2020 - Publications Repository - Gdańsk University of Technology

Show publications from the year

Publications from the year 2020

Show all

Effects of Ca2+, Mg2+, Na+, and K+ substitutions on the microstructure and electrical properties of GdCoO3 ceramics
- Sea-Fue Wang
- Yung-Fu Hsu
- Yi-Le Liao
- Tung Lin
- Piotr Jasiński
2020 JOURNAL OF ELECTROCERAMICS
GdCoO3-δ, Gd0.975Na0.025CoO3-δ, Gd0.98K0.02CoO3-δ, Gd0.98Ca0.02CoO3-δ, and GdCo0.99Mg0.01O3-δ ceramics were prepared via a solid-state reaction route. Among the dopants studied, substitution with Ca2+ slightly enhanced the densfication of GdCoO3 ceramics. All the lattice parameters of the doped ceramics were larger than those of pure GdCoO3-δ ceramic (a = 5.223 Å, b = 5.389 Å and c = 7.451 Å), and their cell volumes increased by 0.30% to 1.40% because the substitution ions were larger in size. X-ray diffraction and scanning electron microscopy results indicate that no second phase is present. The average grain size of the GdCoO3 ceramics (7.6 μm) slightly increased by the Na+, K+ and Mg2+ substitutions and decreased by the Ca2+ substitution. In all cases, the intergranular fracture surfaces revealed the presence of trapped pores due to rapid grain growth. The oxidation states and percentages of Co ions were determined from the Co 2p X-ray photoelectron spectra. Na+, K+, Ca2+, and Mg2+ substitution in the GdCoO3-δ ceramic resulted in slight oxidation of the Co ions accompanied by a decrease in oxygen vacancies. After porosity correction using the Bruggeman effective medium approximation, Gd0.98Ca0.02CoO3-δ had the largest electrical conductivity at all measured temperatures among the compositions studied, which was 144% higher at 500 °C and 16% higher at 800 °C compared to those of GdCoO3-δ ceramic (500 °C: 133.3 S·cm−1; 800 °C: 692.4 S·cm−1). The substantial increase in the electrical conductivity of the doped GdCoO3-δ ceramics is due to the electronic compensation of acceptor doping, Na′′Gd, K′′Gd, and Ca′Gd, which resulted in the formation of hole carriers and the elimination of oxygen vacancies (V∙∙o), which generated additional Co4+ (Co∙Co).
Effects of CO2 and Nd:YAG Laser Remelting of the Ti6Al4V Alloy on the Surface Quality and Residual Stresses
- Magdalena Jażdżewska
2020 Full text Advances in Materials Science
The titanium alloys are materials susceptible to tribological wear and the laser treatment can be applied in surface treatment processes to obtain for example higher hardness level. From the other side, it is important to take into consideration, that hardness increase that can be connected with cracks . The aim of this research was to investigate the effects of different lasers and the process parameters on the form and level of residual stresses in the Ti6Al4V alloy, which determine the initiation and propagation of cracking. Two lasers were used, the CO2 and Nd:YAG lasers. The specimens were remelted in liquid nitrogen, water or calm air at different pre-heating temperature. The different laser power and scan rates were applied. The increase in energy density increased the number of cracks, the change of an environment and pre-heating affected alo the surface cracking. The cracks observed after remelting with Nd:YAG laser were longer than those observed after treatment with CO2 laser. The compressive stresses after the CO2 laser treatment, and tensile stresses after treatment with the Nd:YAG laser, were found. The appearance of cracks was attributed to an excessive energy density. The different distribution of heat energy inside and around the laser tracks was discussed as the origin of presence either tensile or compressive stresses in the alloy treated with different lasers
Effects of Micro-Arc Oxidation Process Parameters on Characteristics of Calcium-Phosphate Containing Oxide Layers on the Selective Laser Melted Ti13Zr13Nb Alloy
- Magda Dziaduszewska
- Andrzej Zieliński
- Tomasz Seramak
- Masaya Shimabukuro
- Takao Hanawa
2020 Full text Coatings
Titania-based films on selective laser melted Ti13Zr13Nb have been formed by micro-arc oxidation (MAO) at different process parameters (voltage, current, processing time) in order to evaluate the impact of MAO process parameters in calcium and phosphate (Ca + P) containing electrolyte on surface characteristic, early-stage bioactivity, nanomechanical properties, and adhesion between the oxide coatings and substrate. The surface topography, surface roughness, pore diameter, elemental composition, crystal structure, surface wettability, and the early stagebioactivity in Hank’s solution were evaluated for all coatings. Hardness, maximum indent depth, Young’s modulus, and Ecoating/Esubstrate, H/E, H3 /E2 ratios were determined in the case of nanomechanical evaluation while the MAO coating adhesion properties were estimated by the scratch test. The study indicated that the most important parameter of MAO process influencing the coating characteristic is voltage. Due to the good ratio of structural and nanomechanical properties of the coatings, the optimal conditions of MAO process were found at 300 V during 15 min, at 32 mA or 50 mA of current, which resulted in the predictable structure, high Ca/P ratio, high hydrophilicity, the highest demonstrated early-stage bioactivity, better nanomechanical properties, the elastic modulus and hardness well close to the values characteristic for bones, as compared to specimens treated at a lower voltage (200 V) and uncoated substrate, as well as a higher critical load of adhesion and total delamination.
