Albin Pintar

National Institute of Chemistry, Lubliano, Ljubljana, Slovenia

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Publications (92)225.57 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: CeO2–ZrO2 nanomaterials and pure CeO2 (up to 100 mg/L) were not harmful to zebrafish.•Only CuO modified CeO2 affected the growth of zebrafish larvae.•UV-A radiation did not enhance the toxicity of tested nanomaterials.
    Science of The Total Environment 02/2015; 506. · 3.16 Impact Factor
  • Applied Catalysis B Environmental 02/2015; 163:113–122. · 5.83 Impact Factor
  • Applied Catalysis B: Environmental. 01/2015; 164:100–112.
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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.
    ACS Applied Materials & Interfaces 10/2014; · 5.90 Impact Factor
  • Chemical Engineering Journal 10/2014; 254:153–162. · 3.47 Impact Factor
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    ABSTRACT: Complex waste streams originating from extraction processes containing residual organic solvents and increased C/N ratios have not yet been considered as feedstock for biogas production to a great extent. In this study, spent rosehip (Rosa canina L.) solid residue (64 % VS, 22 MJ/kg HHV, 30C/1N) was obtained from an industrial ethanol aided extraction process, and extensively examined in an automated batch bioreactor system for biogas production. Fraction separation of the compact lignocellulosic seeds increased the available sugar and ethanol content, resulting in high biogas potential of the sieved residue (516 NL/kg VS’). In co-digestion of spent rosehip substrate with nondeactivated nitrogen rich microbial co-substrates, methanogenesis was favored (Ym>68 %CH4). In individual digestion of microbial co-substrates, this was not the case, as biogas with 28 vol. % N2 was produced from activated sludge supplement. Therefore, effective inhibition of exogenous microbiota was achieved in the presence of carbonaceous spent rosehip.
    Bioresource Technology 08/2014; · 5.04 Impact Factor
  • International Journal of Hydrogen Energy 08/2014; 39(24):12636–12647. · 3.55 Impact Factor
  • Catalysis Communications 07/2014; · 2.92 Impact Factor
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    ABSTRACT: Catalytic wet air oxidation (CWAO) is classified as an advanced oxidation process, which proved to be highly efficient for the removal of emerging organic pollutant bisphenol A (BPA) from water. In this study, BPA was successfully removed in a batch-recycle trickle-bed reactor over bare titanate nanotube-based catalysts at very short space time of 0.6 min gCAT g−1. The as-prepared titanate nanotubes, which underwent heat treatment at 600 °C, showed high activity for the removal of aqueous BPA. Liquid-phase recycling (5- or 10-fold recycle) enabled complete BPA conversion already at 200 °C, together with high conversion of total organic carbon (TOC), i.e., 73 and 98 %, respectively. The catalyst was chemically stable in the given range of operating conditions for 189 h on stream.
    Environmental Science and Pollution Research 05/2014; · 2.76 Impact Factor
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    ABSTRACT: Ceria zirconia solid solution with a high specific surface area and oxygen storage capacity was used to support NiCo bimetallic nanoparticles and was successfully employed as a catalyst in the methane–CO2 reforming reaction. During the reforming test with an equimolar CH4/CO2 ratio at 1023 K, an initial catalyst deactivation was observed, which was followed by a slow self-reactivation. The catalyst reached its initial activity after approximately 400 h TOS with negligible carbon accumulation and H2 and CO yields of 71 and 85 %, respectively. Catalyst deactivation in the initial 25 h of reaction could be correlated to the oxidation of nanosized NiCo particles by water produced through the reversed water gas shift reaction pathway. With prolonged time on stream, sintering and growth of nanosized NiCo particles occurs, which makes them less susceptible to oxidation and slowly leads to their reduction and reactivation. In parallel, recrystallization of Ce0.8Zr0.2O2 support from cubic crystallites to a more irregular polyhedral shape occurs, which improves the oxygen storage capacity of the material and significantly contributes to the catalyst regeneration. The rate of catalyst regeneration mainly depends on the rate of Ce0.8Zr0.2O2 support recrystallization, which is driven by sintering, and is consequently much slower than the initial deactivation. Upon increasing the CH4/CO2 feed ratio to 1.5 and 2.33, water yields were significantly reduced and the previously observed catalyst deactivation could be strongly decreased or even completely avoided.
