“Air quality monitoring in a museum for preventive conservation : results of a three-year study in the Plantin-Moretus Museum in Antwerp, Belgium”. Krupińska B, Van Grieken R, De Wael K, Microchemical journal 110, 350 (2013). http://doi.org/10.1016/J.MICROC.2013.05.006
Abstract: Through different research projects on air quality in museums, researcher and conservators try identifying various risks of air pollution on materials. The conclusions may be later translated into specific actions for a maximum preservation of the museum collections, a process known as preventive conservation. Air pollution is a particular problem in historical buildings such as museums, because they were not originally built to exhibit and protect art objects in a sustainable way. This article reports on the data and results that were obtained during 10 sampling campaigns, in the period between November 2008 and February 2012 in a museum in Antwerp (Belgium), i.e. Plantin-Moretus Museum/Print Room. Different pollutants were measured inside and outside the museum such as inorganic gases, particulate matter and black carbon. The report specifically addresses environmental factors that may be responsible for damage to the collections present in museums. Thanks to the knowledge about the current situation in the museum, accurate solutions regarding preventive conservation, in general, are suggested.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 3.034
Times cited: 46
DOI: 10.1016/J.MICROC.2013.05.006
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“Spatially resolved (semi)quantitative determination of iron (Fe) in plants by means of synchrotron micro X-ray fluorescence”. Terzano R, Alfeld M, Janssens K, Vekemans B, Schoonjans T, Vincze L, Tomasi N, Pinton R, Cesco S, Analytical and bioanalytical chemistry 405, 3341 (2013). http://doi.org/10.1007/S00216-013-6768-6
Abstract: Iron (Fe) is an essential element for plant growth and development; hence determining Fe distribution and concentration inside plant organs at the microscopic level is of great relevance to better understand its metabolism and bioavailability through the food chain. Among the available microanalytical techniques, synchrotron mu-XRF methods can provide a powerful and versatile array of analytical tools to study Fe distribution within plant samples. In the last years, the implementation of new algorithms and detection technologies has opened the way to more accurate (semi)quantitative analyses of complex matrices like plant materials. In this paper, for the first time the distribution of Fe within tomato roots has been imaged and quantified by means of confocal mu-XRF and exploiting a recently developed fundamental parameter-based algorithm. With this approach, Fe concentrations ranging from few hundreds of ppb to several hundreds of ppm can be determined at the microscopic level without cutting sections. Furthermore, Fe (semi)quantitative distribution maps were obtained for the first time by using two opposing detectors to collect simultaneously the XRF radiation emerging from both sides of an intact cucumber leaf.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 3.431
Times cited: 27
DOI: 10.1007/S00216-013-6768-6
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“Microchemical investigation of bone derived from mice treated with strontium in different chemical forms using scanning electron microscopy and micro-Raman spectroscopy”. Jabłoński MB, Stefaniak EA, Darchuk L, Turzańska K, Gorzelak M, Kuduk R, Dorriné, W, Van Grieken R, Microchemical journal 108, 168 (2013). http://doi.org/10.1016/J.MICROC.2012.10.015
Abstract: We used SEM/EDX and micro-Raman spectroscopy to investigate the chemical changes (both on the level of elementary and molecular composition) of mice bones when strontium is incorporated in their microstructure after being administered in the form of two salts: chloride and ranelate. Strontium accumulated mainly in vicinity of bone edges, both cortical and close to bone marrow. The distribution of other elements comprising bone samples (Ca, P, Mg, K etc.) was also determined by energy-dispersive X-ray analysis (EDX). The area adjacent to a cortical bone edge with accumulated strontium has presented modified Raman spectral profiles. Besides most of the Raman bands typical for both mineral (hydroxyapatite with carbonate substitution type B) and organic phases of a bone, we observed a Raman band at 811 cm− 1. It was detected regularly in the sample with high strontium concentration.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/J.MICROC.2012.10.015
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“Gross alpha and beta activities of airborne particulate samples from Wawel Royal Castle Museum in Cracow, Poland”. Akbulut S, Krupinska B, Worobiec A, Čevik U, Taskin H, Van Grieken R, Samek L, Wiłkojć, E, Journal of radioanalytical and nuclear chemistry 295, 1567 (2013). http://doi.org/10.1007/S10967-012-1983-8
Abstract: Soils are complex mixtures of organic, inorganic materials, and metal compounds from anthropogenic sources. In order to identify the pollution sources, their magnitude and development, several X-ray analytical methods were applied in this study. The concentrations of 16 elements were determined in all the soil samples using energy dispersive X-ray fluorescence spectrometry. Soils of unknown origin were observed by scanning electron microscopy equipped with a Si(Li) X-ray detector using Monte Carlo simulation approach. The mineralogical analyses were carried out using X-ray diffraction spectrometry. Due to the correlations between heavy metals and oxide compounds, the samples were analyzed also by electron probe microanalyzer (EPMA) in order to have information about their oxide contents. On the other hand, soil pH and salinity levels were identified owing to their influence between heavy metal and soil-surface chemistry. Moreover, the geoaccumulation index (I geo) enables the assessment of contamination by comparing current and pre-industrial concentrations.
