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Cobzaru C.,Technical University Gheorghe Asachi | Bordeianu G.,Tehnical College Danubiana | Marinoiu A.,National RD Institute for Cryogenics and Isotopic Technologies ICIT | Apostolescu G.A.,Technical University Gheorghe Asachi | And 5 more authors.
Key Engineering Materials | Year: 2015

The effect of storage time on the composition of the olive and sunflower oils has been investigated. It were studied parameters like free fatty acids (FFA), anisidine value (AV), iodine value (IV), saponification number (SN) and identification of the molecular structure through FT-IR method. During storage (48 months) an increasing in the values of parameters FFA and AV took place that measures the oxidative degradation of oils. The oxidative stability of olive oil stored at room temperature was less than of sunflower oil. Also, significant differences were found among the olive oil and sunflower oil during storage period. © (2015) Trans Tech Publications, Switzerland. Source


Cobzaru C.,Technical University Gheorghe Asachi | Cernatescu C.,Technical University Gheorghe Asachi | Marinoiu A.,National RD Institute for Cryogenics and Isotopic Technologies ICIT
Revue Roumaine de Chimie | Year: 2014

In this study, the effect of the time of treatment with the nitric acid on the adsorption properties of native clinoptilolite and its Na form, destined as adsorbent for removing of azomethines from wastewater was studied. The exchange solutions for Na+ cations were analysed by flame photometry and the XRD, TPD and N2 adsorption methods were used for structural characterization of clinoptilolite samples after the acid treatment. The results show that the treatment with nitric acid for 24 hours affects substantially the adsorption properties of clinoptilolite obtaining a product with a specific area and porous volume higher than the starting material. Source


Marinoiu A.,National RD Institute for Cryogenics and Isotopic Technologies ICIT | Teodorescu C.,Research Center | Carcadea E.,National RD Institute for Cryogenics and Isotopic Technologies ICIT | Raceanu M.,National RD Institute for Cryogenics and Isotopic Technologies ICIT | And 3 more authors.
Materials Today: Proceedings | Year: 2015

Taking into consideration their high surface area, high conductivity, unique graphitized basal plane structure and potential low manufacturing cost, graphene nanocomposites such as Pt/graphene nanocomposites have been investigated as catalyst support for PEMFC applications. All materials were synthesized through a simple method of chemical oxidation and graphite oxide exfoliation, and results were confirmed by characteristic analysis. The structure, morphology and properties were characterized by using X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and thermogravimetric analysis. The XRD pattern clearly showed the complete disappearance of C(200), indicating the formation of graphene which was also confirmed by SEM images Also, an important information about the Pt/graphene nanocomposite has been obtained from chemical and thermogravimetric analysis. The chemical analysis indicates the fact that the Pt/graphene nanocomposite has the following chemical composition: C = 49.79%wt., O = 17.37%wt., H = 4.77%wt., S < 0.005%wt. and N = 3.53%wt. Pt/graphene nanocomposites are more adequate to form composite membranes for PEMFC applications than simple graphene nanocomposites. © 2015 Elsevier Ltd. Source


Marinoiu A.,National RD Institute for Cryogenics and Isotopic Technologies ICIT | Raceanu M.,National RD Institute for Cryogenics and Isotopic Technologies ICIT | Cobzaru C.,Technical University Gheorghe Asachi | Teodorescu C.,OLTCHIM SA | And 3 more authors.
Reaction Kinetics, Mechanisms and Catalysis | Year: 2014

For a hopcalite catalyst (copper manganese oxide), a new preparation method is reported based on a combination of precipitation and redox techniques. A full XRD, N2-adsorption-desorption and SEM-EDX characterization of the resulted samples has been carried out The samples calcined at 300 °C with an amorphous structure were investigated using microactivity equipment for carbon monoxide (CO) removal under different reaction conditions (temperature in the range of 25-80 °C, pressure 0.2-1 bar, initial CO concentration in the 30-200 ppm range). The results showed that the prepared hopcalite exhibited steady performance in the micro-activity reactor regarding the reducing carbon monoxide content down to residual contents. High activity at low temperature was observed for non-crystalline materials and was correlated with the presence of potassium. An increase of CO conversion with increasing pressure and decreasing temperature has been observed. A major remark related to the experimental results was that the rate of CO concentration decrease in the gaseous mixture in the reactor was strongly influenced by the initial value of CO concentration, and therefore for almost all the experimented cases, in less than a minute, the output gaseous mixture contained an adequate CO concentration to be used for fuel cell applications. The stability of the prepared hopcalite was investigated at ambient temperature. In order to determine its lifetimes, a longer term experiments have been carried on and the results showed that the hopcalite was significantly stable and showed over 80 % CO conversion after 60 h. The performances decay steadily to about 50 % after 72 h. The catalyst was regenerated without any difficulty. © Akadémiai Kiadó, Budapest, Hungary 2014. Source


Cobzaru C.,Technical University Gheorghe Asachi | Cernatescu C.,Technical University Gheorghe Asachi | Marinoiu A.,National RD Institute for Cryogenics and Isotopic Technologies ICIT
Revue Roumaine de Chimie | Year: 2014

The native clinoptilolite volcanic tuff (NT) and its Na form (NaNT) as well as dealuminated clinoptilolite (DNT) and its Na form (DNaNT) were investigated as efficient adsorbents for separating the 2,2′-dihydroxydiphenyl azomethine from wastewaters. The effect of parameters such as the pH dye solution, contact time and temperature of adsorption process was examined. The studies show that the DNT and DNaNT samples have a higher capacity of adsorption in comparison with the NT and NaNT samples. Also, the amounts of azomethine dye retained on the dealuminated clinoptilolite are much higher at 60°C than at 40°C. Thus, the adsorbed amount of azomethine dye on DNT sample was about 85% at 60°C, pH=4 and contact time 60 min. (Graph Presented). © 2015, Editions de l'Academie Republique Populaire. All rights reserved. Source

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