“Study of (ir)reversible fouling in MBRs under various operating conditions using new on-line fouling sensor”. Huyskens C, Lenaerts S, Brauns E, Diels L, de Wever H, Separation and purification technology 81, 208 (2011). http://doi.org/10.1016/J.SEPPUR.2011.07.031
Abstract: In this study, a new fouling sensor was validated under different conditions of hydraulic (HRT) and sludge retention time (SRT). The MBR-VFM (membrane bioreactor-VITO Fouling Measurement) allows the simultaneous determination of the physically reversible and irreversible fouling potential of a mixed liquor during a single crossflow filtration test. In accordance with the on-line filtration behavior, the measured reversible and irreversible fouling propensities differed significantly between MBRs operated at different combinations of HRT-SRT. Moreover, a significant negative correlation was found between the on-line permeability and the reversible and irreversible fouling propensity measured by the MBR-VFM. This corresponded to observations made on membrane recovery after physical or chemical cleaning actions. Higher reversible and irreversible fouling were observed at lower HRT, presumably as a consequence of increased concentrations of foulants present. The effect of SRT was much smaller and restricted to the reversible fouling component. Possible explanations for the increased fouling at prolonged SRT are the higher sludge and colloid concentration and the smaller floc size. It can be concluded that the MBR-VFM is a useful tool to monitor fluctuations in a mixed liquors (ir)reversible fouling potential and can contribute to a deeper understanding of the occurring fouling phenomena.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 3.359
Times cited: 15
DOI: 10.1016/J.SEPPUR.2011.07.031
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“Study on alternative approaches to corrosion protection of ballast tanks using an economic model”. De Baere K, Verstraelen H, Rigo P, Van Passel S, Lenaerts S, Potters G, Marine structures 32, 1 (2013). http://doi.org/10.1016/J.MARSTRUC.2013.02.003
Abstract: One of the most relevant problems in ship construction and maintenance nowadays is corrosion in ballast tanks of modern merchant vessels. On the one hand, there is a general consensus that the economic lifespan of such a vessel depends, to a large degree, upon the corrosion state of its ballast tanks, while on the other hand these ballast tanks, located between the outer hull and the cargo tanks, makes routine inspection and maintenance a difficult task. Today, ship's ballast tanks are usually constructed in steel and protected with an epoxy coating backed up by sacrificial zinc anodes. Such a construction has been applied without significant alterations for many years. The objective of this economic study is to compare this construction method with some potential alternatives. The considered alternatives are: (1) an increase in structural scantlings, eliminating the necessity to replace corroded at a cost of real cargo carrying capacity of the ship, (2) application of the novel and more durable TSCF25 coating (3), the use of corrosion resistant steel in ship construction and (4) a standard PSPC15 coating combined with lifetime lasting aluminum sacrificial anodes. A cost model was used to evaluate these alternative options together with sensitivity analysis. It is concluded that the durable coating and the use of lifetime lasting aluminum anodes are bound to improve the actual basic tank concept. Corrosion resistant steel becomes attractive when the steel price becomes competitive.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 2.052
Times cited: 15
DOI: 10.1016/J.MARSTRUC.2013.02.003
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“Tuning the turnover frequency and selectivity of photocatalytic CO2 reduction to CO and methane using platinum and palladium nanoparticles on Ti-Beta zeolites”. Blommaerts N, Hoeven N, Arenas Esteban D, Campos R, Mertens M, Borah R, Glisenti A, De Wael K, Bals S, Lenaerts S, Verbruggen SW, Cool P, Chemical Engineering Journal 410, 128234 (2021). http://doi.org/10.1016/j.cej.2020.128234
Abstract: A Ti-Beta zeolite was used in gas phase photocatalytic CO2 reduction to reduce the charge recombination rate and increase the surface area compared to P25 as commercial benchmark, reaching 607 m2 g-1. By adding Pt nanoparticles, the selectivity can be tuned toward CO, reaching a value of 92% and a turnover frequency (TOF) of 96 µmol.gcat-1.h-1, nearly an order of magnitude higher in comparison with P25. By adding Pd nanoparticles the selectivity can be shifted from CO (70% for a bare Ti-Beta zeolite), toward CH4 as the prevalent species (60%). In this way, the selectivity toward CO or CH4 can be tuned by either using Pt or Pd. The TOF values obtained in this work outperform reported state-of-the-art values in similar research. The improved activity by adding the nanoparticles was attributed to an improved charge separation efficiency, together with a plasmonic contribution of the metal nanoparticles under the applied experimental conditions.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL); Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 6.216
Times cited: 15
DOI: 10.1016/j.cej.2020.128234
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“Selectivity in ligand functionalization of photocatalytic metal oxide nanoparticles for phase transfer and self‐assembly applications”. Borah R, Ninakanti R, Nuyts G, Peeters H, Pedrazo-Tardajos A, Nuti S, Vande Velde C, De Wael K, Lenaerts S, Bals S, Verbruggen S, Chemistry-A European Journal , chem.202100029 (2021). http://doi.org/10.1002/CHEM.202100029
