Albin Pintar

National Institute of Chemistry, Lubliano, Ljubljana, Slovenia

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Publications (126)440.01 Total impact

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    Full-text · Dataset · Nov 2015
  • Magda Cotman · Albin Pintar
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    ABSTRACT: The proficiency testing of wastewater sampling is organized by the Laboratory for Environmental Sciences and Engineering at the National Institute of Chemistry, Slovenia (NIC). Preliminary tests started in 2010 at two candidate sites to choose for a trial the most convenient one. In 2012, we organized the first collaborative field trial on wastewater sampling and such trials continued in 2013 and 2014. Between 16 and 20 sampling teams were selected from those that (1) participate in the national wastewater monitoring program and (2) perform analytical activities in laboratories. The participants used a 6-h time proportional sampling approach. They used sampling equipment with different principles of sample collection which take a series of discrete samples at fixed time intervals. Subsequent analyses involved both field and laboratory measurements. The participants, with only one exception, exhibited required technical skills for measuring field parameters (temperature and pH value). All samples taken were also analyzed at NIC. The variability between reported values of participants in the trials, expressed as CV, was found to be 8.5 %, 11.1 % and 9.5 % for chemical oxygen demand. Of all parameters, the largest variability was found for total organic carbon concentration amounting to 23.7 % and 35.7 %. Particular attention was given to separate the measurement uncertainty contributions arising from sampling and chemical analyses.
    No preview · Article · Oct 2015 · Accreditation and Quality Assurance
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    ABSTRACT: Abstract Bisphenol A (BPA) and its analogues (BPF and BPAF) are a class of industrial chemicals that are proven to elicit endocrine disrupting effects, thus it is important to reduce their concentrations in effluent streams as much as possible. In this study, a simple and highly active glass fiber-supported TiO2 photocatalyst was synthesized and applied in a UV-irradiated three-phase batch and continuous stirred-tank reactor (CSTR) for removal of toxicity and estrogenicity of water dissolved bisphenols. Bioassays of photocatalytically treated aqueous samples showed no estrogenic activity and complete removal of toxicity after 4 h of illumination, which was in accordance with high mineralization extent of bisphenols and their reaction derivatives. The photocatalytic examination of bisphenolic compounds revealed considerably higher stability of BPAF under UV light irradiation, due to two CF3 groups attached to the central C atom. Moreover, these fluorinated groups were responsible for markedly higher toxicity of BPAF to crustaceans D. magna in comparison to non-halogenated BPA and BPF, which manifested daphnids as excellent aquatic species for sensing fluorinated (halogenated) bisphenolic compounds. In addition, photocatalytic oxidation of bisphenol analogues in CSTR demonstrated feasibility of using the immobilized TiO2 photocatalyst in continuous-flow light-assisted water purification systems. Detailed characterization of fresh and used photocatalysts confirmed substantial changes in active material structure. However, the corresponding impact on photocatalyst stability was found insignificant.
    Full-text · Article · Oct 2015 · Applied Catalysis B Environmental
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    ABSTRACT: This study reports a thorough investigation of nanosized CuO/CeO2 materials as an efficient catalyst for decomposition of N2O, which is a strong greenhouse gas largely produced by chemical industry. Effect of terminating CeO2 crystalline planes ({100}, {110}, and {111}) on the behavior of CuO dispersed over CeO2 nanocubes, nanorods and polyhedral crystallites was examined in detail by using a variety of catalyst characterization techniques. The 4 wt % Cu was found as the most advantageous metal loading, whereas higher Cu content resulted in lower dispersion and formation of significantly less active, segregated bulk CuO phase. It was discovered that CuO/CeO2 solids should enable both excessive oxygen mobility on the catalyst surface as well as formation of highly reducible Cu defect sites, in order to ensure high intrinsic activity. Detailed studies further revealed that CeO2 morphology needs to be tailored to expose {100} and {110} high-energy surface planes, as present in CeO2 nanorods. Oxygen mobility and regeneration of active Cu phase on these surface planes is easier, which in turn facilitates higher catalytic activity through the recombination of surface oxygen atoms and desorption as molecular oxygen that replenishes active sites for subsequent catalytic cycles. As a consequence, CuO supported on CeO2 nanorods demonstrated lower activation energy (87 kJ/mol) in N2O decomposition reaction compared to catalysts based on CeO2 nanocubes (102 kJ/mol) or polyhedral CeO2 (92 kJ/mol).
