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Kozjek M, Vengust D, Radošević T, Žitko G, Koren S, Toplak N, Jerman I, Butala M, Podlogar M, Viršek MK. Dissecting giant hailstones: A glimpse into the troposphere with its diverse bacterial communities and fibrous microplastics. Sci Total Environ 2023; 856:158786. [PMID: 36116646 DOI: 10.1016/j.scitotenv.2022.158786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 09/02/2022] [Accepted: 09/11/2022] [Indexed: 06/15/2023]
Abstract
The formation of giant hailstones is a rare weather event that has devastating consequences in inhabited areas. This hazard has been occurring more frequently and with greater size of hailstones in recent years, and thus needs to be better understood. While the generally accepted mechanism is thought to be a process similar to the formation of smaller hailstones but with exceptional duration and stronger updrafts, recent evidence suggests that biotic and abiotic factors also influence the growth of these unusually large ice chunks. In this study, we improved these findings by determining the distribution of a wide variety of these factors throughout the hail volume and expanding the search to include new particles that are common in the environment and are of anthropogenic origin. We melted the concentric layers of several giant hailstones that fell to the ground over a small region in Slovenia in 2019. The samples, up to 13 cm in diameter, were analyzed for biotic and abiotic constituents that could have influenced their formation. Using 16S rRNA-based metagenomics approaches, we identified a highly diverse bacterial community, and by using scanning electron microscopy and Raman spectroscopy, we found natural and synthetic fibers concentrated in the cores of the giant hailstones. For the first time, we were able to detect the existence of microplastic fibers in giant hailstones and determine the changes in the distribution of sand within the volume of the samples. Our results suggest that changes in the composition of hail layers and their great diversity are important factors that should be considered in research. It also appears that anthropogenic microfiber pollutants were a significant factor in the formation of the giant hailstones analyzed in this study.
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Affiliation(s)
- Marko Kozjek
- Institute for water of the Republic of Slovenia, Einspielerjeva 6, 1000 Ljubljana, Slovenia; University of Ljubljana, Biotechnical Faculty, Večna pot 111, 1000 Ljubljana, Slovenia
| | - Damjan Vengust
- Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia
| | - Tina Radošević
- Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia
| | - Gregor Žitko
- University of Ljubljana, Faculty of Chemistry and Chemical Technology, Večna pot 113, 1000 Ljubljana, Slovenia; National institute for chemistry, Hajdrihova ulica 19, 1000 Ljubljana, Slovenia
| | - Simon Koren
- Omega d.o.o., Dolinškova ulica 8, 1000 Ljubljana, Slovenia
| | - Nataša Toplak
- Omega d.o.o., Dolinškova ulica 8, 1000 Ljubljana, Slovenia
| | - Ivan Jerman
- National institute for chemistry, Hajdrihova ulica 19, 1000 Ljubljana, Slovenia
| | - Matej Butala
- University of Ljubljana, Biotechnical Faculty, Večna pot 111, 1000 Ljubljana, Slovenia
| | - Matejka Podlogar
- Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia; University of Ljubljana, Faculty of Chemistry and Chemical Technology, Večna pot 113, 1000 Ljubljana, Slovenia
| | - Manca Kovač Viršek
- Institute for water of the Republic of Slovenia, Einspielerjeva 6, 1000 Ljubljana, Slovenia.
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Vasiljević J, Demšar A, Leskovšek M, Simončič B, Čelan Korošin N, Jerman I, Šobak M, Žitko G, Van de Velde N, Čolović M. Characterization of Polyamide 6/Multilayer Graphene Nanoplatelet Composite Textile Filaments Obtained Via In Situ Polymerization and Melt Spinning. Polymers (Basel) 2020; 12:polym12081787. [PMID: 32785048 PMCID: PMC7464262 DOI: 10.3390/polym12081787] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/02/2020] [Accepted: 08/06/2020] [Indexed: 02/06/2023] Open
Abstract
Studies of the production of fiber-forming polyamide 6 (PA6)/graphene composite material and melt-spun textile fibers are scarce, but research to date reveals that achieving the high dispersion state of graphene is the main challenge to nanocomposite production. Considering the significant progress made in the industrial mass production of graphene nanoplatelets (GnPs), this study explored the feasibility of production of PA6/GnPs composite fibers using the commercially available few-layer GnPs. To this aim, the GnPs were pre-dispersed in molten ε-caprolactam at concentrations equal to 1 and 2 wt %, and incorporated into the PA6 matrix by the in situ water-catalyzed ring-opening polymerization of ε-caprolactam, which was followed by melt spinning. The results showed that the incorporated GnPs did not markedly influence the melting temperature of PA6 but affected the crystallization temperature, fiber bulk structure, crystallinity, and mechanical properties. Furthermore, GnPs increased the PA6 complex viscosity, which resulted in the need to adjust the parameters of melt spinning to enable continuous filament production. Although the incorporation of GnPs did not provide a reinforcing effect of PA6 fibers and reduced fiber tensile properties, the thermal stability of the PA6 fiber increased. The increased melt viscosity and graphene anti-dripping properties postponed melt dripping in the vertical flame spread test, which consequently prolonged burning within the samples.