Effects of the Origin and Deacetylation Degree of Chitosan on Properties of Its Coatings on Titanium
- Milena Supernak-Marczewska
- Andrzej Zieliński
2020 Full text Coatings
The properties of chitosan coatings on titanium surfaces may be influenced by a variety of factors, including their chemical characteristics and the deposition method. The aim of this research was to determine the influence of a chitosan’s origin (a type of shrimp) and deacetylation degree (DD), when deposited on a very smooth titanium surface, on adhesion and biological behavior. The tests were performed using chitosan of a degree of 87% or 84% of deacetylation and that originated from armor crabs or shrimp armor. The technology of fabrication of chitosan coatings was by surface polishing to a smooth surface, oxidation in air, and immersion in a chitosan solution. The surface topographies were analyzed with an atomic force microscope and their water contact angles were measured by a falling drop method with a goniometer. The bioactivity tests were done in in vitro on osteogenic cells, type MC3T3-E1, with a biological microscope. The abrasion of the coatings was examined using a nano tribotester. The obtained results revealed that the adhesion of the coatings onto a smooth, oxidized titanium surface is appropriate as they remain sufficiently adjacent to the surface after wear tests. The source of chitin has a significant influence on biological properties, and the deacetylation degree is much less critical. The performed tests demonstrated the crucial role that the source of chitosan and the applicability of the applied surface treatment play in the preparation of chitosan coatings.
Efficiency of pollutants removal from landfill leachates using Nb/BDD and Si/BDD anodic oxidation
- Barbara Wilk
- Sylwia Fudala-Książek
- Małgorzata Szopińska
- Michał Sobaszek
- Robert Bogdanowicz
- Aneta Łuczkiewicz
2020
Landfill leachates (LLs) is a complex, refectory and difficult to depurate liquid generated from sanitary landfills. It contains excessive levels of biodegradable and in particular non-biodegradable products (e.g. heavy metals, phenols, sulphide, plasticisers). LLs are among the effluents that may pose major environmental concerns, they can be a dangerous source of pollution e.g. due to infiltration into soil and underlying water. The biological refractory nature of LLs makes it necessary to search effective, alternative (other than biodegradation) methods to reduce the contaminant loading of these effluents.In this study, the role of the BDD anodes, with different content of boron and substrates such as silicone and niobium was evaluated in the removal of macropollutants and selected MPs from LLs. By-products formed during electrolysis have been identified, too. The investigations have shown that macropollutants removal efficiency increases with higher applied current density (but also the energetic costs do). The best anode substrate was Nb, yielding very positive pollutants reduction results (better than Si substrate). Moreover, this substrate was durable and resistant to damage. The highest efficiency of macropollutants removal was achieved at 100mA/cm2 current density by BDD 0.5k, Nb (COD= 97.1%, BOD20=93.8%, N-NH4+=62%, TN=29.3%) followed by BDD 10k, Nb (COD= 86.3%, BOD20=63.5%, N-NH4+=40%, TN=34.5%). BDD electrodes were also tested in terms of MPs removal. The obtained results indicate that the BDD10k/Nb anodic oxidation in 0.1 M phosphate buffer solution (pH 7.8) is able to degrade BPA with approximately 80% efficiency, diclofenac sodium with 60%, trimethoprim 96%, sulfamethoxazole 94%, PFOA 90% and PFOS 90%. It was preliminarily found that BDD 0.5k electrode is the most efficient at investigated MPs removal (e.g. BPA removal with 90% efficiency, diclofenac sodium with 85%). Formation of by-products during this process was also observed, e.g. m/z=243 and m/z=241 for BPA, m/z=264 for diclofenac sodium, m/z=284 and m/z =299 for sulfamethoxazole. It can be concluded that BDD/Nb is a promising material in wastewater treatment. The results confirmed high performance of BDD electrodes in pollutants removal from the studied matrixes, nevertheless this method still requires further optimization.