Abstract: Functionalization of photocatalytic metal oxide nanoparticles of TiO 2 , ZnO, WO 3 and CuO with amine‐terminated (oleylamine) and thiol‐terminated (1‐dodecanethiol) alkyl chained ligands was studied under ambient conditions. A high selectivity was observed in the binding specificity of a ligand towards nanoparticles of these different oxides. It was observed that oleylamine binds stably to only TiO 2 and WO 3 , while 1‐dodecanethiol binds stably only to ZnO and CuO. Similarly, polar to non‐polar solvent phase transfer of TiO 2 and WO 3 nanoparticles could be achieved by using oleylamine, but not by 1‐dodecanethiol, while the contrary holds for ZnO and CuO. The surface chemistry of ligand functionalized nanoparticles was probed by ATR‐FTIR spectroscopy, that enabled to elucidate the occupation of the ligands at the active sites. The photo‐stability of the ligands on the nanoparticle surface was determined by the photocatalytic self‐cleaning properties of the material. While TiO 2 and WO 3 degrade the ligands within 24 hours under both UV and visible light, ligands on ZnO and CuO remain unaffected. The gathered insights are also highly relevant from an application point of view. As an example, since the ligand functionalized nanoparticles are hydrophobic in nature, they can thus be self‐assembled at the air‐water interface, for obtaining nanoparticle films with demonstrated photocatalytic as well as anti‐fogging properties.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Sustainable Energy, Air and Water Technology (DuEL); Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)
Impact Factor: 5.317
Times cited: 15
DOI: 10.1002/CHEM.202100029
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“Effect of process parameters on the photocatalytic soot degradation on self-cleaning cementitious materials”. Smits M, Huygh D, Craeye B, Lenaerts S, Catalysis today 230, 250 (2014). http://doi.org/10.1016/J.CATTOD.2013.10.001
Abstract: Soot deposition has the negative ability to devalue the aesthetic appearance of buildings. Titanium dioxide applied on the building material is one way to counteract this problem as it provides air-purifying and self-cleaning properties due to its photocatalytic activity. In literature, photocatalytic soot oxidation was described, but until now, little information was available about the influence of process parameters on the photocatalytic degradation efficiency. The influence of three process parameters was tested in this study, namely TiO2 concentration, soot concentration and water-to-cement ratio (WIC-ratio) of the mortar substrates. The results revealed 50 mu gTiO(2) cm(-2) is better to use on the cementitious materials than 250 mu gTiO(2) cm(-2). The soot concentrations occurring in real-world situations will not inhibit the photocatalyst to be activated by light. Furthermore, the photonic efficiency increases slightly for lower WIC-ratios. This can be of interest for structural building applications, since a lower WIC-ratio results in a lower porosity of the samples and consequently in an increase in mortar strength. (C) 2013 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL); Energy and Materials in Infrastructure and Buildings (EMIB)
Impact Factor: 4.636
Times cited: 14
DOI: 10.1016/J.CATTOD.2013.10.001
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“Photocatalytic process optimisation for ethylene oxidation”. Tytgat T, Hauchecorne B, Abakumov AM, Smits M, Verbruggen SW, Lenaerts S, Chemical engineering journal 209, 494 (2012). http://doi.org/10.1016/j.cej.2012.08.032
Abstract: When studying photocatalysis it is important to consider, beside the chemical approach, the engineering part related to process optimisation. To achieve this a fixed bed photocatalytic set-up consisting of different catalyst placings, in order to vary catalyst distribution, is studied. The use of a fixed quantity of catalyst placed packed or randomly distributed in the reactor, results in an almost double degradation for the distributed catalyst. Applying this knowledge leads to an improved performance with limited use of catalyst. A reactor only half filled with catalyst leads to higher degradation performance compared to a completely filled reactor. Taking into account this simple process optimisation by better distributing the catalyst a more sustainable photocatalytic air purification process is achieved. (C) 2012 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 6.216
Times cited: 12
DOI: 10.1016/j.cej.2012.08.032
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“CFD modeling of transient adsorption/desorption behavior in a gas phase photocatalytic fiber reactor”. Verbruggen SW, Keulemans M, van Walsem J, Tytgat T, Lenaerts S, Denys S, Chemical engineering journal 292, 42 (2016). http://doi.org/10.1016/J.CEJ.2016.02.014
Abstract: We present the use of computational fluid dynamics (CFD) for accurately determining the adsorption parameters of acetaldehyde on photocatalytic fiber filter material, integrated in a continuous flow system. Unlike the traditional analytical analysis based on Langmuir adsorption, not only steady-state situations but also transient phenomena can be accounted for. Air displacement effects in the reactor and gas detection cell are investigated and inherently made part of the model. Incorporation of a surface aldol condensation reaction in the CFD analysis further improves the accuracy of the model which enables to extract precise, intrinsic adsorption parameters for situations in which analytical analysis would otherwise fail.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 6.216
Times cited: 12
DOI: 10.1016/J.CEJ.2016.02.014
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“Validation of a newly developed FTIR in situ reactor: real time study of photocatalytic degradation of nitric oxide”. Hauchecorne B, Tytgat T, Terrens D, Vanpachtenbeke F, Lenaerts S, Infrared physics and technology 53, 469 (2010). http://doi.org/10.1016/J.INFRARED.2010.09.008