    Full-text · Article · Jul 2015 · ACS Catalysis
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    ABSTRACT: The enhanced oxidative potential of sludge carbon/TiO2 nano composites (SNCs), applied as heterogeneous catalysts in advanced oxidation processes (AOPs), was studied. Fabrification of efficient SNCs using different methods and successful evaluation of their catalytic oxidative activity is reported for the first time. Surface modification processes of hydrothermal deposition, chemical treatment and sol-gel solution resulted in improved catalytic activity and good surface chemistry of the SNCs. The solids obtained after chemical treatment and hydrothermal deposition processes exhibit excellent crystallinity and photocatalytic activity. The highest photocatalytic rate was obtained for the material prepared using hydrothermal deposition technique, compared to other nanocomposites. Further, improved removal of bisphenol A (BPA) from aqueous phase by means of catalytic ozonation and catalytic wet air oxidation processes is achieved over the solid synthesized using chemical treatment method. The present results demonstrate that the addition of TiO2 on the surface of sludge carbon (SC) increases catalytic oxidative activity of SNCs. The latter produced from harmful sludge materials can be therefore used as cost-effective and efficient sludge derived catalysts for the removal of hazardous pollutants. Copyright © 2015. Published by Elsevier B.V.
    Full-text · Article · Jul 2015 · Journal of Hazardous Materials
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    ABSTRACT: Experiments were performed to study the effects of short and long-term exposure to bisphenol A (BPA) on a freshwater crustacean isopod Asellus aquaticus (L.). Two life stages of isopods were exposed to a range of BPA concentrations, from aqueous and two dietary sources, in the form of with BPA spiked conditioned alder leaf (Alnus glutinosa) discs, or spiked formulated sediment, to determine the relative importance of each source of exposure on the uptake of this contaminant. Several lethal and sublethal endpoints were evaluated in this study to measure the potential effects of BPA on A. aquaticus, including mortality, growth and feeding rate inhibition, mobility inhibition, de-pigmentation and molting disturbances. They signify a correlation to BPA levels and a difference in BPA uptake efficiency from different uptake sources. Results of acute exposure to BPA show a greater sensitivity of test systems using juvenile specimens with a 96h LC50 of 8.6mgL(-1) BPA in water medium and a 96h LC50 of 13.5mgL(-1) BPA in sediment. In comparison, adult isopods show a 96h LC50 of 25.1mgL(-1) BPA in water medium and a 96h LC50 of 65.1mgL(-1) BPA in sediment. Observed endpoints of chronic exposures suggest the alder leave discs to be the most efficient uptake source of BPA, in contrast to uptake from water or heterogeneous sediment. Significant (p<0.05) growth inhibition, with a 21d NOEC of 0.5/2.5mgL(-1) (for juvenile/adult organisms), and feeding rate inhibition, with a 21d NOEC of 0.5/1.0mgL(-1) (for juvenile/adult organisms), were proven to be the most sensitive toxicity endpoints. An even more sensitive effect turned out to be molting frequency, which was significantly reduced; a 21d NOEC was 1.0mgL(-1) of BPA for adult organisms and an even lower 21d NOEC of 0.05mgL(-1) of BPA for juveniles. The observed endpoints are recorded at very low, non-toxic exposure concentrations, indicating that BPA acts as an endocrine disrupting compound, as well as a toxic substance. We also determined the importance of the direct dietary uptake of the pollutants, significant for juveniles as well as adult animals. Copyright © 2015 Elsevier Inc. All rights reserved.
    No preview · Article · Jul 2015 · Ecotoxicology and Environmental Safety
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    ABSTRACT: Low-temperature catalytic decarboxylation was studied for continuous treatment of model wastewaters containing acetic and formic acid. A three-phase trickle-bed reactor was operated at Tr=75–240 °C, PN2=10 bar, ΦG=50 NmL/min and ΦL=0.5 mL/min. Before and after reaction, 3 wt. % Ru/TiO2 catalyst was thoroughly characterized (N2 physisorption, XRD, TPO, H2-TPR, CHNS, DRIFTS). CH3COOH decarboxylation at sufficiently high temperatures (T>225 °C) resulted in higher than 80 % selectivity for CH4 and CO2, stable catalyst activity and no accumulation of carbonaceous deposits. Low selectivity for H2 and CO2 (<60 %) was achieved during HCOOH decarboxylation, with simultaneous occurrence of CO and CO2 methanation reactions, as well as coke accumulation resulting in catalyst deactivation.