Keywords: A1 Journal article; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Laboratory Experimental Medicine and Pediatrics (LEMP)
DOI: 10.1007/S10967-012-1983-8
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“Biotemplated diatom silica-titania materials for air purification”. Van Eynde E, Tytgat T, Smits M, Verbruggen SW, Hauchecorne B, Lenaerts S, Photochemical &, photobiological sciences 12, 690 (2013). http://doi.org/10.1039/C2PP25229E
Abstract: We present a novel manufacture route for silicatitania photocatalysts using the diatom microalga Pinnularia sp. Diatoms self-assemble into porous silica cell walls, called frustules, with periodic micro-, meso- and macroscale features. This unique hierarchical porous structure of the diatom frustule is used as a biotemplate to incorporate titania by a solgel methodology. Important material characteristics of the modified diatom frustules under study are morphology, crystallinity, surface area, pore size and optical properties. The produced biosilicatitania material is evaluated towards photocatalytic activity for NOx abatement under UV radiation. This research is the first step to obtain sustainable, well-immobilised silicatitania photocatalysts using diatoms.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 2.344
Times cited: 18
DOI: 10.1039/C2PP25229E
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“Photocatalytic degradation of soot deposition : self-cleaning effect on titanium dioxide coated cementitious materials”. Smits M, Chan C kit, Tytgat T, Craeye B, Costarramone N, Lacombe S, Lenaerts S, Chemical engineering journal 222, 411 (2013). http://doi.org/10.1016/J.CEJ.2013.02.089
Abstract: Diesel soot emissions deteriorate the appearance of architectural building materials by soot fouling. This soot deposition devalue the aesthetic value of the building. A solution to counteract this problem is applying titanium dioxide on building materials. TiO2 can provide air-purifying and self-cleaning properties due to its photocatalytic activity. In literature, photocatalytic soot oxidation is observed on glass or silicon substrates. However, degradation of soot by photocatalysis was not yet investigated on cementitious samples (mortar, concrete) although it is one of the most frequently used building materials. In this study, photocatalytic soot oxidation by means of TiO2 coated cementitious samples is addressed. The soot removal capacity of four types of TiO2 layers, coated on mortar samples, is evaluated by means of two detection methods. The first method is based on colorimetric measurements, while the second method uses digital image processing to calculate the area of soot coverage. The experimental data revealed that cementitious materials coated with commercially available TiO2 exhibited self-cleaning properties as it was found that all coated samples were able to remove soot. The P25 coating gave the best soot degradation performance, while the Eoxolit product showed the slowest soot degradation rate. In addition, gas chromatography measurements in a closed chamber experiment with P25 confirmed that complete mineralization of about 60% of the soot was obtained within 24 hours since CO2 was the sole observed oxidation product. Due to its realistic approach, this study proves that photocatalytic soot removal on TiO2 coated cementitious surfaces is possible in practice, which is an important step towards the practical application of self-cleaning building materials.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 6.216
Times cited: 43
DOI: 10.1016/J.CEJ.2013.02.089
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“Unravelling the mysteries of gas phase photocatalytic reaction pathways by studying the catalyst surface : a literature review of different Fourier transform infrared spectroscopic reaction cells used in the field”. Hauchecorne B, Lenaerts S, Journal of photochemistry and photobiology: C: photochemistry reviews 14, 72 (2013). http://doi.org/10.1016/J.JPHOTOCHEMREV.2012.09.003
Abstract: Unlike the profound knowledge of the reaction mechanisms occurring in water phase photocatalysis, still fairly little is known on the reaction mechanisms occurring on the catalyst surface when dealing with gaseous pollutants. Unfortunately, there are some differences between both reactions. For one, there are no abundant hydroxyl radicals present in the gas phase, so that possibly other species prove to be important in abating the pollutant. In order to unravel the mysteries of gas phase photocatalytic reaction pathways, in situ techniques must be used to allow the detection and identification of reaction intermediates on a working catalyst. Several techniques were already used in the past, of which Fourier transform infrared spectroscopy seems to be the most versatile. This review will therefore give a selective overview of different spectroscopic reaction cells constructed for the in situ study of photocatalytic gas phase reactions.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 12.317
Times cited: 8
DOI: 10.1016/J.JPHOTOCHEMREV.2012.09.003
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“Combined use of synchrotron radiation based micro-X-ray fluorescence, micro-X-ray diffraction, micro-X-ray absorption near-edge, and micro-fourier transform infrared spectroscopies for revealing an alternative degradation pathway of the pigment cadmium yellow in a painting by Van Gogh”. van der Snickt G, Janssens K, Dik J, de Nolf W, Vanmeert F, Jaroszewicz J, Cotte M, Falkenberg G, Van der Loeff L, Analytical chemistry 84, 10221 (2012). http://doi.org/10.1021/AC3015627