Abstract: For many years, photocatalysis has been proposed as one of the promising techniques to abate environmental pollutants. To improve these reactions it is vital to know the reaction mechanisms of the photocatalytic degradation. This new reactor will make it possible to study the catalytic surface at the moment the reactions occur. By the means of UV LED illumination there is no need of an external UV lamp and thus lowers the cost. The validation of this newly developed reactor is done by investigating the photocatalytic reaction mechanism of nitric oxide (NO) and comparing these findings with those already discussed in literature. From these results, it became clear that the newly developed FTIR in situ reactor allows real time study of photocatalytic degradations.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 1.713
Times cited: 12
DOI: 10.1016/J.INFRARED.2010.09.008
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“Characterization of silver-polymer core–shell nanoparticles using electron microscopy”. Claes N, Asapu R, Blommaerts N, Verbruggen SW, Lenaerts S, Bals S, Nanoscale 10, 9186 (2018). http://doi.org/10.1039/C7NR09517A
Abstract: Silver-polymer core–shell nanoparticles show interesting optical properties, making them widely applicable in the field of plasmonics. The uniformity, thickness and homogeneity of the polymer shell will affect the properties of the system which makes a thorough structural characterization of these core–shell silver-polymer nanoparticles of great importance. However, visualizing the shell and the particle simultaneously is far from straightforward due to the sensitivity of the polymer shell towards the electron beam. In this study, we use different 2D and 3D electron microscopy techniques to investigate different structural aspects of the polymer coating.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 7.367
Times cited: 11
DOI: 10.1039/C7NR09517A
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“Photocatalysis assisted simultaneous carbon oxidation and NOx reduction”. Liao L, Heylen S, Sree SP, Vallaey B, Keulemans M, Lenaerts S, Roeffaers MBJ, Martens JA, Applied catalysis : B : environmental 202, 381 (2017). http://doi.org/10.1016/J.APCATB.2016.09.042
Abstract: Photocatalysis assisted oxidation of carbon black was performed using TiO2 photocatalyst under UV illumination in an atmosphere with NO, O-2 and water vapor at 150 degrees C. Carbon is oxidized mainly to CO2 while NO is selectively converted to N-2. Enhanced O-2 and NO concentrations have a positive effect on the carbon oxidation rate. At a concentration of 3000 ppm NO and 13.3% O-2 in the gas phase the carbon oxidation rate reaches 2.3 mu g(carbon)/mg(TiO2) h, at a formal electron/photon quantum efficiency of 0.019. HR SEM images reveal uniform gradual reduction of the carbon particle size irrespective of the distance to TiO2 photocatalyst particles in the presence of NO, O-2 and H2O. (C) 2016 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 9.446
Times cited: 11
DOI: 10.1016/J.APCATB.2016.09.042
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“Self-assembled ligand-capped plasmonic Au nanoparticle films in the Kretschmann configuration for sensing of volatile organic compounds”. Borah R, Smets J, Ninakanti R, Tietze ML, Ameloot R, Chigrin DN, Bals S, Lenaerts S, Verbruggen SW, ACS applied nano materials 5, acsanm.2c02524 (2022). http://doi.org/10.1021/ACSANM.2C02524
Abstract: Films of close-packed Au nanoparticles are coupled electrodynamically through their collective plasmon resonances. This collective optical response results in enhanced light–matter interactions, which can be exploited in various applications. Here, we demonstrate their application in sensing volatile organic compounds, using methanol as a test case. Ordered films over several cm2 were obtained by interfacial self-assembly of colloidal Au nanoparticles (∼10 nm diameter) through controlled evaporation of the solvent. Even though isolated nanoparticles of this size are inherently nonscattering, when arranged in a close-packed film the plasmonic coupling results in a strong reflectance and absorbance. The in situ tracking of vapor phase methanol concentration through UV–vis transmission measurements of the nanoparticle film is first demonstrated. Next, in situ ellipsometry of the self-assembled films in the Kretschmann (also known as ATR) configuration is shown to yield enhanced sensitivity, especially with phase difference measurements, Δ. Our study shows the excellent agreement between theoretical models of the spectral response of self-assembled films with experimental in situ sensing experiments. At the same time, the theoretical framework provides the basis for the interpretation of the various observed experimental trends. Combining periodic nanoparticle films with ellipsometry in the Kretschmann configuration is a promising strategy toward highly sensitive and selective plasmonic thin-film devices based on colloidal fabrication methods for volatile organic compound (VOC) sensing applications.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 5.9
Times cited: 11
DOI: 10.1021/ACSANM.2C02524
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“Plasmon resonance of gold and silver nanoparticle arrays in the Kretschmann (attenuated total reflectance) vs. direct incidence configuration”. Borah R, Ninakanti R, Bals S, Verbruggen SW, Scientific reports 12, 15738 (2022). http://doi.org/10.1038/S41598-022-20117-7
