Staff

Alexander Gogos

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Dr. Alexander Gogos

Department Process Engineering

About Me

Current research

Fate of engineered nanomaterials in managed waste facilities
Managed waste facilities (“reactors”) act as crucial conduits for engineered nanomaterials (ENMs) prior to release to the environment . Key reactors include wastewater treatment plants, solid waste and dedicated sewage sludge incinerators, and landfills. Within each reactor, ENM can be physically (aggregation) and chemically (speciation) transformed, and the initial coating may be replaced by other substances (‘eco-corona’) or biologically degraded. The physical-chemical properties of the transformed ENMs are however are still very poorly investigated. Thus, the aim of this project is to establish transformation and release rates of ENM during their passage through different reactors.


Peer reviewed publications

•    Gogos, A., Voegelin, A. and Kaegi, R. Influence of organic compounds on the sulfidation of copper oxide nanoparticles. Environmental Science: Nano, 2018, DOI: 10.1039/C8EN00523K .
•    Kah, M., Kookana, R.S., Gogos, A. and Bucheli, T.D., A critical evaluation of nanopesticides and nanofertilizers against their conventional analogues, Nature Nanotechnology 2018; 13: 677–684.
•    Gogos, A., Thalmann, B., Voegelin, A. and Kaegi, R. Sulfidation kinetics of copper oxide nanoparticles. Environmental Science: Nano, 2017; 4(8):1733-1741.
•    Moll, J., Klingenfuss, F., Widmer, F., Gogos, A. , Bucheli, T.D., Hartmann, M. and van der Heijden, M.G.A. Effects of titanium dioxide nanoparticles on soil microbial communities and wheat biomass. Soil Biology and Biochemistry 2017; 111: 85-93.
•    Gogos A., Moll J., Klingenfuss F., Heijden M., Irin F., Green MJ et al. Vertical transport and plant uptake of nanoparticles in a soil mesocosm experiment. Journal of Nanobiotechnology. 2016;14(1):1
•    Moll, J., Gogos, A., Bucheli, T. D., Widmer, F., & Heijden, M. G. Effect of nanoparticles on red clover and its symbiotic microorganisms. Journal of Nanobiotechnology. 2016;14(1), 1.
•    Moll, J., Okupnik, A., Gogos, A., Knauer, K., Bucheli, T. D., van der Heijden, M. G., & Widmer, F. Effects of Titanium Dioxide Nanoparticles on Red Clover and Its Rhizobial Symbiont. PLOS ONE. 2016;11(5).
•   Petersen, E. J., Flores-Cervantes, D. X., Bucheli, T. D., Elliott, L., Fagan, J. A., Gogos, A., et al.  Quantification of carbon nanotubes in environmental matrices: Current capabilities, case studies, and future prospects. Environmental Science & Technology 2016;50(9):4587-605.
•    Gogos A, Kaegi R, Zenobi R, Bucheli TD. Capabilities of asymmetric flow field-flow fractionation coupled to multi-angle light scattering to detect carbon nanotubes in soot and soil. Environmental Science: Nano. 2014;1(6):584-94
•    Mortimer M, Gogos A, Bartolomé N, Kahru A, Bucheli TD, Slaveykova VI. Potential of Hyperspectral Imaging Microscopy for Semi-quantitative Analysis of Nanoparticle Uptake by Protozoa. Environmental Science and Technology. 2014;48(15):8760-7.
•    Gogos A, Knauer K, Bucheli TD. Nanomaterials in Plant Protection and Fertilization: Current State, Foreseen Applications, and Research Priorities. Journal of Agricultural and Food Chemistry 2012;60(39):9781-92
•    Evangelou MWH, Deram A, Gogos A, Studer B, Schulin R. Assessment of suitability of tree species for the production of biomass on trace element contaminated soils. Journal of Hazardous Materials. 2012;209-210(0):233-9

