia sinensis plant have been analyzed for caffeine content. In recent years, caffeine received increasing attention in food and pharmaceutical industries, due to its pharmacological properties which comprise stimulation of the central nervous system, peripheral vasoconstriction, relaxation of the smooth muscle and myocardial stimulation. The aim of this study was to determine the content of caffeine in different varieties of Camellia sinensis extract in aqueous, acid and alcoholic media. The content of caffeine was determined by using two methods: cyclic voltammetry and high-performance liquid chromatography (HPLC).
Journal of Optoelectronics and Advanced Materials, 2009
Bioactive compounds encapsulating for controlled protection and release is an actuality field, wi... more Bioactive compounds encapsulating for controlled protection and release is an actuality field, with involved in supramolecular chemistry, biochemistry, drugs products, cosmetics and food-processing fields. The controlled protection and release of bio-molecules represent a large and actuality field, with application, especially in drugs, cosmetics and food-processing industries. Cyclodextrins were the first studying compounds regarding to complexing behavior and catalytic properties, in order to copy the enzymes. In this paper it was achieved the synthesis of titanium dioxide undoped and doped with metallic ions, silver and iron, through sol-gel method, and also their complexation with α- / β-cyclodextrins through co-crystallization method. The obtained nanomaterials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), thermogravimetry (TG) and Fourier transform infrared spectroscopy (FT-IR).
The paper presents the obtaining of liposomes containing titanium dioxide nanoparticles by using ... more The paper presents the obtaining of liposomes containing titanium dioxide nanoparticles by using the ultrasonication method. Natural lecithin and titanium dioxide doped with Au+ ions were used for obtaining the liposome micro/nanocapsules and these were analyzed by scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. Generally, the liposomes have not a higher uniformity, being formed by agglomerated capsules with various diameters up to 500 nm, as is revealed by SEM and TEM analyses. These liposomes contain titanium dioxide nanoparticles as is demonstrated by EDS analysis. The composition of liposomes containing titanium dioxide was: 25.5-49% lecithin, 1.3-2% TiO2, and 48.8-73.2% water (on the basis of EDS analysis).
Reducing the costs associated with water management, improving water quality and the environment ... more Reducing the costs associated with water management, improving water quality and the environment are fundamental requirements of sustainable development. Maintaining the optimal level of phosphorus has a direct impact on water quality and the biological system. Current methods used in tertiary wastewater treatment for phosphorus removal present several disadvantages that influence the final water processing cost. Therefore, it is essential for water quality and food safety to develop ecological, cheap and highly efficient materials. This study reported the first comparative assessment of three different types of materials (magnetic, semiconductors and composite) as environmentally friendly, cheap adsorbents for phosphorus removal from wastewater. Several experiments were done to investigate the influence of adsorbent type, dosage and contact time on the efficiency of the processes. The adsorption process was fast and equilibrium was reached within 150 min. We found that the phosphor...
Truffles are the rarest species and appreciated species of edible fungi and are well-known for th... more Truffles are the rarest species and appreciated species of edible fungi and are well-known for their distinctive aroma and high nutrient content. However, their chemical composition largely depends on the particularities of their grown environment. Recently, various studies investigate the phytoconstituents content of different species of truffles. However, this research is still very limited for Romanian truffles. This study reports the first complete metabolites profiles identification based on gas chromatography-mass spectrometry (GC-MS) and electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-QTOF-MS) of two different types of Romania truffles: Tuber magnatum pico and Tuber brumale. In mass spectra (MS) in positive mode, over 100 metabolites were identified from 14 secondary metabolites categories: amino acids, terpenes, alkaloids, flavonoids, organic acids, fatty acids, phenolic acids, sulfur compounds, sterols, hydrocarbons, etc. Additionally, the biologica...