Abstract: While the behaviour of plasmonic solid thin films in the Kretschmann (also known as Attenuated Total Reflection, ATR) configuration is well-understood, the use of discrete nanoparticle arrays in this optical configuration is not thoroughly explored. It is important to do so, since close packed plasmonic nanoparticle arrays exhibit exceptionally strong light-matter interactions by plasmonic coupling. The present work elucidates the optical properties of plasmonic Au and Ag nanoparticle arrays in both the direct normal incidence and Kretschmann configuration by numerical models, that are validated experimentally. First, hexagonal close packed Au and Ag nanoparticle films/arrays are obtained by air–liquid interfacial assembly. The numerical models for the rigorous solution of the Maxwell’s equations are validated using experimental optical spectra of these films before systematically investigating various parameters. The individual far-field/near-field optical properties, as well as the plasmon relaxation mechanism of the nanoparticles, vary strongly as the packing density of the array increases. In the Kretschmann configuration, the evanescent fields arising from p – and s -polarized (or TM and TE polarized) incidence have different directional components. The local evanescent field intensity and direction depends on the polarization, angle of incidence and the wavelength of incidence. These factors in the Kretschmann configuration give rise to interesting far-field as well as near-field optical properties. Overall, it is shown that plasmonic nanoparticle arrays in the Kretschmann configuration facilitate strong broadband absorptance without transmission losses, and strong near-field enhancement. The results reported herein elucidate the optical properties of self-assembled nanoparticle films, pinpointing the ideal conditions under which the normal and the Kretschmann configuration can be exploited in multiple light-driven applications.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 4.6
Times cited: 11
DOI: 10.1038/S41598-022-20117-7
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“Activity versus selectivity in photocatalysis : morphological or electronic properties tipping the scale”. Keulemans M, Verbruggen SW, Hauchecorne B, Martens JA, Lenaerts S, Journal of catalysis 344, 221 (2016). http://doi.org/10.1016/J.JCAT.2016.09.033
Abstract: In this paper a structure-activity and structure-selectivity relation is established for three commercial TiO2 sources (P25, P90, and PC500). Morphological and electronic parameters of the photocatalysts are determined using widely applicable and inexpensive characterization procedures. More specifically, the electronic properties are rigorously characterized using an electron titration method yielding quantitative information on the amount of defect sites present in the catalyst. Surface photovoltage measurements on the other hand provide complementary information on the charge carrier recombination process. As model reaction, the degradation of a solid layer of stearic acid is studied using an in situ FTIR reaction cell that enables to investigate the catalyst surface and possible formation of reaction intermediates while the reactions are ongoing. We show that the order of photocatalytic conversion is PC500 > P90 > P25, matching the order of favorable morphological properties. In terms of selectivity to CO2 formation (complete mineralization), however, this trend is reversed: P25 > P90 > PC500, now matching the order of advantageous electronic properties, i.e. low charge carrier recombination and high charge carrier generation. With this we intend to provide new mechanistic insights using a wide variety of physical, (wet) chemical and operando analysis methods that aid the development of performant (self-cleaning) photocatalytic materials.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 6.844
Times cited: 10
DOI: 10.1016/J.JCAT.2016.09.033
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“CFD investigation of a multi-tube photocatalytic reactor in non-steady-state conditions”. van Walsem J, Verbruggen SW, Modde B, Lenaerts S, Denys S, Chemical engineering journal 304, 808 (2016). http://doi.org/10.1016/J.CEJ.2016.07.028
Abstract: A novel multi-tube photoreactor is presented with a high efficiency (over 90% conversion) toward the degradation of acetaldehyde in air under UV conditions with an incident intensity of 2.1 mW cm−2. A CFD model was developed to simulate the transient adsorption and photocatalytic degradation processes of acetaldehyde in this reactor design and to estimate the corresponding kinetic parameters through an optimization routine using the experimentally determined outlet concentration profiles. The CFD model takes into account the entire reactor geometry and all relevant flow parameters, in contrast to analytical methods that often oversimplify the physical and chemical process characteristics. Using CFD, we show that both adsorption and desorption rate constants increase by respectively one and two orders of magnitude when the UV light is switched on, which clearly affects the transient behavior. The agreement of the experimental and modelled concentration profiles is excellent as evidenced by a coefficient of determination of at least 0.965. To demonstrate the reliability and accuracy of all parameters obtained from the modelling approach, an ultimate validation test was performed using other conditions than the ones used for estimating the kinetic parameters. The model was able to accurately simulate simultaneous adsorption, desorption and photocatalytic degradation.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 6.216
Times cited: 10
DOI: 10.1016/J.CEJ.2016.07.028
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“Controllable nitrogen doping in as deposited TiO2 film and its effect on post deposition annealing”. Deng S, Verbruggen SW, Lenaerts S, Martens JA, Van den Berghe S, Devloo-Casier K, Devulder W, Dendoover J, Deduytsche D, Detavernier C, Journal of vacuum science and technology: A: vacuum surfaces and films 32, 01a123 (2014). http://doi.org/10.1116/1.4847976
Abstract: In order to narrow the band gap of TiO2, nitrogen doping by combining thermal atomic layer deposition (TALD) of TiO2 and plasma enhanced atomic layer deposition (PEALD) of TiN has been implemented. By altering the ratio between TALD TiO2 and PEALD TiN, the as synthesized TiOxNy films showed different band gaps (from 1.91 eV to 3.14 eV). In situ x-ray diffraction characterization showed that the crystallization behavior of these films changed after nitrogen doping. After annealing in helium, nitrogen doped TiO2 films crystallized into rutile phase while for the samples annealed in air a preferential growth of the anatase TiO2 along (001) orientation was observed. Photocatalytic tests of the degradation of stearic acid were done to evaluate the effect of N doping on the photocatalytic activity.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 1.374