Efficient Method for the Concentration Determination of Fmoc Groups Incorporated in the Core-Shell Materials by Fmoc–Glycine
- Elzbieta Szczepanska
- Beata Grobelna
- Jacek Ryl
- Amanda Kulpa
- Tadeusz Ossowski
- Pawel Niedzialkowski
2020 Full text MOLECULES
In this paper, we described the synthesis procedure of TiO2@SiO2 core-shell modified with 3-(aminopropyl)trimethoxysilane (APTMS). The chemical attachment of Fmoc–glycine (Fmoc–Gly–OH) at the surface of the core-shell structure was performed to determine the amount of active amino groups on the basis of the amount of Fmoc group calculation. We characterized nanostructures using various methods: transmission electron microscope (TEM), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) to confirm the modification effectiveness. The ultraviolet-visible spectroscopy (UV-vis) measurement was adopted for the quantitative determination of amino groups present on the TiO2@SiO2 core-shell surface by determination of Fmoc substitution. The nanomaterials were functionalized by Fmoc–Gly–OH and then the fluorenylmethyloxycarbonyl (Fmoc) group was cleaved using 20% (v/v) solution of piperidine in DMF. This reaction led to the formation of a dibenzofulvene–piperidine adduct enabling the estimation of free Fmoc groups by measurement the maximum absorption at 289 and 301 nm using UV-vis spectroscopy. The calculations of Fmoc loading on core-shell materials was performed using different molar absorption coefficient: 5800 and 6089 dm3 × mol−1 × cm−1 for λ = 289 nm and both 7800 and 8021 dm3 × mol−1 × cm−1 for λ = 301 nm. The obtained results indicate that amount of Fmoc groups present on TiO2@SiO2–(CH2)3–NH2 was calculated at 6 to 9 µmol/g. Furthermore, all measurements were compared with Fmoc–Gly–OH used as the model sample
EIA in teaching sustainable development and environmental protection in engineering education
- Aleksandra Sas-Bojarska
2020 Full text World Transactions on Engineering and Technology Education
A multifaceted approach in teaching the environmental impact assessment (EIA) as a way to stress the role of environmental education in technical sciences is the focus of this article. The EIA is an example of an effective tool that supports spatial planning in implementing sustainable development. The aim is to present the idea and benefits of a facilitative and collaborative approach in teaching the EIA, stressing the role of student co-operation and involvement, as well as a participatory and interdisciplinary approach. Inspiring controversial case studies present different problems and approaches as examples of best practice. The teaching method underlies the necessity of understanding wider processes leading to environmental threats and the ways to prevent them, crossing different disciplines. Such an approach, attractive to students, can present the EIA not only as a formal procedure, but as a useful tool for environmental protection. Consequently, it may strengthen the student’s future activities in implementing the idea of sustainable development in practice.
Ekspertyza dotycząca opinii geotechnicznej na temat stanu podłoża gruntowego pod budynkiem w północnej części Dworca Głównego w Gdańsku.