Environmental Engineering and Management Journal, 2012
The purpose of the present work was to study comparatively the sorption of humic acids from water... more The purpose of the present work was to study comparatively the sorption of humic acids from water on Ag doped natural and synthetic zeolite envisaging the advanced drinking water treatment. Synthetic zeolite ZA nanoparticles were synthesized from natural clinoptilolite as Si source and sodium aluminate as Al source. The silver doped natural and synthetic zeolites were characterized by instrumental analysis methods, i.e., X-ray diffraction (XRD), scanning electron microscopy (SEM/EDX) and FT-IR spectroscopy. The equilibrium adsorption studies for humic acid allowed to assess the sorption capacity of the each zeolite, described by the adsorption isotherms, which informs about the surface properties and affinity of the material for the investigated pollutant. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) adsorption isotherms were used to determine the equilibrium constants for the adsorption of the humic acid on the zeolite for various conditions, e.g., humic acid concentrations and zeolite amount. Also, adsorption kinetics has been studied in terms of pseudo-first-order and pseudo-second-order to elucidate some sorption mechanistic aspects. All determined equilibrium and kinetic parameters showed that silver doped synthetic zeolite exhibited better adsorptive affinity and capacity for humic acid removal from aqueous solutions, in comparison with the silver doped natural zeolite.
Environmental Engineering and Management Journal, 2009
This paper presents the preliminary results of photocatalytic oxidation of humic acid from water ... more This paper presents the preliminary results of photocatalytic oxidation of humic acid from water using two types of catalysts, i.e., TiO 2 and Ag-doped TiO 2 modified zeolite (TMZ and Ag-TMZ). TMZ and Ag-TMZ, with zeolite granulation of 315-500 µm was synthesized by sol-gel method, and the morphology and composition of the unmodified/modified zeolite were characterized by BET (Brunauer-Emmet-Teller) method, X-ray Diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX). The sorption process played a major role in photoxidation process, and a slight higher photodegradation rate of humic acid from water was obtained for TiO 2 modified zeolite. The photodegradation process of humic acid from water by using catalysts of TiO 2 and Ag-doped TiO 2 led to a complete mineralization.
Two samples of Na-Ta oxides were synthesized by the hydrothermal method at reaction temperatures ... more Two samples of Na-Ta oxides were synthesized by the hydrothermal method at reaction temperatures of 160 • C (sample A) and 200 • C (sample B). For reference, a third sample of pure NaTaO3 was prepared by the sol-gel method (sample C). Using X-ray diffraction, scanning electron microscopy, UV-vis diffuse reflectance spectra and electric measurements, structural, morphologic, spectroscopic and electric properties of samples were investigated. The structural characterization by X-ray diffraction revealed that samples A and B are mixtures of Na-Ta oxides (including NaTaO3 and other compounds), whilst sample C is pure NaTaO3. UV-vis diffuse reflectance spectra allowed evaluation of the band gap energy (Eg), resulting in 3.88 eV for sample A, 3.93 eV for sample B and 4.1 eV for sample C. Electrical resistivity measurements, over the temperature range 300-450 K, showed a typical semiconductor behavior of the investigated samples, with the effective activation energy, Ea of 0.47 eV (sample A), 0.45 eV (sample B) and 0.82 eV (sample C). Based on the Mott variable range hopping model, the conductivity mechanism in the investigated samples was analyzed. The results shown that the density of states at the Fermi-level, N (EF) is constant in the investigated temperature range and the typical values of N (EF) are 0.713×10 18 eV −1 cm −3 (sample A), 0.621 × 10 18 eV −1 cm −3 (sample B) and 0.855 × 10 17 eV −1 cm −3 (sample C). Other parameters of VRH model such as the hopping distance R and the hopping energy W have also been computed and the following values at the room temperature were obtained: R = 15.7 nm and W = 86 meV (for sample A); R = 16.3 nm and W = 89 meV (for sample B) and R = 26.7 nm and W = 147 meV (for sample C).
Annals of West University of Timisoara - Physics, 2015
Two samples of NaTaOUsing X-ray diffraction (XRD), it shows that samples S1 and S2 are mixtures o... more Two samples of NaTaOUsing X-ray diffraction (XRD), it shows that samples S1 and S2 are mixtures of Na-Ta oxides (TaThe frequency (f) dependencies of complex impedance, Z(f) = Z’(f) - i Z’’(f) of the samples, over the frequency range 20 Hz - 2 MHz, at room temperature are presented. The real component Z’ of the complex impedance decreases with increasing frequency and the imaginary component Z’’ has two maximum corresponding to two relaxation processes.The results obtained from the complex impedance spectroscopy, Z’’(Z’) showed the appearance of two semicircles, corresponding to grain and grain boundary mechanism. Experimental results have been fitted with two parallel RC equivalent circuits connected in series and the parameters R and C have been evaluated.
Uploads
Papers by Ioan Grozescu