Times cited: 10
DOI: 10.1116/1.4847976
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“Effect of pretreatment and temperature on the properties of Pinnularia biosilica frustules”. Van Eynde E, Lenaerts B, Tytgat T, Verbruggen SW, Hauchecorne B, Blust R, Lenaerts S, RSC advances 4, 56200 (2014). http://doi.org/10.1039/C4RA09305D
Abstract: Diatoms are unicellular microalgae that self-assemble an intricate porous silica cell wall, called frustule. Diatom frustules possess a unique combination of physical and chemical properties (chemical inertness, high mechanical strength, large surface area, low density, good porosity and highly ordered features on the nano-to-micro scale) making diatom frustules suited for many nanotechnological applications. For most proposed applications the organic material covering the frustules needs to be removed. In this paper we investigate the effect of different frustule cleaning methods (drying, autoclavation, SDS/EDTA treatment, H2O2 treatment and HNO3 treatment) and subsequent heat treatment at different temperatures (105 °C, 350 °C, 550 °C and 750 °C) on the material characteristics of the diatom Pinnularia sp. Material characteristics under study are morphology, surface area, pore size, elemental composition and organic content. The cleaned Pinnularia frustules are subsequently investigated as adsorbents to remove methylene blue (MB) from aqueous solution.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 3.108
Times cited: 10
DOI: 10.1039/C4RA09305D
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“Cost-effectiveness analysis to assess commercial TiO2 photocatalysts for acetaldehyde degradation in air”. Verbruggen SW, Tytgat T, Van Passel S, Martens JA, Lenaerts S, Chemicke zvesti 68, 1273 (2014). http://doi.org/10.2478/S11696-014-0557-3
Abstract: In the commercialisation of photocatalytic air purifiers, the performance as well as the cost of the catalytic material plays an important role. Where most comparative studies only regard the photocatalytic activity as a decisive parameter, in this study both activity and cost are taken into account. Using a cost-effectiveness analysis, six different commercially available TiO2-based catalysts are evaluated in terms of their activities in photocatalytic degradation of acetaldehyde as a model reaction for indoor air purification.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 1.258
Times cited: 10
DOI: 10.2478/S11696-014-0557-3
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“Environmental impact of microbial protein from potato wastewater as feed ingredient : comparative consequential life cycle assessment of three production systems and soybean meal”. Spiller M, Muys M, Papini G, Sakarika M, Buyle M, Vlaeminck SE, Water Research 171, 115406 (2020). http://doi.org/10.1016/J.WATRES.2019.115406
Abstract: Livestock production is utilizing large amounts of protein-rich feed ingredients such as soybean meal. The proven negative environmental impacts of soybean meal production incentivize the search for alternative protein sources. One promising alternative is Microbial Protein (MP), i.e. dried microbial biomass. To date, only few life cycle assessments (LCAs) for MP have been carried out, none of which has used a consequential modelling approach nor has been investigating the production of MP on food and beverage wastewater. Therefore, the objective of this study is to evaluate the environmental impact of MP production on a food and beverage effluent as a substitute for soybean meal using a consequential modelling approach. Three different types of MP production were analysed, namely consortia containing Aerobic Heterotrophic Bacteria (AHB), Microalgae and AHB (MaB), and Purple Non-Sulfur Bacteria (PNSB). The production of MP was modelled for high-strength potato wastewater (COD = 10 kg/m3) at a flow rate of 1,000 m3/day. LCA results were compared against soybean meal production for the endpoint impact categories human health, ecosystems, and resources. Soybean meal showed up to 52% higher impact on human health and up to 87% higher impact on ecosystems than MP. However, energy-related aspects resulted in an 8–88% higher resource exploitation for MP. A comparison between the MP production systems showed that MaB performed best when considering ecosystems (between 13 and 14% better) and resource (between 71 and 80% better) impact categories, while AHB and PNSB had lower values for the impact category human health (8–12%). The sensitivity analysis suggests that the conclusions drawn are robust as in the majority of 1,000 Monte Carlo runs the initial results are confirmed. In conclusion, it is suggested that MP is an alternative protein source of comparatively low environmental impact that should play a role in the future protein transition, in particular when further process improvements can be implemented and more renewable or waste energy sources will be used.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL); Energy and Materials in Infrastructure and Buildings (EMIB)
Impact Factor: 12.8
Times cited: 10
DOI: 10.1016/J.WATRES.2019.115406
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“Purple non-sulphur bacteria and plant production: benefits for fertilization, stress resistance and the environment”. Sakarika M, Spanoghe J, Sui Y, Wambacq E, Grunert O, Haesaert G, Spiller M, Vlaeminck SE, Microbial biotechnology 13, 1336 (2020). http://doi.org/10.1111/1751-7915.13474