    ChemCatChem 04/2014; · 5.18 Impact Factor
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    ABSTRACT: Abstract Bisphenol A (BPA) is a well-known endocrine disruptor with adverse oestrogen-like effects eliciting adverse effects in humans and wildlife. For this reason it is necessary to set up an efficient removal of BPA from wastewaters, before they are discharged into surface waters. The aim of this study was to compare the efficiency of BPA removal from aqueous samples with photolytic, photocatalytic, and UV/H2O2 oxidation. BPA solutions were illuminated with different bulbs (halogen; 17 W UV, 254 nm; and 150 W UV, 365 nm) with or without the TiO2 P-25 catalyst or H2O2 (to accelerate degradation). Acute toxicity and oestrogenic activity of treated samples were determined using luminescent bacteria (Vibrio fischeri), water fleas (Daphnia magna), zebrafish embryos (Danio rerio), and Yeast Estrogen Screen (YES) assay with genetically modified yeast Saccharomyces cerevisiae. The results confirmed that BPA is toxic and oestrogenically active. Chemical analysis showed a reduction of BPA levels after photolytic treatment and 100 % conversion of BPA by photocatalytic and UV/H2O2 oxidation. The toxicity and oestrogenic activity of BPA were largely reduced in photolytically treated samples. Photocatalytic oxidation, however, either did not reduce BPA toxic and oestrogenic effects or even increased them in comparison with the baseline, untreated BPA solution. Our findings suggest that chemical analysis is not sufficient to determine the efficiency of advanced oxidation processes in removing pollutants from water and needs to be complemented with biological tests.
    Archives of Industrial Hygiene and Toxicology 03/2014; · 0.67 Impact Factor
  • Applied Catalysis A: General. 01/2014;
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    ABSTRACT: Abstract The influence of structural, morphological and surface properties on photocatalytic activity of pristine and modified titanate nanotubes was carefully described and discussed in the following study. Titanate nanotubes (TNTs) were prepared via alkaline hydrothermal synthesis route followed by acid washing at ambient conditions. The resulting high specific surface area nanotubular solids were further modified by two distinguished post-treatments: (i) heat-treatment in the temperature range from 300 to 700 °C, and (ii) peroxide-treatment at room temperature. Bisphenol A (BPA), a well-known endocrine disrupting compound (EDC), was selected as a testing molecule to evaluate the photodegradation potency of the modified TNTs. The resulting BPA and TOC removals confirmed that crystallinity and BET surface area of examined heat-treated solids play a crucial role in governing the photooxidation reaction. Regarding the peroxide-treated TNTs, a nearly three-fold improvement in BPA removal was attained in comparison to the pristine TNTs, which can be attributed to the redox reaction of surface titanium(IV) peroxo groups. However, the exposure of anatase-based samples to the H2O2 medium resulted in deteriorated photocatalytic oxidation of the model compound, due to recovery of surface Ti3+ defect sites, leading to increased e−–h+ recombination and decreased oxygen adsorption. In addition, a carbon-based elemental analysis of the heat-treated TNTs (TNT_500) and standard TiO2 P25 stressed the potential of tailor-made crystalline TNTs to be applied as photocatalysts for long-term removal of aqueous organics, due to low accumulation of carbonaceous deposits during the photodegradation runs.
    Catalysis Today 01/2014; · 3.31 Impact Factor
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    ABSTRACT: With the advancement of drug delivery systems based on mesoporous silica nanoparticles (MSNs), a simple and efficient method regulating the drug release kinetics is needed. We developed redox-responsive release systems with three levels of hindrance around the disulfide bond. A model drug (rhodamine B dye) was loaded into MSNs' mesoporous voids. The pore opening was capped with β-cyclodextrin in order to prevent leakage of drug. Indeed, in absence of a reducing agent the systems exhibited little leakage, while the addition of dithiothreitol cleaved the disulfide bonds and enabled the release of cargo. The release rate and the amount of released dye were tuned by the level of hindrance around disulfide bonds, with the increased hindrance causing a decrease in the release rate as well as in the amount of released drug. Thus, we demonstrated the ability of the present mesoporous systems to intrinsically control the release rate and the amount of the released cargo by only minor structural variations. Furthermore, an in vivo experiment on zebrafish confirmed that the present model delivery system is non-teratogenic.