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Affiliation(s)
- Jelena Vasiljević
- Faculty of Natural Sciences and Engineering, University of Ljubljana, Aškerčeva 12, 1000 Ljubljana, Slovenia; (A.D.); (M.L.); (B.S.)
- Correspondence: (J.V.); (I.J.); Tel.: +386-1-20-03-200 (J.V.); +386-1-4760-440 (I.J.)
| | - Andrej Demšar
- Faculty of Natural Sciences and Engineering, University of Ljubljana, Aškerčeva 12, 1000 Ljubljana, Slovenia; (A.D.); (M.L.); (B.S.)
| | - Mirjam Leskovšek
- Faculty of Natural Sciences and Engineering, University of Ljubljana, Aškerčeva 12, 1000 Ljubljana, Slovenia; (A.D.); (M.L.); (B.S.)
| | - Barbara Simončič
- Faculty of Natural Sciences and Engineering, University of Ljubljana, Aškerčeva 12, 1000 Ljubljana, Slovenia; (A.D.); (M.L.); (B.S.)
| | - Nataša Čelan Korošin
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, 1000 Ljubljana, Slovenia;
| | - Ivan Jerman
- National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia; (M.Š.); (G.Ž.); (N.V.d.V.); (M.Č.)
- Correspondence: (J.V.); (I.J.); Tel.: +386-1-20-03-200 (J.V.); +386-1-4760-440 (I.J.)
| | - Matic Šobak
- National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia; (M.Š.); (G.Ž.); (N.V.d.V.); (M.Č.)
| | - Gregor Žitko
- National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia; (M.Š.); (G.Ž.); (N.V.d.V.); (M.Č.)
| | - Nigel Van de Velde
- National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia; (M.Š.); (G.Ž.); (N.V.d.V.); (M.Č.)
| | - Marija Čolović
- National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia; (M.Š.); (G.Ž.); (N.V.d.V.); (M.Č.)
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Chouhan RS, Žitko G, Fajon V, Živković I, Pavlin M, Berisha S, Jerman I, Vesel A, Horvat M. A Unique Interactive Nanostructure Knitting based Passive Sampler Adsorbent for Monitoring of Hg 2+ in Water. Sensors (Basel) 2019; 19:s19153432. [PMID: 31387298 PMCID: PMC6696128 DOI: 10.3390/s19153432] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 07/31/2019] [Accepted: 08/01/2019] [Indexed: 01/17/2023]
Abstract
This work reports the development of ultralight interwoven ultrathin graphitic carbon nitride (g-CN) nanosheets for use as a potential adsorbent in a passive sampler (PAS) designed to bind Hg2+ ions. The g-CN nanosheets were prepared from bulk g-CN synthesised via a modified high-temperature short-time (HTST) polycondensation process. The crystal structure, surface functional groups, and morphology of the g-CN nanosheets were characterised using a battery of instruments. The results confirmed that the as-synthesized product is composed of few-layered nanosheets. The adsorption efficiency of g-CN for binding Hg2+ (100 ng mL−1) in sea, river, rain, and Milli-Q quality water was 89%, 93%, 97%, and 100%, respectively, at natural pH. Interference studies found that the cations tested (Co2+, Ca2+, Zn2+, Fe2+, Mn2+, Ni2+, Bi3+, Na+, and K+) had no significant effect on the adsorption efficiency of Hg2+. Different parameters were optimised to improve the performance of g-CN such as pH, contact time, and amount of adsorbent. Optimum conditions were pH 7, 120 min incubation time and 10 mg of nanosheets. The yield of nanosheets was 72.5%, which is higher compared to other polycondensation processes using different monomers. The g-CN sheets could also be regenerated up to eight times with only a 20% loss in binding efficiency. Overall, nano-knitted g-CN is a promising low-cost green adsorbent for use in passive samplers or as a transducing material in sensor applications.
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Affiliation(s)
- Raghuraj S Chouhan
- Institute "Jožef Stefan", Department of Environmental Sciences, Jamova 39, 1000 Ljubljana, Slovenia.
| | - Gregor Žitko
- Institute "Jožef Stefan", Department of Surface Engineering, Jamova 39, 1000 Ljubljana, Slovenia
| | - Vesna Fajon
- Institute "Jožef Stefan", Department of Environmental Sciences, Jamova 39, 1000 Ljubljana, Slovenia
| | - Igor Živković
- Institute "Jožef Stefan", Department of Environmental Sciences, Jamova 39, 1000 Ljubljana, Slovenia
| | - Majda Pavlin
- Institute "Jožef Stefan", Department of Environmental Sciences, Jamova 39, 1000 Ljubljana, Slovenia
| | | | - Ivan Jerman
- Institute "Jožef Stefan", Department of Surface Engineering, Jamova 39, 1000 Ljubljana, Slovenia
| | | | - Milena Horvat
- Institute "Jožef Stefan", Department of Environmental Sciences, Jamova 39, 1000 Ljubljana, Slovenia
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