Abstract: Purple non-sulphur bacteria (PNSB) are phototrophic microorganisms, which increasingly gain attention in plant production due to their ability to produce and accumulate high-value compounds that are beneficial for plant growth. Remarkable features of PNSB include the accumulation of polyphosphate, the production of pigments and vitamins and the production of plant growth-promoting substances (PGPSs). Scattered case studies on the application of PNSB for plant cultivation have been reported for decades, yet a comprehensive overview is lacking. This review highlights the potential of using PNSB in plant production, with emphasis on three key performance indicators (KPIs): fertilization, resistance to stress (biotic and abiotic) and environmental benefits. PNSB have the potential to enhance plant growth performance, increase the yield and quality of edible plant biomass, boost the resistance to environmental stresses, bioremediate heavy metals and mitigate greenhouse gas emissions. Here, the mechanisms responsible for these attributes are discussed. A distinction is made between the use of living and dead PNSB cells, where critical interpretation of existing literature revealed the better performance of living cells. Finally, this review presents research gaps that remain yet to be elucidated and proposes a roadmap for future research and implementation paving the way for a more sustainable crop production.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 5.7
Times cited: 10
DOI: 10.1111/1751-7915.13474
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“Synthesis and characterization of photoreactive TiO2carbon nanosheet composites”. Kurttepeli M, Deng S, Verbruggen SW, Guzzinati G, Cott DJ, Lenaerts S, Verbeeck J, Van Tendeloo G, Detavernier C, Bals S, The journal of physical chemistry: C : nanomaterials and interfaces 118, 21031 (2014). http://doi.org/10.1021/jp5067499
Abstract: We report the atomic layer deposition of titanium dioxide on carbon nanosheet templates and investigate the effects of postdeposition annealing in a helium environment using different characterization techniques. The crystallization of the titanium dioxide coating upon annealing is observed using in situ X-ray diffraction. The (micro)structural characterization of the films is carried out by scanning electron microscopy and advanced transmission electron microscopy techniques. Our study shows that the annealing of the atomic layer deposition processed and carbon nanosheets templated titanium dioxide layers in helium environment resulting in the formation of a porous, nanocrystalline and photocatalytically active titanium dioxide-carbon nanosheet composite film. Such composites are suitable for photocatalysis and dye-sensitized solar cells applications.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 4.536
Times cited: 9
DOI: 10.1021/jp5067499
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“Cyclist exposure to black carbon, ultrafine particles and heavy metals : an experimental study along two commuting routes near Antwerp, Belgium”. Hofman J, Samson R, Joosen S, Blust R, Lenaerts S, Environmental research 164, 530 (2018). http://doi.org/10.1016/J.ENVRES.2018.03.004
Abstract: Urban environments typically exhibit large atmospheric pollution variation, in both space and time. In contrast to traditional monitoring networks suffering from a limited spatial coverage, mobile platforms enable personalized high-resolution monitoring, providing valuable insights into personal atmospheric pollution exposure, and the identification of potential pollution hotspots. This study evaluated personal cyclist exposure to UFPs, BC and heavy metals whilst commuting near Antwerp, Belgium, by performing mobile measurements with wearable black carbon (BC) and ultrafine particle (UFP) instruments. Loaded micro-aethalometer filterstrips were chemically analysed and the inhaled pollutant dose determined from the exhibited heart rate. Considerable spatial pollutant variation was observed along the travelled routes, with distinct contributions from spatial factors (e.g. traffic intersections, urban park and market) and temporary events. On average 300% higher BC, 20% higher UFP and changing elemental concentrations are observed along the road traffic route (RT), when compared to the bicycle highway route (BH). Although the overall background pollution determines a large portion of the experienced personal exposure (in this case 53% for BC and 40% for UFP), cyclists can influence their personal atmospheric pollution exposure, by selecting less exposed commuting routes. Our results, hereby, strengthen the body of evidence in favour of further policy investments in isolated bicycle infrastructure.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Times cited: 9
DOI: 10.1016/J.ENVRES.2018.03.004
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“Fabrication of perovskite capillary membranes for high temperature gas separation”. Van Noyen J, Middelkoop V, Buysse C, Kovalevsky A, Snijkers F, Buekenhoudt A, Mullens S, Luyten J, Kretzschmar J, Lenaerts S, Catalysis today 193, 172 (2012). http://doi.org/10.1016/J.CATTOD.2012.03.005
Abstract: Oxygen-permeable perovskites with mixed ionic-electronic conducting properties can play an important role in carbon capture and storage techniques. Their ability to separate oxygen from air is needed, more specifically, in oxy-fuel and pre-combustion technologies. In this work, the first detailed comparative analysis and new results are reported on four types of Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF) capillary membranes: non-coated sulphur-containing; catalyst-coated sulphur-containing; non-coated sulphur-free and catalyst-coated sulphur-free. The fabrication of BSCF capillaries by a spinning technique based on phase inversion is further discussed and their oxygen separation performances are interpreted. The comparison of the performance of these different generations of BSCF capillaries of similar dimensions demonstrates a significant impact of the sulphur contamination on both the oxygen flux through the membrane and the activation energy of the overall oxygen transport mechanism. Careful attention is paid to the effect of activation layers on both sulphur-free and sulphur-containing types of capillaries. Additional long-term testing of the sulphur-free BSCF capillaries is presented, where partial decomposition of the membrane surface was observed due to kinetic demixing. (c) 2012 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 4.636