Curriculum Vitae
    
2015-present    PostDoc in the Department of Process Engineering, Eawag, Switzerland
   
2011-2015         PhD student in Environmental Analytical Chemistry, Agroscope/ETH Zurich, Switzerland
                          Thesis: "Engineered nanomaterials in the agricultural environment: current state of                           applications and development of analytical methods"   
    
2003-2010         German diploma "Biology", RWTH Aachen, Germany
                           Thesis, conducted at the Soil Protection Group, ETH Zurich : “Application of                                   woolhydrolysate as a biochelator for the biofortification of mineral micronutrients for                                  human nutrition”



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Publications

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A critical evaluation of nanopesticides and nanofertilizers against their conventional analogues

Among a wide range of possible applications of nanotechnology in agriculture, there has been a particular interest in developing novel nanoagrochemicals. While some concerns have been expressed regarding altered risk profile of the new products, many foresee a great potential to support the necessary increase in global food production in a sustainable way. A critical evaluation of nanoagrochemicals against conventional analogues is essential to assess the associated benefits and risks. In this assessment, recent literature was critically analysed to determine the extent to which nanoagrochemicals differ from conventional products. Our analysis was based on 78 published papers and shows that median gain in efficacy relative to conventional products is about 20–30%. Environmental fate of agrochemicals can be altered by nanoformulations, but changes may not necessarily translat controls. Currently, there is no comprehensive study in the literature that evaluates efficacy and environmental impact of nanoagrochemicals under field conditions. This is a crucial knowledge gap and more work will thus be necessary for a sound evaluation of the benefits and new risks that nanoagrochemicals represent relative to existing products.
Kah, M.; Kookana, R. S.; Gogos, A.; Bucheli, T. D. (2018) A critical evaluation of nanopesticides and nanofertilizers against their conventional analogues, Nature Nanotechnology, 13(8), 677-684, doi:10.1038/s41565-018-0131-1, Institutional Repository

Sulfidation kinetics of copper oxide nanoparticles

Sulfidation of copper oxide nanoparticles (CuO NPs) in urban wastewater systems is expected to influence their impact on the environment. However, the kinetics of this reaction has not been studied to date and the reaction mechanism remains largely unexplored. We therefore investigated the sulfidation kinetics of CuO NPs reacted with bisulfide (HS−) at concentrations relevant to wastewater systems. Pristine CuO NPs (50 nm, 7.7 μM) were reacted with HS− (26.4–105.6 μM) in oxic solutions buffered to pH 8.0. The reaction progress was monitored using silver nitrate to quench the reaction and selectively dissolve the copper sulfides (Cux) and zincon to spectrophotometrically quantify the released Cu2+. In addition, the reaction products were characterized at selected time points using analytical electron microscopy and X-ray absorption spectroscopy (XAS). The sulfidation rate of the CuO NPs was best described by a pseudo first order rate law and the corresponding half-life times ranged between 1 and 6 minutes. XAS results showed that crystalline CuO NPs rapidly transformed into amorphous CuxS and gradually into crystalline CuS (covellite). The comparable size of pristine and transformed primary particles, the similar morphology of their aggregates, and the initial formation of CuO–CuxS core–shell structures revealed by analytical electron microscopy suggest that the initial sulfidation occurred via a direct conversion reaction mechanism. Our findings suggest that CuO NPs released from various sources into wastewater will rapidly transform into amorphous CuxS and eventually recrystallize into covellite.
Gogos, A.; Thalmann, B.; Voegelin, A.; Kaegi, R. (2017) Sulfidation kinetics of copper oxide nanoparticles, Environmental Science: Nano, 4(8), 1733-1741, doi:10.1039/C7EN00309A, Institutional Repository

Quantification of carbon nanotubes in environmental matrices: current capabilities, case studies, and future prospects