    No preview · Article · Jun 2015 · RSC Advances
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    ABSTRACT: In this study, photocatalytic and catalytic wet-air oxidation (CWAO) processes were used to examine removal efficiency of bisphenol A from aqueous samples over several titanate nanotube-based catalysts. Unexpected toxicity of treated bisphenol A (BPA) samples by means of CWAO process to some tested species was determined. In addition, the CWAO effluent was recycled 5 or 10-fold in order to increase the number of interactions between the liquid phase and catalyst. Consequently, the ICP-MS analysis indicated higher concentrations of some toxic metals like chromium, nickel, molybdenum, silver, and zinc in the recycled samples in comparison to both single-pass sample and photocatalytically treated solution. The highest toxicity of 5- and 10-fold recycled solutions in CWAO process was observed to water fleas, which could be correlated to high concentrations of chromium, nickel, and silver detected in tested samples. The obtained results clearly demonstrated that aqueous samples treated by means of advanced oxidation processes should always be analyzed using (i) chemical analyses to assess removal of BPA and total organic carbon from treated aqueous samples as well as (ii) a battery of aquatic organisms from different taxonomic groups to determine possible toxicity.
    Full-text · Article · Apr 2015 · Water Science & Technology
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    ABSTRACT: To attain sustained activity and stability in CH4-CO2 dry reforming (CCDR), two nanocomposite materials comprising silicon carbide or alumina and ceria-zirconia were introduced to support cobalt-nickel (CoNi) catalysts. Following the sequential impregnation-ultrasonication-deposition precipitation procedure, catalysts were systematically characterized and their performances were tested at 1.2 bar and 750 oC, where undiluted CH4-CO2 (ratio = 1: 1) streams simulating biogas and the real industrial conditions were fed into a continuous flow reactor. For CCDR reactions conducted at WHSV = 12 L/(gcat∙h), good activity and stability were shown for both catalysts. Carbon content as low as 0.3 wt. % and high conversions (70-78 % and 78-88 % for CH4 and CO2, respectively) were recorded over 23 h and 550 h tests. Interestingly, by increasing the WHSV value to an order of magnitude higher, i.e., at 120 L/(gcat∙h) with all other conditions held constant, a 6 h short-term test showed remarkably high conversions near equilibrium values, implying that the reactions still occurred within the thermodynamic regime despite a reduced ten-fold mass of catalyst bed. This infers that not all active sites available on the catalyst surface were fully exploited. Compared to previous catalyst performances, the progress made in this work is ascribed to the synergistic effects from selected support materials that contributed remarkable redox properties, high surface area, mechanical and thermal stability to the catalysts.
    No preview · Article · Apr 2015 · Industrial & Engineering Chemistry Research
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    ABSTRACT: This study investigates how morphology, active metal content and oxygen storage capacity of various bimetallic NiCo/CeZrO2 materials influence their catalytic activity and stability in the methane dry reforming reaction. Catalyst preparation procedure and chemical composition were steered to finally obtain materials, which do not accumulate carbon during the CH4/CO2 reforming reaction. Oxygen storage capacity of the CeZrO2 catalyst support was identified to play a vital role in retarding carbon accumulation over the tested NiCo/CeZrO2 materials. This property can be fully developed when a nanocrystalline solid solution of CeO2 and ZrO2 is formed. Secondly, a high dispersion of nickel and cobalt is crucial for two reasons: (i) catalysts which contain larger NiCo bimetallic particles (for example with 12–18 wt.% active metal loading) exhibit a low metal-support interphase that results in enhanced coke formation rates; (ii) additionally, only a marginal gain in methane reforming rates are achieved at higher loadings, compared to catalysts with a 3–6 wt.% active metal content. We demonstrated that a NiCo/CeZrO2 catalyst under relevant operating conditions after 400 h TOS maintains 79 and 84% conversion of CH4 and CO2, with negligible coke accumulation.