Abstract: Over the past years a number of studies have described the instability of the pigment cadmium yellow (CdS). In a previous paper we have shown how cadmium sulfide on paintings by James Ensor oxidizes to CdSO4 center dot H2O. The degradation process gives rise to the fading of the bright yellow color and the formation of disfiguring white crystals that are present on the paint surface in approximately 50 mu m sized globular agglomerations. Here, we study cadmium yellow in the painting “Flowers in a blue vase” by Vincent van Gogh. This painting differs from the Ensor case in the fact that (a) a varnish was superimposed onto the degraded paint surface and (b) the CdS paint area is entirely covered with an opaque crust. The latter obscures the yellow color completely and thus presents a seemingly more advanced state of degradation. Analysis of a cross-sectioned and a crushed sample by combining scanning microscopic X-ray diffraction (mu-XRD), microscopic X-ray absorption near-edge spectroscopy (mu-XANES), microscopic X-ray fluorescence (mu-XRF) based chemical state mapping and scanning microscopic Fourier transform infrared (mu-FT-IR) spectrometry allowed unravelling the complex alteration pathway. Although no crystalline CdSO4 compounds were identified on the Van Gogh paint samples, we conclude that the observed degradation was initially caused by oxidation of the original CdS pigment, similar as for the previous Ensor case. However, due to the presence of an overlying varnish containing lead-based driers and oxalate ions, secondary reactions took place. In particular, it appears that upon the photoinduced oxidation of its sulfidic counterion, the Cd2+ ions reprecipitated at the paint/varnish interface after having formed a complex with oxalate ions that themselves are considered to be degradation products of the resin and/or oil in the varnish. The SO42- anions, for their part, found a suitable reaction partner in Pb2+ ions stemming from a dissolved lead-based siccative that was added to the varnish to promote its drying. The resulting opaque anglesite compound in the varnish, in combination with the underlying CdC2O4 layer at the paint/varnish interface, account for the orange-gray crust that is disfiguring the painting on a macroscopic level. In this way, the results presented in this paper demonstrate how, through a judicious combined use of several microanalytical methods with speciation capabilities, many new insights can be obtained from two minute, but highly complex and heterogeneous paint samples.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 6.32
Times cited: 59
DOI: 10.1021/AC3015627
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“Mineral dust variability in central West Antarctica associated with ozone depletion”. Cataldo M, Evangelista H, Simões JC, Godoi RHM, Simmonds I, Hollanda MH, Wainer I, Aquino F, Van Grieken R, Atmospheric chemistry and physics 13, 2165 (2013). http://doi.org/10.5194/ACP-13-2165-2013
Abstract: We present here data of mineral dust variability retrieved from an ice core of the central West Antarctic, spanning the last five decades. Main evidence provided by the geochemical analysis is that northerly air mass incursions to the coring site, tracked by insoluble dust microparticles, have declined over the past 50 yr. This result contrasts with dust records from ice cores reported to the coastal West Antarctic that show increases since mid-20th century. We attribute this difference to regional climatic changes due to the ozone depletion and its implications to westerly winds. We found that the diameters of insoluble microparticles in the central West Antarctica ice core are significantly correlated with cyclone depth (energy) and wind intensity around Antarctica.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.5194/ACP-13-2165-2013
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“Influence of the deposition method, temperature and deposition time on the corrosion inhibition of lead dodecanoate coatings deposited on lead surfaces”. De Keersmaecker M, De Wael K, Adriaens A, Journal of solid state electrochemistry 17, 1259 (2013). http://doi.org/10.1007/S10008-012-1964-4
Abstract: Electrochemical impedance measurements have been used to investigate the influence of the deposition method, including time and temperature, upon the corrosion inhibition characteristics of lead dodecanoate coatings on lead electrodes. The results were analysed using multivariate statistics and show that, in general, these easily prepared coatings are very protective against corrosion. The temperature proves to be an important parameter for the quality and the corrosion inhibition efficiency of the coating. A comparison between two different electrochemically assisted deposition methods, immersion using a reduction pretreatment and cyclic voltammetry, does not show significant differences. Using the immersion technique at room temperature, the deposition time was tested as the third influencing parameter for the corrosion inhibition efficiency of the deposited lead dodecanoate coatings. A longer deposition time of the lead into the sodium dodecanoate solution provides a layer with a somewhat higher corrosion resistance.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 2.316
Times cited: 4
DOI: 10.1007/S10008-012-1964-4
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“Photocatalytic removal of soot : unravelling of the reaction mechanism by EPR and in situ FTIR spectroscopy”. Smits M, Ling Y, Lenaerts S, Van Doorslaer S, ChemPhysChem : a European journal of chemical physics and physical chemistry 13, 4251 (2012). http://doi.org/10.1002/CPHC.201200674
Abstract: Photocatalytic soot oxidation is studied on P25 TiO2 as an important model reaction for self-cleaning processes by means of electron paramagnetic resonance (EPR) and Fourier transform infrared (FTIR) spectroscopy. Contacting of carbon black with P25 leads on the one hand to a reduction of the local dioxygen concentration in the powder. On the other hand, the weakly adsorbed radicals on the carbon particles are likely to act as alternative traps for the photogenerated conduction-band electrons. We find furthermore that the presence of dioxygen and oxygen-related radicals is vital for the photocatalytic soot degradation. The complete oxidation of soot to CO2 is evidenced by in situ FTIR spectroscopy, no intermediate CO is detected during the photocatalytic process.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 3.075
Times cited: 9
DOI: 10.1002/CPHC.201200674
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“The non-destructive determination of REE in fossilized bone using synchrotron radiation induced K-line X-ray microfluorescence analysis”. Janssens K, Vincze L, Vekemans B, Williams CT, Radtke M, Haller M, Knöchel A, Fresenius' journal of analytical chemistry 363, 413 (1999). http://doi.org/10.1007/S002160051212