    ACS Applied Materials & Interfaces 04/2013; · 5.90 Impact Factor
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    ABSTRACT: Model aqueous solution of bisphenol A (BPA) of 10 mg L–1 was treated in a continuous and sequential catalytic wet air oxidation (CWAO)/aerobic bioreactor (BR) system. Wet oxidation with titanate nanotube-based catalyst resulted in nearly complete removal of BPA (>99%) at a very short space time of 0.3 min·gCAT·g–1. The main identified oxidation products in the CWAO effluent were acetic acid, formic acid and p-hydroxyacetophenone (p-HAP). All of these compounds were consequently and efficiently removed in the BR system at a hydraulic residence time (HRT) of 7.2 h. Although apparent toxicity of the CWAO effluent was found higher than of the initial BPA solution, the former could be successfully detoxified through aerobic biodegradation. The combined system thus presents a potential treatment process for the efficient removal of BPA and its oxidative derivatives from wastewaters.
    Industrial & Engineering Chemistry Research. 01/2013; 52(26):9301-9307.
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    ABSTRACT: Titanate nanotube-based catalysts were prepared via alkaline hydrothermal synthesis route followed by heat-treatment at different temperatures, ranging from 300 to 700 degrees C. The resulting metal-free solids were then applied as a catalyst in a three-phase trickle-bed reactor, where catalytic wet air oxidation (CWAO) reactions of model aqueous bisphenol A (BPA) solution were performed. Mainly, the CWAO experiments were conducted at 200 degrees C with oxygen partial pressure of 10 bar over 300 mg of a catalyst. It was observed in the given range of operating conditions that BPA undergoes both non-catalytic as well as catalytic oxidation routes, while the latter is far more pronounced. At 210 degrees C and in the presence of 0.5 g of titanate nanotube-based catalyst, which was annealed at 600 degrees C, complete BPA removal was obtained. From TOC point of view, approximately 70% conversion was achieved indicating the persistence of refractory intermediates of lower carboxylic acids. The cross-section of results derived from various analytical techniques, which were used to identify surface, textural and morphological properties, revealed that balanced physicochemical properties are required to achieve meaningful extent of BPA removal. During 2-4 day time on stream, no catalyst deactivation occurred that could be attributed to the dissolution of active powders, or to the carbonaceous deposits accumulated on the catalyst surface. Therefore, these nanotubular materials can be regarded as innocuous and efficient long-term catalysts for oxidation of hazardous organic compounds (such as BPA) in the CWAO process. (c) 2012 Elsevier B.V. All rights reserved.
    Applied Catalysis B Environmental 01/2013; 132:342-352. · 5.83 Impact Factor
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    ABSTRACT: It is important to understand each analytical system and its limitations when performing any chromatographic measurements. In the present paper, a methodology for method validation and measurement uncertainty evaluation for the measurement of volume fractions of selected gases (CO2, CO, CH4, H2) in simulated reformate gas streams by using gas chromatography was developed. A detailed procedure for in-house method validation based on a simple experimental design and consistent statistics is presented. The analytical protocol allowed us to quantify gases in volume fractions from 2.00 to 100.0 mL/(100 mL) with satisfactory recoveries. We proved that the method was selective for the measurement of gases in simulated reformate gas stream. In addition, a step-by-step illustration of modelling approach for measurement uncertainty evaluation of each component is also provided. Uncertainty arising from repeatability and trueness is relatively low, while the contribution from reproducibility is of higher level for all the analytes tested. The main reason for this is changes in atmospheric pressure that affect gas chromatographic measurements. Solution of this problem could be more frequent calibration of apparatus, yielding to higher costs and more time-consuming process, or by measuring the atmospheric pressure and using it to correct the response of the gas chromatograph for resulting variations in sample size. The obtained results confirm that it is imperative to fully characterize the analytical system before proceeding with an analysis.