    Full-text · Article · Mar 2015 · Catalysis Today
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    ABSTRACT: 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.
    Full-text · Article · Mar 2015 · International Journal of Hydrogen Energy
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    Moom Sinn Aw · Milena Zorko · Petar Djinović · Albin Pintar
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    ABSTRACT: This study explores CeZrO2 deposited over commercial β-SiC, and a highly ordered 3D β-SiC synthesised in the laboratory via electrophoretic deposition, as well as γ-Al2O3 in order to prepare three types of dual support for NiCo bimetallic catalyst in CH4-CO2 dry reforming (DR). CeZrO2 was deposited over γ-Al2O3 and β-SiC by dry impregnation (DI), wet impregnation (WI) and 2-step deposition precipitation (DP). XRD analysis indicated that the constituents of the dual supports were retained after calcination, as well as before and after the DR reaction. CeZrO2 remained as a mixed oxide solid solution, whilst alumina formed spinel structures with Ni and Co before the catalysts were reduced in H2 during the pretreatment step prior to the activity tests. During 550 h stability tests, WI, 2-step SICAT/CeZrO2 and 2-step γ-Al2O3/CeZrO2 solids were identified as the most promising catalysts, maintaining high DR activities without deactivation. Notably, 2-step SiC(SICAT) and 2-step γ-Al2O3/CeZrO2 samples recorded the highest yield (H2 = 77%, CO = 90%; H2 = 71%, CO = 81%), with a coke content of 7.7 and 0.6 wt.%, respectively. Carbon deposition for the former is high; contrarily, for WI SiC(SICAT) solid, it accumulated a lower amount of 2.6 wt.%. No agglomeration of CeZrO2 and NiCo phases was observed, evidencing excellent robustness and thermal resistance of these dual supports.
    Full-text · Article · Mar 2015 · Applied Catalysis B Environmental
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    ABSTRACT: 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/m(2), exposure dose 9.0 J/cm(2)) 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.
    Full-text · Article · Feb 2015 · Science of The Total Environment
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    ABSTRACT: Dry reforming of methane with CO2 was investigated over bi-metallic W and Ni incorporated mesoporous alumina catalysts prepared by the one-pot sol-gel route. Powdered materials were thoroughly characterized (N2-physisorption, XRD, XPS, SEM-EDX, TGA-DTA, TPH) prior and post catalytic runs, performed at 600 and 750 oC. High surface area W-Ni incorporated mesoporous alumina catalysts (SBET=178-192 m2/g) synthesized in this work showed excellent performance for the conversion of model biogas to synthesis gas. The Ni-W containing materials exhibited high catalytic activity, which was maintained throughout 150 hours TOS long-term operation at 750 oC. Increase of the W loading (0-10-15 wt. %) at fixed nickel amount (5 wt. %) resulted in prevented deactivation of the catalyst, most prominent at 600 °C, and minimization of coke formation on the surface of the catalyst. Tungsten incorporation was thus proven to significantly enhance and stabilize the overall catalyst performance.
    No preview · Article · Feb 2015 · Industrial & Engineering Chemistry Research
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    ABSTRACT: Different chemical modifications were performed to the natural aluminosilicate Montanit300® in order to improve its catalytic activity in PE depolymerization. Performance of such prepared catalysts was compared to established solid acid catalysts, such as HZSM-5, sulfonated and fluorinated γ-Al2O3 and amorphous silica–alumina. Pyridine TG and DRIFTS characterization revealed mild acid treatment and aluminum grafting as successful in increasing acid site density through impurity removal and specific surface area increase. Mesoporous catalyst structure that allows facile diffusion through its pore network, together with high-density Brønsted acid sites, was found to be crucial to obtain high catalytic activity. The T50 value for PE depolymerization was lowered by 162 °C with sulfonated γ-Al2O3 solid, compared to non-catalyzed reaction, whereas with aluminum-grafted Montanit300® catalyst this value was lowered by 65 °C. PE depolymerization products present in the condensed liquid phase using aluminum-grafted Montanit300® catalyst were exclusively alkanes with chain length up to 21 carbon atoms. Liquid, coke and gas yields were found to be 53, 0.4 and 46.6%, respectively, the latter consisting of linear and branched C2–C4 alkenes and alkanes.