Times cited: 9
DOI: 10.1016/J.CATTOD.2012.03.005
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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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“Plasma-enhanced atomic layer deposition of silver using Ag(fod)(PEt3) and NH3-plasma”. Minjauw MM, Solano E, Sree SP, Asapu R, Van Daele M, Ramachandran RK, Heremans G, Verbruggen SW, Lenaerts S, Martens JA, Detavernier C, Dendooven J, Chemistry of materials 29, 7114 (2017). http://doi.org/10.1021/ACS.CHEMMATER.7B00690
Abstract: A plasma-enhanced atomic layer deposition (ALD) process using the Ag(fod)(PEt3) precursor [(triethylphosphine)(6,6,7,7,8,8,8-heptafluoro-2,2-dimethy1-3,5-octanedionate)silver(I)] in combination with NH3-plasma is reported. The steady growth rate of the reported process (0.24 +/- 0.03 nm/cycle) was found to be 6 times larger than that of the previously reported Ag ALD process based on the same precursor in combination with H-2-plasma (0.04 +/- 0.02 nm/cycle). The ALD characteristics of the H-2-plasma and NH3-plasma processes were verified. The deposited Ag films were polycrystalline face-centered cubic Ag for both processes. The film morphology was investigated by ex situ scanning electron microscopy and grazing-incidence small-angle X-ray scattering, and it was found that films grown with the NH3-plasma process exhibit a much higher particle areal density and smaller particle sizes on oxide substrates compared to those deposited using the H-2-plasma process. This control over morphology of the deposited Ag is important for applications in catalysis and plasmonics. While films grown with the H-2-plasma process had oxygen impurities (similar to 9 atom %) in the bulk, the main impurity for the NH3-plasma process was nitrogen (similar to 7 atom %). In situ Fourier transform infrared spectroscopy experiments suggest that these nitrogen impurities are derived from NH surface groups generated during the NH3-plasma, which interact with the precursor molecules during the precursor pulse. We propose that the reaction of these surface groups with the precursor leads to additional deposition of Ag atoms during the precursor pulse compared to the H-2-plasma process, which explains the enhanced growth rate of the NH3-plasma process.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 9.466
Times cited: 9
DOI: 10.1021/ACS.CHEMMATER.7B00690
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“Reducing the cost of ballast tank corrosion : an economic modeling approach”. De Baere K, Verstraelen H, Rigo P, Van Passel S, Lenaerts S, Potters G, Marine structures 32, 136 (2013). http://doi.org/10.1016/J.MARSTRUC.2012.10.009
Abstract: One of the most relevant problems in ship construction and maintenance nowadays concerns the corrosion in the double hull space ballast tanks of modern merchant vessels. On the one hand, there is a general consensus that the economic life span of such a vessel depends primarily upon the corrosion state of its ballast tanks, while on the other hand, the position of these tanks, squeezed between the outer hull and the loading tanks, makes routine inspection and maintenance almost impossible. Today, ship's ballast tanks are usually constructed in grade A steel and protected with a standard epoxy coating, backed up with sacrificial zinc anodes. Such a construction has been applied without significant alterations for many years. However, the objective of this economic study is to compare this construction method with some feasible alternatives. The considered alternatives are: (1) an increase of the scantlings, eliminating the necessity to replace corroded steel but diminishing the cargo carrying capacity of the ship, (2) application of the novel and more durable TSCF25 coating (3), the use of corrosion resistant steel in ship construction or (4) a standard PSPC15 coating combined with lifetime lasting aluminum sacrificial anodes. After running each alternative through a cost model including an extensive sensitivity analysis, it is concluded that the durable coating and the use of lifetime lasting aluminum anodes are bound to improve the actual basic tank concept. Corrosion resistant steel becomes attractive depending upon the evolution of the international steel market.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 2.052
Times cited: 9
DOI: 10.1016/J.MARSTRUC.2012.10.009
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“Microwave-assisted synthesis of mesoporous titania with increased crystallinity, specific surface area, and photocatalytic activity”. Meire M, Verbruggen SW, Lenaerts S, Lommens P, Van Der Voort P, Van Driessche I, Journal of materials science 51, 9822 (2016). http://doi.org/10.1007/S10853-016-0215-Y
Abstract: Mesoporous titanium dioxide is a material finding its use in a wide range of applications. For many of these, it is important to achieve a high degree of crystallinity in the material. It is generally accepted that the use of the soft templating approach to synthesize mesoporous titania, results in a compromise between crystallinity and specific surface area due to thermal instability of the used templates. In this paper, we explore how the use of microwave irradiation can influence the crystallinity, specific surface area, and the electronic properties of mesoporous titania. Therefore, we combined microwave radiation with an evaporation-induced self-assembly (EISA) synthesis. We show that additional microwave treatment at carefully chosen synthesis steps can enhance the crystallinity with 20 % without causing significant loss of surface area (>360 m2/g). Surface photovoltage measurements were used to investigate the electronic properties. The photocatalytic activity of the samples was evaluated in aqueous media by following the degradation of an industrial dye, methylene blue, and the herbicide isoproturon under UV irradiation and in gaseous media looking at the degradation of acetaldehyde, a common indoor pollutant under UVA irradiation. In all cases, the microwave treatment results in more active materials.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 2.599