- Rafał Ossowski
- Marcin Cudny
- Mariusz Wyroślak
2020
Opinia przygotowana na podstawie umowy zawartej w Gdańsku, pomiędzy Mostostal Warszawa Spółka Akcyjna z siedzibą: 02-673 Warszawa, ul. Konstruktorska 12A oraz Politechniką Gdańską, Wydział Inżynierii Lądowej i Środowiska z siedzibą przy ul. Gabriela Narutowicza 11/12, 80-233 Gdańsk.
Ekspertyza dotycząca ustalenia przyczyn nieszczelności ścian szczelinowych oraz płyty fundamentowej wraz z propozycją rozwiązania naprawczego mającego na celu skuteczne uszczelnienie (likwidację przecieków) kondygnacji podziemnych budynku biurowego LPP FASHION LAB zlokalizowanego w Gdańsku przy ulicy Łąkowej 35/26 i 37/38
- Marcin Cudny
- Mariusz Wyroślak
- Maciej Niedostatkiewicz
- Rafał Ossowski
2020
Zlecenie firmy Mostostal SA z siedzibą w Warszawie przy ulicy Konstruktorskiej 12A na wykonanie ekspertyzy technicznej dotyczącej ustalenia przyczyn nieszczelności ścian szczelinowych oraz płyty fundamentowej wraz z propozycją rozwiązania naprawczego mającego na celu skuteczne uszczelnienie (likwidacje przecieków) kondygnacji podziemnych budynku biurowego LPP FASHION LAB zlokalizowanego w Gdańsku przy ulicy Łąkowej 35/36 i 37/38.
Ekspertyza techniczna w zakresie wyjaśnienia oznaczeń „j.mb.”, „j.bt.” i „bet.” znajdujących się na mapie zasadniczej, w odniesieniu do przepisów Prawa Budowlanego i stanu faktycznego.
- Joanna Wojtas
- Stefan Niewitecki
2020
W ekspertyzie odniesiono się do definicji drogi, jako budowli zgodnie z definicjami ustawy Prawa Budowlanego i przepisów pokrewnych. Ponadto wyjaśniono oznaczenia obszarów: jezdni i nawierzchni znajdujących się na mapie zasadniczej - mapie do celów projektowych w odniesieniu do obowiązujacych przepisów oraz stanu faktycznego.
Eksperyment: Ekslibris
- Krzysztof Wróblewski
2020
Eksperyment: Ekslibris Wystawa online 12 eksperymentalnych ekslibrisów inspirowanych wybranymi książkami Güntera Grassa, stworzonych specjalnie dla Gdańskiej Galerii Miejskiej przez zaproszonych do projektu artystów. Przy okazji cotygodniowej inauguracji poszczególnych ekslibrisów, będziemy przybliżać Wam sylwetki każdego z artystów, a także przypominać ważne dla nich projekty, w których wzięli udział. Produktem finalnym całego projektu, oprócz wystawy online, będzie kalendarz na rok 2021 ilustrowany powstałymi ekslibrisami i opatrzony komentarzem kuratorskim. Wszystkie powstałe prace trafią do kolekcji Gdańskiej Galerii Miejskiej. Artyści: Alicja Karska i Aleksandra Went, Tomasz Kopcewicz, Agata Nowosielska, Anna Orbaczewska, Patrycja Orzechowska, Maciek Salamon, Dominika Skutnik, Dorota Walentynowicz, Adam Witkowski, Ania Witkowska, Krzysztof Wróblewski, Marcin Zawicki Kuratorka: Marta Wróblewska Projekt animacji: Katarzyna Łygońska Projekt identyfikacji wizualnej: Patrycja Orzechowska Udźwiękowienie animacji: Piotr Kaliński Kuratorka pragnie szczególnie podziękować Dominice Skutnik za impuls do odkrycia potencjału sztuki ekslibrisu i podjęcia próby przeniesienia jej we współczesne realia artystyczne.
