Publications by authors named "Paweł Baran"

5 Publications

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SO sorption properties of fly ash zeolites.

Turk J Chem 2020 11;44(1):155-167. Epub 2020 Feb 11.

Department of Coal Chemistry and Environmental Sciences, Faculty of Energy and Fuels, AGH University of Science and Technology, Kraków Poland.

In the presented study, the sulfur dioxide sorption properties of fly ash zeolite X were investigated. Sorption tests were performed on fly ash zeolite samples that were not prepared specially for sorption, in addition to dried samples and samples in the presence of water vapor. The samples saturated with water vapor showed the highest sorption capacity. The sorption capacity of the samples additionally dried prior to the sorption experiment was higher than that of the samples that were not specially prepared for the sorption test. Regeneration tests indicated relatively good regeneration properties. The obtained results were described with the use of Langmuir, Sips, and Dubinin-Astakhov models, with the Dubinin-Astakhov model providing the best fit.
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http://dx.doi.org/10.3906/kim-1905-50DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7751809PMC
February 2020

High-Entropy Perovskites as Multifunctional Metal Oxide Semiconductors: Synthesis and Characterization of (GdNdLaSmY)CoO.

ACS Appl Electron Mater 2020 Oct 18;2(10):3211-3220. Epub 2020 Sep 18.

Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, Al. Mickiewicza 30, 30059 Kraków, Poland.

Single-phase multicomponent perovskite-type cobalt oxide containing five cations in equiatomic amounts on the A-site, namely, (GdNdLaSmY)CoO, has been synthesized via the modified coprecipitation hydrothermal method. Using an original approach for heat treatment, which comprises quenching utilizing liquid nitrogen as a cooling medium, a single-phase ceramic with high configuration entropy, crystallizing in an orthorhombic distorted structure was obtained. It reveals the anomalous temperature dependence of the lattice expansion with two weak transitions at approx. 80 and 240 K that are assigned to gradual crossover from the low- via intermediate- to high-spin state of Co. The compound exhibits weak ferromagnetism at ≤ 10 K and signatures of antiferromagnetic correlations in the paramagnetic phase. Ab initio calculations predict a band gap Δ = 1.18 eV in the ground-state electronic structure with the dominant contribution of O_p and Co_d orbitals in the valence and conduction bands, respectively. Electronic transport measurements confirm the negative temperature coefficient of resistivity characteristic to a semiconducting material and reveal a sudden drop in activation energy at ∼ 240 K from ∼ 1 eV in the low-temperature phase to ∼ 0.3 eV at room temperature. The possibility of fine tuning of the semiconducting band gap via a subtle change in A-site stoichiometry is discussed.
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http://dx.doi.org/10.1021/acsaelm.0c00559DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7660934PMC
October 2020

CO sorption and regeneration properties of fly ash zeolites synthesized with the use of differentiated methods.

Sci Rep 2020 Feb 4;10(1):1825. Epub 2020 Feb 4.

AGH University of Science and Technology, Faculty of Energy and Fuels, al. A. Mickiewicza 30, 30-059, Kraków, Poland.

Production of fly ash zeolites may be an attractive method for the utilization of solid wastes from the energy sector. Different methods of synthesis often yield a variety of zeolite types, thereby affecting the properties of the resulting materials. The attention paid to carbon dioxide emission reduction technologies fully justifies the study of the sorption behaviours of fly ash zeolites synthesized by different methods. This work investigates the sorption properties of fly ash zeolites synthesized with different methods using CO. Sorption capacity and adsorption isotherms were determined following the volumetric method and textural parameters were resolved according to the Dubinin-Astakhov (DA) method. The CO sorption capacity was in the range 0.24-4.16 mmol/g. The relationships between structure and sorption behaviour were studied for each synthesis method. Some strong similarities between commercial zeolites and fly ash zeolites were found. The mechanism for sorption was proved to be physisorption which is fully reversible under selected conditions. The observed trends were used to identify the best sorbent.
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http://dx.doi.org/10.1038/s41598-020-58591-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7000786PMC
February 2020

A review of the fate of engineered nanomaterials in municipal solid waste streams.

Waste Manag 2018 May 21;75:427-449. Epub 2018 Feb 21.

Department of Water-Atmosphere-Environment, Institute of Waste Management, University of Natural Resources and Life Sciences, Muthgasse 107, 1190 Vienna, Austria.

Significant knowledge and data gaps associated with the fate of product-embedded engineered nanomaterials (ENMs) in waste management processes exist that limit our current ability to develop appropriate end-of-life management strategies. This review paper was developed as part of the activities of the IWWG ENMs in Waste Task Group. The specific objectives of this review paper are to assess the current knowledge associated with the fate of ENMs in commonly used waste management processes, including key processes and mechanisms associated with ENM fate and transport in each waste management process, and to use that information to identify the data gaps and research needs in this area. Literature associated with the fate of ENMs in wastes was reviewed and summarized. Overall, results from this literature review indicate a need for continued research in this area. No work has been conducted to quantify ENMs present in discarded materials and an understanding of ENM release from consumer products under conditions representative of those found in relevant waste management process is needed. Results also indicate that significant knowledge gaps associated with ENM behaviour exist for each waste management process investigated. There is a need for additional research investigating the fate of different types of ENMs at larger concentration ranges with different surface chemistries. Understanding how changes in treatment process operation may influence ENM fate is also needed. A series of specific research questions associated with the fate of ENMs during the management of ENM-containing wastes have been identified and used to direct future research in this area.
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http://dx.doi.org/10.1016/j.wasman.2018.02.012DOI Listing
May 2018

CO2 adsorption properties of char produced from brown coal impregnated with alcohol amine solutions.

Environ Monit Assess 2016 Jul 17;188(7):416. Epub 2016 Jun 17.

Faculty of Energy and Fuels, AGH University of Science and Technology, Aleja Mickiewicza 30, 30-059, Cracow, Poland.

Carbon dioxide (CO2) emission reduction is critical to mitigating climate change. Power plants for heating and industry are significant sources of CO2 emissions. There is a need for identifying and developing new, efficient methods to reduce CO2 emissions. One of the methods used is flue gas purification by CO2 capture through adsorption. This study aimed to develop CO2 adsorbent out of modified brown coal impregnated with solutions of first-, second-, and third-order amines. Low-temperature nitrogen adsorption isotherms and CO2 isotherms were measured for the prepared samples. The results of experiments unexpectedly revealed that CO2 sorption capacity decreased after impregnation. Due to lack of strait trends in CO2 sorption capacity decrease, the results were closely analyzed to find the reason for the inconsistencies. It was revealed that different amines represent different affinities for CO2 and that the size and structure of impregnating factor has influence on the CO2 sorption capacity of impregnated material. The character of a support was also noticeable as well for impregnation results as for the affinity to CO2. The influence of amine concentration used was investigated along with the comparison on how the theoretical percentage of the impregnation on the support influenced the results. The reaction mechanism of tertiary amine was taken into consideration in connection to no presence of water vapor during the experiments. Key findings were described in the work and provide a strong basis for further studies on CO2 adsorption on amine-impregnated support.
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http://dx.doi.org/10.1007/s10661-016-5423-zDOI Listing
July 2016
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