Times cited: 8
DOI: 10.1007/S10853-016-0215-Y
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“Surface photovoltage measurements : a quick assessment of the photocatalytic activity?”.Verbruggen SW, Dirckx JJJ, Martens JA, Lenaerts S, Catalysis today 209, 215 (2013). http://doi.org/10.1016/J.CATTOD.2012.11.010
Abstract: Surface photovoltage (SPV) measurements can contribute to a better understanding of electronic properties of photocatalysts under illumination. Direct linking of SPV data to the actual photocatalytic activity remains troublesome. This work aims to discuss SPV measurements from a photocatalytic point of view. By means of several application-based scenarios we illustrate that the trend between SPV and photocatalysis strongly depends on parameters such as the crystal structure, surface modifications, morphology and humidity. This makes the interpretation far from straightforward.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 4.636
Times cited: 8
DOI: 10.1016/J.CATTOD.2012.11.010
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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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“Diatom silica-titania photocatalysts for air purification by bio-accumulation of different titanium sources”. Van Eynde E, Hu Z-Y, Tytgat T, Verbruggen SW, Watte J, Van Tendeloo G, Van Driessche I, Blust R, Lenaerts S, Environmental science : nano 3, 1052 (2016). http://doi.org/10.1039/C6EN00163G
Abstract: We present a green, biological production route for silica-titania photocatalysts using diatom microalgae. Diatoms are single-celled, eukaryotic microalgae (2-2000 mu m) that self-assemble soluble silicon (Si(OH)(4)) into intricate silica cell walls, called frustules. These diatom frustules are formed under ambient conditions and consist of hydrated silica with specific 3D morphologies and micro-meso or macroporosity. A remarkable characteristic of diatoms is their ability to bioaccumulate soluble titanium from cell culture medium and incorporate them into their nanostructured silica cell wall. Controlled cultivation of the diatom Pinnularia sp. on soluble titanium in a batch process resulted in the biological immobilisation of titanium dioxide in the porous 3D architecture of the frustules. Six different titanium sources are tested. The silica-titania frustules were isolated by treating the harvested Pinnularia cells with nitric acid (65%) or by high temperature treatment. Thermal annealing converted the amorphous titania into crystalline titania. The produced silica-titania material is evaluated towards photocatalytic activity for acetaldehyde (C2H4O) abatement. Frustules cultivated with TiBaldH showed the highest photocatalytic performance. Comparison of the photocatalytic activity with P25 reveals that P25 has a 4 fold higher photocatalytic activity, but when photocatalytic activity is normalized for titania content, the frustules show double activity. Further material characterization (morphology, crystallinity, surface area and elemental distribution) of the TiBaldH silica-titania frustules provides additional insight into their structure-activity relationship. These natural biosilicatitania materials have excellent properties for photocatalytic purposes, including high surface area (108 m(2) g(-1)) and good porosity, and show reliable immobilization of TiO2 in the ordered structure of the diatom frustule.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 6.047
Times cited: 7
DOI: 10.1039/C6EN00163G
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“Layer-by-Layer-Stabilized Plasmonic Gold-Silver Nanoparticles on TiO2: Towards Stable Solar Active Photocatalysts”. Dingenen F, Blommaerts N, Van Hal M, Borah R, Arenas-Esteban D, Lenaerts S, Bals S, Verbruggen SW, Nanomaterials 11, 2624 (2021). http://doi.org/10.3390/nano11102624
Abstract: To broaden the activity window of TiO2, a broadband plasmonic photocatalyst has been designed and optimized. This plasmonic ‘rainbow’ photocatalyst consists of TiO2 modified with gold–silver composite nanoparticles of various sizes and compositions, thus inducing a broadband interaction with polychromatic solar light. However, these nanoparticles are inherently unstable, especially due to the use of silver. Hence, in this study the application of the layer-by-layer technique is introduced to create a protective polymer shell around the metal cores with a very high degree of control. Various TiO2 species (pure anatase, PC500, and P25) were loaded with different plasmonic metal loadings (0–2 wt %) in order to identify the most solar active composite materials. The prepared plasmonic photocatalysts were tested towards stearic acid degradation under simulated sunlight. From all materials tested, P25 + 2 wt % of plasmonic ‘rainbow’ nanoparticles proved to be the most promising (56% more efficient compared to pristine P25) and was also identified as the most cost-effective. Further, 2 wt % of layer-by-layer-stabilized ‘rainbow’ nanoparticles were loaded on P25. These layer-by-layer-stabilized metals showed superior stability under a heated oxidative atmosphere, as well as in a salt solution. Finally, the activity of the composite was almost completely retained after 1 month of aging, while the nonstabilized equivalent lost 34% of its initial activity. This work shows for the first time the synergetic application of a plasmonic ‘rainbow’ concept and the layer-by-layer stabilization technique, resulting in a promising solar active, and long-term stable photocatalyst.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 3.553
Times cited: 7
DOI: 10.3390/nano11102624
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