    Full-text · Article · Feb 2015 · Catalysis Today
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    ABSTRACT: High surface area CeO2 nanospheres as an active catalyst support were synthesized using glycothermal approach. Different loadings of copper (4, 6, 10 and 15 wt.%) were supported by wet impregnation method. Prepared materials were characterized by means of TEM, SEM-EDX, XRD, UV-Vis diffuse reflectance, N2 adsorption/desorption, DRIFT and H2-TPR techniques, and tested for the catalytic reaction of nitrous oxide decomposition. The best activity in the N2O degradation was found for the sample containing 10 wt.% of Cu that can be attributed to the highest number of small CuO clusters on the catalyst surface. Further increase of copper content strongly affects the dispersion and leads to the formation of less active segregated CuO phase, which was confirmed by XRD, UV-Vis and H2-TPR results. Accordingly to UV–Vis examination and DRIFT analysis using CO as a probe molecule, all solids contain Cu+1 ions which play a crucial role in the N2O decomposition mechanism. The synthesized catalysts were also tested in wet or NO containing atmospheres, where an inhibiting effect takes place and leads to shifting of conversion profiles to higher temperature by 65 and 10 °C, correspondingly. It was found out that the formation of a new, crystalline CuO·3H2O phase occurs in water vapour containing atmosphere, which can result in catalyst deactivation. However, this effect is fully reversible and the catalyst is able to replenish initial activity in dry atmosphere. Potentiality of CuO/CeO2 materials in catalytic N2O decomposition in industrial processes was confirmed by long-term stability tests performed in the period of 50 h in the presence of inhibiting gas components.
    Full-text · Article · Feb 2015 · Applied Catalysis B Environmental
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    ABSTRACT: CoFe, CoW, NiFe and NiW bimetallic pairs deposited over CeO2–ZrO2 promoted ordered mesoporous γ-Al2O3 were tested in the methane dry reforming reaction. The catalysts were characterized by N2 adsorption, wide and small angle XRD, TEM, UV-vis DRS and H2-TPR techniques. Upon thermal treatment, diffusion of Ni and Co into the alumina matrix occurred, resulting in the formation of corresponding aluminate spinels. Based on UV-vis characterization, the formation of bulk Fe2O3 could be only tentatively assigned to the NiFe/AlCZ catalyst. Bulk Co3O4 is likely present in both CoW and CoFe catalysts. CoFe/AlCZ and NiFe/AlCZ catalysts achieved high and stable methane conversion rates of 8.8 and 6.0 mmol of CH4 per gcat per min, respectively. The activity of tungsten-containing catalysts (CoW/AlCZ and NiW/AlCZ) was substantially lower compared to iron-containing catalysts (2.8 and 0.8 mmol of CH4 per gcat per min, respectively) and their deactivation was likely related to sintering and oxidation of active metal clusters. A low carbon content was accumulated on the surface of spent NiFe/AlCZ, CoFe/AlCZ and NiW/AlCZ catalysts after 20 h tests (0.6–1.2 wt%), indicating the high efficiency of the redox promoter under dry reforming conditions.
    No preview · Article · Jan 2015 · Catalysis Science & Technology
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    ABSTRACT: Abstract In this study, we report a simple synthesis procedure of anatase/rutile/brookite TiO2 nanocomposite material, designed for efficient transformation of emerging water pollutants (e.g. bisphenol A) to CO2 and H2O as final products of complete photo-oxidation. Sol-gel procedure with a subsequent hydrothermal treatment carried out at mild temperature and in the presence of 3 M HCl led to the formation of TiO2 nanomaterial, which consists of anatase (43 %), rutile (24 %) and brookite (33 %) polymorph phases within the same material. For the purpose of efficient evaluation of nanocomposite activity, individual polymorphs of anatase, rutile and brookite were also prepared using the same precursor material. Individual polymorph phases within the nanocomposite material crystallized separately and formed mixed agglomerates; the polymorphs were regularly shaped and randomly distributed in agglomerates, where some of the anatase particles exhibited truncated octahedron morphology, rutile was in the form of tetragonal prisms with pyramidal termination and brookite was shaped as blocky particles, which were found to be the smallest within the nanocomposite material (∼ 20 nm). Newly synthesized TiO2 nanocomposite was highly active in terms of mineralization, since after 60 min of irradiation under UV light almost 60 % of water dissolved pollutant bisphenol A was successfully transformed into CO2 in H2O. On the other hand, the benchmark TiO2 P25 Degussa catalyst reached a lower extent of mineralization, which is due to significantly less expressed resistance to accumulation of carbonaceous deposits on the catalyst surface.