Abstract: The sensitivity and applicability of the synchrotron radiation induced X-ray microfluorescence (mu-SRXRF) spectrometer at the Hamburg synchrotron laboratory Hasylab for the determination of the distribution of trace concentrations of rare-earth elements (REE) in fossilized bone are discussed and critically compared to those of other trace analytical methods such as instrumental neutron activation analysis (INAA) and LAMP-ICPMS (laser ablation microprobe inductively-coupled plasma mass spectrometry). Measurements were carried out on two bone samples from contrasting terrestrial depositional environments at Olduvai Gorge (Tanzania). Results indicate that the microdistribution of the REE in these biological materials is not homogeneous and that the relative abundance of these elements can provide information on the palaeoenvironment during the fossilization process. The heterogeneous distribution of the REE can be determined in a quantitative and completely non-destructive manner provided the concentrations of individual REE are above 10 mu g/g.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1007/S002160051212
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“Removal of natural organic matter from water by using ion-exchange resins”. Kabsch-Korbutowicz M, Krupinska B, Przemysl chemiczny
T2 –, Scientific and Technical Conference on Water and Wastewater Basis for, Environmental Protection (School of Quality Water 2008), MAY 28-30, 2008, Kolobrzeg, POLAND 87, 473 (2008)
Abstract: Four aq. solns. contg. natural peat components and the water from Odra river were treated with 3 anion-exchange resins (2.5 to 15 cm(3) of resin per 1 dm(3) of the sample) for 5-60 min to remove the org. matter. The process efficiency was detd. by UV absorbance (254 nm) and colour intensity measurements. The treatment resulted in discoloration of the solns. A resin with weak alky, was the most efficient. The degree of removal increased with increasing the resin dose and contact time. The presence of inorg. anions in the soins. contributed to a decrease of process effectivity.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Mineral dust variability in central West Antarctica associated with ozone depletion”. Cataldo, Evangelista H, Simões JC, Godoi RHM, Simmonds I, Hollanda MH, Wainer I, Aquino FE, Van Grieken R, Atmospheric chemistry and physics discussions 12, 12685 (2012). http://doi.org/10.5194/ACPD-12-12685-2012
Abstract: Here we show that mineral dust retrieved from an ice core in the central West Antarctic sector, spanning the last five decades, provides evidence that northerly air mass incursions into Antarctica, tracked by dust microparticles, have slightly declined. This result contrasts with dust in ice core records reported in West/coastal Antarctica, which show significant increases to the present day. We attribute that difference, in part, to changes in the regional climate regime triggered by the ozone depletion and its consequences for the polar vortex intensity. The vortex maintains the Antarctic central region relatively isolated from mid-latitude air mass incursions with implications to the intensification of the Westerlies and to a persistent positive phase of the Southern Annular Mode. We also show that variability of the diameter of insoluble microparticles in central West Antarctica can be modeled by linear/quadratic functions of both cyclone depth (energy) and wind intensity around Antarctica.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.5194/ACPD-12-12685-2012
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“Self-inhibition can limit biologically enhanced TCE dissolution from a TCE DNAPL”. Haest PJ, Springael D, Seuntjens P, Smolders E, Chemosphere 89, 1369 (2012). http://doi.org/10.1016/J.CHEMOSPHERE.2012.05.097
Abstract: Biodegradation of trichloroethene (TCE) near a Dense Non Aqueous Phase Liquid (DNAPL) can enhance the dissolution rate of the DNAPL by increasing the concentration gradient at the DNAPL-water interface. Two-dimensional flow-through sand boxes containing a ICE DNAPL and inoculated with a TCE dechlorinating consortium were set up to measure this bio-enhanced dissolution under anaerobic conditions. The total mass of TCE and daughter products in the effluent of the biotic boxes was 3-6 fold larger than in the effluent of the abiotic box. However, the mass of daughter products only accounted for 19-55% of the total mass of chlorinated compounds in the effluent, suggesting that bio-enhanced dissolution factors were maximally 1.3-2.2. The enhanced dissolution most likely primarily resulted from variable DNAPL distribution rather than biodegradation. Specific dechlorination rates previously determined in a stirred liquid medium were used in a reactive transport model to identify the rate limiting factors. The model adequately simulated the overall TCE degradation when predicted resident microbial numbers approached observed values and indicated an enhancement factor for TCE dissolution of 1.01. The model shows that dechlorination of TCE in the 20 box was limited due to the short residence time and the self-inhibition of the TCE degradation. A parameter sensitivity analysis predicts that the bio-enhanced dissolution factor for this TCE source zone can only exceed a value of 2 if the TCE self-inhibition is drastically reduced (when a TCE tolerant dehalogenating community is present) or if the DNAPL is located in a low-permeable layer with a small Darcy velocity. (C) 2012 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.CHEMOSPHERE.2012.05.097
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“Component-specific toxic concerns of the inhalable fraction of urban road dust”. Potgieter-Vermaak S, Rotondo G, Novacovic V, Rollins S, Van Grieken R, Environmental geochemistry and health 34, 689 (2012). http://doi.org/10.1007/S10653-012-9488-5