Carbon nanotubes (CNTs) have numerous exciting potential applications and some that have reached commercialization. As such, quantitative measurements of CNTs in key environmental matrices (water, soil, sediment, and biological tissues) are needed to address concerns about their potential environmental and human health risks and to inform application development. However, standard methods for CNT quantification are not yet available. We systematically and critically review each component of the current methods for CNT quantification including CNT extraction approaches, potential biases, limits of detection, and potential for standardization. This review reveals that many of the techniques with the lowest detection limits require uncommon equipment or expertise, and thus, they are not frequently accessible. Additionally, changes to the CNTs (e.g., agglomeration) after environmental release and matrix effects can cause biases for many of the techniques, and biasing factors vary among the techniques. Five case studies are provided to illustrate how to use this information to inform responses to real-world scenarios such as monitoring potential CNT discharge into a river or ecotoxicity testing by a testing laboratory. Overall, substantial progress has been made in improving CNT quantification during the past ten years, but additional work is needed for standardization, development of extraction techniques from complex matrices, and multimethod comparisons of standard samples to reveal the comparability of techniques.
Petersen, E. J.; Flores-Cervantes, D. X.; Bucheli, T. D.; Elliott, L. C. C.; Fagan, J. A.; Gogos, A.; Hanna, S.; Kägi, R.; Mansfield, E.; Montoro Bustos, A. R.; Plata, D. L.; Reipa, V.; Westerhoff, P.; Winchester, M. R. (2016) Quantification of carbon nanotubes in environmental matrices: current capabilities, case studies, and future prospects, Environmental Science and Technology, 50(9), 4587-4605, doi:10.1021/acs.est.5b05647, Institutional Repository

Capabilities of asymmetric flow field-flow fractionation coupled to multi-angle light scattering to detect carbon nanotubes in soot and soil

Analytical detection and quantification of multi-walled carbon nanotubes (MWCNTs) in complex matrices such as soils is very challenging. In an initial approach to this task, we identify MWCNTs by making use of their different (e.g., rod-like) shape compared to other (native) soil particles and in particular soot, which is ubiquitously present in soils. A shape factor ρ, determined using asymmetric flow field-flow fractionation coupled to multi-angle light scattering (aF4-MALS), was used to discriminate MWCNTs of different aspect ratios, as well as mixtures of soot and MWCNTs, in pure suspensions. MALS results were additionally confirmed using automated electron microscopy image analysis. We then analyzed different soil types which consistently showed ρ-values that differed from pure MWCNTs. To test the performance of the method for MWCNT detection in such complex matrices, we conducted standard additions of a MWCNT as well as soot to an agricultural soil. Extracts from these MWCNT-spiked soils showed increased ρ-values compared to soot-spiked or native soil. The method detection limit for the MWCNT was 1.6 to 4.0 mg g−1 soil and lies within the range of commonly used black carbon quantification methods, but is much higher than any currently predicted environmental concentration. Additionally, the method is currently limited by a relatively narrow dynamic range of ρ. Despite these limitations, our results suggest that aF4-MALS provides specific shape information that may be linked to an actual MWCNT presence in soils. Further method improvement potential is outlined along different steps of the workflow.
Gogos, A.; Kaegi, R.; Zenobi, R.; Bucheli, T. D. (2014) Capabilities of asymmetric flow field-flow fractionation coupled to multi-angle light scattering to detect carbon nanotubes in soot and soil, Environmental Science: Nano, 1(6), 584-594, doi:10.1039/c4en00070f, Institutional Repository

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Address

E-Mail: alexander.gogos@eawag.ch
Phone:
Fax: +41 58 765 7499
Address: Eawag
St. Gallen
St. Gallen St. Gallen
Office: LA D 1.25
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Research Group

Particle laboratory

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Focalpoints

  • Development of new analytical methods for nanoparticle detection in environmental systems
  • Fate and transformation of nanoparticles in waste management systems
  • Development of new hyphenated field-flow fractionation approaches for nanoparticle characterization

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