    Accreditation and Quality Assurance 01/2013; 18(3). · 1.13 Impact Factor
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    ABSTRACT: Catalytic wet air oxidation (CWAO) of aqueous bisphenol A (BPA) solution was studied in a continuous-flow trickle-bed reactor in the presence of titanate nanotube-based catalysts. These active metal-free solids were prepared by alkaline hydrothermal synthesis followed by heat treatment at temperatures ranging from 300 to 700 °C, so that they would have varying physicochemical properties. The aim of the study was to investigate the removal efficiency of titanate nanotube-based catalysts used in the CWAO process to remove toxicity and estrogenicity of BPA at a very short space time of 0.6 min·gCAT·g–1. In addition, noncatalytic BPA degradation in the presence of inert SiC particles was also performed. As a result, significantly higher estrogenicity and toxic effects of the liquid-phase sample compared to the catalytic oxidation experiments were observed. Complete removal of estrogenicity and high reduction of toxicity from aqueous solution were achieved at 210 °C over 0.5 g of catalyst that had been annealed at 600 °C.
    Industrial & Engineering Chemistry Research. 01/2013; 52(35):12559-12566.
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    ABSTRACT: Bisphenol A (BPA) is a well known endocrine disruptor. Significantly less is known about its ability to induce antioxidant defense and oxidative stress in aquatic organisms. This is an interesting subject because BPA can act both as a prooxidant (induces the formation of reactive oxygen species) and an antioxidant. The aim of the present study was to elucidate if BPA induces changes in the activities of antioxidant enzymes catalase (CAT) and glutathione S-transferases (GSTs) and the level of lipid peroxidation in crustacean Daphnia magna. These biomarkers were followed after acute (48h) and chronic (21d) exposure period. Interestingly, CAT and GSTs were changed in the same manner after both exposure durations. The most observable change in daphnids was the increase of GSTs activities, measured with 1,2-chloro-4-dinitrobenzene as a substrate. No GSTs activities with ethacrynic acid and 1,2-dichloro-4-nitrobenzene as substrates were detected. The activity of CAT and the level of lipid peroxidation remained unchanged in daphnids exposed to sublethal concentrations of BPA. The reproduction rate was considerably affected already at 1.73mg/L while the growth was only affected at the highest concentration (13.8mg/L), where also significant mortality was observed.
    Ecotoxicology and Environmental Safety 10/2012; · 2.20 Impact Factor
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    ABSTRACT: TiO2 doped with 0.1–10% Nd3+ or 1.8% nitrogen or co-doped with both dopants as well as Nd2Ti2O7 are synthesized by a sol–gel. The phase composition, crystal structure, morphology, optical properties and binding energies of the doped titania were investigated. The photocatalytic activity was tested for malachite green dye degradation and compared with the results obtained by dopant-free TiO2 synthesized using the same procedure and with the commercial Degussa P25 product. The influence of the dopant type and relative content, temperature of ignition in the course of the synthesis, pH of the reaction medium and the type of the illumination light on the efficiency of the prepared catalysts were determined. A positive effect of Nd- and N-doping on the apparent degradation rate constant under UV irradiation and negative one of Nd-presence at solar illumination is found. Nd–N-codoping has a negative effect on the photocatalytic activity.
    Materials Research Bulletin. 09/2012; 47(9):2165–2177.

Publication Stats

741 Citations
225.57 Total Impact Points

Institutions

  • 1995–2014
    • National Institute of Chemistry
      • • Laboratory of Environmental Sciences and Engineering
      • • Laboratory for Catalysis and Chemical Reaction Engineering
      Lubliano, Ljubljana, Slovenia
  • 1992–2009
    • University of Ljubljana
      Lubliano, Ljubljana, Slovenia
  • 2004
    • Jožef Stefan Institute
      Lubliano, Ljubljana, Slovenia
    • French National Centre for Scientific Research
      • Institut de recherches sur la catalyse et l`environment de Lyon (IRCELYON)
      Lutetia Parisorum, Île-de-France, France