Abstract: Continuous global urbanisation causes an ever-growing ecological footprint of pollution. Road dust (RD), one of these pollutants, poses a health concern due to carcinogenic and toxic components potentially present in the micron-sized fractions. The literature reports on the concentrations of trace, toxic metals and metalloids present in RD (Hooker and Nathanail in Chem Geol 226:340-351, 2006), but the literature on its molecular composition is limited. Recent reports on the bioaccessibility of platinum group metals are also reported (Colombo et al. in Chem Geol 226:340-351, 2008). In vitro and animal toxicological studies confirmed that the chemical composition of inhaled particles plays a major role in its toxic, genotoxic and carcinogenic mechanisms, but the component-specific toxic effects are still not understood. Particle-bound airborne transition metals can also lead to the production of reactive oxygen species in lung tissue; a special concern amongst particularly susceptible cohorts (children and elderly). The characterisation of the molecular composition of the fine fraction is evidently of importance for public health. During a pilot study, partially characterised size-fractioned RD samples (Barrett et al. in Eviron Sci Technol 44:2940-2946, 2010) were analysed for their elemental concentration using X-ray fluorescence spectrometry and inductively coupled plasma mass spectrometry. In addition, separately dispersed particles (200 particles per size fraction) were analysed individually by means of computer-controlled electron probe X-ray micro-analysis (CC-EPXMA) and their molecular structure probed by studying elemental associations. These were correlated with micro-Raman spectroscopy (MRS) results. It was found that the fine fraction (< 38 mu m) had the highest Pb (238 ppm) and Cr (171 ppm) concentrations. The CC-EPXMA data showed > 50 % association of Cr-rich particles with Pb, and the MRS data showed that the Cr was mostly present as lead chromate and therefore in the Cr(VI) oxidation state. Concentrations of both Pb and Cr decreased substantially (279 (< 38 mu m)-13 ppm (< 1 mm); 171 (< 38 mu m)-91 ppm (< 1 mm), respectively) in the larger fractions. Apart from rather alarmingly high concentrations of oxidative stressors (Cu, Fe, Mn), the carcinogenic and toxic potential of the inhalable fraction is evident. Preliminary bioaccessibility data indicated that both Cr and Pb are readily mobilised in artificial lysosomal liquid and up to 19 % of Cr and 47 % of Pb were released.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1007/S10653-012-9488-5
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“Stable carbon isotopic ratio measurement of polycyclic aromatic hydrocarbons as a tool for source identification and apportionment : a review of analytical methodologies”. Buczyńska AJ, Geypens B, Van Grieken R, De Wael K, Talanta : the international journal of pure and applied analytical chemistry 105, 435 (2013). http://doi.org/10.1016/J.TALANTA.2012.10.075
Abstract: The measurement of the ratio of stable isotopes of carbon (13C/12C expressed as a δ13C) in the individual components of a sample may be used as a means to identify the origin of these components. This article reviews the approaches and reports on the successes and failures of source identification and apportionment of Polycyclic Aromatic Hydrocarbons (PAHs) with the use of compound-specific isotope analysis (CSIA). One of the conditions for a precise and accurate analysis of isotope ratios with the use of GC-C-IRMS is the need for well separated peaks, with no co-elutions, and reduced unresolved complex mixture (UCM). Additionally, special care needs to be taken for an investigation of possible isotope fractionation effects introduced during the analytical treatment of samples. With the above-mentioned problems in mind, this review discusses in detail and compares current laboratory methodologies, mainly in the extraction and subsequent clean-up techniques used for environmental samples (air particulate matter, soil and sediments). Sampling strategies, the use of isotopic internal standards and the ranges for precision and accuracy are also reported and discussed.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 4.162
Times cited: 19
DOI: 10.1016/J.TALANTA.2012.10.075
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“Chemical boundary conditions for the classification of aerosol particles using computer controlled electron probe microanalysis”. Anaf W, Horemans B, Van Grieken R, De Wael K, Talanta : the international journal of pure and applied analytical chemistry 101, 420 (2012). http://doi.org/10.1016/J.TALANTA.2012.09.051
Abstract: A method for the classification of individual aerosol particles using computer controlled electron probe microanalysis is presented. It is based on chemical boundary conditions (CBC) and enables quick and easy processing of a large set of elemental concentration data (mass%), derived from the X-ray spectra of individual particles. The particles are first classified into five major classes (sea salt related, secondary inorganic, minerals, iron-rich and carbonaceous), after which advanced data mining can be performed by examining the elemental composition of particles within each class into more detail (e.g., by ternary diagrams). The CBC method is validated and evaluated by comparing its results with the output obtained with hierarchical cluster analysis (HCA) for well-known standard particles as well as real aerosol particles collected with a cascade impactor. The CBC method gives reliable results and has a major advantage compared to HCA. CBC is based on boundary conditions that are derived from chemical logical thinking and does not require a translation of a mathematical algorithm output as does HCA. Therefore, the CBC method is more objective and enables comparison between samples without intermediate steps.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 4.162
Times cited: 3
DOI: 10.1016/J.TALANTA.2012.09.051
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“Fullerene-C60 sensor for ultra-high sensitive detection of bisphenol-A and its treatment by green technology”. Rather JA, De Wael K, Sensors and actuators : B : chemical 176, 110 (2013). http://doi.org/10.1016/J.SNB.2012.08.081
