221. Effect of synthesis route of mesoporous zirconia based Ni catalysts on coke minimization in conversion of biogas to synthesis gasHande Mustu, Sena Yaşyerli, Nail Yaşyerli, Gülşen Doğu, Timur Doğu, Petar Djinović, Albin Pintar, 2015, izvirni znanstveni članek Povzetek: Mesoporous zirconia and nickel incorporated zirconia catalysts were prepared following different routes. Synthesis of mesoporous zirconia and Ni incorporated zirconia with very narrow pore size distributions and high surface area was achieved. Ni incorporated mesoporous zirconia materials showed high activity in carbon dioxide reforming of methane, performed at 600 °C. Coke formation during dry reforming was eliminated over the Ni incorporated zirconia catalyst prepared by the one-pot procedure, using Pluronic P123 as the surfactant. It was shown that Ni was very well distributed within this material with cluster sizes smaller than the detection limit of XRD. This catalyst also showed highly stable catalytic performance. However, the catalysts prepared by the impregnation method showed higher activity but much higher coke formation than the catalyst prepared by the one-pot route.
Ključne besede: Biogas, syngas, dry reforming, mesoporous zirconia, coke
Objavljeno v DiRROS: 12.02.2015; Ogledov: 4572; Prenosov: 756
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222. Amino- and ionic liquid-functionalised nanocrystalline ZnO via silane anchoring - an antimicrobial synergyMarjeta Čepin, Vasko Jovanovski, Matejka Podlogar, Zorica Crnjak Orel, 2015, izvirni znanstveni članek Povzetek: Temperature has critical impact on food quality and
safety within food supply chain, therefore, food should
be kept at the defined storage temperature range.
Final consumer should be assured when buying food
about actual temperature and thermal history of the
selected food product and this is why it should be indicated
on the packed or prepacked item.
The chromogenic temperature indicator for cold food
chain was prepared from suitable active material
packed in the properly structured holder. When temperature
rises above the defined storage temperature,
the active material changes colour and physical state
(solid/liquid). Simultaneously, special packaging structure
enables irreversible recording of the time exposed
to the elevated temperature. The active material was
made of thermochromic composite, consisting of dye,
developer and solvent. It changes colour at its melting
point, being coloured below and discoloured above
it. The temperature is called activation temperature of
the composite. Its value was adjusted by appropriate
solvent and additives used for preparation of the composite,
to reach the desired value. The temperature
dependent colour change of the composite was determined
by colorimetric measurements. The conditions
for best observation of the change by naked eye were
also examined. The structure of the active material’s
holder was analyzed for best displaying of the time
spend at high temperature (above the activation temperature).
Functioning of the indicator was examined with
growth of pathogens as a function of migration of
the active material at temperature above the required
storage temperature of the food. It was found out that
the described chromogenic temperature indicator for
cold food chain shows the thermal history of food storage
by colour-, phase- and migration changes of the
active composite material and consequently would be
reliable as indicator in cold food chain to indicate temperature
abuse and would disclose potential growth of
psychrophilic microorganisms.
Ključne besede: Chromogenic temperature indicator, Food
cold chain, Food quality and safety, Temperature control, Thermal history
Objavljeno v DiRROS: 16.12.2014; Ogledov: 5876; Prenosov: 867
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223. Post-polymerization modification of poly(L-glutamic acid) with d-(+)-glucosaminePeter Perdih, Sašo Čebašek, Alenka Možir, Ema Žagar, 2014, izvirni znanstveni članek Povzetek: Carboxyl functional groups of poly(L-glutamic acid) (PGlu) were modified with
a D-(+)-glucosamine (GlcN) by amidation using 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-
methylmorpholinium chloride (DMTMM) as a coupling reagent. The coupling reaction
was performed in aqueous medium without protection of hydroxyl functional groups of
D-(+)-glucosamine. Poly(L-glutamic acid) and GlcN functionalized polyglutamates
(P(Glu-GlcN)) were thoroughly characterized by 1D and 2D NMR spectroscopy and
SEC-MALS to gain detailed information on their structure, composition and molar mass
characteristics. The results reveal successful functionalization with GlcN through the
amide bond and also to a minor extent through ester bond formation in position 1 of GlcN.
In addition, a ratio between the α- and β-form of glucosamine substituent coupled to
polyglutamate repeating units as well as the content of residual dimethoxy triazinyl active
ester moiety in the samples were evaluated.
Ključne besede: poly(L-glutamic acid), glucosamine, glycopolypeptide
Objavljeno v DiRROS: 16.12.2014; Ogledov: 4268; Prenosov: 845
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224. The hazard assessment of nanostructured CeO [sub] 2-based mixed oxides on the zebrafish Danio rerio under environmentally relevant UV-A exposureAnita Jemec Kokalj, Petar Djinović, Ilja Gasan Osojnik Črnivec, Albin Pintar, 2015, izvirni znanstveni članek Povzetek: The effect of nanomaterials on biota under realistic environmental conditions is an important question. However, there is still a lack of knowledge on how different illumination conditions alter the toxicity of some photocatalytic nanomaterials. We have investigated how environmentally relevant UV-A exposure (intensity 8.50 ± 0.61 W/m2, exposure dose 9.0 J/cm2) affected the toxicity of cerium oxide (CeO2)-based nanostructured materials to the early-life stages of zebrafish Danio rerio. Pure cerium oxide (CeO2), copper–cerium (CuO–CeO2) (with a nominal 10, 15 and 20 mol.% CuO content), cerium–zirconium (CeO2–ZrO2) and nickel and cobalt (Ni–Co) deposited over CeO2–ZrO2 were tested. It was found that under both illumination regimes, none of the tested materials affected the normal development or induced mortality of zebrafish early-life stages up to 100 mg/L. Only in the case of CuO–CeO2, the growth of larvae was decreased (96 h LOEC values for CuCe10, CuCe15 and CuCe20 were 50, 50 and 10 mg/L, respectively). To conclude, CeO2-based nanostructured materials are not severely toxic to zebrafish and environmentally relevant UV-A exposure does not enhance their toxicity.
Ključne besede: Nickel cobalt nanocrystalline catalysts, UV-A phototoxicity, UV-shielding, zebrafish
Objavljeno v DiRROS: 16.12.2014; Ogledov: 8907; Prenosov: 524
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