    Full-text · Article · Jan 2015 · Applied Catalysis B Environmental
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    ABSTRACT: Zinc(II) oxide nanoparticles were used for the stabilization of dicyclopentadiene (DCPD)−water-based high internal phase emulsions (HIPEs), which were subsequently cured using ring-opening metathesis polymerization (ROMP). The morphology of the resulting ZnO- pDCPD nanocomposite foams was investigated in correlation to the nanoparticle loading and nanoparticle surface chemistry. While hydrophilic ZnO nanoparticles were found to be unsuitable for stabilizing the HIPE, oleic acid coated, yet hydrophobic, ZnO nanoparticles were effectiv HIPE stabilizers, yielding polymer foams with ZnO nanoparticles located predominately at their surface. These inorganic/organic hybrid foam-materials were subsequently calcined at 550 °C for 15 min to obtain inorganic macroporous ZnO foams with a morphology reminiscent to the original hybrid foam, and a specific surface area of 1.5 m2 g−1. Longer calcination time (550 °C, 15h) resulted in a sea urchin like morphology of the ZnO foams, characterized by higher specific surface area of 5.5 m2 g−1. The latter foam type showed an appealing catalytic performance in the catalytic wet air oxidation (CWAO) process for the destruction of bisphenol A.
    Full-text · Article · Oct 2014 · ACS Applied Materials & Interfaces
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    ABSTRACT: Ordered mesoporous CuO-CeO2 mixed oxides with different Cu loadings were synthesized by means of hard template replication approach using mesoporous silica KIT-6 as a template. Prepared materials were characterized by SEM-EDX, XRD, UV-Vis DR, N-2 adsorption/desorption, and H-2-TPR techniques. The catalytic decomposition of N2O was studied in a fixed-bed reactor in the temperature range from 300 degrees C to 600 degrees C and GHSV = 45,000 h(-1). Solids prepared by replication approach showed superior catalytic activity in comparison to materials synthesized by conventional preparation methods. Among the solids tested, the highest conversion of N2O was observed in the presence of a catalyst containing 40 mol.% Cu. Reduction of prepared samples occurs at much lower temperatures in comparison to individual CuO and CeO2 oxides due to synergetic effect present in mixed oxides. N2O decomposition tests revealed very good agreement between the catalytic activity and material reducibility, which increased with increasing Cu content from 25 to 40 mol.%. Formation of segregated CuO phase was observed for samples with Cu content above 40 mol.%. Accordingly to UV-Vis examination, all solids contain Cu+1 and Ce+3, which play a crucial role in the N2O decomposition mechanism. In wet (1.5 vol.% H2O) or NO (1.5 vol.%) containing atmospheres, where inhibiting effect due to competitive adsorption of water and NO molecules on active sites takes place, resulting conversion profiles were shifted to higher temperature by 70 degrees C and 25 degrees C, respectively. Results of long-term stability test performed in the period of 50 h confirmed good catalytic stability of an investigated material, which can be attributed to catalyst ability to regenerate active sites by desorption of formed oxygen from the catalyst surface.
    Full-text · Article · Oct 2014 · The Chemical Engineering Journal

Publication Stats

3k Citations
440.01 Total Impact Points

Institutions

  • 1994-2015
    • National Institute of Chemistry
      • • Laboratory of Environmental Sciences and Engineering
      • • Laboratory for Catalysis and Chemical Reaction Engineering
      Lubliano, Ljubljana, Slovenia
  • 1992-2013
    • University of Ljubljana
      • Faculty of Chemistry and Chemical Technology
      Lubliano, Ljubljana, Slovenia
  • 2004
    • French National Centre for Scientific Research
      • Institut de recherches sur la catalyse et l`environment de Lyon (IRCELYON)
      Lutetia Parisorum, Île-de-France, France