Abstract: Endocrine disruptors (EDCs) are environmental pollutants that, once incorporated into an organism, affect the hormonal balance of humans and various species. Its presence in environment is of great importance in water quality related questions. The proposed method describes the development of an accurate, sensitive and selective sensor for the detection of bisphenol-A (BPA) and its treatment by green technology. A fullerene (C60) fabricated electrochemical sensor was developed for the ultrasensitive detection of BPA. The homemade sensor was characterized by scanning electron microscopy, electrochemical impedance spectroscopy and chronocoulometry. The influence of measuring parameters such as pH and C60 loading on the analytical performance of the sensor was evaluated. Various kinetic parameters such as electron transfer number (n); charge transfer coefficient (α); electrode surface area (A) and diffusion coefficient (D) were also calculated. Under the optimal conditions, the oxidation peak current was linear over the concentration range of 74 nM to 0.23 μM with the detection limit (LOD) of 3.7 nM. The fabricated sensor was successfully applied to the determination of BPA in wastewater samples and it has promising analytical applications for the direct determination of BPA at trace level.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 5.401
Times cited: 79
DOI: 10.1016/J.SNB.2012.08.081
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“C60-functionalized MWCNT based sensor for sensitive detection of endocrine disruptor vinclozolin in solubilized system and wastewater”. Rather JA, De Wael K, Sensors and actuators : B : chemical 171/172, 907 (2012). http://doi.org/10.1016/J.SNB.2012.06.003
Abstract: A novel fullerene (C60) functionalized multi-walled carbon nanotubes (MWCNTs) fabricated electrochemical sensor was developed for the sensitive determination of the endocrine disruptor vinclozolin in a solubilized system of cetyltrimethyl ammonium bromide (CTAB). The home-made sensor was characterized by scanning electron microscopy and electrochemical impedance spectroscopy. It was found that the nanocomposite film of C60MWCNTs on GCE exhibits electrocatalytic activity towards vinclozolin reduction and also lowers the reduction overpotential. The influence of the optimization parameters such as pH, effect of CTAB concentration and effect of loading of composite mixture of C60 and MWCNTs on the analytical performance of the sensor was evaluated. Various kinetic parameters such as electron transfer number (n), proton transfer number (m), charge transfer coefficient (α) and diffusion coefficient (D) were also calculated. Under optimized conditions, the squarewave reduction peak current was linear over the concentration range of 2.548.75 μM with the detection and quantification limit of 0.091 μM and 0.3 μM respectively. The fabricated sensor was successfully applied to the detection of vinclozolin in wastewater with good recovery ranging from 97.6 to 103.6%.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 5.401
Times cited: 26
DOI: 10.1016/J.SNB.2012.06.003
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“Perspectives of Plasma-treated Solutions as Anticancer Drugs”. Attri P, Bogaerts A, Anti-cancer agents in medicinal chemistry 19, 436 (2019). http://doi.org/10.2174/187152061904190521102345
Keywords: A1 Journal article; Pharmacology. Therapy; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.598
Times cited: 2
DOI: 10.2174/187152061904190521102345
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“How process parameters and packing materials tune chemical equilibrium and kinetics in plasma-based CO2 conversion”. Uytdenhouwen Y, Bal Km, Michielsen I, Neyts Ec, Meynen V, Cool P, Bogaerts A, Chemical engineering journal 372, 1253 (2019). http://doi.org/10.1016/j.cej.2019.05.008
Abstract: Plasma (catalysis) reactors are increasingly being used for gas-based chemical conversions, providing an alternative method of energy delivery to the molecules. In this work we explore whether classical concepts such as
equilibrium constants, (overall) rate coefficients, and catalysis exist under plasma conditions. We specifically
investigate the existence of a so-called partial chemical equilibrium (PCE), and how process parameters and
packing properties influence this equilibrium, as well as the overall apparent rate coefficient, for CO2 splitting in
a DBD plasma reactor. The results show that a PCE can be reached, and that the position of the equilibrium, in
combination with the rate coefficient, greatly depends on the reactor parameters and operating conditions (i.e.,
power, pressure, and gap size). A higher power, higher pressure, or smaller gap size enhance both the equilibrium constant and the rate coefficient, although they cannot be independently tuned. Inserting a packing
material (non-porous SiO2 and ZrO2 spheres) in the reactor reveals interesting gap/material effects, where the
type of material dictates the position of the equilibrium and the rate (inhibition) independently. As a result, no
apparent synergistic effect or plasma-catalytic behaviour was observed for the non-porous packing materials
studied in this reaction. Within the investigated parameters, equilibrium conversions were obtained between 23
and 71%, while the rate coefficient varied between 0.027 s−1 and 0.17 s−1. This method of analysis can provide
a more fundamental insight in the overall reaction kinetics of (catalytic) plasma-based gas conversion, in order
to be able to distinguish plasma effects from true catalytic enhancement.
Keywords: A1 Journal article; Laboratory of adsorption and catalysis (LADCA); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 6.216
Times cited: 3
DOI: 10.1016/j.cej.2019.05.008
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“Plasma for cancer treatment: How can RONS penetrate through the cell membrane? Answers from computer modeling”. Bogaerts A, Yusupov M, Razzokov J, Van der Paal J, Frontiers of Chemical Science and Engineering (2019). http://doi.org/10.1007/s11705-018-1786-8
Abstract: Plasma is gaining increasing interest for cancer
treatment, but the underlying mechanisms are not yet fully
understood. Using computer simulations at the molecular
level, we try to gain better insight in how plasma-generated
reactive oxygen and nitrogen species (RONS) can
penetrate through the cell membrane. Specifically, we
compare the permeability of various (hydrophilic and
hydrophobic) RONS across both oxidized and nonoxidized cell membranes. We also study pore formation,
and how it is hampered by higher concentrations of
cholesterol in the cell membrane, and we illustrate the
much higher permeability of H2O2 through aquaporin
channels. Both mechanisms may explain the selective
cytotoxic effect of plasma towards cancer cells. Finally, we
also discuss the synergistic effect of plasma-induced
oxidation and electric fields towards pore formation.