E-LEARNING NA POLITECHNICE GDAŃSKIEJ - HISTORIA ROZWOJU W LATACH 1995-2020
- Anita Dąbrowicz-Tlałka
- Anna Grabowska
2020 Full text
Internet oraz kształcenie oparte na wykorzystaniu e-technologii stały się nieodłącznym elementem edukacji. Artykuł przedstawia zarys historii rozwoju e-learningu na Politechnice Gdańskiej, przykładowe rozwiązania technologiczne, elementy tworzenia struktur organizacyjnych oraz związanych z legislacją, a także wybrane projekty wykorzystujące szeroko pojęte e-technologie w edukacji akademickiej realizowanej na Uczelni
Electric and magnetic properties of Lanthanum Barium Cobaltite
- Iga Szpunar
- Sebastian Lech Wachowski
- Tadeusz Miruszewski
- Kacper Dzierzgowski
- Karolina Górnicka
- Tomasz Klimczuk
- Magnus H. Sorby
- Maria Balaguer
- José M Serra
- Ragnar Strandbakke
- Aleksandra Dorota Mielewczyk-Gryń
- Maria Gazda
2020 Full text JOURNAL OF THE AMERICAN CERAMIC SOCIETY
The cubic Ba0.5La0.5CoO3‐δ was synthesized using solid state reaction. The structural properties were determined by the simultaneous refinement of Synchrotron Powder X‐ray Diffraction and Neutron Powder Diffraction data. Iodometric titration was used to examine the oxygen stoichiometry and average cobalt oxidation state. Low‐temperature magnetic studies show soft ferromagnetic character of fully oxidized material, with θP = 198(3) K and μeff = 2.11(2) μB. Electric measurements show the thermally activated nature of conductivity at low temperatures, whereas, due to the variable oxidation and spin state of cobalt, a single charge transport mechanism cannot be distinguished. Around room temperature, a wide transition from thermally activated conductivity to semi‐metallic behavior is observed. Under the inert atmos-phere, the oxygen content lowers and the cation ordering takes place, leading to coex-istence of two, ordered and disordered, phases. As a result of this change, thermally activated conductivity is observed also at high temperatures in inert atmosphere.
ELECTRICAL CONDUCTIVITY AND pH IN SURFACE WATER AS TOOL FOR IDENTIFICATION OF CHEMICAL DIVERSITY
- Joanna Potapowicz
- Danuta Szumińska
- Małgorzata Szopińska
- Czapiewski Sebastian
- Żaneta Polkowska
2020 Full text Ecological Chemistry and Engineering S - Chemia i Inżynieria Ekologiczna S
In the present study, the creeks and lakes located at the western shore of Admiralty Bay were analysed. The impact of various sources of water supply was considered, based on the parameters of temperature, pH and specific electrolytic conductivity (SEC25). All measurements were conducted during a field campaign in January-February 2017. A multivariate dataset was also created and a biplot of SEC25 and pH of the investigated waters was performed. The average temperatures of the investigated waters were 0.10-8.10 °C. The pH values indicate that most of the water environments of the analysed area are slightly acidic to alkaline (5.26-8.50) with two exceptions: Siodlo II Creek (9.26) and Petrified Forest Creek (8.95), which are characterised by greater alkalinity. At the measurement points closest to the Baranowski Glacier and Ecology Glacier, SEC25 values were the lowest (26.8-61.1 μS·cm–1), while the remaining values ranged from 79.0 to 382 μS·cm–1 for the whole studied area. Based on the results it is concluded that the periodic intensive inflow of ablation waters, combined with morphological changes in the glacier front, causes a significant variability in the outflow network, creating the conditions for changes in basic physicochemical parameters. Moreover, it is observed that local depressions in the terrain form sedimentation traps in which, alongside fine-grained deposits, compounds can accumulate that originate from in situ sedimentation and that are also associated with surface runoff from the melting of snow cover, buried ice and permafrost.
Electrical conductivity of nanostructured acceptor-doped ceria fabricated by spark plasma sintering (SPS)
- Ahsanul Kabir
- Sofie Colding-Jørgensen
- Sebastian Molin
- Vincenzo Esposito
2020 MATERIALS LETTERS
High purity nanoscale powders (~10–15 nm size) of two different compositions of ceria, doped with Gd3+ and Ca2+, have been consolidated by spark plasma sintering (SPS) at different temperatures. Fully-dense samples were observed only at a sintering temperature of 980 °C. The as-sintered samples showed rather fast grain growth with an average grain size below 300 nm. The electrical properties of the samples were evaluated by impedance spectroscopy over a wide range of temperatures (300–550 °C) in air. Electrical conductivity significantly enhanced with increasing sintering temperature. The compounds show an electrical blocking effect at the grain boundary, depending on the doping cations.