Keywords plasma medicine, cancer treatment, computer
modelling, cell membrane, reactive oxygen and nitrogen
species
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.712
Times cited: 5
DOI: 10.1007/s11705-018-1786-8
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“Nanosecond Pulsed Discharge for CO2Conversion: Kinetic Modeling To Elucidate the Chemistry and Improve the Performance”. Heijkers S, Martini LM, Dilecce G, Tosi P, Bogaerts A, The journal of physical chemistry: C : nanomaterials and interfaces 123, 12104 (2019). http://doi.org/10.1021/acs.jpcc.9b01543
Abstract: We study the mechanisms of CO2 conversion in a nanosecond repetitively pulsed (NRP) discharge, by means of a chemical kinetics model. The calculated conversions and energy efficiencies are in reasonable agreement with experimental results over a wide range of specific energy input values, and the same applies to the evolution of gas temperature and CO2 conversion as a function of time in the afterglow, indicating that our model provides a realistic picture of the underlying mechanisms in the NRP discharge and can be used to identify its limitations and thus to suggest further improvements. Our model predicts that vibrational excitation is very important in the NRP discharge, explaining why this type of plasma yields energy-efficient CO2 conversion. A significant part of the CO2 dissociation occurs by electronic excitation from the lower vibrational levels toward repulsive electronic states, thus resulting in dissociation. However, vibration−translation (VT) relaxation (depopulating the higher vibrational levels) and CO + O recombination (CO + O + M → CO2 + M), as well as mixing of the converted gas with fresh gas entering the plasma in between the pulses, are limiting factors for the conversion and energy efficiency. Our model predicts that extra cooling, slowing down the rate of VT relaxation and of the above recombination reaction, thus enhancing the contribution of the highest vibrational levels to the overall CO2 dissociation, can further improve the performance of the NRP discharge for energy-efficient CO2 conversion.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 4
DOI: 10.1021/acs.jpcc.9b01543
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“Transport of cystine across xC-antiporter”. Ghasemitarei M, Yusupov M, Razzokov J, Shokri B, Bogaerts A, Archives of biochemistry and biophysics 664, 117 (2019). http://doi.org/10.1016/j.abb.2019.01.039
Abstract: Extracellular cystine (CYC) uptake by xC antiporter is important for the cell viability. Especially in cancer cells, the upregulation of xC activity is observed, which protects these cells from intracellular oxidative stress. Hence, inhibition of the CYC uptake may eventually lead to cancer cell death. Up to now, the molecular level mechanism of the CYC uptake by xC antiporter has not been studied in detail. In this study, we applied several different simulation techniques to investigate the transport of CYC through xCT, the light subunit of the xC antiporter, which is responsible for the CYC and glutamate translocation. Specifically, we studied the permeation of CYC across three model systems, i.e., outward facing (OF), occluded (OCC) and inward facing (IF) configurations of xCT. We also investigated the effect of mutation of Cys327 to Ala within xCT, which was also studied experimentally in literature. This allowed us to qualitatively compare our computation results with experimental observations, and thus, to validate our simulations. In summary, our simulations provide a molecular level mechanism of the transport of CYC across the xC antiporter, more specifically, which amino acid residues in the xC antiporter play a key role in the uptake, transport and release of CYC.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.165
Times cited: 3
DOI: 10.1016/j.abb.2019.01.039
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“Overcoming Old Scaling Relations and Establishing New Correlations in Catalytic Surface Chemistry: Combined Effect of Charging and Doping”. Bal KM, Neyts EC, The journal of physical chemistry: C : nanomaterials and interfaces 123, 6141 (2019). http://doi.org/10.1021/acs.jpcc.9b01216
Abstract: Optimization of catalytic materials for a given application is greatly constrained by linear scaling relations. Recently, however, it has been demonstrated that it is possible to reversibly modulate the chemisorption of molecules on nanomaterials by charging (i.e., injection or removal of electrons) and hence reversibly and selectively modify catalytic activity beyond structure−activity correlations. The fundamental physical relation between the properties of the material, the charging process, and the chemisorption energy, however, remains unclear, and a systematic exploration and optimization of charge-switchable sorbent materials is not yet possible. Using hybrid DFT calculations of CO2 chemisorption on hexagonal boron nitride nanosheets with several types of defects and dopants, we here reveal the existence of fundamental correlations between the electron affinity of a material and charge-induced chemisorption, show how defect engineering can be used to modulate the strength and efficiency of the adsorption process, and demonstrate that excess electrons stabilize many topological defects. We then show how these insights could be exploited in the development of new electrocatalytic materials and the synthesis of doped nanomaterials. Moreover, we demonstrate that calculated chemical properties of charged materials are highly sensitive to the employed computational methodology because of the self-interaction error, which underlines the theoretical challenge posed by such systems.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 5
DOI: 10.1021/acs.jpcc.9b01216
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“Reaction of chloride anion with atomic oxygen in aqueous solutions: can cold plasma help in chemistry research?”.Gorbanev Y, Van der Paal J, Van Boxem W, Dewilde S, Bogaerts A, Physical chemistry, chemical physics 21, 4117 (2019). http://doi.org/10.1039/C8CP07550F