Electrochemical and in silico approaches for liver metabolic oxidation of antitumor-active triazoloacridinone C -1305
- Agnieszka Potęga
- Dorota Żelaszczyk
- Zofia Mazerska
2020 Full text Journal of Pharmaceutical Analysis
5-Dimethylaminopropylamino-8-hydroxytriazoloacridinone (C-1305) is a promising antitumor compound developed in our laboratory. A better understanding of its metabolic transformations is still needed to explain the multidirectional mechanism of pharmacological action of triazoloacridinone derivatives at all. Thus, the aim of the current work was to predict oxidative pathways of C-1305 that would reflect its phase I metabolism. The multi-tool analysis of C-1305 metabolism included electrochemical conversion and in silico sites of metabolism predictions in relation to liver microsomal model. In the framework of the first approach, an electrochemical cell was coupled on-line to an electrospray ionization mass spectrometer. The effluent of the electrochemical cell was also injected onto a liquid chromatography column for the separation of different products formed prior to mass spectrometry analysis. In silico studies were performed using MetaSite software. Standard microsomal incubation was employed as a reference procedure. We found that C-1305 underwent electrochemical oxidation primarily on the dialkylaminoalkylamino moiety. An unknown so far N-dealkylated and hydroxylated C-1305 products have been identified. The electrochemical system was also able to simulate oxygenation reactions. Similar pattern of C-1305 metabolism has been predicted using in silico approach. Both proposed strategies showed high agreement in relation to the generated metabolic products of C-1305. Thus, we concluded that they can be considered as simple alternatives to enzymatic assays, affording time and cost efficiency.
Electrochemical detection of 4,4',5,5'-tetranitro-1H,1'H-2,2'-biimidazole on boron-doped diamond/graphene nanowall electrodes
- Anna Dettlaff
- Paweł Jakóbczyk
- Michał Sobaszek
- Mateusz Ficek
- Bartłomiej Dec
- Aneta Łuczkiewicz
- Mateusz Szala
- Jacek Wojas
- Tadeusz Ossowski
- Robert Bogdanowicz
2020 Full text IEEE SENSORS JOURNAL
We present a promising approach to the electroanalytical detection of a specific nitroaromatic explosive in landfill leachates (LLs) that originated from a municipal solid waste plant. The paper is focused but not limited to the sensing of 4,4',5,5'-tetranitro-1H,1'H-2,2'-biimidazole (TNBI) using differential pulse voltammetry and cyclic voltammetry. Highly electroactive nanocarbon was applied to determine low concentrations of the analyte in the complex interfering matrix as leachate samples. The mechanism of nitro- group reduction is attributed to the sensing effect, as revealed in the voltammograms of TNBI. The developed sensor model has two linear regions extending from 0.02 ppm to 1.4 ppm and from 2 ppm to 16 ppm resulting from adsorption and diffusion-controlled processes, respectively. The limit of detection was as low as 0.52 ppm (1.66 μM L-1) thanks to the electrochemical performance of the joint effect of the diamond/graphene composite nanowall surface.
Electrochemical determination of nitroaromatic explosives at boron-doped diamond/graphene nanowall electrodes: 2,4,6-trinitrotoluene and 2,4,6-trinitroanisole in liquid effluents
- Anna Dettlaff
- Paweł Jakóbczyk
- Mateusz Ficek
- B. Wilk
- M. Szala
- J. Wojtas
- Tadeusz Ossowski
- Robert Bogdanowicz
2020 Full text JOURNAL OF HAZARDOUS MATERIALS
The study is devoted to the electrochemical detection of trace explosives on boron-doped diamond/graphene nanowall electrodes (B:DGNW). The electrodes were fabricated in a one-step growth process using chemical vapour deposition without any additional modifications. The electrochemical investigations were focused on the determination of the important nitroaromatic explosive compounds, 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitroanisole (TNA). The distinct reduction peaks of both studied compounds were observed regardless of the pH value of the solution. The reduction peak currents were linearly related to the concentration of TNT and TNA in the range from 0.05–15 ppm. Nevertheless, two various linear trends were observed, attributed respectively to the adsorption processes at low concentrations up to the diffusional character of detection for larger contamination levels. The limit of detection of TNT and TNA is equal to 73 ppb and 270 ppb, respectively. Moreover, the proposed detection strategy has been applied under real conditions with a significant concentration of interfering compounds – in landfill leachates. The proposed bare B:DGNW electrodes were revealed to have a high electroactive area towards the voltammetric determination of various nitroaromatic compounds with a high rate of repeatability, thus appearing to be an attractive nanocarbon surface for further applications.
Electrochemical oxidation of PFOA and PFOS in landfill leachates at low and highly boron-doped diamond electrodes
- Mattia Pierpaoli
- Małgorzata Szopińska
- Barbara Wilk
- Michał Sobaszek
- Aneta Łuczkiewicz
- Robert Bogdanowicz
- Sylwia Fudala-Książek
2020 Full text JOURNAL OF HAZARDOUS MATERIALS
Polyfluorinated alkyl substances (PFASs) may reach landfill leachates (LLs) due to improper waste management. In this study perfluorooctanoate (PFOA) and perfluorooctane sulphonate (PFOS) were used as representatives of PFASs in the decomposition on boron-doped diamond electrodes (BDDs) with high (10k ppm) and low (0.5k ppm) boron doping concentrations. The result shows that although better COD removal efficacies are obtained on the low-doped BDD (59 % after 8 h), the decomposition rate of PFOA and PFOS was not affected by boron doping. In LLs, at the current density of 75 mA/cm2, averaged removal efficiencies of 80 % and 78 % were achieved for PFOA and PFOS, respectively. But besides concentration of mother compounds, the presence of intermediates during electrolysis should be monitored. After 8 h of LL electrolysis, the presence of long-chain degradates C6 F13 and C6 F13 COO˗ was still observed only in 10k BDD-PFOA assays, while during 0.5k assays C 6F13 and C6 F13 COO˗ form more intesively at the beginning of the process. This indirectly confirms the more intensive generation of perfluoroalkoxy and hydroxyl radicals and higher susceptibility to electrolysis of PFOA’s long-chain intermediates on 0.5k BDD. This is the first study reporting BDD-electrolysis as promising in PFAS removal from the complex matrix of LLs, despite the oxidation of competing LLs components.
Electrochemical performance of thin free-standing boron-doped diamond nanosheet electrodes
- Robert Bogdanowicz
- Mateusz Ficek
- Natalia Malinowska
- Sanju Gupta
- Romney Meek
- Paweł Niedziałkowski
- Michał Rycewicz
- Sawczak Mirosław
- Jacek Ryl
- Tadeusz Ossowski
2020 Full text JOURNAL OF ELECTROANALYTICAL CHEMISTRY
In the following work we describe preparation and the electrochemical performance of thin and free-standing heavy boron-doped diamond (BDD) nanosheets. The investigated foils were deposited on Ta substrate using microwave plasma-enhanced chemical vapor deposition technique (MPECVD). Foils of two B-dopant densities were investigated, obtained on the base of 10 k and 20 k ppm [B]/[C] ratio in the gas admixture. The obtained foils can be easily peeled from substrate in deionized water to be then attached to other material, in this case polydimethylsiloxane (PDMS). We have shown that the top surface and the bottom side of investigated boron-doped diamond nanosheet possess significantly altered morphology and physico-chemical properties, revealed by electron microscopy, Raman spectroscopy and electrochemistry. The voltammetric response of investigated BDD foils as working electrodes indicates the highest activity for the nanosheet with higher dopant concentration, in particular on its top surface. Furthermore, electrodes are characterized with altered kinetics, characteristic for partially blocked electrodes with quasi-reversible charge transfer.