Abstract: Cold atmospheric plasma in contact with solutions has many applications, but its chemistry contains many unknowns such as the undescribed reactions with solutes. By combining experiments and modelling, we report the first direct demonstration of the reaction of chloride with oxygen atoms in aqueous solutions exposed to cold plasma.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.123
Times cited: 4
DOI: 10.1039/C8CP07550F
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“Importance of plasma discharge characteristics in plasma catalysis: Dry reforming of methane vs. ammonia synthesis”. De Meyer R, Gorbanev Y, Ciocarlan R-G, Cool P, Bals S, Bogaerts A, Chemical Engineering Journal 488, 150838 (2024). http://doi.org/10.1016/j.cej.2024.150838
Abstract: Plasma catalysis is a rapidly growing field, often employing a packed-bed dielectric barrier discharge plasma reactor. Such dielectric barrier discharges are complex, especially when a packing material (e.g., a catalyst) is introduced in the discharge volume. Catalysts are known to affect the plasma discharge, though the underlying mechanisms influencing the plasma physics are not fully understood. Moreover, the effect of the catalysts on the plasma discharge and its subsequent effect on the overall performance is often overlooked. In this work, we deliberately design and synthesize catalysts to affect the plasma discharge in different ways. These Ni or Co alumina-based catalysts are used in plasma-catalytic dry reforming of methane and ammonia synthesis. Our work shows that introducing a metal to the dielectric packing can affect the plasma discharge, and that the distribution of the metal is crucial in this regard. Further, the altered discharge can greatly influence the overall performance. In an atmospheric pressure dielectric barrier discharge reactor, this apparently more uniform plasma yields a significantly better performance for ammonia synthesis compared to the more conventional filamentary discharge, while it underperforms in dry reforming of methane. This study stresses the importance of analyzing the plasma discharge in plasma catalysis experiments. We hope this work encourages a more critical view on the plasma discharge characteristics when studying various catalysts in a plasma reactor.
Keywords: A1 Journal Article; Gas conversion Dry reforming of methane Ammonia Microdischarges Dielectric barrier discharge; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 15.1
DOI: 10.1016/j.cej.2024.150838
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“Effect of Gas Composition on Temperature and CO2Conversion in a Gliding Arc Plasmatron reactor: Insights for Post‐Plasma Catalysis from Experiments and Computation”. Xu W, Van Alphen S, Galvita VV, Meynen V, Bogaerts A, ChemSusChem (2024). http://doi.org/10.1002/cssc.202400169
Abstract: Plasma‐based CO<sub>2</sub>conversion has attracted increasing interest. However, to understand the impact of plasma operation on post‐plasma processes, we studied the effect of adding N<sub>2</sub>, N<sub>2</sub>/CH<sub>4</sub>and N<sub>2</sub>/CH<sub>4</sub>/H<sub>2</sub>O to a CO<sub>2</sub>gliding arc plasmatron (GAP) to obtain valuable insights into their impact on exhaust stream composition and temperature, which will serve as feed gas and heat for post‐plasma catalysis (PPC). Adding N<sub>2</sub>improves the CO<sub>2</sub>conversion from 4 % to 13 %, and CH<sub>4</sub>addition further promotes it to 44 %, and even to 61 % at lower gas flow rate (6 L/min), allowing a higher yield of CO and hydrogen for PPC. The addition of H<sub>2</sub>O, however, reduces the CO<sub>2</sub>conversion from 55 % to 22 %, but it also lowers the energy cost, from 5.8 to 3 kJ/L. Regarding the temperature at 4.9 cm post‐plasma, N<sub>2</sub>addition increases the temperature, while the CO<sub>2</sub>/CH<sub>4</sub>ratio has no significant effect on temperature. We also calculated the temperature distribution with computational fluid dynamics simulations. The obtained temperature profiles (both experimental and calculated) show a decreasing trend with distance to the exhaust and provide insights in where to position a PPC bed.
Keywords: A1 Journal Article; CO2 conversion · Plasma · Gliding arc plasmatron · Temperature profiles · Computational modelling; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 8.4
DOI: 10.1002/cssc.202400169
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“Accurate Reaction Probabilities for Translational Energies on Both Sides of the Barrier of Dissociative Chemisorption on Metal Surfaces”. Gerrits N, Jackson B, Bogaerts A, The Journal of Physical Chemistry Letters 15, 2566 (2024). http://doi.org/10.1021/acs.jpclett.3c03408
Abstract: Molecular dynamics simulations are essential for a better understanding of dissociative chemisorption on metal surfaces, which is often the rate-controlling step in heterogeneous and plasma catalysis. The workhorse quasi-classical trajectory approach ubiquitous in molecular dynamics is able to accurately predict reactivity only for high translational and low vibrational energies. In contrast, catalytically relevant conditions generally involve low translational and elevated vibrational energies. Existing quantum dynamics approaches are intractable or approximate as a result of the large number of degrees of freedom present in molecule−metal surface reactions. Here, we extend a ring polymer molecular dynamics approach to fully include, for the first time, the degrees of freedom of a moving metal surface. With this approach, experimental sticking probabilities for the dissociative chemisorption of methane on Pt(111) are reproduced for a large range of translational and vibrational energies by including nuclear quantum effects and employing full-dimensional simulations.
Keywords: A1 Journal Article; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 5.7
DOI: 10.1021/acs.jpclett.3c03408
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